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Sample records for antibody variants produced

  1. The neutralization sensitivity of viruses representing human immunodeficiency virus type 1 variants of diverse subtypes from early in infection is dependent on producer cell, as well as characteristics of the specific antibody and envelope variant.

    PubMed

    Provine, Nicholas M; Cortez, Valerie; Chohan, Vrasha; Overbaugh, Julie

    2012-05-25

    Neutralization properties of human immunodeficiency virus (HIV-1) are often defined using pseudoviruses grown in transformed cells, which are not biologically relevant HIV-1 producer cells. Little information exists on how these viruses compare to viruses produced in primary lymphocytes, particularly for globally relevant HIV-1 strains. Therefore, replication-competent chimeras encoding envelope variants from the dominant HIV-1 subtypes (A, C, and D) obtained early after infection were generated and the neutralization properties explored. Pseudoviruses generated in 293T cells were the most sensitive to antibody neutralization. Replicating viruses generated in primary lymphocytes were most resistant to neutralization by plasma antibodies and most monoclonal antibodies (b12, 4E10, 2F5, VRC01). These differences were not associated with differences in envelope content. Surprisingly, the virus source did not impact neutralization sensitivity of most viruses to PG9. These findings suggest that producer cell type has a major effect on neutralization sensitivity, but in an antibody dependent manner.

  2. Heterologous expressed toxic and non-toxic peptide variants of toxin CssII are capable to produce neutralizing antibodies against the venom of the scorpion Centruroides suffusus suffusus.

    PubMed

    Hernández-Salgado, Kenya; Estrada, Georgina; Olvera, Alejandro; Coronas, Fredy I; Possani, Lourival D; Corzo, Gerardo

    2009-08-15

    Two toxic and one non-toxic recombinant peptide variants of the mammalian neurotoxin CssII was cloned into the expression vector pQE30 containing a 6His-tag and a Factor Xa proteolytic cleavage site. The toxic recombinant peptides rCssII, HisrCssII and the non-toxic rCssIIE15R were expressed under induction with isopropyl thiogalactoside (IPTG), isolated using chromatographic techniques and folded correctly in vitro. The three recombinant variants showed similar secondary structures as the native CssII, but only the rCssIIE15R was not toxic to mice at concentrations up to 30microg/20g mouse body weight when injected intraperitoneally. All three recombinant peptides were capable of displacing the native CssII from their receptor sites in rat brain synaptosomes, suggesting that they had similar structural and functional characteristics of the native peptides. The three recombinant variants of CssII and the native one were used as antigens for immunization of New Zealand rabbits. The antibodies present in the rabbit antisera were able to recognize the native CssII. Additionally and more importantly, the sera of the immunized rabbits were able to neutralize both the native toxin CssII and the whole soluble venom of the scorpion Centruroides suffusus suffusus. These results indicate that the recombinant peptides can be used to produce antidotes against the venom of this species of scorpion.

  3. Discovery and characterization of antibody variants using mass spectrometry-based comparative analysis for biosimilar candidates of monoclonal antibody drugs.

    PubMed

    Li, Wenhua; Yang, Bin; Zhou, Dongmei; Xu, Jun; Ke, Zhi; Suen, Wen-Chen

    2016-07-01

    Liquid chromatography mass spectrometry (LC-MS) is the most commonly used technique for the characterization of antibody variants. MAb-X and mAb-Y are two approved IgG1 subtype monoclonal antibody drugs recombinantly produced in Chinese hamster ovary (CHO) cells. We report here that two unexpected and rare antibody variants have been discovered during cell culture process development of biosimilars for these two approved drugs through intact mass analysis. We then used comprehensive mass spectrometry-based comparative analysis including reduced light, heavy chains, and domain-specific mass as well as peptide mapping analysis to fully characterize the observed antibody variants. The "middle-up" mass comparative analysis demonstrated that the antibody variant from mAb-X biosimilar candidate was caused by mass variation of antibody crystalline fragment (Fc), whereas a different variant with mass variation in antibody antigen-binding fragment (Fab) from mAb-Y biosimilar candidate was identified. Endoproteinase Lys-C digested peptide mapping and tandem mass spectrometry analysis further revealed that a leucine to glutamine change in N-terminal 402 site of heavy chain was responsible for the generation of mAb-X antibody variant. Lys-C and trypsin coupled non-reduced and reduced peptide mapping comparative analysis showed that the formation of the light-heavy interchain trisulfide bond resulted in the mAb-Y antibody variant. These two cases confirmed that mass spectrometry-based comparative analysis plays a critical role for the characterization of monoclonal antibody variants, and biosimilar developers should start with a comprehensive structural assessment and comparative analysis to decrease the risk of the process development for biosimilars.

  4. Glycosylation of plant produced human antibodies.

    PubMed

    Kallolimath, Somanath; Steinkellner, Herta

    2015-12-23

    Human immunoglobulins circulate as highly heterogeneously glycosylated mixture of otherwise homogeneous protein backbones. A series of studies, mainly on IgG, have unequivocally proven that antibodies modulate their effector function through sugars present in the Fc domain. However, our limited technology in producing complex proteins such as antibodies, with defined glycan structures hamper in depths studies. This review introduces a plant based expression platform enabling engineering of antibody glycans. The procedure is based on the simultaneous delivery of appropriate constructs, carrying cDNAs of target proteins (e.g. heavy and light chain of antibodies) in combination with human glycosylation enzymes into plant leaves. Harvesting of recombinant proteins one week post construct delivery allows high speed and flexibility. Major achievements include the production of functional active slialylated pentameric IgMs in tobacco leaves. The system provides a viable approach to the generation of antibodies with defined glycoforms on demand, contributing to studies on antibody glycans and the development of novel antibody based drugs.

  5. Charge heterogeneity: Basic antibody charge variants with increased binding to Fc receptors

    PubMed Central

    Hintersteiner, Beate; Lingg, Nico; Zhang, Peiqing; Woen, Susanto; Hoi, Kong Meng; Stranner, Stefan; Wiederkum, Susanne; Mutschlechner, Oliver; Schuster, Manfred; Loibner, Hans; Jungbauer, Alois

    2016-01-01

    ABSTRACT We identified active isoforms of the chimeric anti-GD2 antibody, ch14.18, a recombinant antibody produced in Chinese hamster ovary cells, which is already used in clinical trials.1,2,3 We separated the antibody by high resolution ion-exchange chromatography with linear pH gradient elution into acidic, main and basic charge variants on a preparative scale yielding enough material for an in-depth study of the sources and the effects of microheterogeneity. The binding affinity of the charge variants toward the antigen and various cell surface receptors was studied by Biacore. Effector functions were evaluated using cellular assays for antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity. Basic charge variants showed increased binding to cell surface receptor FcγRIIIa, which plays a major role in regulating effector functions. Furthermore, increased binding of the basic fractions to the neonatal receptor was observed. As this receptor mediates the prolonged half-life of IgG in human serum, this data may well hint at an increased serum half-life of these basic variants compared to their more acidic counterparts. Different glycoform patterns, C-terminal lysine clipping and N-terminal pyroglutamate formation were identified as the main structural sources for the observed isoform pattern. Potential differences in structural stability between individual charge variant fractions by nano differential scanning calorimetry could not been detected. Our in-vitro data suggests that the connection between microheterogeneity and the biological activity of recombinant antibody therapeutics deserves more attention than commonly accepted. PMID:27559765

  6. Isolation and Characterization of Monoclonal Antibody Charge Variants by Free Flow Isoelectric Focusing.

    PubMed

    Hosken, Brian D; Li, Charlene; Mullappally, Berny; Co, Carl; Zhang, Boyan

    2016-06-07

    Capillary isoelectric focusing (cIEF) is widely used in the biopharmaceutical industry to measure the charge distribution of therapeutic proteins. The implementation of this technology has created a new challenge. Capillary volumes are on the order of hundreds of nanoliters and cannot be scaled up for the preparative collection of charge variants. This makes it difficult to identify the charge variants in a cIEF electropherogram. Therefore, preparative IEF methods are needed to fractionate charge variants for characterization. We used free-flow electrophoresis (FFE) to isolate monoclonal antibody charge variants observed in a cIEF electropherogram. The same antibody was also fractionated using the Rotofor and Offgel instruments for comparison. A strategy for purifying the fractionated charge variants and downstream characterization is described. Acidic and basic variants were identified and related back to the analytical cIEF charge profile. This study establishes free-flow isoelectric focusing as a valuable tool for characterizing therapeutic proteins.

  7. Considerations in producing preferentially reduced half-antibody fragments.

    PubMed

    Makaraviciute, Asta; Jackson, Carolyn D; Millner, Paul A; Ramanaviciene, Almira

    2016-02-01

    Half-antibody fragments are a promising reagent for biosensing, drug-delivery and labeling applications, since exposure of the free thiol group in the Fc hinge region allows oriented reaction. Despite the structural variations among the molecules of different IgG subclasses and those obtained from different hosts, only generalized preferential antibody reduction protocols are currently available. Preferential reduction of polyclonal sheep anti-digoxin, rabbit anti-Escherichia coli and anti-myoglobin class IgG antibodies to half-antibody fragments has been investigated. A mild reductant 2-mercaptoethylamine (2-MEA) and a slightly stronger reductant tris(2-carboxyethyl)phosphine (TCEP) were used and the fragments obtained were quantitatively determined by SDS-PAGE analysis. It has been shown that the yields of half-antibody fragments could be increased by lowering the pH of the reduction mixtures. However, antibody susceptibility to the reductants varied. At pH4.5 the highest yield of sheep anti-digoxin IgG half-antibody fragments was obtained with 1M 2-MEA. Conversely, rabbit IgG half-antibody fragments could only be obtained with the stronger reductant TCEP. Preferential reduction of rabbit anti-myoglobin IgG antibodies was optimized and the highest half-antibody yield was obtained with 35 mM TCEP. Finally, it has been demonstrated that produced anti-myoglobin half-IgG fragments retained their binding activity.

  8. Studies on the Transfer of Antibody Producing Capacity

    PubMed Central

    Nossal, G. J. V.

    1959-01-01

    Normal adult spleen cells were antigenically stimulated by incubation with isolated flagella from Salmonella bacteria, and after neutralization of free antigen and washing, were transferred to normal and sublethally X-irradiated mice and rats of various ages by intraperitoneal injection. Neonatal rats and Hall Institute mice could not produce antibody following such injections, but more mature rats and Hall Institute mice, and neonatal C3H mice, could produce antibody. Cells from immunized spleens were secondarily stimulated in vitro and transferred to neonatal and more mature recipients. Regardless of the age of the recipients, antibody production typical of a secondary response ensued. Cells from neonatal rat spleens were stimulated in vitro and transferred to more mature recipient rats. Some antibody production resulted. The theoretical implications of these findings are discussed. PMID:13653734

  9. Vaccination with peptide mimotopes produces antibodies recognizing bacterial capsular polysaccharides.

    PubMed

    Wu, Yang; Zhang, Qibo; Sales, Debra; Bianco, Albert Edward; Craig, Alister

    2010-09-07

    A phage display peptide library was screened using a panel of antibodies to the capsular polysaccharides of Streptococcus agalactiae and Neisseria meningitidis. Mimotopes NPDHPRVPTFMA (2-8), LIPFHKHPHHRG (3-2) and EQEIFTNITDRV (G3) showing the highest binding capacity and strongest ELISA reaction were selected for immunization experiments. These mimotopes were either synthesised as oligodeoxynucleotides for DNA immunization or MAP (multiple antigen peptide) for peptide immunization. Mimotope-DNA vaccination, particularly for G3, induced antibodies recognizing a number of target bacteria. This response was seen after the second boost injection and was significantly enhanced by the 3rd boost injection with a Th1-associated profile, which was dominated by IgG2a, followed by IgG1. Mimotope-MAP immunization also produced strong humoral immune responses to the bacteria. Antibodies from G3 DNA immunization reacted with the surface molecules of S. agalactiae, N. meningitidis and Escherichia coli K5 shown by indirect immunofluorescence staining, indicating a possible localization to the bacterial capsule. Antibodies produced both from DNA/MAP immunization reacted with purified bacterial capsular polysaccharides by ELISA and were of high avidity. We have further characterized peptide G3 by a 'tiling path' study to examine the effect of changing individual residues in the peptide in raising antibodies, which showed that the EIFTN motif in G3 was important in generating antibodies to several capsulated bacteria. We conclude that mimotope immunization with DNA or MAP potentially induces strong antibody responses against encapsulated bacteria. It is suggested that the antibody targets are polysaccharides, and these antibodies may cross react at least among closely related species of bacteria.

  10. Neutralizing monoclonal antibodies recognize antigenic variants among isolates of infectious hematopoietic necrosis virus

    USGS Publications Warehouse

    Winton, J.R.; Arakawa, C.N.; Lannan, C.N.; Fryer, J.L.

    1988-01-01

    eutralizing monoclonal antibodies were developed against strains of infectious hematopoietic necrosis virus (IHNV) from steelhead trout Salmo gairdneri in the Deschutes River of Oregon, chinook salmon Oncorhynchus tshawytscha in the Sacramento River of California, and rainbow trout Salmo gairdneri reared in the Hagerman Valley of Idaho, USA. These antibodies were tested for neutralization of 12 IHNV isolates obtained from salmonids in Japan, Alaska, Washington, Oregon, California, and Idaho. The antibodies recognized antigenic variants among the isolates and could be used to separate the viruses into 4 groups. The members of each group tended to be related by geographic area rather than by source host species, virulence, or date of isolation.

  11. Simulation model for overloaded monoclonal antibody variants separations in ion-exchange chromatography.

    PubMed

    Guélat, Bertrand; Ströhlein, Guido; Lattuada, Marco; Delegrange, Lydia; Valax, Pascal; Morbidelli, Massimo

    2012-08-31

    A model was developed for the design of a monoclonal antibody charge variants separation process based on ion-exchange chromatography. In order to account for a broad range of operating conditions in the simulations, an explicit pH and salt concentration dependence has been included in the Langmuir adsorption isotherm. The reliability of this model was tested using experimental chromatographic retention times as well as information about the structural characteristics of the different charge variants, e.g. C-terminal lysine groups and deamidated groups. Next, overloaded isocratic elutions at various pH and salt concentrations have been performed to determine the saturation capacity of the ion-exchanger. Furthermore, the column simulation model was applied for the prediction of monoclonal antibody variants separations with both pH and salt gradient elutions. A good prediction of the elution times and peak shapes was observed, even though none of the model parameters was adjusted to fit the experimental data. The trends in the separation performance obtained through the simulations were generally sufficient to identify the most promising operating conditions. The predictive column simulation model thus developed in this work, including a set of parameters determined through specific independent experiments, was experimentally validated and offers a useful basis for a rational optimization of monoclonal antibody variants separation processes on ion-exchange chromatography.

  12. Aglycosylated antibodies and antibody fragments produced in a scalable in vitro transcription-translation system

    PubMed Central

    Yin, Gang; Garces, Eudean D; Yang, Junhao; Zhang, Juan; Tran, Cuong; Steiner, Alexander R; Roos, Christine; Bajad, Sunil; Hudak, Susan; Penta, Kalyani; Zawada, James; Pollitt, Sonia

    2012-01-01

    We describe protein synthesis, folding and assembly of antibody fragments and full-length aglycosylated antibodies using an Escherichia coli-based open cell-free synthesis (OCFS) system. We use DNA template design and high throughput screening at microliter scale to rapidly optimize production of single-chain Fv (scFv) and Fab antibody fragments that bind to human IL-23 and IL-13α1R, respectively. In addition we demonstrate production of aglycosylated immunoglobulin G (IgG1) trastuzumab. These antibodies are produced rapidly over several hours in batch mode in standard bioreactors with linear scalable yields of hundreds of milligrams/L over a 1 million-fold change in scales up to pilot scale production. We demonstrate protein expression optimization of translation initiation region (TIR) libraries from gene synthesized linear DNA templates, optimization of the temporal assembly of a Fab from independent heavy chain and light chain plasmids and optimized expression of fully assembled trastuzumab that is equivalent to mammalian expressed material in biophysical and affinity based assays. These results illustrate how the open nature of the cell-free system can be used as a seamless antibody engineering platform from discovery to preclinical development of aglycosylated monoclonal antibodies and antibody fragments as potential therapeutics. PMID:22377750

  13. Antibody

    MedlinePlus

    An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples ... microorganisms (bacteria, fungi, parasites, and viruses) and chemicals. Antibodies may be produced when the immune system mistakenly ...

  14. Characterization of alanine to valine sequence variants in the Fc region of nivolumab biosimilar produced in Chinese hamster ovary cells

    PubMed Central

    Li, Yantao; Fu, Tuo; Liu, Tao; Guo, Huaizu; Guo, Qingcheng; Xu, Jin; Zhang, Dapeng; Qian, Weizhu; Dai, Jianxin; Li, Bohua; Guo, Yajun; Hou, Sheng; Wang, Hao

    2016-01-01

    ABSTRACT Nivolumab is a therapeutic fully human IgG4 antibody to programmed death 1 (PD-1). In this study, a nivolumab biosimilar, which was produced in our laboratory, was analyzed and characterized. Sequence variants that contain undesired amino acid sequences may cause concern during biosimilar bioprocess development. We found that low levels of sequence variants were detected in the heavy chain of the nivolumab biosimilar by ultra performance liquid chromatography (UPLC) and tandem mass spectrometry. It was further identified with UPLC-MS/MS by IdeS or trypsin digestion. The sequence variant was confirmed through addition of synthetic mutant peptide. Subsequently, the mixing base signal of normal and mutant sequence was detected through DNA sequencing. The relative levels of mutant A424V in the Fc region of the heavy chain have been detected and demonstrated to be 12.25% and 13.54%, via base peak intensity (BPI) and UV chromatography of the tryptic peptide mapping, respectively. A424V variant was also quantified by real-time PCR (RT-PCR) at the DNA and RNA level, which was 19.2% and 16.8%, respectively. The relative content of the mutant was consistent at the DNA, RNA and protein level, indicating that the A424V mutation may have little influence at transcriptional or translational levels. These results demonstrate that orthogonal state-of-the-art techniques such as LC- UV- MS and RT-PCR should be implemented to characterize recombinant proteins and cell lines for development of biosimilars. Our study suggests that it is important to establish an integrated and effective analytical method to monitor and characterize sequence variants during antibody drug development, especially for antibody biosimilar products. PMID:27050807

  15. Producing and recognizing words with two pronunciation variants: evidence from novel schwa words.

    PubMed

    Bürki, Audrey; Frauenfelder, Ulrich H

    2012-01-01

    This study examined the lexical representations and psycholinguistic mechanisms underlying the production and recognition of novel words with two pronunciation variants in French. Participants first learned novel schwa words (e.g., /ʃənyk/), which varied in their alternating status (i.e., whether these words were learned with one or two variants) and, for alternating words, in the frequency of their variants. They were then tested in picture-naming (free or induced) and recognition memory tasks (i.e., deciding whether spoken items were learned during the experiment or not). Results for free naming show an influence of variant frequency on responses, more frequent variants being produced more often. Moreover, our data show an effect of the alternating status of the novel words on naming latencies, with longer latencies for alternating than for nonalternating novel words. These induced naming results suggest that both variants are stored as lexical entries and compete during the lexeme selection process. Results for recognition show an effect of variant frequency on reaction times and no effect of variant type (i.e., schwa versus reduced variant). Taken together, our findings suggest that participants both comprehend and produce novel French schwa words using two lexical representations, one for each variant.

  16. Global and Local Conformation of Human IgG Antibody Variants Rationalizes Loss of Thermodynamic Stability.

    PubMed

    Edgeworth, Matthew J; Phillips, Jonathan J; Lowe, David C; Kippen, Alistair D; Higazi, Daniel R; Scrivens, James H

    2015-12-07

    Immunoglobulin G (IgG) monoclonal antibodies (mAbs) are a major class of medicines, with high specificity and affinity towards targets spanning many disease areas. The antibody Fc (fragment crystallizable) region is a vital component of existing antibody therapeutics, as well as many next generation biologic medicines. Thermodynamic stability is a critical property for the development of stable and effective therapeutic proteins. Herein, a combination of ion-mobility mass spectrometry (IM-MS) and hydrogen/deuterium exchange mass spectrometry (HDX-MS) approaches have been used to inform on the global and local conformation and dynamics of engineered IgG Fc variants with reduced thermodynamic stability. The changes in conformation and dynamics have been correlated with their thermodynamic stability to better understand the destabilising effect of functional IgG Fc mutations and to inform engineering of future therapeutic proteins.

  17. Chromatographic separation of three monoclonal antibody variants using multicolumn countercurrent solvent gradient purification (MCSGP).

    PubMed

    Müller-Späth, Thomas; Aumann, Lars; Melter, Lena; Ströhlein, Guido; Morbidelli, Massimo

    2008-08-15

    Multicolumn countercurrent solvent gradient purification (MCSGP) is a continuous chromatographic process developed in recent years (Aumann and Morbidelli, 2007a; Aumann et al., 2007) that is particularly suited for applications in the field of bioseparations. Like batch chromatography, MCSGP is suitable for three-fraction chromatographic separations and able to perform solvent gradients but it is superior in terms of solvent consumption, yield, purity, and productivity due to the countercurrent movement of the liquid and the solid phases. In this work, the MCSGP process is applied to the separation of three monoclonal antibody variants on a conventional preparative cation exchange resin. The experimental process performance was compared to simulations based on a lumped kinetic model. Yield and purity values of the target variant of 93%, respectively were obtained experimentally. The batch reference process was clearly outperformed by the MCSGP process.

  18. Anti-D Antibodies in Pregnant D Variant Antigen Carriers Initially Typed as RhD+

    PubMed Central

    Lukacevic Krstic, Jelena; Dajak, Slavica; Bingulac-Popovic, Jasna; Dogic, Vesna; Mratinovic-Mikulandra, Jela

    2016-01-01

    Background To evaluate the incidence, the consequences, and the prevention strategy of anti-D alloimmunizations of D variant carriers in the obstetric population of Split-Dalmatia County, Croatia. Methods RhD immunization events were evaluated retrospectively for the period between 1993 and 2012. Women were tested for RhD antigen and irregular antibodies. Those with anti-D antibody who were not serologically D- were genotyped for RHD. They were evaluated for their obstetric and transfusion history and their titer of anti-D. The neonates were evaluated for RhD status, direct antiglobulin test (DAT), hemoglobin and bilirubin levels, transfusion therapy as well as phototherapy and outcome. Results Out of 104,884 live births 102,982 women were tested for RhD antigen. Anti-D immunization occurred in 184 women which accounts for 0.9% of individuals at risk of anti-D formation. 181 cases occurred in women serologically typed as D-. Three women were partial D carriers (DVa n = 2, DNB n = 1), initially typed RhD+, and recognized as D variant carriers after the immunization occurred. Anti-D titer varied from 1:1 to 1:16. Six children were RhD+, four had positive DAT, and two underwent phototherapy. Conclusion Anti-D immunization occurred in pregnant partial D carriers (DVa, DNB). RhD+ children had serologic markers of hemolytic disease of the fetus and newborn (HDFN), with no cases of severe HDFN. PMID:27994529

  19. A LAIR-1 insertion generates broadly reactive antibodies against malaria variant antigens

    PubMed Central

    Abdi, Abdirahman; Perez, Mathilde Foglierini; Geiger, Roger; Tully, Claire Maria; Jarrossay, David; Maina Ndungu, Francis; Wambua, Juliana; Bejon, Philip; Fregni, Chiara Silacci; Fernandez-Rodriguez, Blanca; Barbieri, Sonia; Bianchi, Siro; Marsh, Kevin; Thathy, Vandana; Corti, Davide; Sallusto, Federica

    2016-01-01

    Plasmodium falciparum antigens expressed on the surface of infected erythrocytes are important targets of naturally acquired immunity against malaria, but their high number and variability provide the pathogen with a powerful means of escape from host antibodies1–4. Although broadly reactive antibodies against these antigens could be useful as therapeutics and in vaccine design, their identification has proven elusive. Here, we report the isolation of human monoclonal antibodies that recognize erythrocytes infected by different P. falciparum isolates and opsonize these cells by binding to members of the RIFIN family. These antibodies acquired broad reactivity through a novel mechanism of insertion of a large DNA fragment between the V and DJ segments. The insert, which is both necessary and sufficient for binding to RIFINs, encodes the entire 100 amino acid collagen-binding domain of LAIR-1, an Ig superfamily inhibitory receptor encoded on chromosome 19. In each of the two donors studied, the antibodies are produced by a single expanded B cell clone and carry distinct somatic mutations in the LAIR-1 domain that abolish binding to collagen and increase binding to infected erythrocytes. These findings illustrate, with a biologically relevant example, a novel mechanism of antibody diversification by interchromosomal DNA transposition and demonstrate the existence of conserved epitopes that may be suitable candidates for the development of a malaria vaccine. PMID:26700814

  20. A LAIR1 insertion generates broadly reactive antibodies against malaria variant antigens.

    PubMed

    Tan, Joshua; Pieper, Kathrin; Piccoli, Luca; Abdi, Abdirahman; Foglierini, Mathilde; Geiger, Roger; Tully, Claire Maria; Jarrossay, David; Ndungu, Francis Maina; Wambua, Juliana; Bejon, Philip; Fregni, Chiara Silacci; Fernandez-Rodriguez, Blanca; Barbieri, Sonia; Bianchi, Siro; Marsh, Kevin; Thathy, Vandana; Corti, Davide; Sallusto, Federica; Bull, Peter; Lanzavecchia, Antonio

    2016-01-07

    Plasmodium falciparum antigens expressed on the surface of infected erythrocytes are important targets of naturally acquired immunity against malaria, but their high number and variability provide the pathogen with a powerful means of escape from host antibodies. Although broadly reactive antibodies against these antigens could be useful as therapeutics and in vaccine design, their identification has proven elusive. Here we report the isolation of human monoclonal antibodies that recognize erythrocytes infected by different P. falciparum isolates and opsonize these cells by binding to members of the RIFIN family. These antibodies acquired broad reactivity through a novel mechanism of insertion of a large DNA fragment between the V and DJ segments. The insert, which is both necessary and sufficient for binding to RIFINs, encodes the entire 98 amino acid collagen-binding domain of LAIR1, an immunoglobulin superfamily inhibitory receptor encoded on chromosome 19. In each of the two donors studied, the antibodies are produced by a single expanded B-cell clone and carry distinct somatic mutations in the LAIR1 domain that abolish binding to collagen and increase binding to infected erythrocytes. These findings illustrate, with a biologically relevant example, a novel mechanism of antibody diversification by interchromosomal DNA transposition and demonstrate the existence of conserved epitopes that may be suitable candidates for the development of a malaria vaccine.

  1. An antibody raised against a pathogenic serpin variant induces mutant-like behaviour in the wild-type protein

    PubMed Central

    Irving, James A.; Miranda, Elena; Haq, Imran; Perez, Juan; Kotov, Vadim R.; Faull, Sarah V.; Motamedi-Shad, Neda; Lomas, David A.

    2015-01-01

    A monoclonal antibody (mAb) that binds to a transient intermediate may act as a catalyst for the corresponding reaction; here we show this principle can extend on a macro molecular scale to the induction of mutant-like oligomerization in a wild-type protein. Using the common pathogenic E342K (Z) variant of α1-antitrypsin as antigen–whose native state is susceptible to the formation of a proto-oligomeric intermediate–we have produced a mAb (5E3) that increases the rate of oligomerization of the wild-type (M) variant. Employing ELISA, gel shift, thermal stability and FRET time-course experiments, we show that mAb5E3 does not bind to the native state of α1-antitrypsin, but recognizes a cryptic epitope in the vicinity of the post-helix A loop and strand 4C that is revealed upon transition to the polymerization intermediate, and which persists in the ensuing oligomer. This epitope is not shared by loop-inserted monomeric conformations. We show the increased amenity to polymerization by either the pathogenic E342K mutation or the binding of mAb5E3 occurs without affecting the energetic barrier to polymerization. As mAb5E3 also does not alter the relative stability of the monomer to intermediate, it acts in a manner similar to the E342K mutant, by facilitating the conformational interchange between these two states. PMID:25738741

  2. Mechanistic modeling of ion-exchange process chromatography of charge variants of monoclonal antibody products.

    PubMed

    Kumar, Vijesh; Leweke, Samuel; von Lieres, Eric; Rathore, Anurag S

    2015-12-24

    Ion-exchange chromatography (IEX) is universally accepted as the optimal method for achieving process scale separation of charge variants of a monoclonal antibody (mAb) therapeutic. These variants are closely related to the product and a baseline separation is rarely achieved. The general practice is to fractionate the eluate from the IEX column, analyze the fractions and then pool the desired fractions to obtain the targeted composition of variants. This is, however, a very cumbersome and time consuming exercise. A mechanistic model that is capable of simulating the peak profile will be a much more elegant and effective way to make a decision on the pooling strategy. This paper proposes a mechanistic model, based on the general rate model, to predict elution peak profile for separation of the main product from its variants. The proposed approach uses inverse fit of process scale chromatogram for estimation of model parameters using the initial values that are obtained from theoretical correlations. The packed bed column has been modeled along with the chromatographic system consisting of the mixer, tubing and detectors as a series of dispersed plug flow and continuous stirred tank reactors. The model uses loading ranges starting at 25% to a maximum of 70% of the loading capacity and hence is applicable to process scale separations. Langmuir model has been extended to include the effects of salt concentration and temperature on the model parameters. The extended Langmuir model that has been proposed uses one less parameter than the SMA model and this results in a significant ease of estimating the model parameters from inverse fitting. The proposed model has been validated with experimental data and has been shown to successfully predict peak profile for a range of load capacities (15-28mg/mL), gradient lengths (10-30CV), bed heights (6-20cm), and for three different resins with good accuracy (as measured by estimation of residuals). The model has been also

  3. Quality assurance of monoclonal antibody pharmaceuticals based on their charge variants using microchip isoelectric focusing method.

    PubMed

    Kinoshita, Mitsuhiro; Nakatsuji, Yuki; Suzuki, Shigeo; Hayakawa, Takao; Kakehi, Kazuaki

    2013-09-27

    Monoclonal antibody (mAb) pharmaceuticals are much more complex than small-molecule drugs. Such complex characteristics raise challenging questions for regulatory evaluation. Although heterogeneity in mAbs based on their charge variants has been mainly evaluated using gel-based isoelectric focusing (IEF) method, recent development in capillary electrophoresis and microchip electrophoresis has made it possible to assure their heterogeneities in more easy and rapid manner. In the present paper, we customized the imaged microchip isoelectric focusing (mIEF) for the analysis of mAbs, and compared the customized version with the conventional capillary isoelectric focusing (cIEF) method, and found that mIEF has much higher performance in operations, and its resolving powers are comparable with those obtained by cIEF.

  4. Biological properties of two distinct pilus types produced by isogenic variants of Neisseria gonorrhoeae P9.

    PubMed Central

    Lambden, P R; Robertson, J N; Watt, P J

    1980-01-01

    Isogenic variants from a single strain of Neisseria gonorrhoeae were shown to produce two distinct types of pili. These pili, designated alpha and beta, differed in both subunit molecular weight and in ability to attach to buccal epithelial cells. Images PMID:6101593

  5. Recognition of influenza H3N2 variant virus by human neutralizing antibodies

    PubMed Central

    Bangaru, Sandhya; Nieusma, Travis; Kose, Nurgun; Thornburg, Natalie J.; Kaplan, Bryan S.; King, Hannah G.; Singh, Vidisha; Lampley, Rebecca M.; Cisneros, Alberto; Edwards, Kathryn M.; Edupuganti, Srilatha; Lai, Lilin; Richt, Juergen A.; Webby, Richard J.; Ward, Andrew B.; Crowe, James E.

    2016-01-01

    Since 2011, over 300 human cases of infection, especially in exposed children, with the influenza A H3N2 variant (H3N2v) virus that circulates in swine in the US have been reported. The structural and genetic basis for the lack of protection against H3N2v induced by vaccines containing seasonal H3N2 antigens is poorly understood. We isolated 17 human monoclonal antibodies (mAbs) that neutralized H3N2v virus from subjects experimentally immunized with an H3N2v candidate vaccine. Six mAbs exhibited very potent neutralizing activity (IC50 < 200 ng/ml) against the H3N2v virus but not against current human H3N2 circulating strains. Fine epitope mapping and structural characterization of antigen-antibody complexes revealed that H3N2v specificity was attributable to amino acid polymorphisms in the 150-loop and the 190-helix antigenic sites on the hemagglutinin protein. H3N2v-specific antibodies also neutralized human H3N2 influenza strains naturally circulating between 1995 and 2005. These results reveal a high level of antigenic relatedness between the swine H3N2v virus and previously circulating human strains, consistent with the fact that early human H3 seasonal strains entered the porcine population in the 1990s and reentered the human population, where they had not been circulating, as H3N2v about a decade later. The data also explain the increased susceptibility to H3N2v viruses in young children, who lack prior exposure to human seasonal strains from the 1990s. PMID:27482543

  6. Genetic variants are major determinants of CSF antibody levels in multiple sclerosis.

    PubMed

    Goris, An; Pauwels, Ine; Gustavsen, Marte W; van Son, Brechtje; Hilven, Kelly; Bos, Steffan D; Celius, Elisabeth Gulowsen; Berg-Hansen, Pål; Aarseth, Jan; Myhr, Kjell-Morten; D'Alfonso, Sandra; Barizzone, Nadia; Leone, Maurizio A; Martinelli Boneschi, Filippo; Sorosina, Melissa; Liberatore, Giuseppe; Kockum, Ingrid; Olsson, Tomas; Hillert, Jan; Alfredsson, Lars; Bedri, Sahl Khalid; Hemmer, Bernhard; Buck, Dorothea; Berthele, Achim; Knier, Benjamin; Biberacher, Viola; van Pesch, Vincent; Sindic, Christian; Bang Oturai, Annette; Søndergaard, Helle Bach; Sellebjerg, Finn; Jensen, Poul Erik H; Comabella, Manuel; Montalban, Xavier; Pérez-Boza, Jennifer; Malhotra, Sunny; Lechner-Scott, Jeannette; Broadley, Simon; Slee, Mark; Taylor, Bruce; Kermode, Allan G; Gourraud, Pierre-Antoine; Sawcer, Stephen J; Andreassen, Bettina Kullle; Dubois, Bénédicte; Harbo, Hanne F

    2015-03-01

    Immunological hallmarks of multiple sclerosis include the production of antibodies in the central nervous system, expressed as presence of oligoclonal bands and/or an increased immunoglobulin G index-the level of immunoglobulin G in the cerebrospinal fluid compared to serum. However, the underlying differences between oligoclonal band-positive and -negative patients with multiple sclerosis and reasons for variability in immunoglobulin G index are not known. To identify genetic factors influencing the variation in the antibody levels in the cerebrospinal fluid in multiple sclerosis, we have performed a genome-wide association screen in patients collected from nine countries for two traits, presence or absence of oligoclonal bands (n = 3026) and immunoglobulin G index levels (n = 938), followed by a replication in 3891 additional patients. We replicate previously suggested association signals for oligoclonal band status in the major histocompatibility complex region for the rs9271640*A-rs6457617*G haplotype, correlated with HLA-DRB1*1501, and rs34083746*G, correlated with HLA-DQA1*0301 (P comparing two haplotypes = 8.88 × 10(-16)). Furthermore, we identify a novel association signal of rs9807334, near the ELAC1/SMAD4 genes, for oligoclonal band status (P = 8.45 × 10(-7)). The previously reported association of the immunoglobulin heavy chain locus with immunoglobulin G index reaches strong evidence for association in this data set (P = 3.79 × 10(-37)). We identify two novel associations in the major histocompatibility complex region with immunoglobulin G index: the rs9271640*A-rs6457617*G haplotype (P = 1.59 × 10(-22)), shared with oligoclonal band status, and an additional independent effect of rs6457617*G (P = 3.68 × 10(-6)). Variants identified in this study account for up to 2-fold differences in the odds of being oligoclonal band positive and 7.75% of the variation in immunoglobulin G index. Both traits are associated with clinical features of disease such

  7. Genetic variants are major determinants of CSF antibody levels in multiple sclerosis

    PubMed Central

    Pauwels, Ine; Gustavsen, Marte W.; van Son, Brechtje; Hilven, Kelly; Bos, Steffan D.; Celius, Elisabeth Gulowsen; Berg-Hansen, Pål; Aarseth, Jan; Myhr, Kjell-Morten; D’Alfonso, Sandra; Barizzone, Nadia; Leone, Maurizio A.; Martinelli Boneschi, Filippo; Sorosina, Melissa; Liberatore, Giuseppe; Kockum, Ingrid; Olsson, Tomas; Hillert, Jan; Alfredsson, Lars; Bedri, Sahl Khalid; Hemmer, Bernhard; Buck, Dorothea; Berthele, Achim; Knier, Benjamin; Biberacher, Viola; van Pesch, Vincent; Sindic, Christian; Bang Oturai, Annette; Søndergaard, Helle Bach; Sellebjerg, Finn; Jensen, Poul Erik H.; Comabella, Manuel; Montalban, Xavier; Pérez-Boza, Jennifer; Malhotra, Sunny; Lechner-Scott, Jeannette; Broadley, Simon; Slee, Mark; Taylor, Bruce; Kermode, Allan G.; Gourraud, Pierre-Antoine; Sawcer, Stephen J.; Andreassen, Bettina Kullle; Dubois, Bénédicte; Harbo, Hanne F.

    2015-01-01

    Immunological hallmarks of multiple sclerosis include the production of antibodies in the central nervous system, expressed as presence of oligoclonal bands and/or an increased immunoglobulin G index—the level of immunoglobulin G in the cerebrospinal fluid compared to serum. However, the underlying differences between oligoclonal band-positive and -negative patients with multiple sclerosis and reasons for variability in immunoglobulin G index are not known. To identify genetic factors influencing the variation in the antibody levels in the cerebrospinal fluid in multiple sclerosis, we have performed a genome-wide association screen in patients collected from nine countries for two traits, presence or absence of oligoclonal bands (n = 3026) and immunoglobulin G index levels (n = 938), followed by a replication in 3891 additional patients. We replicate previously suggested association signals for oligoclonal band status in the major histocompatibility complex region for the rs9271640*A-rs6457617*G haplotype, correlated with HLA-DRB1*1501, and rs34083746*G, correlated with HLA-DQA1*0301 (P comparing two haplotypes = 8.88 × 10−16). Furthermore, we identify a novel association signal of rs9807334, near the ELAC1/SMAD4 genes, for oligoclonal band status (P = 8.45 × 10−7). The previously reported association of the immunoglobulin heavy chain locus with immunoglobulin G index reaches strong evidence for association in this data set (P = 3.79 × 10−37). We identify two novel associations in the major histocompatibility complex region with immunoglobulin G index: the rs9271640*A-rs6457617*G haplotype (P = 1.59 × 10−22), shared with oligoclonal band status, and an additional independent effect of rs6457617*G (P = 3.68 × 10−6). Variants identified in this study account for up to 2-fold differences in the odds of being oligoclonal band positive and 7.75% of the variation in immunoglobulin G index. Both traits are associated with clinical features of disease such

  8. A study of monoclonal antibody-producing CHO cell lines: what makes a stable high producer?

    PubMed

    Chusainow, Janet; Yang, Yuan Sheng; Yeo, Jessna H M; Toh, Poh Choo; Asvadi, Parisa; Wong, Niki S C; Yap, Miranda G S

    2009-03-01

    Generating stable, high-producing cell lines for recombinant protein production requires an understanding of the potential limitations in the cellular machinery for protein expression. In order to increase our understanding of what makes a stable high producer, we have generated a panel of 17 recombinant monoclonal antibody expressing Chinese hamster ovary subclones (CHO-mAb) with specific productivities ranging between 3 and 75 pg cell(-1) day(-1) using the dihydrofolate reductase (dhfr) expression system and compared the molecular features of these high- and low-producer clones. The relative heavy chain (HC) and light chain (LC) transgene copy numbers and mRNA levels were determined using real-time quantitative PCR (RT qPCR). We observed that not only higher transgene copy numbers and mRNA levels of both HC and LC were characteristic for the high-producer clones as compared to the low-producer clones but also a more favorable HC to LC transgene copy numbers ratio. By studying the long-term stability of the CHO-mAb subclones in the absence of methotrexate (MTX) selective pressure over 36 passages we observed a 35-92% decrease in volumetric productivity, primarily caused by a significant decrease in HC and LC mRNA levels with little change in the transgene copy numbers. Using Southern blot hybridization we analyzed the HC and LC transgene integration patterns in the host chromosome and their changes in course of gene amplification and long-term culturing. We observed that MTX-induced gene amplification caused chromosomal rearrangements resulting in clonal variability in regards to growth, productivity, and stability. No further obvious DNA rearrangements occurred during long-term culturing in the absence of MTX, indicating that other mechanisms were responsible for the decreased transcription efficiency. Our results implicate that the amplified transgene sequences were arranged in tandem repeats potentially triggering repeat-induced gene silencing. We hypothesize

  9. Is there a difference among human populations in the rate with which mutation produces electrophoretic variants?

    PubMed Central

    Neel, J V; Rothman, E

    1981-01-01

    Data are summarized that suggest that tropical-zone/tribal/nonindustrialized populations have higher frequencies of certain types of protein variants than temperate-zone/civilized/industrial populations, and it is demonstrated that these differences are not an artifact produced by the contagious type of sampling used with respect to tribal populations. Evidence is reviewed that suggests that a possible explanation of this difference is higher mutation rates in the tribal populations studied. PMID:6942419

  10. Neutralizing antibodies against rotavirus produced in transgenically labelled purple tomatoes.

    PubMed

    Juárez, Paloma; Presa, Silvia; Espí, Joaquín; Pineda, Benito; Antón, María T; Moreno, Vicente; Buesa, Javier; Granell, Antonio; Orzaez, Diego

    2012-04-01

    Edible fruits are inexpensive biofactories for human health-promoting molecules that can be ingested as crude extracts or partially purified formulations. We show here the production of a model human antibody for passive protection against the enteric pathogen rotavirus in transgenically labelled tomato fruits. Transgenic tomato plants expressing a recombinant human immunoglobulin A (hIgA_2A1) selected against the VP8* peptide of rotavirus SA11 strain were obtained. The amount of hIgA_2A1 protein reached 3.6 ± 0.8% of the total soluble protein in the fruit of the transformed plants. Minimally processed fruit-derived products suitable for oral intake showed anti-VP8* binding activity and strongly inhibited virus infection in an in vitro virus neutralization assay. In order to make tomatoes expressing hIgA_2A1 easily distinguishable from wild-type tomatoes, lines expressing hIgA_2A1 transgenes were sexually crossed with a transgenic tomato line expressing the genes encoding Antirrhinum majus Rosea1 and Delila transcription factors, which confer purple colour to the fruit. Consequently, transgenically labelled purple tomato fruits expressing hIgA_2A1 have been developed. The resulting purple-coloured extracts from these fruits contain high levels of recombinant anti-rotavirus neutralizing human IgA in combination with increased amounts of health-promoting anthocyanins.

  11. Antiviral antibody-producing cells in parenchymatous organs during persistent virus infection

    PubMed Central

    1987-01-01

    In mice persistently infected with lymphocytic choriomeningitis virus (LCMV), the parenchymatous organs contain infiltrates of mononuclear cells, the sizes and numbers of which vary between strains and become more numerous and extensive when the animals grow older. Histologically, these were found to possess a tissue-like structure, and by use of immunohistologic procedures they were shown to contain plasma cells secreting IgM and IgG. Cells of kidneys, livers, brains, and spleens of LCMV carrier mice were dispersed by digestion with trypsin, leukocytes were separated by density gradient centrifugation, and numbers of cells producing antibodies against LCMV were determined by use of a solid-phase immunoenzymatic technique. In all these organs, cells producing LCMV-specific IgM and IgG antibodies were demonstrated, the latter more numerous than the former. Their numbers correlated with numbers and extent of the lymphoid cell infiltrates. The blood of the same mice was essentially free of antiviral antibody-forming cell. The proportion of cells producing LCMV-specific antibodies to all cells producing Ig of any specificity varied between organs, being lowest in spleen, intermediate in liver and kidney, and highest in the brain, where in individual mice up to 90% of all active cells produced virus- specific antibodies. The LCMV carrier mouse should prove to be a useful animal model to investigate antibody production in parenchymatous organs during persistent virus infections. PMID:3546579

  12. Envelope Variants Circulating as Initial Neutralization Breadth Developed in Two HIV-Infected Subjects Stimulate Multiclade Neutralizing Antibodies in Rabbits

    PubMed Central

    Malherbe, Delphine C.; Pissani, Franco; Sather, D. Noah; Guo, Biwei; Pandey, Shilpi; Sutton, William F.; Stuart, Andrew B.; Robins, Harlan; Park, Byung; Krebs, Shelly J.; Schuman, Jason T.; Kalams, Spyros; Hessell, Ann J.

    2014-01-01

    ABSTRACT Identifying characteristics of the human immunodeficiency virus type 1 (HIV-1) envelope that are effective in generating broad, protective antibodies remains a hurdle to HIV vaccine design. Emerging evidence of the development of broad and potent neutralizing antibodies in HIV-infected subjects suggests that founder and subsequent progeny viruses may express unique antigenic motifs that contribute to this developmental pathway. We hypothesize that over the course of natural infection, B cells are programmed to develop broad antibodies by exposure to select populations of emerging envelope quasispecies variants. To test this hypothesis, we identified two unrelated subjects whose antibodies demonstrated increasing neutralization breadth against a panel of HIV-1 isolates over time. Full-length functional env genes were cloned longitudinally from these subjects from months after infection through 2.6 to 5.8 years of infection. Motifs associated with the development of breadth in published, cross-sectional studies were found in both subjects. We compared the immunogenicity of envelope vaccines derived from time points obtained during and after broadening of neutralization activity within these subjects. Rabbits were coimmunized four times with selected multiple gp160 DNAs and gp140-trimeric envelope proteins. The affinity of the polyclonal response increased as a function of boosting. The most rapid and persistent neutralization of multiclade tier 1 viruses was elicited by envelopes that were circulating in plasma at time points prior to the development of 50% neutralization breadth in both human subjects. The breadth elicited in rabbits was not improved by exposure to later envelope variants. These data have implications for vaccine development in describing a target time point to identify optimal envelope immunogens. IMPORTANCE Vaccine protection against viral infections correlates with the presence of neutralizing antibodies; thus, vaccine components capable

  13. A human-mouse hybridoma producing monoclonal antibody against human sperm coating antigen.

    PubMed Central

    Kyurkchiev, S D; Shigeta, M; Koyama, K; Isojima, S

    1986-01-01

    Since anti-sperm antibodies were first discovered in the sera of women, the relationship of these antibodies to sterility has been studied by many investigators. In order to determine the antigens of spermatozoa responsible for raising antibodies to spermatozoa in humans, many studies have been carried out by purifying human spermatozoa cell membrane and seminal plasma components. Since it was found that the purification was difficult by physiochemical procedures, the immunoaffinity chromatography bound monoclonal antibody (Mab) to spermatozoa antigens was attempted for this purpose. The establishment of hybridomas producing Mabs to human seminal plasma and human spermatozoa was reported by Shigeta et al. (1980), Isojima, Koyoma & Fujiwara (1982), Lee et al. (1982) and Isahakia & Alexander (1984). The ordinary approaches to obtain the Mabs consisted of xenogenic immunization with human semen and cell fusion of immunized spleen cells with mouse myeloma cells. However, the antigenic epitopes of human spermatozoa, which induced antibody production, are xenogenic for the mouse, and therefore there is a possibility that there is a difference in recognized antigenic epitopes in humans as isotypic and in mice as xenogenic. In order to study these antigenic epitopes, which correspond to antibodies against spermatozoa in women, the establishment of human-mouse hybridomas, which produced anti-semen antibodies as produced in sterile women, became essential. In these studies, we used recently developed cell fusion techniques to fuse immunized human peripheral lymphocytes with mouse myeloma cells. PMID:3456978

  14. Improved variants of SrtA for site-specific conjugation on antibodies and proteins with high efficiency

    PubMed Central

    Chen, Long; Cohen, Justin; Song, Xiaoda; Zhao, Aishan; Ye, Zi; Feulner, Christine J.; Doonan, Patrick; Somers, Will; Lin, Laura; Chen, Peng R.

    2016-01-01

    Sortase mediated ligation is a highly specific platform for conjugation that relies on the specificity of the transpeptidase Sortase A (SrtA) for short peptide sequences (LPXTG and GGG). SrtA retains its specificity while accepting a wide range of potential substrates, but its broad use is limited by the wild-type enzyme’s poor kinetics, which require large amounts of SrtA and extended reaction times for efficient conjugation. Prior explorations have aimed to improve the kinetics of SrtA with limited success. Herein we describe the discovery of further improved SrtA variants with increased efficiency for the conjugation reaction, and demonstrate their robustness in labelling proteins and antibodies in a site-specific manner. Our variants require significantly lower amounts of enzyme than WT SrtA and can be used to attach small molecules to the N or C-terminus of the heavy or light chain in antibodies with excellent yields. These improved variants can also be used for highly efficient site-specific PEGylation. PMID:27534437

  15. Protein adsorption on ion exchange resins and monoclonal antibody charge variant modulation.

    PubMed

    Guélat, Bertrand; Khalaf, Rushd; Lattuada, Marco; Costioli, Matteo; Morbidelli, Massimo

    2016-05-20

    A novel multicomponent adsorption equilibrium model for proteins on ion-exchange resins is developed on a statistical thermodynamic basis including surface coverage effects and protein-resin and protein-protein interactions. The resulting model exhibits a general competitive Langmuirian behavior and was applied to the study and optimization of the separation of monoclonal antibody charge variants on two strong cation exchangers. The model accounts explicitly for the effect of both pH and salt concentration, and its parameters can be determined in diluted conditions, that is, through physically sound assumptions, all model parameters can be obtained using solely experiments in diluted conditions, and be used to make predictions in overloaded conditions. The parameterization of the model and optimization of the separation is based on a two-step approach. First, gradient experiments in diluted conditions are undertaken in order to determine the model parameters. Based on these experiments and on information about the proteins of interest and the stationary phase used, all the model parameters can be estimated. Second, using the parameterized model, an initial Pareto optimization is undertaken where overloaded operating conditions are investigated. Experiments from this Pareto set are then used to refine the estimation of the model parameters. A second Pareto optimization can then be undertaken, this time with the refined parameters. This can be repeated until a satisfactory set of model parameters is found. This iterative approach is shown to be extremely efficient and to provide large amounts of knowledge based on only a few experiments. It is shown that due to the strong physical foundation of the model and the very low number of adjustable parameters, the number of iterations is expected to be at most two or three. Furthermore, the model based tool is improved as more experimental knowledge is provided, allowing for better estimations of the chromatographic

  16. Effects of different amino acids in culture media on surfactin variants produced by Bacillus subtilis TD7.

    PubMed

    Liu, Jin-Feng; Yang, Juan; Yang, Shi-Zhong; Ye, Ru-Qiang; Mu, Bo-Zhong

    2012-04-01

    Surfactin produced by Bacillus subtilis has different variants, which are affected by the composition of substrate available. To demonstrate the effects of amino acids on surfactin variants, B. subtilis TD7 was cultivated under the same conditions but with different amino acids supplied in media, respectively, and the type as well as the proportion of surfactin variants produced was analyzed with electrospray ionization mass spectrometry and gas chromatography-mass spectrometry. The result shows that the addition of different amino acids significantly influences the proportion of surfactin variants with different fatty acids. When Arg, Gln, or Val was added to the culture medium of B. subtilis TD7, the proportion of produced surfactin variants with even β-hydroxy fatty acids significantly increased, while the addition of Cys, His, Ile, Leu, Met, Ser, or Thr enhanced the proportion of surfactin variants with odd β-hydroxy fatty acids markedly. This result may be of some reference value in enhancing the production of specific surfactin variants as well as in the research on the relationship between culture media and the corresponding products of a certain bacterium.

  17. Identification of a Putative Crf Splice Variant and Generation of Recombinant Antibodies for the Specific Detection of Aspergillus fumigatus

    PubMed Central

    Schütte, Mark; Thullier, Philippe; Pelat, Thibaut; Wezler, Xenia; Rosenstock, Philip; Hinz, Dominik; Kirsch, Martina Inga; Hasenberg, Mike; Frank, Ronald; Schirrmann, Thomas; Gunzer, Matthias

    2009-01-01

    Background Aspergillus fumigatus is a common airborne fungal pathogen for humans. It frequently causes an invasive aspergillosis (IA) in immunocompromised patients with poor prognosis. Potent antifungal drugs are very expensive and cause serious adverse effects. Their correct application requires an early and specific diagnosis of IA, which is still not properly achievable. This work aims to a specific detection of A. fumigatus by immunofluorescence and the generation of recombinant antibodies for the detection of A. fumigatus by ELISA. Results The A. fumigatus antigen Crf2 was isolated from a human patient with proven IA. It is a novel variant of a group of surface proteins (Crf1, Asp f9, Asp f16) which belong to the glycosylhydrolase family. Single chain fragment variables (scFvs) were obtained by phage display from a human naive antibody gene library and an immune antibody gene library generated from a macaque immunized with recombinant Crf2. Two different selection strategies were performed and shown to influence the selection of scFvs recognizing the Crf2 antigen in its native conformation. Using these antibodies, Crf2 was localized in growing hyphae of A. fumigatus but not in spores. In addition, the antibodies allowed differentiation between A. fumigatus and related Aspergillus species or Candida albicans by immunofluorescence microscopy. The scFv antibody clones were further characterized for their affinity, the nature of their epitope, their serum stability and their detection limit of Crf2 in human serum. Conclusion Crf2 and the corresponding recombinant antibodies offer a novel approach for the early diagnostics of IA caused by A. fumigatus. PMID:19675673

  18. Generation of polyclonal antibodies against recombinant human glucocerebrosidase produced in Escherichia coli.

    PubMed

    Novo, Juliana Branco; Oliveira, Maria Leonor Sarno; Magalhães, Geraldo Santana; Morganti, Ligia; Raw, Isaías; Ho, Paulo Lee

    2010-11-01

    Deficiency of the lysosomal glucocerebrosidase (GCR) enzyme results in Gaucher's disease, the most common inherited storage disorder. Treatment consists of enzyme replacement therapy by the administration of recombinant GCR produced in Chinese hamster ovary cells. The production of anti-GCR antibodies has already been described with placenta-derived human GCR that requires successive chromatographic procedures. Here, we report a practical and efficient method to obtain anti-GCR polyclonal antibodies against recombinant GCR produced in Escherichia coli and further purified by a single step through nickel affinity chromatography. The purified GCR was used to immunize BALB/c mice and the induction of anti-GCR antibodies was evaluated by enzyme-linked immunosorbent assay. The specificity of the antiserum was also evaluated by western blot analysis against recombinant GCR produced by COS-7 cells or against endogenous GCR of human cell lines. GCR was strongly recognized by the produced antibodies, either as cell-associated or as secreted forms. The detected molecular masses of 59-66 kDa are in accordance to the expected size for glycosylated GCR. The GCR produced in E. coli would facilitate the production of polyclonal (shown here) and monoclonal antibodies and their use in the characterization of new biosimilar recombinant GCRs coming in the near future.

  19. The fibrous form of intracellular inclusion bodies in recombinant variant fibrinogen-producing cells is specific to the hepatic fibrinogen storage disease-inducible variant fibrinogen.

    PubMed

    Arai, Shinpei; Ogiwara, Naoko; Mukai, Saki; Takezawa, Yuka; Sugano, Mitsutoshi; Honda, Takayuki; Okumura, Nobuo

    2017-02-04

    Fibrinogen storage disease (FSD) is a rare disorder that is characterized by the accumulation of fibrinogen in hepatocytes and induces liver injury. Six mutations in the γC domain (γG284R, γT314P, γD316N, the deletion of γG346-Q350, γG366S, and γR375W) have been identified for FSD. Our group previously established γ375W fibrinogen-producing Chinese hamster ovary (CHO) cells and observed aberrant large granular and fibrous forms of intracellular inclusion bodies. The aim of this study was to investigate whether fibrous intracellular inclusion bodies are specific to FSD-inducible variant fibrinogen. Thirteen expression vectors encoding the variant γ-chain were stably or transiently transfected into CHO cells expressing normal fibrinogen Aα- and Bβ-chains or HuH-7 cells, which were then immunofluorescently stained. Six CHO and HuH-7 cell lines that transiently produced FSD-inducible variant fibrinogen presented the fibrous (3.2-22.7 and 2.1-24.5%, respectively) and large granular (5.4-25.5 and 7.7-23.9%) forms of intracellular inclusion bodies. Seven CHO and HuH-7 cell lines that transiently produced FSD-non-inducible variant fibrinogen only exhibit the large granular form. These results demonstrate that transiently transfected variant fibrinogen-producing CHO cells and inclusion bodies of the fibrous form may be useful in non-invasive screening for FSD risk factors for FSD before its onset.

  20. Adsorption of deamidated antibody variants on macroporous and dextran-grafted cation exchangers: II. Adsorption kinetics.

    PubMed

    Tao, Yinying; Carta, Giorgio; Ferreira, Gisela; Robbins, David

    2011-03-18

    Single and multicomponent batch adsorption kinetics were obtained for deamidated mAb variants on two commercial cation exchangers, one with an open macroporous structure--UNOsphere S--and the other with charged dextran grafts--Capto S. The adsorption kinetics for the macroporous matrix was found to be controlled largely by pore diffusion. The effective diffusivity estimated from single component data was a fraction of the mAb free solution diffusivity, and its value could be used to accurately predict the adsorption kinetics for two- and three-component systems. In this case, when two or more variants were adsorbed simultaneously, both experimental and predicted results showed a temporary overshoot of the amount adsorbed above the equilibrium value for the more deamidated variant followed by a gradual approach to equilibrium. Adsorption rates on the dextran grafted material were much faster than those observed for the macroporous matrix for both single component and simultaneous adsorption cases. In this case, no significant overshoot was observed for the more deamidated forms. The Capto S adsorption kinetics could be described well by a diffusion model with an adsorbed phase driving force for single component adsorption and for the simultaneous adsorption of multiple variants. However, this model failed to predict the adsorption kinetics when more deamidated forms pre-adsorbed on the resin were displaced by less deamidated ones. In this case, the kinetics of the displacement process was much slower indicating that the pre-adsorbed components severely hindered transport of the more strongly bound variants. Overall, the results indicate that despite the lower capacity, the macroporous resin may be more efficient in process applications where displacement of one variant by another takes place as a result of the faster and more predictable kinetics.

  1. Preferential association of a functional variant in complement receptor 2 with antibodies to double-stranded DNA

    PubMed Central

    Zhao, Jian; Giles, Brendan M; Taylor, Rhonda L; Yette, Gabriel A; Lough, Kara M; Ng, Han Leng; Abraham, Lawrence J; Wu, Hui; Kelly, Jennifer A; Glenn, Stuart B; Adler, Adam J; Williams, Adrienne H; Comeau, Mary E; Ziegler, Julie T; Marion, Miranda; Alarcón-Riquelme, Marta E; Alarcón, Graciela S; Anaya, Juan-Manuel; Bae, Sang-Cheol; Kim, Dam; Lee, Hye-Soon; Criswell, Lindsey A; Freedman, Barry I; Gilkeson, Gary S; Guthridge, Joel M; Jacob, Chaim O; James, Judith A; Kamen, Diane L; Merrill, Joan T; Sivils, Kathy Moser; Niewold, Timothy B; Petri, Michelle A; Ramsey-Goldman, Rosalind; Reveille, John D; Scofield, R Hal; Stevens, Anne M; Vilá, Luis M; Vyse, Timothy J; Kaufman, Kenneth M; Harley, John B; Langefeld, Carl D; Gaffney, Patrick M; Brown, Elizabeth E; Edberg, Jeffrey C; Kimberly, Robert P; Ulgiati, Daniela; Tsao, Betty P; Boackle, Susan A

    2016-01-01

    Objectives Systemic lupus erythematosus (SLE; OMIM 152700) is characterised by the production of antibodies to nuclear antigens. We previously identified variants in complement receptor 2 (CR2/CD21) that were associated with decreased risk of SLE. This study aimed to identify the causal variant for this association. Methods Genotyped and imputed genetic variants spanning CR2 were assessed for association with SLE in 15 750 case-control subjects from four ancestral groups. Allele-specific functional effects of associated variants were determined using quantitative real-time PCR, quantitative flow cytometry, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP)-PCR. Results The strongest association signal was detected at rs1876453 in intron 1 of CR2 (pmeta=4.2×10−4, OR 0.85), specifically when subjects were stratified based on the presence of dsDNA autoantibodies (case-control pmeta=7.6×10−7, OR 0.71; case-only pmeta=1.9×10−4, OR 0.75). Although allele-specific effects on B cell CR2 mRNA or protein levels were not identified, levels of complement receptor 1 (CR1/CD35) mRNA and protein were significantly higher on B cells of subjects harbouring the minor allele (p=0.0248 and p=0.0006, respectively). The minor allele altered the formation of several DNA protein complexes by EMSA, including one containing CCCTC-binding factor (CTCF), an effect that was confirmed by ChIP-PCR. Conclusions These data suggest that rs1876453 in CR2 has long-range effects on gene regulation that decrease susceptibility to lupus. Since the minor allele at rs1876453 is preferentially associated with reduced risk of the highly specific dsDNA autoantibodies that are present in preclinical, active and severe lupus, understanding its mechanisms will have important therapeutic implications. PMID:25180293

  2. Surface display vectors for selective detection and isolation of high level antibody producing cells.

    PubMed

    Lang, Sabine; Drewello, Delia; Wichter, Johannes; Nommay, Audrey; Wilms, Burkhard; Knopf, Hans-Peter; Jostock, Thomas

    2016-11-01

    Cell line generation for production of biopharmaceuticals in mammalian cells usually involves intensive screening of clones to identify the rare high producers. In order to facilitate efficient and selective fluorescence activated cell sorting (FACS) based enrichment and cloning of antibody producing CHO cells, we developed a special vector setup by inserting a leaky translation termination signal between the heavy chain of an IgG antibody and an IgG transmembrane domain. Partial read-through during translation of the antibody heavy chain leads to display of a subset of the produced antibody on the surface of the expressing cell. We could show that the level of surface expression correlates well with the productivity. By applying FACS, high producing cells can be selectively enriched and cloned. Two sequential FACS enrichment cycles were performed which led to more than eightfold increased productivities of transfected and selected cell populations without cloning. The combination of selective FACS enrichment and FACS cloning with the new vector setup led to a sevenfold higher average productivity of the resulting clones as compared to a reference vector. Productivity and production stability assessment of clones generated with the new vector showed no negative impact of the co-expression of transmembrane antibody. Clone productivities of 4 g/L in a generic shake flask fed-batch model were achieved. Thus, this new vector setup facilitates fast and selective isolation of high producing production cell lines and allows significant reduction of clone screening efforts during cell line development for production cell lines. Additionally, the high productivity of FACS-enriched but non-clonal cell populations supports rapid, high yield, and cost efficient material production in early project phases. Biotechnol. Bioeng. 2016;113: 2386-2393. © 2016 Wiley Periodicals, Inc.

  3. Towards the molecular characterization of the stable producer phenotype of recombinant antibody-producing NS0 myeloma cells.

    PubMed

    Prieto, Y; Rojas, L; Hinojosa, L; González, I; Aguiar, D; de la Luz, K; Castillo, A; Pérez, R

    2011-08-01

    The loss of heterologous protein expression is one of the major problems faced by industrial cell line developers and has been reported by several authors. Therefore, the understanding of the mechanisms involved in the generation of stable and high producer cell lines is a critical issue, especially for those processes based on long term continuous cultures. We characterized two recombinant NS0 myeloma cell lines expressing Nimotuzumab, a humanized anti-human epidermal growth factor receptor (EGFR) antibody. The hR3/H7 clone is a stable producer obtained from the unstable hR3/t16 clone. The unstable clone was characterized by a bimodal distribution of intracellular immunoglobulin staining using flow cytometry. Loss of antibody production was due to the emergence of a non-producer cell subpopulation that increased with cell generation number. Immunoglobulin heavy chain (HC) and light chain (LC) ratio (HC/LC) was lower for the unstable phenotype. Proteomic maps using two dimensional gel electrophoresis (2DE) were obtained for both clones, at initial cell culture time and after 40 generations. Fifteen proteins potentially associated with the phenomenon of production stability were identified. The hR3/H7 stable clone showed an up-regulated expression pattern for most of these proteins. The regulation of recombinant antibody production by the host NS0 myeloma cell line most likely involves simultaneously cellular processes such as DNA transcription, mRNA processing, protein synthesis and folding, vesicular transport, glycolysis and energy production, according to the proteins identified in the present proteomic study.

  4. Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

    PubMed Central

    Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

    2012-01-01

    Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-Stx2B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx2EDL933, stx2vha, stx2vhb, stx2g, stx1EDL933, and stx1d were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 115 ng/ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for two strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli. PMID:22919675

  5. DIFFERENTIATION AND FUNCTIONAL EXPRESSION OF POTENTIAL ANTIBODY-PRODUCING CELLS IN THE PRESENCE OF CHLORAMPHENICOL

    PubMed Central

    Schoenberg, Melvin D.; Moore, Richard D.; Weisberger, Austin S.

    1967-01-01

    Rabbits were immunized with diphtheria toxoid combined with complete Freund's adjuvant. Half of the animals were started on intramuscular injections of chloramphenicol 24 hr before the injection of the antigens. There was a general depression of protein synthesis in the immune system in the presence of chloramphenicol, but a greater effect on the synthesis of antibody than on the synthesis of proteins necessary for reproduction and maturation. In contrast to the finding of antibody in cells of the spleen and in the circulation of the control animals, those animals receiving chloramphenicol did not have measurable circulating antibody, and their spleens contained only a few cells with intracytoplasmic antibody late in the course of the experiment. Cytologically there was maturation of potential antibody-producing cells in the red pulp and nonfollicular white pulp of the spleen while the animals were receiving chloramphenicol. These cells developed more slowly, and were fewer and smaller than those of the control animals. They had numerous small, electron-opaque particles in their cytoplasm early in development. Ribosomes were synthesized, though fewer in number. The endoplasmic reticulum formed more slowly. PMID:10976231

  6. Generation and Characterization of Monoclonal Antibodies against a Cyclic Variant of Hepatitis C Virus E2 Epitope 412-422

    PubMed Central

    Sandomenico, Annamaria; Leonardi, Antonio; Berisio, Rita; Sanguigno, Luca; Focà, Giuseppina; Focà, Annalia; Ruggiero, Alessia; Doti, Nunzianna; Muscariello, Livio; Barone, Daniela; Farina, Claudio; Owsianka, Ania; Vitagliano, Luigi

    2016-01-01

    anti-HCV antibodies. MAbs that specifically recognize a cyclic variant of the epitope bind to soluble E2 with a lower affinity than other blocking antibodies and do not neutralize virus. The structure of the complex between one such MAb and the cyclic epitope, together with new structural data showing the linear peptide bound to neutralizing MAbs in extended conformations, suggests that the epitope displays a conformational flexibility that contributes to neutralization escape. Such features can be of major importance for the design of epitope-based anti-HCV vaccines. PMID:26819303

  7. Crystal structure of a 3B3 variant - A broadly neutralizing HIV-1 scFv antibody

    SciTech Connect

    Clark, K. Reed; Walsh, Scott T.R.

    2009-12-10

    We present the crystal structure determination of an anti-HIV-1 gp120 single-chain variable fragment antibody variant, 3B3, at 2.5 {angstrom} resolution. This 3B3 variant was derived from the b12 antibody, using phage display and site-directed mutagenesis of the variable heavy chain (V{sub H}) complementary-determining regions (CDRs). 3B3 exhibits enhanced binding affinity and neutralization activity against several cross-clade primary isolates of HIV-1 by interaction with the recessed CD4-binding site on the gp120 envelope protein. Comparison with the structures of the unbound and bound forms of b12, the 3B3 structure closely resembles these structures with minimal differences with two notable exceptions. First, there is a reorientation of the CDR-H3 of the V{sub H} domain where the primary sequences evolved from b12 to 3B3. The structural changes in CDR-H3 of 3B3, in light of the b12-gp120 complex structure, allow for positioning an additional Trp side chain in the binding interface with gp120. Finally, the second region of structural change involves two peptide bond flips in CDR-L3 of the variable light (VL) domain triggered by a point mutation in CDR-H3 of Q100eY resulting in changes in the intramolecular hydrogen bonding patterning between the VL and VH domains. Thus, the enhanced binding affinities and neutralization capabilities of 3B3 relative to b12 probably result from higher hydrophobic driving potential by burying more aromatic residues at the 3B3-gp120 interface and by indirect stabilization of intramolecular contacts of the core framework residues between the VL and VH domains possibly through more favorable entropic effect through the expulsion of water.

  8. Activation of clones producing self-reactive antibodies by foreign antigen and antiidiotype antibody carrying the internal image of the antigen.

    PubMed Central

    Bailey, N C; Fidanza, V; Mayer, R; Mazza, G; Fougereau, M; Bona, C

    1989-01-01

    Because we found in previous work that a high fraction of antibodies exhibiting various specificities bound to glutamic acid 50-tyrosine50 homopolymer (GT) and expressed pGAT cross-reactive idiotype (IdX), we studied the activation of clones producing multireactive antibodies in 1-mo-old MRL/lpr and C3H/HeJ mice bearing VHJ haplotype. The activation of such clones was studied after mice were immunized with GT in CFA, HP20 (an anti-Id MAb carrying the internal image of GT in the D region), and a synthetic peptide corresponding to the D segment of HP20. Our results indicate that immunized mice produced both GT- and self-reactive antibodies. Study of the immunochemical properties of MAb showed that they exhibit multispecific properties and bind with similar-affinity constants to GT or self-antigens such as DNA, Smith antigen (Sm), and IgG2a. An important fraction of antibodies obtained from MRL/lpr mice immunized with HP20 expressed pGAT IdX and some of these antibodies share IdX expressed on anti-DNA, Sm, and rheumatoid factor (RFs) antibodies. The hybridomas producing multispecific autoantibodies use heavy-chain- (VH) and light-chain-variable region (VK) genes from various V gene families, suggesting that they do not derive from the pool of GAT precursors. Sequencing of VH and VK genes of two antibodies show that they can use closely related VHJ558, unmutated VK1, or different VK genes than those used by anti-GT antibodies. Our data demonstrate that clones producing antibodies binding to GT and self-antigens with similar-affinity constants can be activated by foreign or anti-Id antibodies carrying the internal image of the antigen or even by a synthetic peptide corresponding to the D segment of anti-Id antibodies. Images PMID:2760212

  9. [An efficient method for producing monoclonal antibodies against multi-pass membrane proteins].

    PubMed

    Yagi, Hideki; Masuko, Takashi

    2013-01-01

    Antibodies have greatly contributed to the development of medical science and pharmacology, because of their high specificity. The cell fusion method has developed monoclonal antibodies (mAb) technology, such that massive amounts of mAb with a uniform structure can be produced. Although mAb have been produced against many proteins so far, the production of mAb against multi-pass transmembrane proteins, such as G-protein coupled receptor (GPCR) and various transporter proteins has been extremely difficult. The complicated structures, poorly extracellular regions, and high hydrophobicity of multiple-transmembrane proteins make it difficult to produce mAb against them. Production of mAb that recognize the extracellular region of living cells is thought to be important in determining the ability of a protein. Based on these findings, we tried to produce mAb against a multi-pass transmembrane transporter using green fluorescent protein (GFP)-fused full-length target proteins as immunogens. Furthermore, the immunizing method has proved to be important in generating functional mAb. We succeeded in producing functional mAb that react against the extracellular region of a 12-pass transmembrane transporter in a living cell. Based on this success, we began to produce mAb against seven-transmembrane GPCR. In this symposium, we report on the results of producing mAb against S1P receptors, a type of GPCR.

  10. Directed evolution of chemotaxis inhibitory protein of Staphylococcus aureus generates biologically functional variants with reduced interaction with human antibodies.

    PubMed

    Gustafsson, Erika; Rosén, Anna; Barchan, Karin; van Kessel, Kok P M; Haraldsson, Karin; Lindman, Stina; Forsberg, Cecilia; Ljung, Lill; Bryder, Karin; Walse, Björn; Haas, Pieter-Jan; van Strijp, Jos A G; Furebring, Christina

    2010-02-01

    Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) is a protein that binds and blocks the C5a receptor (C5aR) and formylated peptide receptor, thereby inhibiting the immune cell recruitment associated with inflammation. If CHIPS was less reactive with existing human antibodies, it would be a promising anti-inflammatory drug candidate. Therefore, we applied directed evolution and computational/rational design to the CHIPS gene in order to generate new CHIPS variants displaying lower interaction with human IgG, yet retaining biological function. The optimization was performed in four rounds: one round of random mutagenesis to add diversity into the CHIPS gene and three rounds of DNA recombination by Fragment INduced Diversity (FIND). Every round was screened by phage selection and/or ELISA for decreased interaction with human IgG and retained C5aR binding. The mean binding of human anti-CHIPS IgG decreased with every round of evolution. For further optimization, new amino acid substitutions were introduced by rational design, based on the mutations identified during directed evolution. Finally, seven CHIPS variants with low interaction with human IgG and retained C5aR blocking capacity could be identified.

  11. Rapid characterization of hybridomas producing monoclonal antibodies against platelet β3 integrin using ELIspot.

    PubMed

    Maenner, Denis; Werth, Silke; Bein, Gregor; Santoso, Sentot

    2016-12-01

    Generally, B-cell responses against human platelet antigens are assessed by the serological detection of specific platelet antibodies, mostly against β3 integrin. However, this approach seems to be of low sensitivity, since platelet autoantibodies against αIIbβ3 are detected in only 50% of all patients with immune thrombocytopenia (ITP). In this study, a novel B-cell ELIspot method was established to characterize the specificity of mouse monoclonal antibodies (moabs) against human β3 integrin. Moabs produced by hybridomas were immobilized on membrane and bound antibodies were visualized as spots using biotinylated recombinant proteins αIIbβ3 or αvβ3 and the enzyme labeled streptavidin-substrate system. Three hybridomas, Gi5, Gi16 and AP3, designated previously as anti-αIIbβ3, anti-αIIb and anti-β3, respectively, were investigated. Hybridoma producing moab against CD177 was used as the negative control. Whereas AP3 reacted with αIIbβ3 and αvβ3, Gi5 only formed spots with αIIbβ3. Titration analysis showed that the number of spots correlated significantly with the number of seeded cells. Approximately 15 antibody producing hybridoma cells could be identified among 10(3) nonproducing B-cells. Furthermore, superior correlation with the total number of IgG producing cells was obtained. Analysis of the third hybridoma, Gi16 (anti-αIIb), showed only few spots with αIIbβ3, indicating that this hybridoma contained different clones (producer and non-producer). Significant increased number of spots could be identified after re-cloning of these clones by limiting dilution method. Our results demonstrate that this B-cell ELIspot assay can be used for the identification of a small number of hybridoma cells producing moabs against β3 integrin, verification of their monoclonality, productivity and for determining their specificity in the early state of workup steps. In the future, this approach may be useful to define B-cell clones in patients who developed

  12. Distinct reactivity of the commercially available monoclonal antibodies of D-dimer and plasma FDP testing to the molecular variants of fibrin degradation products.

    PubMed

    Madoiwa, Seiji; Kitajima, Isao; Ohmori, Tsukasa; Sakata, Yoichi; Mimuro, Jun

    2013-10-01

    Fibrin degradation products (FDP) are an important marker of coagulopathy. We assessed the reactivity of the monoclonal antibodies used in clinical laboratory testing (6 D-dimer reagents, D-dimer-1-6; 4 plasma FDP reagents, plasma FDP-1-4) to quantify FDP using in vitro-generated FDP as well as FDP in clinical samples. The monoclonal antibodies used in D-dimer-1, -2, -5, and -6 reacted poorly to the low molecular weight forms of in vitro-generated FDP. The monoclonal antibodies used in D-dimer-3 and -4 had better reactivity to the low molecular weight forms of in vitro-generated FDP. The monoclonal antibodies used in plasma FDP-2, -3, and -4 reacted well to the high and low molecular weight FDP forms, while the monoclonal antibody in plasma FDP-1 reacted poorly to the low molecular weight FDP forms. Analysis of clinical samples revealed deviations in FDP molecular weight forms in DIC samples. The reactivity of the monoclonal antibodies of laboratory FDP testing to FDP variants in clinical samples was similar to that of in vitro-generated FDP. In conclusion, the monoclonal antibodies used in clinical laboratories to detect FDP have distinct reactivity to the molecular variants of FDP generated in vitro as well as those present in clinical samples. Our findings support the consensus for the standardization of D-dimer and plasma FDP testing.

  13. Characterization of acidic and basic variants of IgG1 therapeutic monoclonal antibodies based on non-denaturing IEF fractionation.

    PubMed

    Dada, Oluwatosin O; Jaya, Nomalie; Valliere-Douglass, John; Salas-Solano, Oscar

    2015-08-20

    Characterization of both the acidic and basic regions of imaged capillary isoelectric focusing (icIEF) profile of an IgG1 antibody was achieved through preparative immobilized pH gradient isoelectric focusing (IPG-IEF) fractionation. Recent attempts at using this method to fractionate charge variants of monoclonal antibodies (mAbs) have shown promising results, but identification of the chemical modifications in the variants was limited to the basic species. We have optimized the method to achieve enrichment of each variant across the icIEF profile of an IgG1 mAb. The fractionation was followed by extended characterization to elucidate the composition of the acidic, main, and basic species observed in the icIEF profile. Deamidation, sialylation, glycation, and fragmentation were identified as the main modifications contributing to acidic variants of the mAb while C-terminal lysine, C-terminal proline amidation, and uncyclized N-terminal glutamine were the major species contributing to the basic variants. This characterization allows a better understanding of the modifications that contribute to the charge variants observed by icIEF, facilitating the evaluation of impacts on product safety and efficacy.

  14. Atypical and classical memory B cells produce Plasmodium falciparum neutralizing antibodies

    PubMed Central

    Muellenbeck, Matthias F.; Ueberheide, Beatrix; Amulic, Borko; Epp, Alexandra; Fenyo, David; Busse, Christian E.; Esen, Meral; Theisen, Michael; Mordmüller, Benjamin

    2013-01-01

    Antibodies can protect from Plasmodium falciparum (Pf) infection and clinical malaria disease. However, in the absence of constant reexposure, serum immunoglobulin (Ig) levels rapidly decline and full protection from clinical symptoms is lost, suggesting that B cell memory is functionally impaired. We show at the single cell level that natural Pf infection induces the development of classical memory B cells (CM) and atypical memory B cells (AtM) that produce broadly neutralizing antibodies against blood stage Pf parasites. CM and AtM contribute to anti-Pf serum IgG production, but only AtM show signs of active antibody secretion. AtM and CM were also different in their IgG gene repertoire, suggesting that they develop from different precursors. The findings provide direct evidence that natural Pf infection leads to the development of protective memory B cell antibody responses and suggest that constant immune activation rather than impaired memory function leads to the accumulation of AtM in malaria. Understanding the memory B cell response to natural Pf infection may be key to the development of a malaria vaccine that induces long-lived protection. PMID:23319701

  15. Trans-splicing as a novel method to rapidly produce antibody fusion proteins

    SciTech Connect

    Iwasaki, Ryohei; Kiuchi, Hiroki; Ihara, Masaki; Mori, Toshihiro; Kawakami, Masayuki; Ueda, Hiroshi

    2009-07-03

    To cultivate the use of trans-splicing as a novel means to rapidly express various antibody fusion proteins, we tried to express antibody-reporter enzyme fusions in a COS-1 co-transfection model. When a vector designed to induce trans-splicing with IgH pre-mRNA was co-transfected with a vector encoding the mouse IgM locus, the expression of V{sub H}-secreted human placental alkaline phosphatase (SEAP) as well as Fab-SEAP were successfully expressed both in mRNA and protein levels. Especially, the vectors encoding complementary sequence to S{mu} as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one. Since S{mu} sequence should exist in every IgH pre-mRNA, our finding will lead to the rapid production and analysis of various antibody-enzyme fusions suitable for enzyme-linked immunosorbent assay (ELISA) or antibody-dependent enzyme prodrug therapy (ADEPT).

  16. A Novel Pathogenic BRCA1 Splicing Variant Produces Partial Intron Retention in the Mature Messenger RNA

    PubMed Central

    Esposito, Maria Valeria; Nunziato, Marcella; Starnone, Flavio; Telese, Antonella; Calabrese, Alessandra; D’Aiuto, Giuseppe; Pucci, Pietro; D’Aiuto, Massimiliano; Baralle, Francisco; D’Argenio, Valeria; Salvatore, Francesco

    2016-01-01

    About 10% of all breast cancers arise from hereditary mutations that increase the risk of breast and ovarian cancers; and about 25% of these are associated with the BRCA1 or BRCA2 genes. The identification of BRCA1/BRCA2 mutations can enable physicians to better tailor the clinical management of patients; and to initiate preventive measures in healthy carriers. The pathophysiological significance of newly identified variants poses challenges for genetic counseling. We characterized a new BRCA1 variant discovered in a breast cancer patient during BRCA1/2 screening by next-generation sequencing. Bioinformatic predictions; indicating that the variant is probably pathogenetic; were verified using retro-transcription of the patient’s RNA followed by PCR amplifications performed on the resulting cDNA. The variant causes the loss of a canonic donor splice site at position +2 in BRCA1 intron 21; and consequently the partial retention of 156 bp of intron 21 in the patient’s transcript; which demonstrates that this novel BRCA1 mutation plays a pathogenetic role in breast cancer. These findings enabled us to initiate appropriate counseling and to tailor the clinical management of this family. Lastly; these data reinforce the importance of studying the effects of sequence variants at the RNA level to verify their potential role in disease onset. PMID:28009814

  17. Proteomic Analysis of Host Cell Protein Dynamics in the Culture Supernatants of Antibody-Producing CHO Cells

    PubMed Central

    Park, Jin Hyoung; Jin, Jong Hwa; Lim, Myung Sin; An, Hyun Joo; Kim, Jong Won; Lee, Gyun Min

    2017-01-01

    Chinese hamster ovary (CHO) cells are the most common cell line used for the production of therapeutic proteins including monoclonal antibodies (mAbs). Host cell proteins (HCPs), secreted and released from lysed cells, accumulate extracellularly during the cultures of recombinant CHO (rCHO) cells, potentially impairing product quality. In an effort to maintain good mAb quality during the cultures, HCPs accumulated extracellularly in batch and fed-batch cultures of a mAb-producing rCHO cell line were identified and quantified by nanoflow liquid chromatography-tandem mass spectrometry, followed by their gene ontology and functional analysis. Due to higher cell concentration and longer culture duration, more HCPs were identified and quantitated in fed-batch culture (2145 proteins identified and 1673 proteins quantified) than in batch culture (1934 proteins identified and 1486 proteins quantified). Clustering analysis of HCPs showed that the concentration profiles of HCPs affecting mAb quality (Lgmn, Ctsd, Gbl1, and B4galt1) correlated with changes in mAb quality attributes such as aggregation, charge variants, and N-glycosylation during the cultures. Taken together, the dataset of HCPs obtained in this study provides insights into determining the appropriate target proteins to be removed during both the cultures and purification steps for ensuring good mAb quality. PMID:28281648

  18. Semiautomated pH gradient ion-exchange chromatography of monoclonal antibody charge variants.

    PubMed

    Talebi, Mohammad; Shellie, Robert A; Hilder, Emily F; Lacher, Nathan A; Haddad, Paul R

    2014-10-07

    A new approach using a chromatography system equipped with isocratic pumps and an electrolytic eluent generator (EG) is introduced, replacing external pH gradient delivery using conventional gradient systems, in which bottled buffers with preadjusted pH are mixed using a gradient pump. The EG is capable of generating high purity base or acid required for online preparation of the buffer at the point of use, utilizing deionized water as the only carrier stream. Typically, the buffer was generated from online titration of a reagent composed of low molecular weight amines. The reagent was delivered isocratically into a static mixing tee, where it was titrated to the required pH with electrolytically generated base or acid. The required pH gradient was thus conveniently generated by electrically controlling the concentration of titrant. Also, since the pH was adjusted at the point of use, this approach offered enhanced throughput in terms of eluent preparation time and labor, and with a more reproducible pH profile. The performance of the system was demonstrated by running pH gradients ranging from pH 8.2 to 10.9 on a polymer monolith cation-exchange column for high throughput profiling of charge heterogeneity of intact, basic therapeutic monoclonal antibodies. A high degree of flexibility in modulating the key parameters of the pH gradient, including the buffer concentration, the pH gradient slope and the operating pH range was demonstrated. This enabled fine-tuning of the separation conditions for each individual antibody in order to enhance the chromatographic resolution.

  19. Combined Linkage and Association Studies Show that HLA Class II Variants Control Levels of Antibodies against Epstein-Barr Virus Antigens

    PubMed Central

    Cobat, Aurélie; Guergnon, Julien; Brice, Pauline; Fermé, Christophe; Carde, Patrice; Hermine, Olivier; Pendeven, Catherine Le-; Amiel, Corinne; Taoufik, Yassine; Alcaïs, Alexandre; Theodorou, Ioannis; Besson, Caroline; Abel, Laurent

    2014-01-01

    Over 95% of the adult population worldwide is infected with Epstein-Barr virus (EBV). EBV infection is associated with the development of several cancers, including Hodgkin lymphoma (HL). Elevated levels of anti-EBV antibodies have been associated with increased risk of HL. There is growing evidence that genetic factors control the levels of antibodies against EBV antigens. Here, we conducted linkage and association studies to search for genetic factors influencing either anti-viral capsid antigen (VCA) or anti-Epstein Barr nuclear antigen-1 (EBNA-1) IgG levels in a unique cohort of 424 individuals of European origin from 119 French families recruited through a Hodgkin lymphoma (HL) patient. No major locus controlling anti-VCA antibody levels was identified. However, we found that the HLA region influenced anti-EBNA-1 IgG titers. Refined association studies in this region identified a cluster of HLA class II variants associated with anti-EBNA-1 IgG titers (e.g. p = 5×10–5 for rs9268403). The major allele of rs9268403 conferring a predisposition to high anti-EBNA-1 antibody levels was also associated with an increased risk of HL (p = 0.02). In summary, this study shows that HLA class II variants influenced anti-EBNA-1 IgG titers in a European population. It further shows the role of the same variants in the risk of HL. PMID:25025336

  20. Immunodominant epitope and properties of pyroglutamate-modified Abeta-specific antibodies produced in rabbits.

    PubMed

    Acero, G; Manoutcharian, K; Vasilevko, V; Munguia, M E; Govezensky, T; Coronas, G; Luz-Madrigal, A; Cribbs, D H; Gevorkian, G

    2009-08-18

    N-truncated and N-modified forms of amyloid beta (Abeta) peptide are found in diffused and dense core plaques in Alzheimer's disease (AD) and Down's syndrome patients as well as transgenic mouse models of AD. Although the pathological significance of these shortened forms Abeta is not completely understood, previous studies have demonstrated that these peptides are significantly more resistant to degradation, aggregate more rapidly in vitro and exhibit similar or, in some cases, increased toxicity in hippocampal neuronal cultures compared to the full length peptides. In the present study we further investigated the mechanisms of toxicity of one of the most abundant N-truncated/modified Abeta peptide bearing amino-terminal pyroglutamate at position 3 (AbetaN3(pE)). We demonstrated that AbetaN3(pE) oligomers induce phosphatidyl serine externalization and membrane damage in SH-SY5Y cells. Also, we produced AbetaN3(pE)-specific polyclonal antibodies in rabbit and identified an immunodominant epitope recognized by anti-AbetaN3(pE) antibodies. Our results are important for developing new immunotherapeutic compounds specifically targeting AbetaN3(pE) aggregates since the most commonly used immunogens in the majority of vaccines for AD have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Abeta, which is absent in N-amino truncated peptides.

  1. IMMUNODOMINANT EPITOPE AND PROPERTIES OF PYROGLUTAMATE-MODIFIED Aβ-SPECIFIC ANTIBODIES PRODUCED IN RABBITS

    PubMed Central

    Acero, G.; Manoutcharian, K.; Vasilevko, V.; Munguia, M.E.; Govezensky, T.; Coronas, G.; Luz-Madrigal, A.; Cribbs, DH.; Gevorkian, G.

    2009-01-01

    N-truncated and N-modified forms of amyloid beta (Aß) peptide are found in diffused and dense core plaques in Alzheimer’s disease (AD) and Down’s syndrome patients as well as transgenic mouse models of AD. Although the pathological significance of these shortened forms Aβ is not completely understood, previous studies have demonstrated that these peptides are significantly more resistant to degradation, aggregate more rapidly in vitro and exhibit similar or, in some cases, increased toxicity in hippocampal neuronal cultures compared to the full-length peptides. In the present study we further investigated the mechanisms of toxicity of one of the most abundant Ntruncated/modified Aβ peptide bearing amino-terminal pyroglutamate at position 3 (AβN3(pE)). We demonstrated that AβN3(pE) oligomers induce phosphatidyl serine externalization and membrane damage in SH-SY5Y cells. Also, we produced AβN3(pE)-specific polyclonal antibodies in rabbit and identified an immunodominant epitope recognized by anti-AβN3(pE) antibodies. Our results are important for developing new immunotherapeutic compounds specifically targeting AβN3(pE) aggregates since the most commonly used immunogens in the majority of vaccines for AD have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Aβ, which is absent in N-amino truncated peptides. PMID:19545911

  2. Feasibility studies of using the Catfish Immune System to produce monoclonal antibodies

    SciTech Connect

    Poston, T.M.

    1987-03-01

    The objective of these studies was to determine the feasibility of using a teleost cell line to produce monoclonal antibodies. Studies were undertaken to demonstrate the production of a polyclonal response of channel catfish (Icatalurus punctatus) challenged with mycotoxins coupled to a protein carrier. Companion studies were also performed to induce a permanent cell line with catfish lymphocytes. Attempts to demonstrate a polyclonal response to haptenized mycotoxins were inconclusive. Tests to induce an immortal, permanent cell line with benzene and x-ray irradiated cells were also inconclusive. 3 refs., 13 tabs.

  3. Mutation Detection in an Antibody-Producing Chinese Hamster Ovary Cell Line by Targeted RNA Sequencing

    PubMed Central

    Zhang, Siyan; Hughes, Jason D.; Murgolo, Nicholas; Levitan, Diane; Chen, Janice; Liu, Zhong

    2016-01-01

    Chinese hamster ovary (CHO) cells have been used widely in the pharmaceutical industry for production of biological therapeutics including monoclonal antibodies (mAb). The integrity of the gene of interest and the accuracy of the relay of genetic information impact product quality and patient safety. Here we employed next-generation sequencing, particularly RNA-seq, and developed a method to systematically analyze the mutation rate of the mRNA of CHO cell lines producing a mAb. The effect of an extended culturing period to mimic the scale of cell expansion in a manufacturing process and varying selection pressure in the cell culture were also closely examined. PMID:27088091

  4. Bioengineering of a Nisin A‐producing Lactococcus lactis to create isogenic strains producing the natural variants Nisin F, Q and Z

    PubMed Central

    Piper, Clare; Hill, Colin; Cotter, Paul D.; Ross, R. Paul

    2011-01-01

    Summary Nisin is the prototypical example of the lantibiotic family of antimicrobial peptides and has been employed as a food preservative for over half a century. It has also attracted attention due to its potency against a number of multidrug‐resistant clinical pathogens. Nisin A is the originally isolated form of Nisin and a further five natural variants have been described which differ by up to 10 amino acids (of 34 in total in Nisin A). Nisins A, Z, F and Q are produced by Lactococcus lactis, while Nisins U and U2 are produced by Streptococcus sp. In this study we bioengineered the nisA gene of a Nisin A producer to generate genes encoding Nisins Z, F, Q, U and U2. We determined that while active Nisin Z, F and Q can be produced against this genetic background, active forms of Nisin U and U2 are not generated. Minimum inhibitory concentration studies with Nisin A, Z, F and Q variants against a series of different clinically significant pathogens establish differences in specific activities against selected targets. Nisin F was most impressive, being the most active, or one of the most active, against the MRSA strain ST 525, EC 676, EC 725, VISA 22900, VISA 22781, hVISA 35197, Staphylococcus aureus 8325‐4 and L. lactis HP. Nisin Z was most active against ST 299, hVISA 32683 and, together with Nisin F, HP but had contrastingly poor activity against ST 525, EC 676 and 8325‐4. Nisin F, Q and A exhibited similar potency against VISA 22900. This was the only target against which Nisin Q and Nisin A were among the most active variants. PMID:21375711

  5. Vaccine-elicited antibody that neutralizes H5N1 influenza and variants binds the receptor site and polymorphic sites

    DOE PAGES

    Winarski, Katie L.; Thornburg, Natalie J.; Yu, Yingchun; ...

    2015-07-13

    Antigenic drift of circulating seasonal influenza viruses necessitates an international vaccine effort to reduce the impact on human health. A critical feature of the seasonal vaccine is that it stimulates an already primed immune system to diversify memory B cells to recognize closely related, but antigenically distinct, influenza glycoproteins (hemagglutinins). Influenza pandemics arise when hemagglutinins to which no preexisting adaptive immunity exists acquire the capacity to infect humans. Hemagglutinin 5 is one subtype to which little preexisting immunity exists and is only a few acquired mutations away from the ability to transmit efficiently between ferrets, and possibly humans. In thismore » paper, we describe the structure and molecular mechanism of neutralization by H5.3, a vaccine-elicited antibody that neutralizes hemagglutinin 5 viruses and variants with expanded host range. H5.3 binds in the receptor-binding site, forming contacts that recapitulate many of the sialic acid interactions, as well as multiple peripheral interactions, yet is not sensitive to mutations that alter sialic acid binding. H5.3 is highly specific for a subset of H5 strains, and this specificity arises from interactions to the periphery of the receptor-binding site. Finally, H5.3 is also extremely potent, despite retaining germ line-like conformational flexibility.« less

  6. Vaccine-elicited antibody that neutralizes H5N1 influenza and variants binds the receptor site and polymorphic sites

    SciTech Connect

    Winarski, Katie L.; Thornburg, Natalie J.; Yu, Yingchun; Sapparapu, Gopal; Crowe, James. E.; Spiller, Benjamin W.

    2015-07-13

    Antigenic drift of circulating seasonal influenza viruses necessitates an international vaccine effort to reduce the impact on human health. A critical feature of the seasonal vaccine is that it stimulates an already primed immune system to diversify memory B cells to recognize closely related, but antigenically distinct, influenza glycoproteins (hemagglutinins). Influenza pandemics arise when hemagglutinins to which no preexisting adaptive immunity exists acquire the capacity to infect humans. Hemagglutinin 5 is one subtype to which little preexisting immunity exists and is only a few acquired mutations away from the ability to transmit efficiently between ferrets, and possibly humans. In this paper, we describe the structure and molecular mechanism of neutralization by H5.3, a vaccine-elicited antibody that neutralizes hemagglutinin 5 viruses and variants with expanded host range. H5.3 binds in the receptor-binding site, forming contacts that recapitulate many of the sialic acid interactions, as well as multiple peripheral interactions, yet is not sensitive to mutations that alter sialic acid binding. H5.3 is highly specific for a subset of H5 strains, and this specificity arises from interactions to the periphery of the receptor-binding site. Finally, H5.3 is also extremely potent, despite retaining germ line-like conformational flexibility.

  7. Vaccine-elicited antibody that neutralizes H5N1 influenza and variants binds the receptor site and polymorphic sites

    PubMed Central

    Winarski, Katie L.; Thornburg, Natalie J.; Yu, Yingchun; Sapparapu, Gopal; Crowe, James. E.; Spiller, Benjamin W.

    2015-01-01

    Antigenic drift of circulating seasonal influenza viruses necessitates an international vaccine effort to reduce the impact on human health. A critical feature of the seasonal vaccine is that it stimulates an already primed immune system to diversify memory B cells to recognize closely related, but antigenically distinct, influenza glycoproteins (hemagglutinins). Influenza pandemics arise when hemagglutinins to which no preexisting adaptive immunity exists acquire the capacity to infect humans. Hemagglutinin 5 is one subtype to which little preexisting immunity exists and is only a few acquired mutations away from the ability to transmit efficiently between ferrets, and possibly humans. Here, we describe the structure and molecular mechanism of neutralization by H5.3, a vaccine-elicited antibody that neutralizes hemagglutinin 5 viruses and variants with expanded host range. H5.3 binds in the receptor-binding site, forming contacts that recapitulate many of the sialic acid interactions, as well as multiple peripheral interactions, yet is not sensitive to mutations that alter sialic acid binding. H5.3 is highly specific for a subset of H5 strains, and this specificity arises from interactions to the periphery of the receptor-binding site. H5.3 is also extremely potent, despite retaining germ line-like conformational flexibility. PMID:26170302

  8. Verotoxins in Bovine and Meat Verotoxin-Producing Escherichia coli Isolates: Type, Number of Variants, and Relationship to Cytotoxicity▿

    PubMed Central

    Krüger, Alejandra; Lucchesi, Paula M. A.; Parma, Alberto E.

    2011-01-01

    In this study, we determined vt subtypes and evaluated verotoxicity in basal as well as induced conditions of verotoxin-producing Escherichia coli (VTEC) strains isolated from cattle and meat products. Most (87%) of the 186 isolates carried a vt2 gene. Moreover, the vt2 subtype, which is associated with serious disease, was present in 42% of our VTEC collection. The other vt subtypes detected were vt1, vt1d, vt2vha, vt2vhb, vt2O118, vt2d (mucus activatable), and vt2g. A total of 41 (22%) of the isolates possessed more than one vt subtype in its genome, and among them the most frequent combination was vt1/vt2, but we also observed multiple combinations among vt2 subtypes. Differences in verotoxicity titers were found among a selection of 54 isolates. Among isolates with a single vt2 variant, those carrying the vt2 subtype had high titers under both uninduced and induced conditions. However, the highest increase in cytotoxicity under mitomycin C treatment was detected among the strains carrying vt2vha or vt2hb variants. Notably, the isolates carrying the vt1 subtype showed a lesser increase than that of most of the vt2-positive VTEC strains. Furthermore, the presence of more than one vt gene variant in the same isolate was not reflected in higher titers, and generally the titers were lower than those for strains with only one gene variant. The main observation was that both basal and induced cytotoxic effects seemed to be associated with the type and number of vt variants more than with the serotype or origin of the isolate. PMID:21037301

  9. Development and Characterization of Recombinant Antibody Fragments That Recognize and Neutralize In Vitro Stx2 Toxin from Shiga Toxin-Producing Escherichia coli

    PubMed Central

    Luz, Daniela; Chen, Gang; Maranhão, Andrea Q.; Rocha, Leticia B.; Sidhu, Sachdev; Piazza, Roxane M. F.

    2015-01-01

    Background Stx toxin is a member of the AB5 family of bacterial toxins: the active A subunit has N-glycosidase activity against 28S rRNA, resulting in inhibition of protein synthesis in eukaryotic cells, and the pentamer ligand B subunits (StxB) bind to globotria(tetra)osylceramide receptors (Gb3/Gb4) on the cell membrane. Shiga toxin-producing Escherichia coli strains (STEC) may produce Stx1 and/or Stx2 and variants. Strains carrying Stx2 are considered more virulent and related to the majority of outbreaks, besides being usually associated with hemolytic uremic syndrome in humans. The development of tools for the detection and/or neutralization of these toxins is a turning point for early diagnosis and therapeutics. Antibodies are an excellent paradigm for the design of high-affinity, protein-based binding reagents used for these purposes. Methods and Findings In this work, we developed two recombinant antibodies; scFv fragments from mouse hybridomas and Fab fragments by phage display technology using a human synthetic antibody library. Both fragments showed high binding affinity to Stx2, and they were able to bind specifically to the GKIEFSKYNEDDTF region of the Stx2 B subunit and to neutralize in vitro the cytotoxicity of the toxin up to 80%. Furthermore, the scFv fragments showed 79% sensitivity and 100% specificity in detecting STEC strains by ELISA. Conclusion In this work, we developed and characterized two recombinant antibodies against Stx2, as promising tools to be used in diagnosis or therapeutic approaches against STEC, and for the first time, we showed a human monovalent molecule, produced in bacteria, able to neutralize the cytotoxicity of Stx2 in vitro. PMID:25790467

  10. New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum.

    PubMed

    Skinner, Craig; Patfield, Stephanie; Khalil, Rowaida; Kong, Qiulian; He, Xiaohua

    2016-01-01

    Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently discovered in

  11. New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum

    PubMed Central

    Skinner, Craig; Patfield, Stephanie; Khalil, Rowaida; Kong, Qiulian

    2016-01-01

    ABSTRACT Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently

  12. Repair of 254 nm ultraviolet-induced (6-4) photoproducts: monoclonal antibody recognition and differential defects in xeroderma pigmentosum complementation groups A, D, and variant

    SciTech Connect

    Hiramoto, T.; Matsunaga, T.; Ichihashi, M.; Nikaido, O.; Fujiwara, Y.; Mishima, Y. )

    1989-11-01

    Repair kinetics of ultraviolet (UV) light-induced (6-4) photoproducts in xeroderma pigmentosum complementation group A, D, and variant cells were studied by the enzyme-linked immunosorbent assay (ELISA) using a specific monoclonal antibody raised against (6-4) photoproducts, together with unscheduled DNA synthesis (UDS) and loss of T4 endonuclease V-susceptible sites (ESS). Group AXP35KO cells completely failed to repair both ESS (cyclobutane pyrimidine dimers) and antibody-recognizing (6-4) photoproducts until tested 24 h after irradiation, and had 2% early-time UDS. Group DXP43KO cells showed about 10% removal of both (6-4) photoproducts and ESS in 24 h, despite showing a residually higher level of 40% early-time and cumulative UDS. Thus, the results substantiated the extreme UV hypersensitivity of XP group A and D cells. However, XP52KO variant cells exhibited the normal level of UDS and ESS loss, but a slightly reduced repair of antibody-recognizing (6-4) photoproducts at 6 and 12 h after irradiation, which may account for a small UV hypersensitivity of the XP variant cells.

  13. Risk of squamous cell skin cancer after organ transplant associated with antibodies to cutaneous papillomaviruses, polyomaviruses, and TMC6/8 (EVER1/2) variants.

    PubMed

    Madeleine, Margaret M; Carter, Joseph J; Johnson, Lisa G; Wipf, Gregory C; Davis, Connie; Berg, Daniel; Nelson, Karen; Daling, Janet R; Schwartz, Stephen M; Galloway, Denise A

    2014-10-01

    Squamous cell skin cancer (SCSC) disproportionately affects organ transplant recipients, and may be related to increased viral replication in the setting of immune suppression. We conducted a nested case-control study among transplant recipients to determine whether SCSC is associated with antibodies to cutaneous human papillomaviruses (HPV), to genes associated with a rare genetic susceptibility to HPV (TMC6/TMC8), or to human polyomaviruses (HPyV). Cases (n = 149) had histologically confirmed SCSC, and controls (n = 290) were individually matched to cases on time since transplant, type of transplant, gender, and race. All subjects had serum drawn immediately prior to transplant surgery. Antibodies to 25 cutaneous HPVs and six HPyVs were assayed by detection of binding to virus-like particles, and 11 TMC6/8 variants were genotyped. After correction for multiple comparisons, only antibodies to HPV37 were associated with SCSC (OR 2.0, 95% CI 1.2-3.4). Common genetic variants of TMC6/8 were not associated with SCSC, but three variants in TMC8 (rs12452890, rs412611, and rs7208422) were associated with greater seropositivity for species 2 betapapillomaviruses among controls. This study suggests that some betaHPVs, but not polyomaviruses, may play a role in the excess risk of SCSC among transplant recipients.

  14. [Importance of the conjugated antibody for the induction of selective effect of adriamycin conjugated with anti AFP monoclonal antibody and entrapped in liposomes against AFP producing tumors].

    PubMed

    Konno, H; Kumai, K; Tsubouchi, T; Ishibiki, K; Abe, O; Tadakuma, T; Yasuda, T; Nagaike, K; Hosokawa, S; Sakaguchi, S

    1989-06-01

    We investigated experimentally the effect of adriamycin (ADM) conjugated with anti alpha-fetoprotein (AFP) monoclonal antibodies and entrapped in liposomes (Lip-ADM = AbAFP) in vitro or in vivo. In the present study, we examined the importance of the conjugated antibody for the induction of selective therapeutic effect of Lip-ADM = AbAFP against AFP producing tumors. As the target tumors, AFP producing human hepatoma strain, Li-7, and AFP non-producing human breast cancer strain, MX-1 maintained in BALB/c nu/nu male mice were used. In order to evaluate the importance of the conjugated antibody, we prepared also ADM conjugated with normal mouse IgG, and entrapped in liposomes Lip-ADM = NIgG, of which therapeutic effects were compared with that of Lip-ADM = AbAFP. Judging from the tumor growth curve and the tumor weight, the therapeutic effect of Lip-ADM = AbAFP was greater against Li-7 than that of Lip-ADM = NIgG. On the other hand, both conjugates showed similar effects against MX-1. As the results it is suggested that the antibody which recognizes the antigen expressed on the target tumor cells can solely increase the therapeutic effect of ADM entrapped in liposomes (Lip-ADM) and that the main factors which contribute to the efficient therapeutic effect of the conjugate were the sensitibility to ADM, the affinity of the tumor cells to liposomes and the superiority of the conjugated antibody.

  15. Novel Exons and Splice Variants in the Human Antibody Heavy Chain Identified by Single Cell and Single Molecule Sequencing

    PubMed Central

    Vollmers, Christopher; Penland, Lolita; Kanbar, Jad N.; Quake, Stephen R.

    2015-01-01

    Antibody heavy chains contain a variable and a constant region. The constant region of the antibody heavy chain is encoded by multiple groups of exons which define the isotype and therefore many functional characteristics of the antibody. We performed both single B cell RNAseq and long read single molecule sequencing of antibody heavy chain transcripts and were able to identify novel exons for IGHA1 and IGHA2 as well as novel isoforms for IGHM antibody heavy chain. PMID:25611855

  16. Characterization of anti-CD20 monoclonal antibody produced by transgenic silkworms (Bombyx mori).

    PubMed

    Tada, Minoru; Tatematsu, Ken-ichiro; Ishii-Watabe, Akiko; Harazono, Akira; Takakura, Daisuke; Hashii, Noritaka; Sezutsu, Hideki; Kawasaki, Nana

    2015-01-01

    In response to the successful use of monoclonal antibodies (mAbs) in the treatment of various diseases, systems for expressing recombinant mAbs using transgenic animals or plants have been widely developed. The silkworm (Bombyx mori) is a highly domesticated insect that has recently been used for the production of recombinant proteins. Because of their cost-effective breeding and relatively easy production scale-up, transgenic silkworms show great promise as a novel production system for mAbs. In this study, we established a transgenic silkworm stably expressing a human-mouse chimeric anti-CD20 mAb having the same amino acid sequence as rituximab, and compared its characteristics with rituximab produced by Chinese hamster ovary (CHO) cells (MabThera®). The anti-CD20 mAb produced in the transgenic silkworm showed a similar antigen-binding property, but stronger antibody-dependent cell-mediated cytotoxicity (ADCC) and weaker complement-dependent cytotoxicity (CDC) compared to MabThera. Post-translational modification analysis was performed by peptide mapping using liquid chromatography/mass spectrometry. There was a significant difference in the N-glycosylation profile between the CHO- and the silkworm-derived mAbs, but not in other post-translational modifications including oxidation and deamidation. The mass spectra of the N-glycosylated peptide revealed that the observed biological properties were attributable to the characteristic N-glycan structures of the anti-CD20 mAbs produced in the transgenic silkworms, i.e., the lack of the core-fucose and galactose at the non-reducing terminal. These results suggest that the transgenic silkworm may be a promising expression system for the tumor-targeting mAbs with higher ADCC activity.

  17. Identification and characterization of a truncated variant of the 5-hydroxytryptamine(2A) receptor produced by alternative splicing.

    PubMed

    Guest, P C; Salim, K; Skynner, H A; George, S E; Bresnick, J N; McAllister, G

    2000-09-08

    We have identified an alternatively spliced 5-hydroxytryptamine 2A receptor (5-HT(2A)-R) transcript by PCR of human brain cDNA using degenerate oligonucleotide primers to transmembrane (TM) domains 3 and 7 of the 5-HT(2)-R subfamily. The variant contains a 118-bp insertion at the exon II/III boundary of the 5-HT(2A)-R, which produces a frame shift in the coding sequence and a premature stop codon. PCR analysis showed that the truncated receptor (5-HT(2A-tr)) and native 5-HT(2A)-R were co-expressed in most brain tissues, with the highest levels being found in hippocampus, corpus collosum, amygdala and caudate nucleus. Western blot analysis of HEK-293 cells transfected transiently with a 5-HT(2A-tr) construct showed that a 30-kDa protein was expressed on cell membranes. Co-transfection studies showed no effect of the 5-HT(2A-tr) variant on 3H-ketanserin binding to the native 5-HT(2A)-R or on functional coupling of the 5-HT(2A)-R to 5-HT-stimulated Ca(2+) mobilization. The functional significance of the 5-HT(2A-tr) variant and other truncated receptors remains to be established.

  18. Metabolic analysis of antibody producing Chinese hamster ovary cell culture under different stresses conditions.

    PubMed

    Badsha, Md Bahadur; Kurata, Hiroyuki; Onitsuka, Masayoshi; Oga, Takushi; Omasa, Takeshi

    2016-07-01

    Chinese hamster ovary (CHO) cells are commonly used as the host cell lines concerning their ability to produce therapeutic proteins with complex post-translational modifications. In this study, we have investigated the time course extra- and intracellular metabolome data of the CHO-K1 cell line, under a control and stress conditions. The addition of NaCl and trehalose greatly suppressed cell growth, where the maximum viable cell density of NaCl and trehalose cultures were 2.2-fold and 2.8-fold less than that of a control culture. Contrariwise, the antibody production of both the NaCl and trehalose cultures was sustained for a longer time to surpass that of the control culture. The NaCl and trehalose cultures showed relatively similar dynamics of cell growth, antibody production, and substrate/product concentrations, while they indicated different dynamics from the control culture. The principal component analysis of extra- and intracellular metabolome dynamics indicated that their dynamic behaviors were consistent with biological functions. The qualitative pattern matching classification and hierarchical clustering analyses for the intracellular metabolome identified the metabolite clusters whose dynamic behaviors depend on NaCl and trehalose. The volcano plot revealed several reporter metabolites whose dynamics greatly change between in the NaCl and trehalose cultures. The elastic net identified some critical, intracellular metabolites that are distinct between the NaCl and trehalose. While a relatively small number of intracellular metabolites related to the cell growth, glucose, glutamine, lactate and ammonium ion concentrations, the mechanism of antibody production was suggested to be very complicated or not to be explained by elastic net regression analysis.

  19. CHO-gmt5, a novel CHO glycosylation mutant for producing afucosylated and asialylated recombinant antibodies.

    PubMed

    Haryadi, Ryan; Zhang, Peiqing; Chan, Kah Fai; Song, Zhiwei

    2013-01-01

    Engineered zinc-finger nucleases (ZFNs) are powerful tools for creating double-stranded-breaks (DSBs) in genomic DNA in a site-specific manner. These DSBs generated by ZFNs can be repaired by homology-directed repair or nonhomologous end joining, in which the latter can be exploited to generate insertion or deletion mutants. Based on published literature, we designed a pair of zinc-finger nucleases and inactivated the GDP-fucose transporter gene (Slc35c1) in a previously reported CHO mutant that has a dysfunctional CMP-sialic acid transporter gene (Slc35a1). The resulting mutant cell line, CHO-gmt5, lacks functional GDP-fucose transporter and CMP-sialic acid transporter. As a result, these cells can only produce asialylated and afucosylated glycoproteins. It is now widely recognized that removal of the core fucose from the N-glycans attached to Asn(297) of human IgG1 significantly enhances its binding to its receptor, FcγRIIIa, and thereby dramatically improves antibody-dependent cellular cytotoxicity (ADCC). Recent reports showed that removal of sialic acid from IgG1 also enhances ADCC. Therefore, CHO-gmt5 may represent a more advantageous cell line for the production of recombinant antibodies with enhanced ADCC. These cells show comparable growth rate to wild type CHO-K1 cells and uncompromised transfection efficiency, which make them desirable for use as a production line.

  20. DARPA Antibody Technology Program. Standardized Test Bed for Antibody Characterization: Characterization of an MS2 ScFv Antibody Produced by Illumina

    DTIC Science & Technology

    2016-08-01

    interactions. The Joint Product Management Office for Biosurveillance (JPMO BSV) Critical Reagents Program has recently instituted a quality program...provision of consistent, high- quality assays and reagents for current biodetection platforms as well as the development and validation of future systems...platforms. 15. SUBJECT TERMS Antibody Antibody Technology Program (ATP) Quality Enzyme-linked immunosorbent assay (ELISA) Biosurveillance Single-chain

  1. Hypoallergenic Variant of the Major Egg White Allergen Gal d 1 Produced by Disruption of Cysteine Bridges

    PubMed Central

    Dhanapala, Pathum; Withanage-Dona, Dulashi; Tang, Mimi L. K.; Doran, Tim; Suphioglu, Cenk

    2017-01-01

    Background: Gal d 1 (ovomucoid) is the dominant allergen in the chicken egg white. Hypoallergenic variants of this allergen can be used in immunotherapy as an egg allergy treatment approach. We hypothesised that disruption of two of the nine cysteine-cysteine bridges by site-directed mutagenesis will allow the production of a hypoallergenic variant of the protein; Methods: Two cysteine residues at C192 and C210 in domain III of the protein were mutated to alanine using site-directed mutagenesis, to disrupt two separate cysteine-cysteine bridges. The mutated and non-mutated proteins were expressed in Escherichia coli (E. coli) by induction with isopropyl β-d-1-thiogalactopyranoside (IPTG). The expressed proteins were analysed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting to confirm expression. Immunoglobulin E (IgE) reactivity of the two proteins was analysed, by immunoblotting, against a pool of egg-allergic patients’ sera. A pool of non-allergic patients’ sera was also used in a separate blot as a negative control; Results: Mutant Gal d 1 showed diminished IgE reactivity in the immunoblot by showing lighter bands when compared to the non-mutated version, although there was more of the mutant protein immobilised on the membrane when compared to the wild-type protein. The non-allergic negative control showed no bands, indicating an absence of non-specific binding of secondary antibody to the proteins; Conclusion: Disruption of two cysteine bridges in domain III of Gal d 1 reduces IgE reactivity. Following downstream laboratory and clinical testing, this mutant protein can be used in immunotherapy to induce tolerance to Gal d 1 and in egg allergy diagnosis. PMID:28230769

  2. Neonatal antibody responses are attenuated by interferon-γ produced by NK and T cells during RSV infection.

    PubMed

    Tregoning, John S; Wang, Belinda Lei; McDonald, Jacqueline U; Yamaguchi, Yuko; Harker, James A; Goritzka, Michelle; Johansson, Cecilia; Bukreyev, Alexander; Collins, Peter L; Openshaw, Peter J

    2013-04-02

    Respiratory syncytial virus (RSV) infects most children in the first year of life and is a major single cause of hospitalization in infants and young children. There is no effective vaccine, and antibody generated by primary neonatal infection is poorly protective against reinfection even with antigenically homologous viral strains. Studying the immunological basis of these observations in neonatal mice, we found that antibody responses to infection were low and unaffected by CD4 depletion, in contrast with adult mice, which had stronger CD4-dependent antibody responses. Natural killer cell depletion or codepletion of CD4(+) and CD8(+) cells during neonatal RSV infection caused a striking increase in anti-RSV antibody titer. These cells are major sources of the cytokine IFN-γ, and blocking IFN-γ also enhanced RSV-specific antibody responses in neonates. In addition, infection with a recombinant RSV engineered to produce IFN-γ reduced antibody titer, confirming that IFN-γ plays a pivotal role in inhibition of antibody responses after neonatal infection. These unexpected findings show that the induction of a strong cellular immune response may limit antibody responses in early life and that vaccines that induce IFN-γ-secreting cells might, in some situations, be less protective than those that do not.

  3. Neonatal antibody responses are attenuated by interferon-γ produced by NK and T cells during RSV infection

    PubMed Central

    Tregoning, John S.; Wang, Belinda Lei; McDonald, Jacqueline U.; Yamaguchi, Yuko; Harker, James A.; Goritzka, Michelle; Johansson, Cecilia; Bukreyev, Alexander; Collins, Peter L.; Openshaw, Peter J.

    2013-01-01

    Respiratory syncytial virus (RSV) infects most children in the first year of life and is a major single cause of hospitalization in infants and young children. There is no effective vaccine, and antibody generated by primary neonatal infection is poorly protective against reinfection even with antigenically homologous viral strains. Studying the immunological basis of these observations in neonatal mice, we found that antibody responses to infection were low and unaffected by CD4 depletion, in contrast with adult mice, which had stronger CD4-dependent antibody responses. Natural killer cell depletion or codepletion of CD4+ and CD8+ cells during neonatal RSV infection caused a striking increase in anti-RSV antibody titer. These cells are major sources of the cytokine IFN-γ, and blocking IFN-γ also enhanced RSV-specific antibody responses in neonates. In addition, infection with a recombinant RSV engineered to produce IFN-γ reduced antibody titer, confirming that IFN-γ plays a pivotal role in inhibition of antibody responses after neonatal infection. These unexpected findings show that the induction of a strong cellular immune response may limit antibody responses in early life and that vaccines that induce IFN-γ–secreting cells might, in some situations, be less protective than those that do not. PMID:23509276

  4. Anti-Lipid IgG Antibodies Are Produced via Germinal Centers in a Murine Model Resembling Human Lupus

    PubMed Central

    Wong-Baeza, Carlos; Reséndiz-Mora, Albany; Donis-Maturano, Luis; Wong-Baeza, Isabel; Zárate-Neira, Luz; Yam-Puc, Juan Carlos; Calderón-Amador, Juana; Medina, Yolanda; Wong, Carlos; Baeza, Isabel; Flores-Romo, Leopoldo

    2016-01-01

    Anti-lipid IgG antibodies are produced in some mycobacterial infections and in certain autoimmune diseases [such as anti-phospholipid syndrome, systemic lupus erythematosus (SLE)]. However, few studies have addressed the B cell responses underlying the production of these immunoglobulins. Anti-lipid IgG antibodies are consistently found in a murine model resembling human lupus induced by chlorpromazine-stabilized non-bilayer phospholipid arrangements (NPA). NPA are transitory lipid associations found in the membranes of most cells; when NPA are stabilized they can become immunogenic and induce specific IgG antibodies, which appear to be involved in the development of the mouse model of lupus. Of note, anti-NPA antibodies are also detected in patients with SLE and leprosy. We used this model of lupus to investigate in vivo the cellular mechanisms that lead to the production of anti-lipid, class-switched IgG antibodies. In this murine lupus model, we found plasma cells (Gr1−, CD19−, CD138+) producing NPA-specific IgGs in the draining lymph nodes, the spleen, and the bone marrow. We also found a significant number of germinal center B cells (IgD−, CD19+, PNA+) specific for NPA in the draining lymph nodes and the spleen, and we identified in situ the presence of NPA in these germinal centers. By contrast, very few NPA-specific, extrafollicular reaction B cells (B220+, Blimp1+) were found. Moreover, when assessing the anti-NPA IgG antibodies produced during the experimental protocol, we found that the affinity of these antibodies progressively increased over time. Altogether, our data indicate that, in this murine model resembling human lupus, B cells produce anti-NPA IgG antibodies mainly via germinal centers. PMID:27746783

  5. Production of different glycosylation variants of the tumour-targeting mAb H10 in Nicotiana benthamiana: influence on expression yield and antibody degradation.

    PubMed

    Lombardi, Raffaele; Donini, Marcello; Villani, Maria Elena; Brunetti, Patrizia; Fujiyama, Kazuhito; Kajiura, Hiroyuki; Paul, Matthew; Ma, Julian K-C; Benvenuto, Eugenio

    2012-10-01

    We previously described the expression of a tumour-targeting antibody (mAb H10) in Nicotiana benthamiana by vacuum-agro-infiltration and the remarkable yields of highly pure protein achieved. The objective of the present work was to investigate different strategies for transient overexpression of the mAb H10 in which glycan configuration was modulated and assess how these strategies affect the accumulation yield and stability of the antibody. To this aim, three procedures have been assayed: (1) Site-directed mutagenesis to abolish the glycosylation site; (2) endoplasmic reticulum retention (C-terminal SEKDEL fusion) to ensure predominantly high-mannose type glycans; and (3) expression in a N. benthamiana RNAi down-regulated line in which β1,2-xylosyltransferase and α1,3-fucosyltransferase gene expression is silenced. The three antibody variants (H10-Mut) (H10-SEKDEL) (H10(XylT/FucT)) were transiently expressed, purified and characterised for their glycosylation profile, expression/purification yield and antibody degradation pattern. Glycosylation analysis of H10(XylT/FucT) demonstrated the absence of plant complex-type sugars, while H10-SEKDEL, although substantially retained in the ER, revealed the presence of β1,2-xylose and α1,3-fucose residues, indicating a partial escape from the ER retrieval system. Antibody accumulation and purification yields were not enhanced by ER retention. All H10 antibody glyco-forms revealed greater degradation compared to the original, resulting mostly in the formation of Fab fragments. In the case of aglycosylated H10-Mut, more than 95% of the heavy chain was cleaved, confirming the pivotal role of the sugar moiety in protein stability. Identification of possible 'fragile' sites in the H10 antibody hinge region could be of general interest for the development of new strategies to reduce antibody degradation and increase the yield of intact IgGs in plants.

  6. Campylobacter hyointestinalis Isolated from Pigs Produces Multiple Variants of Biologically Active Cytolethal Distending Toxin

    PubMed Central

    Kamei, Kazumasa; Hatanaka, Noritoshi; Asakura, Masahiro; Somroop, Srinuan; Samosornsuk, Worada; Hinenoya, Atsushi; Misawa, Naoaki; Nakagawa, Shinsaku

    2015-01-01

    Campylobacter hyointestinalis isolated from swine with proliferative enteritis often is considered to be pathogenic. While the precise virulence mechanisms of this species remain unclear, we have recently identified a cytolethal distending toxin (cdt) gene cluster in C. hyointestinalis isolated from a patient with diarrhea (W. Samosornsuk et al., J Med Microbiol, 27 July 2015, http://dx.doi.org/10.1099/jmm.0.000145). However, the sequences of the cdt genes in C. hyointestinalis were found to be significantly different and the gene products are immunologically distinct from those of other Campylobacter species. In this study, we demonstrate the presence of a second variant of the cdt gene cluster in C. hyointestinalis, designated cdt-II, while the former is named cdt-I. Sequencing of the cdt-II gene cluster and deduced amino acid sequences revealed that homologies between the subunits CdtA, CdtB, and CdtC of ChCDT-I and ChCDT-II are 25.0, 56.0, and 24.8%, respectively. Furthermore, the CdtB subunit of ChCDT-II was found to be immunologically unrelated to that of ChCDT-I by Ouchterlony double gel diffusion test. Recombinant ChCDT-II also induced cell distention and death of HeLa cells by blocking the cell cycle at G2/M phase. Interestingly, the cdt-II genes were detected in all 23 animal isolates and in 1 human isolate of C. hyointestinalis, and 21 of these strains carried both cdt-I and cdt-II gene clusters. Altogether, our results indicate that ChCDT-II is an important virulence factor of C. hyointestinalis in animals. PMID:26283337

  7. Understanding Transcriptional Enhancement in Monoclonal Antibody-Producing Chinese Hamster Ovary Cells

    NASA Astrophysics Data System (ADS)

    Nicoletti, Sarah E.

    With the demand for monoclonal antibody (mAB) therapeutics continually increasing, the need to better understand what makes a high productivity clone has gained substantial interest. Monoclonal antibody producing Chinese hamster ovary (CHO) cells with different productivities were provided by a biopharmaceutical company for investigation. Gene copy numbers, mRNA levels, and mAb productivities were previously determined for two low producing clones and their amplified progeny. These results showed an increase in mRNA copy number in amplified clones, which correlated to the observed increases in specific productivity of these clones. The presence of multiple copies of mRNA per one copy of DNA in the higher productivity clones has been coined as transcriptional enhancement. The methylation status of the CMV promoter as well as transcription factor/promoter interactions were evaluated to determine the cause of transcriptional enhancement. Methylation analysis via bisulfite sequencing revealed no significant difference in overall methylation status of the CMV promoter. These data did, however, reveal the possibility of differential interactions of transcription factors between the high and low productivity cell clones. This finding was further supported by chromatin immunoprecipitations previously performed in the lab, as well as literature studies. Transcription activator-like effector (TALE) binding proteins were constructed and utilized to selectively immunoprecipitate the CMV promoter along with its associated transcription factors in the different CHO cell clones. Cells were transfected with the TALE proteins, harvested and subjected to a ChIP-like procedure. Results obtained from the TALE ChIP demonstrated the lack of binding of the protein to the promoter and the need to redesign the TALE. Overall, results obtained from this study were unable to give a clear indication as to the causes of transcriptional enhancement in the amplified CHO cell clones. Further

  8. [A case of pharyngeal-cervical-brachial variant of Guillain-Barré syndrome with positive anti-galactocerebroside (Gal-C) IgM antibody].

    PubMed

    Kasuya, J; Miyazono, T; Takenaga, S; Arimura, K; Osame, M; Kusunoki, S

    1999-05-01

    A 49-year-old man presented with hoarseness, dysphagia, muscle atrophy and weakness of deltoid, trapezius, sternocleidomastoid, rhomboid, anterior serratus, infraspinatus and supraspinatus. Anti-Gal-C IgM antibody was positive in the serum. The other antiganglioside antibodies (GM1, GM2, GM3, GD1a, GD1b, GD3, GT1a, GT1b, GQ1b, GA1, GalNAc-GD1a, GM1b) were negative. Patient contracted pneumonia but whether it was due to mycoplasma was not evident. Plasmapheresis improved his clinical state including a decrease of the antibody. This case was diagnosed pharyngeal-cervical-brachial variant of Guillain-Barré syndrome, and anti-Gal-C antibody seemed to be correlated with the pathogenesis of this syndrome. Gal-C is a major glycolipid of myelin and the cell membrane of the myelin-forming cell (oligodendrocytes and Schwann cells) and is free of specific localization and distribution. The mechanism how the anti-Gal-C IgM antibody induced bulbar paralysis and the symptoms localizing neck and upper limbs remains to be known.

  9. Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum.

    PubMed

    Carey, Anne-Marie; Hacking, Kirsty; Picken, Nichola; Honkanen, Suvi; Kelly, Sharon; Niedzwiedzki, Dariusz M; Blankenship, Robert E; Shimizu, Yuuki; Wang-Otomo, Zheng-Yu; Cogdell, Richard J

    2014-11-01

    This study systematically investigated the different types of LH2 produced by Allochromatium (Alc.) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and B800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both α and β polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila.

  10. Nisin H Is a New Nisin Variant Produced by the Gut-Derived Strain Streptococcus hyointestinalis DPC6484

    PubMed Central

    O'Connor, Paula M.; O'Shea, Eileen F.; Guinane, Caitriona M.; O'Sullivan, Orla; Cotter, Paul D.; Hill, Colin

    2015-01-01

    Accumulating evidence suggests that bacteriocin production represents a probiotic trait for intestinal strains to promote dominance, fight infection, and even signal the immune system. In this respect, in a previous study, we isolated from the porcine intestine a strain of Streptococcus hyointestinalis DPC6484 that displays antimicrobial activity against a wide range of Gram-positive bacteria and produces a bacteriocin with a mass of 3,453 Da. Interestingly, the strain was also found to be immune to a nisin-producing strain. Genome sequencing revealed the genetic determinants responsible for a novel version of nisin, designated nisin H, consisting of the nshABTCPRKGEF genes, with transposases encoded between nshP and nshR and between nshK and nshG. A similar gene cluster is also found in S. hyointestinalis LMG14581. Notably, the cluster lacks an equivalent of the nisin immunity gene, nisI. Nisin H is proposed to have the same structure as the prototypical nisin A but differs at 5 amino acid positions—Ile1Phe (i.e., at position 1, nisin A has Ile while nisin H has Phe), Leu6Met, Gly18Dhb (threonine dehydrated to dehydrobutyrine), Met21Tyr, and His31Lys—-and appears to represent an intermediate between the lactococcal nisin A and the streptococcal nisin U variant of nisin. Purified nisin H inhibits a wide range of Gram-positive bacteria, including staphylococci, streptococci, Listeria spp., bacilli, and enterococci. It represents the first example of a natural nisin variant produced by an intestinal isolate of streptococcal origin. PMID:25841003

  11. Biochemical Characterization of Human Anti-Hepatitis B Monoclonal Antibody Produced in the Microalgae Phaeodactylum tricornutum

    PubMed Central

    Vanier, Gaëtan; Hempel, Franziska; Chan, Philippe; Rodamer, Michael; Vaudry, David; Maier, Uwe G.; Lerouge, Patrice; Bardor, Muriel

    2015-01-01

    Monoclonal antibodies (mAbs) represent actually the major class of biopharmaceuticals. They are produced recombinantly using living cells as biofactories. Among the different expression systems currently available, microalgae represent an emerging alternative which displays several biotechnological advantages. Indeed, microalgae are classified as generally recognized as safe organisms and can be grown easily in bioreactors with high growth rates similarly to CHO cells. Moreover, microalgae exhibit a phototrophic lifestyle involving low production costs as protein expression is fueled by photosynthesis. However, questions remain to be solved before any industrial production of algae-made biopharmaceuticals. Among them, protein heterogeneity as well as protein post-translational modifications need to be evaluated. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals including mAbs are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. In this paper, we assess the quality of the first recombinant algae-made mAbs produced in the diatom, Phaeodactylum tricornutum. We are focusing on the characterization of their C- and N-terminal extremities, their signal peptide cleavage and their post-translational modifications including N-glycosylation macro- and microheterogeneity. This study brings understanding on diatom cellular biology, especially secretion and intracellular trafficking of proteins. Overall, it reinforces the positioning of P. tricornutum as an emerging host for the production of biopharmaceuticals and prove that P. tricornutum is suitable for producing recombinant proteins bearing high mannose-type N-glycans. PMID:26437211

  12. Biochemical Characterization of Human Anti-Hepatitis B Monoclonal Antibody Produced in the Microalgae Phaeodactylum tricornutum.

    PubMed

    Vanier, Gaëtan; Hempel, Franziska; Chan, Philippe; Rodamer, Michael; Vaudry, David; Maier, Uwe G; Lerouge, Patrice; Bardor, Muriel

    2015-01-01

    Monoclonal antibodies (mAbs) represent actually the major class of biopharmaceuticals. They are produced recombinantly using living cells as biofactories. Among the different expression systems currently available, microalgae represent an emerging alternative which displays several biotechnological advantages. Indeed, microalgae are classified as generally recognized as safe organisms and can be grown easily in bioreactors with high growth rates similarly to CHO cells. Moreover, microalgae exhibit a phototrophic lifestyle involving low production costs as protein expression is fueled by photosynthesis. However, questions remain to be solved before any industrial production of algae-made biopharmaceuticals. Among them, protein heterogeneity as well as protein post-translational modifications need to be evaluated. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals including mAbs are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. In this paper, we assess the quality of the first recombinant algae-made mAbs produced in the diatom, Phaeodactylum tricornutum. We are focusing on the characterization of their C- and N-terminal extremities, their signal peptide cleavage and their post-translational modifications including N-glycosylation macro- and microheterogeneity. This study brings understanding on diatom cellular biology, especially secretion and intracellular trafficking of proteins. Overall, it reinforces the positioning of P. tricornutum as an emerging host for the production of biopharmaceuticals and prove that P. tricornutum is suitable for producing recombinant proteins bearing high mannose-type N-glycans.

  13. Myeloperoxidase-antineutrophil Cytoplasmic Antibodies with Cytoplasmic Fluorescence Pattern.

    PubMed

    Chhabra, Seema; Minz, Ranjana Walker; Goyal, Lekha; Sharma, Nidhi

    2010-01-01

    We report here two rare cases of myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-positive Wegener's granulomatosis (limited variant) which deceptively produced a cytoplasmic (C-ANCA) pattern on indirect immunofluorescence.

  14. Effect of the Anti-C1s Humanized Antibody TNT009 and its Parental Mouse Variant TNT003 on HLA Antibody-induced Complement Activation - A Preclinical in Vitro Study.

    PubMed

    Wahrmann, M; Mühlbacher, J; Marinova, L; Regele, H; Huttary, N; Eskandary, F; Cohen, G; Fischer, G F; Parry, Graham C; Gilbert, J C; Panicker, S; Böhmig, G A

    2017-03-01

    The classical pathway (CP) of complement is believed to significantly contribute to alloantibody-mediated transplant injury, and targeted complement inhibition is currently considered to be a promising approach for preventing rejection. Here, we investigated the mode of action and efficacy of the humanized anti-C1s monoclonal antibody TNT009 and its parental mouse variant, TNT003, in preclinical in vitro models of HLA antibody-triggered CP activation. In flow cytometric assays, we measured the attachment of C1 subcomponents and C4/C3 split products (C4b/d, C3b/d) to HLA antigen-coated flow beads or HLA-mismatched aortic endothelial cells and splenic lymphocytes. Anti-C1s antibodies profoundly inhibited C3 activation at concentrations >20 μg/ml, both in solid phase and cellular assays. While C4 activation was also prevented, this was not the case for C1 subcomponent attachment. Analysis of serum samples obtained from 68 sensitized transplant candidates revealed that the potency of inhibition was related to the extent of baseline CP activation. This study demonstrates that anti-C1s antibodies TNT009 and TNT003 are highly effective in blocking HLA antibody-triggered complement activation downstream of C1. Our results provide the foundation for clinical studies designed to investigate the potential of TNT009 in the treatment or prevention of complement-mediated tissue injury in sensitized transplant recipients. This article is protected by copyright. All rights reserved.

  15. Characterization of Alpha-Toxin hla Gene Variants, Alpha-Toxin Expression Levels, and Levels of Antibody to Alpha-Toxin in Hemodialysis and Postsurgical Patients with Staphylococcus aureus Bacteremia

    PubMed Central

    Wu, Yuling; Tabor, David E.; Mok, Hoyin; Sellman, Bret R.; Jenkins, Amy; Yu, Li; Jafri, Hasan S.; Rude, Thomas H.; Ruffin, Felicia; Schell, Wiley A.; Park, Lawrence P.; Yan, Qin; Thaden, Joshua T.; Messina, Julia A.; Esser, Mark T.

    2014-01-01

    Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P < 0.01). Both neutralizing (hemodialysis, 1.26 IU/ml, versus postsurgical, 0.95; P < 0.05) and IgG (hemodialysis, 1.94 IU/ml, versus postsurgical, 1.27; P < 0.05) antibody levels were higher in the hemodialysis population. Antibody levels were also significantly higher in patients infected with alpha-toxin-expressing S. aureus isolates (P < 0.05). Levels of both neutralizing antibodies and IgG were similar among patients who were cured and those not cured (failures). Sequence analysis of hla revealed 12 distinct hla genotypes, and all genotypic variants were susceptible to a neutralizing monoclonal antibody in clinical development (MEDI4893). These data demonstrate that alpha-toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study. PMID:25392350

  16. Characterization of cysteine related variants in an IgG2 antibody by LC-MS with an automated data analysis approach.

    PubMed

    Zhang, Yuling; Bailey, Robert; Nightlinger, Nancy; Gillespie, Alison; Balland, Alain; Rogers, Richard

    2015-08-01

    In this communication, a high-throughput method for automated data analysis of cysteine-related product quality attributes (PQAs) in IgG2 antibodies is reported. This method leverages recent advances in the relative quantification of PQAs to facilitate the characterization of disulfide variants and free sulfhydryls (SHs) in IgG2 antibodies. The method uses samples labeled with a mass tag (N-ethyl maleimide [NEM]) followed by enzymatic digestion under non-reducing conditions to maintain the cysteine connectivity. The digested IgG2 samples are separated and detected by mass spectrometry (MS) and the resulting peptide map is analyzed in an automated fashion using Pinpoint software (Thermo Scientific). Previous knowledge of IgG2 disulfide structures can be fed into the Pinpoint software to create workbooks for various disulfide linkages and hinge disulfide variants. In addition, the NEM mass tag can be added to the workbooks for targeted analysis of labeled cysteine-containing peptides. The established Pinpoint workbooks are a high-throughput approach to quantify relative abundances of unpaired cysteines and disulfide linkages, including complicated hinge disulfide variants. This approach is especially efficient for comparing large sets of similar samples such as those created in comparability and stability studies or chromatographic fractions. Here, the high throughput method is applied to quantify the relative abundance of hinge disulfide variants and unpaired cysteines in the IgG2 fractions from non-reduced reversed-phase high-performance liquid chromatography (nrRP-HPLC). The LC-MS data analyzed by the Pinpoint workbook suggests that the nrRP-HPLC separated peaks contain hinge disulfide isoforms and free cysteine pairs for each major disulfide isoform structure.

  17. Recombinant proteinase 3 produced in different expression systems: recognition by anti-PR3 antibodies.

    PubMed

    van der Geld, Y M; Oost-Kort, W; Limburg, P C; Specks, U; Kallenberg, C G

    2000-10-20

    Anti-neutrophil cytoplasm autoantibodies (ANCA) directed against proteinase 3 (PR3) are highly sensitive and specific markers for Wegener's granulomatosis (WG). Consequently, antigen-specific assays for detection of PR3-ANCA are helpful for the diagnosis and follow-up of patients with WG. Purification of PR3 is laborious and requires large amounts of granulocytes. Therefore, several attempts have been made to produce recombinant PR3 that is recognized by PR3-ANCA. The purpose of this study was to compare the recognition of different recombinant forms of PR3 (rPR3) by anti-PR3 antibodies. Recombinant PR3 produced in E. coli (rcPR3), P. pastoris (rpPR3), insect cells using the baculovirus system (rbPR3), the human mast cell line, HMC-1 (HMC-1/PR3-S176A), or the human epithelial cell line, 293 (Delta-rPR3-S176A) as well as purified neutrophil PR3 (nPR3) were used. Recognition of these rPR3s by anti-PR3 antibodies was determined by direct and capture ELISA with 19 PR3-ANCA sera, 13 anti-PR3 mAbs and a rabbit serum raised against human PR3. In the capture ELISA rabbit anti-PR3 strongly bound nPR3 and all rPR3 products. By capture ELISA rcPR3 and rpPR3 were recognized by 11 (57%) and 13 (68%) of the 19 PR3-ANCA sera, respectively, whereas rbPR3, HMC-1/PR3-S176A, Delta-rPR3-S176A and nPR3 were recognized by all PR3-ANCA sera. By direct ELISA rabbit anti-PR3 strongly bound nPR3 and all tested rPR3 products. Using the direct ELISA none of the PR3-ANCA sera recognized rcPR3, whereas rpPR3 and rbPR3 were recognized by two (11%) and 17 (89%) of the 19 PR3-ANCA sera, respectively. All 13 anti-PR3 mAbs recognized nPR3 in the direct as well as in the capture ELISA. The rcPR3 was recognized by two mAbs in the capture ELISA but by none of the mAbs in the direct ELISA. The rpPR3 was recognized by seven mAbs in the capture ELISA and only by two mAbs in the direct ELISA. All but one of the anti-PR3 mAbs recognized rbPR3, whereas HMC-1/PR3-S176A and Delta-rPR3-S176A were recognized by

  18. Identification and characterization of a -1 reading frameshift in the heavy chain constant region of an IgG1 recombinant monoclonal antibody produced in CHO cells

    PubMed Central

    Lian, Zhirui; Wu, Qindong; Wang, Tongtong

    2016-01-01

    ABSTRACT Frameshifts lead to complete alteration of the intended amino acid sequences, and therefore may affect the biological activities of protein therapeutics and pose potential immunogenicity risks. We report here the identification and characterization of a novel -1 frameshift variant in a recombinant IgG1 therapeutic monoclonal antibody (mAb) produced in Chinese hamster ovary cells during the cell line selection studies. The variant was initially observed as an atypical post-monomer fragment peak in size exclusion chromatography. Characterization of the fragment peak using intact and reduced liquid chromatography-mass spectrometry (LC-MS) analyses determined that the fragment consisted of a normal light chain disulfide-linked to an aberrant 26 kDa fragment that could not be assigned to any HC fragment even after considering common modifications. Further analysis using LC-MS/MS peptide mapping revealed that the aberrant fragment contained the expected HC amino acid sequence (1-232) followed by a 20-mer novel sequence corresponding to expression of heavy chain DNA sequence in the -1 reading frame. Examination of the DNA sequence around the frameshift initiation site revealed that a mononucleotide repeat GGGGGG located in the IgG1 HC constant region was most likely the structural root cause of the frameshift. Rapid identification of the frameshift allowed us to avoid use of a problematic cell line containing the frameshift as the production cell line. The frameshift reported here may be observed in other mAb products and the hypothesis-driven analytical approaches employed here may be valuable for rapid identification and characterization of frameshift variants in other recombinant proteins. PMID:26652198

  19. Antibodies to plant-produced Plasmodium falciparum sexual stage protein Pfs25 exhibit transmission blocking activity.

    PubMed

    Farrance, Christine E; Chichester, Jessica A; Musiychuk, Konstantin; Shamloul, Moneim; Rhee, Amy; Manceva, Slobodanka D; Jones, R Mark; Mamedov, Tarlan; Sharma, Satish; Mett, Vadim; Streatfield, Stephen J; Roeffen, Will; van de Vegte-Bolmer, Marga; Sauerwein, Robert W; Wu, Yimin; Muratova, Olga; Miller, Louis; Duffy, Patrick; Sinden, Robert; Yusibov, Vidadi

    2011-01-01

    Malaria is a serious and sometimes fatal mosquito-borne disease caused by a protozoan parasite. Each year, it is estimated that over one million people are killed by malaria, yet the disease is preventable and treatable. Developing vaccines against the parasite is a critical component in the fight against malaria and these vaccines can target different stages of the pathogen's life cycle. We are targeting sexual stage proteins of P. falciparum which are found on the surface of the parasite reproductive cells present in the mosquito gut. Antibodies against these proteins block the progression of the parasite's life cycle in the mosquito, and thus block transmission to the next human host. Transmission blocking vaccines are essential to the malaria eradication program to ease the disease burden at the population level. We have successfully produced multiple versions of the Pfs25 antigen in a plant virus-based transient expression system and have evaluated these vaccine candidates in an animal model. The targets are expressed in plants at a high level, are soluble and most importantly, generate strong transmission blocking activity as determined by a standard membrane feeding assay. These data demonstrate the feasibility of expressing Plasmodium antigens in a plant-based system for the economic production of a transmission blocking vaccine against malaria.

  20. Application of dielectric spectroscopy for monitoring high cell density in monoclonal antibody producing CHO cell cultivations.

    PubMed

    Párta, László; Zalai, Dénes; Borbély, Sándor; Putics, Akos

    2014-02-01

    The application of dielectric spectroscopy was frequently investigated as an on-line cell culture monitoring tool; however, it still requires supportive data and experience in order to become a robust technique. In this study, dielectric spectroscopy was used to predict viable cell density (VCD) at industrially relevant high levels in concentrated fed-batch culture of Chinese hamster ovary cells producing a monoclonal antibody for pharmaceutical purposes. For on-line dielectric spectroscopy measurements, capacitance was scanned within a wide range of frequency values (100-19,490 kHz) in six parallel cell cultivation batches. Prior to detailed mathematical analysis of the collected data, principal component analysis (PCA) was applied to compare dielectric behavior of the cultivations. PCA analysis resulted in detecting measurement disturbances. By using the measured spectroscopic data, partial least squares regression (PLS), Cole-Cole, and linear modeling were applied and compared in order to predict VCD. The Cole-Cole and the PLS model provided reliable prediction over the entire cultivation including both the early and decline phases of cell growth, while the linear model failed to estimate VCD in the later, declining cultivation phase. In regards to the measurement error sensitivity, remarkable differences were shown among PLS, Cole-Cole, and linear modeling. VCD prediction accuracy could be improved in the runs with measurement disturbances by first derivative pre-treatment in PLS and by parameter optimization of the Cole-Cole modeling.

  1. Draft Genome Sequences of Five Shiga Toxin-Producing Escherichia coli Isolates Harboring the New and Recently Described Subtilase Cytotoxin Allelic Variant subAB2-3

    PubMed Central

    Tasara, Taurai; Fierz, Lisa; Schmidt, Herbert

    2017-01-01

    ABSTRACT We present here the draft genome sequences of five Shiga toxin-producing Escherichia coli (STEC) strains which tested positive in a primary subAB screening. Assembly and annotation of the draft genomes revealed that all strains harbored the recently described allelic variant subAB2-3. Based on the sequence data, primers were designed to identify and differentiate this variant. PMID:28232433

  2. Occurrence of antibodies reactive with more than one variant of the putative envelope glycoprotein (gp70) hypervariable region 1 in viremic hepatitis C virus-infected patients.

    PubMed Central

    Scarselli, E; Cerino, A; Esposito, G; Silini, E; Mondelli, M U; Traboni, C

    1995-01-01

    The hepatitis C virus (HCV) is a frequent cause of chronic liver disease. A mechanism proposed as being responsible for virus persistence is evasion of the host immune response through a high mutation rate in crucial regions of the viral genome. We have sequenced the hypervariable region 1 (HVR1) of the virus isolated from three serum samples, collected during 18 months of follow-up, from an asymptomatic HCV-infected patient. A synthetic peptide of 27 amino acids, corresponding to the HVR1 sequence found to be predominant in both the second and third samples, was used as the antigen for detection of antibodies by enzyme-linked immunosorbent assay (ELISA). We observed reactivity against this HVR1 sequence in the first serum sample before the appearance of the viral isolate in the bloodstream; the reactivity increased in the second and third samples while the cognate viral sequence became predominant. Moreover, our results show that antibodies from all three samples recognize a region mapping at the carboxyl-terminal part of the HVR1 and are cross-reactive with the HVR1 sequence previously found in the same patient. The presence of anti-HVR1 antibodies was investigated in a further 142 HCV patients: 121 viremic and 21 nonviremic. Two synthetic peptides were used, the first corresponding to the sequence derived from the patient described above and the second one synthesized according to the sequence of the HCV BK strain. A high frequency of positive reactions against both HVR1 variants was detected in the samples from the viremic individuals. Finally, antibodies cross-reactive with both variants were shown to be present by competitive ELISA in 6 of 10 viremic patients. The potential negative implications of this observation for the host are discussed. PMID:7539508

  3. Distinct short-lived and long-lived antibody-producing cell populations.

    PubMed

    Ho, F; Lortan, J E; MacLennan, I C; Khan, M

    1986-10-01

    This report analyzes the life span of Ig-containing cells (IgCC) in different sites of antibody production. The experimental approach was based upon the observations that most IgCC are derived from proliferating precursors while IgCC themselves are mainly nondividing end cells. Rats were given a continuous infusion of [3H] thymidine via an osmotic pump inserted in the peritoneal cavity. At intervals of 1, 3, 5 or 10 days after starting infusions, tissues were taken and analyzed by a combination of immunohistology and autoradiography to identify the proportions of IgCC which had gone through S phase of the cell cycle during the period of infusion. After 3 days infusion the median and (range) percent-labeled IgCC in the medullary cords of mesenteric and cervical lymph nodes and the red pulp of the spleen were, respectively, 88 (81-90), 75 (66-77) and 88 (82-93). Conversely that for IgCC in bone marrow was only 13 (11-17) and that in the lamina propria of the jejunum 47 (33-68). The rate of increase in labeling of bone marrow IgCC with length of infusion was approximately linear. Extrapolation of this slope suggests that bone marrow IgCC have a life span in excess of 3 weeks. The slopes of increase in IgCC labeled with time for lymph nodes and spleen were clearly biphasic suggesting that while most IgCC in these tissues have a life span of less than 3 days, there is also a minor population of long-lived IgCC. The lamina propria appears to have approximately equal proportions of long and short-lived IgCC. The life span of IgCC, with the exception of IgMCC, appears to be a feature of the site of antibody production rather than the Ig class produced. Almost all IgM-containing cells were found to be short lived.

  4. Definition of glomerular antigens by monoclonal antibodies produced against a human glomerular membrane fraction.

    PubMed

    Neale, T J; Callus, M S; Donovan, L C; Baird, H

    1990-10-01

    Experimental animal models of glomerulonephritis (GN) produced by direct antibody binding to non-basement membrane glomerular capillary wall antigens do not to date have human parallels. To examine the potential for this form of humoral glomerular injury in man, we sought to define discrete human non-GBM glomerular antigenic targets using hybridoma technology. Mice were immunised intraperitoneally with 20-100 micrograms of a human glomerular membrane fraction (HGMF). Six fusions have yielded 12 stable reagents defined by positive glomerular indirect immunofluorescence (IF) and microELISA using HGMF as the screening antigen. Subclass analysis of ascitic McAbs indicated several IgG1, one IgG2b, and three IgM reagents. Distinctive IF patterns of reactivity with epithelial, endothelial or mesangial structures have been observed, with or without peritubular capillary, tubular basement membrane and vessel wall reactivity. Seven normal non-renal human organs and the kidneys of rat, rabbit and sheep have shown patterns characteristic of each individual McAb, restricted to human or with species cross reactivity. To partially characterise McAb-reactive antigens, detergent-solubilised renal cortex and collagenase-solubilised GBM (CS-GBM) extracts have been probed by immunoblot. A unique McAb 7-5Q, reactive with glomerular and tubular epithelial structures, binds major bands of approximately 107 KD and 93 KD in detergent solubilised cortex and a single band of similar size by immunoprecipitation (110 KD). 5-3A (a human-restricted linear-reacting McAb) binds bands of 20-200 KD (major band 58 KD) in CS-GBM. In conclusion, distinct species-restricted and more broadly disposed glomerular epitopes are definable in man by McAbs and are potential targets for humoral injury. Purification of these antigens will allow assay for circulating putative nephritogenic auto-antibody and potentially, McAbs may be useful in screening urine for evidence of occult structural renal disease.

  5. Rapid O serogroup identification of the six clinically relevant Shiga toxin-producing Escherichia coli by antibody microarray

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibody array was developed for the detection of the top six non-O157 Shiga toxin-producing Escherichia coli O serogroups. Sensitivity of the array was 10**5 CFU, and the limit of detection of serogroups in ground beef was 1-10 CFU following 12 h of enrichment. The array utilized a minimal amount...

  6. Neutralization of diverse human immunodeficiency virus type 1 variants by an anti-V3 human monoclonal antibody.

    PubMed Central

    Gorny, M K; Conley, A J; Karwowska, S; Buchbinder, A; Xu, J Y; Emini, E A; Koenig, S; Zolla-Pazner, S

    1992-01-01

    The third variable region (V3) of the HIV-1 gp120 envelope glycoprotein is thought to induce potent neutralizing antibodies which are generally defined as type specific and reactive with individual viral isolates. In contrast, the CD4-binding domain is thought to induce neutralizing antibodies that are group specific and capable of neutralizing all isolates of HIV-1. However, in this study, we used a panel of human monoclonal antibodies to these regions of gp120 which displays specificities and neutralizing activities that challenge these tenets. In particular, we used a human monoclonal antibody to the V3 domain with exceptionally potent and broad neutralizing activity against many diverse HIV-1 isolates. The anti-CD4-binding domain antibodies, on the other hand, showed a more restricted pattern of activity. PMID:1433529

  7. Otitis-Prone Children Produce Functional Antibodies to Pneumolysin and Pneumococcal Polysaccharides

    PubMed Central

    Wiertsema, Selma P.; Corscadden, Karli J.; Mateus, Tulia; Mullaney, Gemma L.; Zhang, Guicheng; Richmond, Peter C.; Thornton, Ruth B.

    2016-01-01

    ABSTRACT The pneumococcus is a major otitis media (OM) pathogen, but data are conflicting regarding whether otitis-prone children have impaired humoral immunity to pneumococcal antigens. We and others have shown that otitis-prone and healthy children have similar antibody titers to pneumococcal proteins and polysaccharides (vaccine and nonvaccine types); however, the quality of antibodies from otitis-prone children has not been investigated. Antibody function, rather than titer, is considered to be a better correlate of protection from pneumococcal disease. Therefore, we compared the capacities of antibodies from otitis-prone (cases) and healthy (controls) children to neutralize pneumolysin, the pneumococcal toxin currently in development as a vaccine antigen, and to opsonize pneumococcal vaccine and nonvaccine serotypes. A pneumolysin neutralization assay was conducted on cholesterol-depleted complement-inactivated sera from 165 cases and 61 controls. A multiplex opsonophagocytosis assay (MOPA) was conducted on sera from 20 cases and 20 controls. Neutralizing and opsonizing titers were calculated with antigen-specific IgG titers to determine antibody potency for pneumolysin, pneumococcal conjugate vaccine (PCV) polysaccharides, and non-PCV polysaccharides. There was no significant difference in antibody potencies between cases and controls for the antigens tested. Antipneumolysin neutralizing titers increased with the number of episodes of acute OM, but antibody potency did not. Pneumolysin antibody potency was lower in children colonized with pneumococci than in noncarriers, and this was significant for the otitis-prone group (P < 0.05). The production of functional antipneumococcal antibodies in otitis-prone children demonstrates that they respond to the current PCV and are likely to respond to pneumolysin-based vaccines as effectively as healthy children. PMID:28031178

  8. Human genetic variants of homologous recombination repair genes first found to be associated with Epstein-Barr virus antibody titers in healthy Cantonese.

    PubMed

    Shen, Guo-Ping; Pan, Qing-Hua; Hong, Ming-Huang; Qin, Hai-De; Xu, Ya-Fei; Chen, Li-Zhen; Feng, Qi-Sheng; Jorgensen, Timothy J; Shugart, Yin Yao; Zeng, Yi-Xin; Jia, Wei-Hua

    2011-09-15

    Epstein-Barr virus (EBV) infection is a major risk factor for nasopharyngeal carcinoma (NPC). Despite high prevalence of infection among the general population worldwide, only a small proportion of infected individuals presents with seropositivity for EBV-specific IgA antibodies. This seropositive subgroup of EBV carriers has an elevated cumulative risk for NPC during their lifetime. Previous studies reported that the host homologous recombination repair (HRR) system participates in EBV lytic replication, suggesting a potential mechanism to influence EBV reactivation status and thus seropositivity. To investigate whether genetic variants of HRR genes are associated with the serostatus in a healthy population, we investigated the association between seropositivity for anti-VCA-IgA and 156 tagging SNPs in 35 genes connected with HRR in an observational study among 755 healthy Cantonese speakers in southern China. Six variant alleles of MDC1, RAD54L, TP53BP1, RPA1, LIG3 and RFC1 exhibited associations with seropositivity (p(trend) from 0.0085 to 0.00027). Our study provides evidence that genetic variation within the HRR might affect an individual's propensity for EBV seropositive status of anti-VCA IgA antibody.

  9. Ebola virus-like particles produced in insect cells exhibit dendritic cell stimulating activity and induce neutralizing antibodies

    SciTech Connect

    Ye Ling; Lin Jianguo; Sun Yuliang; Bennouna, Soumaya; Lo, Michael; Wu Qingyang; Bu Zhigao; Pulendran, Bali; Compans, Richard W. . E-mail: compans@microbio.emory.edu; Yang Chinglai . E-mail: chyang@emory.edu

    2006-08-01

    Recombinant baculoviruses (rBV) expressing Ebola virus VP40 (rBV-VP40) or GP (rBV-GP) proteins were generated. Infection of Sf9 insect cells by rBV-VP40 led to assembly and budding of filamentous particles from the cell surface as shown by electron microscopy. Ebola virus-like particles (VLPs) were produced by coinfection of Sf9 cells with rBV-VP40 and rBV-GP, and incorporation of Ebola GP into VLPs was demonstrated by SDS-PAGE and Western blot analysis. Recombinant baculovirus infection of insect cells yielded high levels of VLPs, which were shown to stimulate cytokine secretion from human dendritic cells similar to VLPs produced in mammalian cells. The immunogenicity of Ebola VLPs produced in insect cells was evaluated by immunization of mice. Analysis of antibody responses showed that most of the GP-specific antibodies were of the IgG2a subtype, while no significant level of IgG1 subtype antibodies specific for GP was induced, indicating the induction of a Th1-biased immune response. Furthermore, sera from Ebola VLP immunized mice were able to block infection by Ebola GP pseudotyped HIV virus in a single round infection assay, indicating that a neutralizing antibody against the Ebola GP protein was induced. These results show that production of Ebola VLPs in insect cells using recombinant baculoviruses represents a promising approach for vaccine development against Ebola virus infection.

  10. Production of monoclonal antibody recognizing a subpopulation of human B lymphocytes producing B cell growth factor (BCGF)

    SciTech Connect

    Witzel, N.; Ambrus, J.L. Jr.; Jurgensen, C.H.; Mostowski, H.; Fauci, A.S.

    1986-03-05

    Several laboratories have recently reported production of B cell growth factors (BCGF) by a variety of human B cell lines. The authors have described production of BCGF by clones of B cell lymphoma lines and by normal Staphylococcus aureus Cowan I-activated B cells. To further evaluate whether BCGF production was the function of particular subpopulations of B cells, they immunized mice with the BCGF producing line Namalva and then developed a panel of hybridomas. Monoclonal antibodies were screened for binding to Namalva and the absence of binding to a non-BCGF producing B cell line. One monoclonal antibody, NN4, which met these criteria was also noted by fluorescence-activated cell sorter analysis to stain clones from a B cell lymphoma line producing BCGF but not clones from the same line which do not produce BCGF. The monoclonal antibody did not stain T cells or monocytes but stained 1-5% of normal human B lymphocytes from peripheral blood or tonsils. Binding of /sup 125/I-labeled NN4 to NN4/sup +/ B cells was not affected by the presence of BCGF. Therefore, NN4 recognizes a unique antigen present on B cell lines which produces BCGF; studies are in progress to determine the significance of this antigen on normal B cells.

  11. Subtilase cytotoxin-encoding subAB2 variants in verotoxin-producing Escherichia coli strains isolated from goats and sheep.

    PubMed

    Orden, José A; Domínguez-Bernal, Gustavo; de la Fuente, Ricardo; Carrión, Javier

    2016-04-01

    Subtilase cytotoxin (SubAB) is a cytotoxin which might contribute to the virulence of verotoxin-producing Escherichia coli (VTEC) strains in humans. Three variants of SubAB encoding genes have been described (subAB1, subAB2-1, and subAB2-2) and it has been suggested that the strains positive for two variants of subAB may be more pathogenic for humans. In this study, 188 subAB2-positive VTEC strains isolated from goats and sheep were investigated for the presence of the subAB2-1 and subAB2-2 variants by PCR. Eighty-one of the 132 (61.4%) caprine strains and 36 of the 56 (64.3%) ovine strains possessed the subAB2-1 variant and all ovine and caprine strains, except one, were positive for the subAB2-2 variant. The results of this study show for first time that the subAB2-1 and subAB2-2 variants are found in caprine subAB2-positive VTEC strains and confirm that both subAB2 variants are detected in ovine subAB2-positive VTEC strains. Since no significant difference in the presence of both subAB2 variants was found among strains belonging to serotypes associated with severe illness in humans and strains not belonging to these serotypes, the occurrence of two subAB2 variants seems not to be associated with a higher risk of severe disease in humans.

  12. Experimental allergic encephalomyelitis (EAE) in mice selectively bred to produce high affinity (HA) or low affinity (LA) antibody responses.

    PubMed Central

    Devey, M E; Major, P J; Bleasdale-Barr, K M; Holland, G P; Dal Canto, M C; Paterson, P Y

    1990-01-01

    Induction of experimental allergic encephalomyelitis (EAE) in mice genetically selected to produce either high affinity (HA) or low affinity (LA) antibody responses has revealed significant differences in disease susceptibility between the two lines. HA mice were highly susceptible to EAE following subcutaneous sensitization to mouse central nervous system (CNS) tissue emulsified in Freund's complete adjuvant (FCA). Furthermore, of HA mice surviving acute EAE, up to 93% subsequently developed chronic relapsing disease (CREAE) characterized by variable demyelinating inflammatory changes within the spinal cord. In contrast, LA mice, despite having a major histocompatability complex (MHC) haplotype associated with susceptibility to EAE, were highly resistant to the disease and showed no signs of CREAE when observed for up to 100 days post-sensitization. Antibodies to myelin basic protein (MBP) were detected in both lines but rising titres of high functional affinity antibodies were only seen in HA mice. These HA and LA lines of mice provide a new approach to the study of EAE and, in particular, the role of antibody and antibody affinity in the chronic relapsing form of the disease. Images Figure 2 PMID:2335373

  13. Macrophages from chickens selected for high antibody response produced more nitric oxide and have greater phagocytic capacity.

    PubMed

    Guimarães, Marco Cesar Cunegundes; Guillermo, Landi Veivi Costilla; Matta, Marcos Fernando de Rezende; Soares, Sandro Gomes; DaMatta, Renato Augusto

    2011-04-15

    Macrophages are fundamental cells of the innate immune system, which, through phagocytosis and nitric oxide production, eliminate pathogens. The aim of the present study was to determine if macrophages from chicken families divergently selected to high and low antibodies response differ in nitric oxide production and phagocytic capacity. Blood monocytes derived macrophages were activated with lipopolysaccharide and supernatant from chicken spleen lymphocytes cultured with Concanavalin A (containing chicken interferon). Nitric oxide production was evaluated in culture supernatants. Phagocytic capacity of activated and non-activated macrophages was assayed using yeasts and IgY opsonized sheep red blood cells. Activated and non-activated macrophages from the high antibodies response family produced higher nitric oxide levels, internalized more yeast and significantly more opsonized sheep red blood cells than macrophages from the low antibodies response family. Moreover, activated macrophages became more elongated and widely spread. These findings indicate that macrophages from the high antibodies response family were more active suggesting that the differences in antibody response also depend on macrophage function.

  14. Cell surface expression of MR1B, a splice variant of the MHC class I-related molecule MR1, revealed with antibodies.

    PubMed

    Yamaguchi, Hisateru; Tsukamoto, Kentaro; Hashimoto, Keiichiro

    2014-01-10

    The major histocompatibility complex (MHC) class I-related molecule, MR1, is highly conserved in mammals and can present bacteria-derived vitamin B metabolites to mucosal-associated invariant T (MAIT) cells, possibly having important defense function in the microbial infection. MR1B is a splice variant of MR1 and possesses an intriguing domain structure with only two extracellular domains resembling some NKG2D ligand molecules. Thus far, cell surface expression of MR1B could not be analyzed with flow cytometry due to a lack of appropriate antibodies reactive with MR1B. Here we clarified the expression of MR1B recombinant protein on the cell surface of the transfected cells by flow cytometry analyses using the antiserum against MR1. Consistently, MR1B tagged with FLAG peptide at the N-terminus also could be detected with anti-FLAG monoclonal antibodies. Our result showed that MR1B can be recognized on the cell surface by macromolecules such as antibodies, indicating its potential of interaction with certain receptor(s). We discuss possibility of interaction of MR1B and/or the full-length MR1 with some receptor(s) other than αβ T cell receptor (TCR) of MAIT cells based on the highly conserved characteristic residues of the ligand-binding domains of MR1 and its MAIT cells αβTCR footprints.

  15. Real time detection of anthrax spores using highly specific anti-EA1 recombinant antibodies produced by competitive panning.

    PubMed

    Love, Tracey E; Redmond, Caroline; Mayers, Carl N

    2008-05-20

    We describe a targeted approach for the production of biological recognition elements capable of fast, specific detection of anthrax spores on biosensor surfaces. The aim was to produce single chain antibodies (scFvs) to EA1, a Bacillus anthracis S-layer protein that is also present, although not identical, in related to Bacillus species. The aim of the work was to produce antibodies that would detect B. anthracis EA1 protein and intact spores with a high degree of specificity, but would not detect other Bacillus species. Existing monoclonal antibodies were evaluated and found to recognise B. anthracis EA1 and S-layer proteins from other closely related Bacillus species. Recombinant anti-EA1 scFvs were isolated from B. anthracis immune library that contained antibody genes raised against B. anthracis spores and purified exosporium. Two approaches for scFv selection were used; standard (non-competitive) panning, and competitive panning. The non-competitive biopanning strategy isolated scFvs that recognised EA1 from B. anthracis, but also cross-reacted with other Bacillus species. In contrast, the competitive panning approach used S-layer proteins from other Bacillus species to generate scFvs that were highly specific to B. anthracis EA1 and demonstrated apparent nanomolar binding affinities. Specific, real time detection of B. anthracis spores was demonstrated with these scFvs using an evanescent wave biosensor, the Resonant Mirror. The approach described can be used to generate specific antibodies to any desired target where homologous proteins also exist in closely related species, and demonstrates clear advantages to using recombinant technology to produce biological recognition elements for detection of biological threat agents.

  16. Vaccination of cattle with a methanogen protein produces specific antibodies in the saliva which are stable in the rumen.

    PubMed

    Subharat, Supatsak; Shu, Dairu; Zheng, Tao; Buddle, Bryce M; Janssen, Peter H; Luo, Dongwen; Wedlock, D Neil

    2015-04-15

    Methane is produced in the rumen of cattle by a group of archaea (single-celled organisms forming a domain distinct from bacteria and eucarya) called methanogens. Vaccination against methanogens has the potential to reduce methane emissions by inducing antibodies in saliva which are transferred to the rumen and diminish the ability of methanogens to produce methane. Since it is likely that an effective vaccination strategy will need to produce high levels of methanogen-specific antibody in the saliva; the choice of adjuvant, route of vaccination and stability of saliva-derived antibody in the rumen all need to be considered. In this study, stability of IgA and IgG in rumen fluid was determined using an in vitro assay. IgA levels in cattle saliva were reduced by only 40% after 8h exposure to rumen contents while IgG levels were reduced by 80%. These results indicated that antibody is relatively stable in the bovine rumen. A trial was conducted in cattle to investigate induction of immune responses to a methanogen protein, recombinant glycosyl transferase protein (rGT2) from Methanobrevibacter ruminantium M1. Groups of cattle (n=6) were vaccinated subcutaneously with rGT2, formulated with Montanide ISA61 with or without the TLR4 agonist, monophosphoryl lipid A (MPL). A control group (n=6) was not vaccinated. Strong antigen-specific IgG and moderate IgA responses were measured in the serum and saliva of the vaccinated animals and antibody was also detected in the rumen.

  17. Glycoprotein-Specific Antibodies Produced by DNA Vaccination Protect Guinea Pigs from Lethal Argentine and Venezuelan Hemorrhagic Fever

    PubMed Central

    Golden, Joseph W.; Maes, Piet; Kwilas, Steven A.; Ballantyne, John

    2016-01-01

    ABSTRACT Several members of the Arenaviridae can cause acute febrile diseases in humans, often resulting in lethality. The use of convalescent-phase human plasma is an effective treatment in humans infected with arenaviruses, particularly species found in South America. Despite this, little work has focused on developing potent and defined immunotherapeutics against arenaviruses. In the present study, we produced arenavirus neutralizing antibodies by DNA vaccination of rabbits with plasmids encoding the full-length glycoprotein precursors of Junín virus (JUNV), Machupo virus (MACV), and Guanarito virus (GTOV). Geometric mean neutralizing antibody titers, as measured by the 50% plaque reduction neutralization test (PRNT50), exceeded 5,000 against homologous viruses. Antisera against each targeted virus exhibited limited cross-species binding and, to a lesser extent, cross-neutralization. Anti-JUNV glycoprotein rabbit antiserum protected Hartley guinea pigs from lethal intraperitoneal infection with JUNV strain Romero when the antiserum was administered 2 days after challenge and provided some protection (∼30%) when administered 4 days after challenge. Treatment starting on day 6 did not protect animals. We further formulated an IgG antibody cocktail by combining anti-JUNV, -MACV, and -GTOV antibodies produced in DNA-vaccinated rabbits. This cocktail protected 100% of guinea pigs against JUNV and GTOV lethal disease. We then expanded on this cocktail approach by simultaneously vaccinating rabbits with a combination of plasmids encoding glycoproteins from JUNV, MACV, GTOV, and Sabia virus (SABV). Sera collected from rabbits vaccinated with the combination vaccine neutralized all four targets. These findings support the concept of using a DNA vaccine approach to generate a potent pan-arenavirus immunotherapeutic. IMPORTANCE Arenaviruses are an important family of emerging viruses. In infected humans, convalescent-phase plasma containing neutralizing antibodies can

  18. The CEA/CD3-Bispecific Antibody MEDI-565 (MT111) Binds a Nonlinear Epitope in the Full-Length but Not a Short Splice Variant of CEA

    PubMed Central

    Huang, Jiaqi; Brohawn, Philip; Morehouse, Chris; Lekstrom, Kristen; Baeuerle, Patrick A.; Wu, Herren; Yao, Yihong; Coats, Steven R.; Dall’Acqua, William; Damschroder, Melissa; Hammond, Scott A.

    2012-01-01

    MEDI-565 (also known as MT111) is a bispecific T-cell engager (BiTE®) antibody in development for the treatment of patients with cancers expressing carcinoembryonic antigen (CEA). MEDI-565 binds CEA on cancer cells and CD3 on T cells to induce T-cell mediated killing of cancer cells. To understand the molecular basis of human CEA recognition by MEDI-565 and how polymorphisms and spliced forms of CEA may affect MEDI-565 activity, we mapped the epitope of MEDI-565 on CEA using mutagenesis and homology modeling approaches. We found that MEDI-565 recognized a conformational epitope in the A2 domain comprised of amino acids 326–349 and 388–410, with critical residues F326, T328, N333, V388, G389, P390, E392, I408, and N410. Two non-synonymous single-nucleotide polymorphisms (SNPs) (rs10407503, rs7249230) were identified in the epitope region, but they are found at low homozygosity rates. Searching the National Center for Biotechnology Information GenBank® database, we further identified a single, previously uncharacterized mRNA splice variant of CEA that lacks a portion of the N-terminal domain, the A1 and B1 domains, and a large portion of the A2 domain. Real-time quantitative polymerase chain reaction analysis of multiple cancers showed widespread expression of full-length CEA in these tumors, with less frequent but concordant expression of the CEA splice variant. Because the epitope was largely absent from the CEA splice variant, MEDI-565 did not bind or mediate T-cell killing of cells solely expressing this form of CEA. In addition, the splice variant did not interfere with MEDI-565 binding or activity when co-expressed with full-length CEA. Thus MEDI-565 may broadly target CEA-positive tumors without regard for expression of the short splice variant of CEA. Together our data suggest that MEDI-565 activity will neither be impacted by SNPs nor by a splice variant of CEA. PMID:22574157

  19. Emergence of Ebola Virus Escape Variants in Infected Nonhuman Primates Treated with the MB-003 Antibody Cocktail.

    PubMed

    Kugelman, Jeffrey R; Kugelman-Tonos, Johanny; Ladner, Jason T; Pettit, James; Keeton, Carolyn M; Nagle, Elyse R; Garcia, Karla Y; Froude, Jeffrey W; Kuehne, Ana I; Kuhn, Jens H; Bavari, Sina; Zeitlin, Larry; Dye, John M; Olinger, Gene G; Sanchez-Lockhart, Mariano; Palacios, Gustavo F

    2015-09-29

    MB-003, a plant-derived monoclonal antibody cocktail used effectively in treatment of Ebola virus infection in non-human primates, was unable to protect two of six animals when initiated 1 or 2 days post-infection. We characterized a mechanism of viral escape in one of the animals, after observation of two clusters of genomic mutations that resulted in five nonsynonymous mutations in the monoclonal antibody target sites. These mutations were linked to a reduction in antibody binding and later confirmed to be present in a viral isolate that was not neutralized in vitro. Retrospective evaluation of a second independent study allowed the identification of a similar case. Four SNPs in previously identified positions were found in this second fatality, suggesting that genetic drift could be a potential cause for treatment failure. These findings highlight the importance selecting different target domains for each component of the cocktail to minimize the potential for viral escape.

  20. Charge variants characterization of a monoclonal antibody by ion exchange chromatography coupled on-line to native mass spectrometry: Case study after a long-term storage at +5°C.

    PubMed

    Leblanc, Y; Ramon, C; Bihoreau, N; Chevreux, G

    2017-03-24

    Numerous putative post-translational modifications may induce variations of monoclonal antibodies charge distribution that can potentially affect their biological activity. The characterization and the monitoring of these charge variants are critical quality requirements to ensure stability and process consistency. Charge variants are usually characterized by preparative ion exchange chromatography, collection of fractions and subsequent reverse-phase liquid chromatography with mass spectrometry analysis. While this process can be automatized by on-line two-dimensional chromatography, it remains often complex and time consuming. For this reason, a straightforward on-line charge variant analysis method is highly desirable and analytical laboratories are actively pursuing efforts to overcome this challenge. In this study, a mixed mode ion exchange chromatographic method using volatile salts and coupled on-line to native mass spectrometry was developed in association with a middle-up approach for a detailed characterization of monoclonal antibodies charge variants. An aged monoclonal antibody, presenting a complex charge variant profile was successfully investigated by this methodology as a case study. Results demonstrate that deamidation of the heavy chain was the major degradation pathway after long-term storage at 5°C while oxidation was rather low. The method was also very useful to identify all the clipped forms of the antibody.

  1. Multiple length peptide-pheromone variants produced by Streptococcus pyogenes directly bind Rgg proteins to confer transcriptional regulation.

    PubMed

    Aggarwal, Chaitanya; Jimenez, Juan Cristobal; Nanavati, Dhaval; Federle, Michael J

    2014-08-08

    Streptococcus pyogenes, a human-restricted pathogen, accounts for substantial mortality related to infections worldwide. Recent studies indicate that streptococci produce and respond to several secreted peptide signaling molecules (pheromones), including those known as short hydrophobic peptides (SHPs), to regulate gene expression by a quorum-sensing mechanism. Upon transport into the bacterial cell, pheromones bind to and modulate activity of receptor proteins belonging to the Rgg family of transcription factors. Previously, we reported biofilm regulation by the Rgg2/3 quorum-sensing circuit in S. pyogenes. The aim of this study was to identify the composition of mature pheromones from cell-free culture supernatants that facilitate biofilm formation. Bioluminescent reporters were employed to detect active pheromones in culture supernatants fractionated by reverse-phase chromatography, and mass spectrometry was used to characterize their properties. Surprisingly, multiple SHPs that varied by length were detected. Synthetic peptides of each variant were tested individually using bioluminescence reporters and biofilm growth assays, and although activities differed widely among the group, peptides comprising the C-terminal eight amino acids of the full-length native peptide were most active. Direct Rgg/SHP interactions were determined using a fluorescence polarization assay that utilized FITC-labeled peptide ligands. Peptide receptor affinities were seen to be as low as 500 nm and their binding affinities directly correlated with observed bioactivity. Revelation of naturally produced pheromones along with determination of their affinity for cognate receptors are important steps forward in designing compounds whose purpose is positioned for future therapeutics aimed at treating infections through the interference of bacterial communication.

  2. Multiple Length Peptide-Pheromone Variants Produced by Streptococcus pyogenes Directly Bind Rgg Proteins to Confer Transcriptional Regulation*

    PubMed Central

    Aggarwal, Chaitanya; Jimenez, Juan Cristobal; Nanavati, Dhaval; Federle, Michael J.

    2014-01-01

    Streptococcus pyogenes, a human-restricted pathogen, accounts for substantial mortality related to infections worldwide. Recent studies indicate that streptococci produce and respond to several secreted peptide signaling molecules (pheromones), including those known as short hydrophobic peptides (SHPs), to regulate gene expression by a quorum-sensing mechanism. Upon transport into the bacterial cell, pheromones bind to and modulate activity of receptor proteins belonging to the Rgg family of transcription factors. Previously, we reported biofilm regulation by the Rgg2/3 quorum-sensing circuit in S. pyogenes. The aim of this study was to identify the composition of mature pheromones from cell-free culture supernatants that facilitate biofilm formation. Bioluminescent reporters were employed to detect active pheromones in culture supernatants fractionated by reverse-phase chromatography, and mass spectrometry was used to characterize their properties. Surprisingly, multiple SHPs that varied by length were detected. Synthetic peptides of each variant were tested individually using bioluminescence reporters and biofilm growth assays, and although activities differed widely among the group, peptides comprising the C-terminal eight amino acids of the full-length native peptide were most active. Direct Rgg/SHP interactions were determined using a fluorescence polarization assay that utilized FITC-labeled peptide ligands. Peptide receptor affinities were seen to be as low as 500 nm and their binding affinities directly correlated with observed bioactivity. Revelation of naturally produced pheromones along with determination of their affinity for cognate receptors are important steps forward in designing compounds whose purpose is positioned for future therapeutics aimed at treating infections through the interference of bacterial communication. PMID:24958729

  3. Antibodies with specificities against a dispase-produced 15-kilodalton hexon fragment neutralize adenovirus type 2 infectivity.

    PubMed Central

    Varga, M J; Bergman, T; Everitt, E

    1990-01-01

    During the entrance of adenovirus type 2 into cells, it has been suggested that the virion undergoes a conformational change. In this investigation, we have further characterized the hypothetical conformational change, which the structural protein hexon undergoes in response to low pH. From pH 5.0 to pH 6.0, the proteolytic enzyme dispase cleaved the hexon into a few distinct fragments with a dominating low-molecular-weight fragment with a molecular weight of 15,000 (15K peptide), whereas between pH 6.5 and pH 8.0, the cleavage of the hexon was negligible. The degradation of the hexon with dispase at low pH was not due to an increased activity or alteration of the active site of dispase at low pH. The 15K fragment was identified as a segment of the N-terminal part of the hexon polypeptide beginning at amino acid residue 5. An immune serum produced in response to acid-treated and glutaraldehyde-fixed hexons contained a small amount of antibodies directed towards the 15K fragment, as judged by Western immunoblotting. An anti-15K antibody fraction was isolated by affinity chromatography by removing antibodies recognizing the hexon in the alkaline configuration. Such antibodies displayed a higher relative titer at pH 5.0 than at pH 7.5 in an enzyme-linked immunosorbent assay. The isolated antibodies showed a specific neutralizing capacity five times higher than that of the corresponding unfractionated polyclonal anti-hexon serum; however, the neutralizing ability was independent of pH. The neutralization of adenovirus type 2 infection by the isolated anti-15K antibodies implies that the N-terminal end of the hexon may play a critical role in the early steps of the virion-cell interaction. Images PMID:1696636

  4. Blocking Synthesis of the Variant Surface Glycoprotein Coat in Trypanosoma brucei Leads to an Increase in Macrophage Phagocytosis Due to Reduced Clearance of Surface Coat Antibodies

    PubMed Central

    Cheung, Jackie L. Y.; Wand, Nadina V.; Ooi, Cher-Pheng; Ridewood, Sophie

    2016-01-01

    The extracellular bloodstream form parasite Trypanosoma brucei is supremely adapted to escape the host innate and adaptive immune system. Evasion is mediated through an antigenically variable Variant Surface Glycoprotein (VSG) coat, which is recycled at extraordinarily high rates. Blocking VSG synthesis triggers a precytokinesis arrest where stalled cells persist for days in vitro with superficially intact VSG coats, but are rapidly cleared within hours in mice. We therefore investigated the role of VSG synthesis in trypanosome phagocytosis by activated mouse macrophages. T. brucei normally effectively evades macrophages, and induction of VSG RNAi resulted in little change in phagocytosis of the arrested cells. Halting VSG synthesis resulted in stalled cells which swam directionally rather than tumbling, with a significant increase in swim velocity. This is possibly a consequence of increased rigidity of the cells due to a restricted surface coat in the absence of VSG synthesis. However if VSG RNAi was induced in the presence of anti-VSG221 antibodies, phagocytosis increased significantly. Blocking VSG synthesis resulted in reduced clearance of anti-VSG antibodies from the trypanosome surface, possibly as a consequence of the changed motility. This was particularly marked in cells in the G2/ M cell cycle stage, where the half-life of anti-VSG antibody increased from 39.3 ± 4.2 seconds to 99.2 ± 15.9 seconds after induction of VSG RNAi. The rates of internalisation of bulk surface VSG, or endocytic markers like transferrin, tomato lectin or dextran were not significantly affected by the VSG synthesis block. Efficient elimination of anti-VSG-antibody complexes from the trypanosome cell surface is therefore essential for trypanosome evasion of macrophages. These experiments highlight the essentiality of high rates of VSG recycling for the rapid removal of host opsonins from the parasite surface, and identify this process as a key parasite virulence factor during a

  5. Blocking Synthesis of the Variant Surface Glycoprotein Coat in Trypanosoma brucei Leads to an Increase in Macrophage Phagocytosis Due to Reduced Clearance of Surface Coat Antibodies.

    PubMed

    Cheung, Jackie L Y; Wand, Nadina V; Ooi, Cher-Pheng; Ridewood, Sophie; Wheeler, Richard J; Rudenko, Gloria

    2016-11-01

    The extracellular bloodstream form parasite Trypanosoma brucei is supremely adapted to escape the host innate and adaptive immune system. Evasion is mediated through an antigenically variable Variant Surface Glycoprotein (VSG) coat, which is recycled at extraordinarily high rates. Blocking VSG synthesis triggers a precytokinesis arrest where stalled cells persist for days in vitro with superficially intact VSG coats, but are rapidly cleared within hours in mice. We therefore investigated the role of VSG synthesis in trypanosome phagocytosis by activated mouse macrophages. T. brucei normally effectively evades macrophages, and induction of VSG RNAi resulted in little change in phagocytosis of the arrested cells. Halting VSG synthesis resulted in stalled cells which swam directionally rather than tumbling, with a significant increase in swim velocity. This is possibly a consequence of increased rigidity of the cells due to a restricted surface coat in the absence of VSG synthesis. However if VSG RNAi was induced in the presence of anti-VSG221 antibodies, phagocytosis increased significantly. Blocking VSG synthesis resulted in reduced clearance of anti-VSG antibodies from the trypanosome surface, possibly as a consequence of the changed motility. This was particularly marked in cells in the G2/ M cell cycle stage, where the half-life of anti-VSG antibody increased from 39.3 ± 4.2 seconds to 99.2 ± 15.9 seconds after induction of VSG RNAi. The rates of internalisation of bulk surface VSG, or endocytic markers like transferrin, tomato lectin or dextran were not significantly affected by the VSG synthesis block. Efficient elimination of anti-VSG-antibody complexes from the trypanosome cell surface is therefore essential for trypanosome evasion of macrophages. These experiments highlight the essentiality of high rates of VSG recycling for the rapid removal of host opsonins from the parasite surface, and identify this process as a key parasite virulence factor during a

  6. Growth suppression of human hepatocellular carcinoma xenografts by a monoclonal antibody CH12 directed to epidermal growth factor receptor variant III.

    PubMed

    Jiang, Hua; Wang, Huamao; Tan, Zhonghua; Hu, Suwen; Wang, Hai; Shi, Bizhi; Yang, Lin; Li, Peiyong; Gu, Jianren; Wang, Hongyang; Li, Zonghai

    2011-02-18

    Human hepatocellular carcinoma (HCC) is considered difficult to cure because it is resistant to radio- and chemotherapy and has a high recurrence rate after curative liver resection. Epidermal growth factor receptor variant III (EGFRvIII) has been reported to express in HCC tissues and cell lines. This article describes the efficacy of an anti-EGFRvIII monoclonal antibody (mAb CH12) in the treatment of HCC xenografts with EGFRvIII expression and the underlying mechanism of EGFRvIII as an oncogene in HCC. The results demonstrated that CH12 bound preferentially to EGFRvIII with a dissociation constant (K(d)) of 1.346 nm/liter. In addition, CH12 induces strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in Huh7-EGFRvIII (with exogenous expression of EGFRvIII) and SMMC-7721 (with endogenous expression of EGFRvIII) cells. Notably, CH12 significantly inhibited the growth of Huh7-EGFRvIII and SMMC-7721 xenografts in vivo with a growth inhibition ratio much higher than C225, a U. S. Food and Drug Administration-approved anti-EGFR antibody. Treatment of the two HCC xenografts with CH12 significantly suppressed tumor proliferation and angiogenesis. Mechanistically, in vivo treatment with CH12 reduced the phosphorylation of constitutively active EGFRvIII, Akt, and ERK. Down-regulation of the apoptotic protectors Bcl-x(L), Bcl-2, and the cell cycle regulator cyclin D1, as well as up-regulation of the cell-cycle inhibitor p27, were also observed after in vivo CH12 treatment. Collectively, these results indicate that the monoclonal antibody CH12 is a promising therapeutic agent for HCC with EGFRvIII expression.

  7. Growth Suppression of Human Hepatocellular Carcinoma Xenografts by a Monoclonal Antibody CH12 Directed to Epidermal Growth Factor Receptor Variant III*

    PubMed Central

    Jiang, Hua; Wang, Huamao; Tan, Zhonghua; Hu, Suwen; Wang, Hai; Shi, Bizhi; Yang, Lin; Li, Peiyong; Gu, Jianren; Wang, Hongyang; Li, Zonghai

    2011-01-01

    Human hepatocellular carcinoma (HCC) is considered difficult to cure because it is resistant to radio- and chemotherapy and has a high recurrence rate after curative liver resection. Epidermal growth factor receptor variant III (EGFRvIII) has been reported to express in HCC tissues and cell lines. This article describes the efficacy of an anti-EGFRvIII monoclonal antibody (mAb CH12) in the treatment of HCC xenografts with EGFRvIII expression and the underlying mechanism of EGFRvIII as an oncogene in HCC. The results demonstrated that CH12 bound preferentially to EGFRvIII with a dissociation constant (Kd) of 1.346 nm/liter. In addition, CH12 induces strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in Huh7-EGFRvIII (with exogenous expression of EGFRvIII) and SMMC-7721 (with endogenous expression of EGFRvIII) cells. Notably, CH12 significantly inhibited the growth of Huh7-EGFRvIII and SMMC-7721 xenografts in vivo with a growth inhibition ratio much higher than C225, a U. S. Food and Drug Administration-approved anti-EGFR antibody. Treatment of the two HCC xenografts with CH12 significantly suppressed tumor proliferation and angiogenesis. Mechanistically, in vivo treatment with CH12 reduced the phosphorylation of constitutively active EGFRvIII, Akt, and ERK. Down-regulation of the apoptotic protectors Bcl-xL, Bcl-2, and the cell cycle regulator cyclin D1, as well as up-regulation of the cell-cycle inhibitor p27, were also observed after in vivo CH12 treatment. Collectively, these results indicate that the monoclonal antibody CH12 is a promising therapeutic agent for HCC with EGFRvIII expression. PMID:21163950

  8. Rotavirus A-specific single-domain antibodies produced in baculovirus-infected insect larvae are protective in vivo

    PubMed Central

    2012-01-01

    Background Single-domain antibodies (sdAbs), also known as nanobodies or VHHs, are characterized by high stability and solubility, thus maintaining the affinity and therapeutic value provided by conventional antibodies. Given these properties, VHHs offer a novel alternative to classical antibody approaches. To date, VHHs have been produced mainly in E. coli, yeast, plants and mammalian cells. To apply the single-domain antibodies as a preventive or therapeutic strategy to control rotavirus infections in developing countries (444,000 deaths in children under 5 years of age) has to be minimized their production costs. Results Here we describe the highly efficient expression of functional VHHs by the Improved Baculovirus Expression System (IBES® technology), which uses a baculovirus expression vector in combination with Trichoplusia ni larvae as living biofactories. Two VHHs, named 3B2 and 2KD1, specific for the inner capsid protein VP6 of Group A rotavirus, were expressed in insect larvae. The IBES® technology achieved very high expression of 3B2 and 2KD1, reaching 2.62% and 3.63% of the total soluble protein obtained from larvae, respectively. These expression levels represent up to 257 mg/L of protein extract after insect processing (1 L extract represents about 125 g of insect biomass or about 375 insect larvae). Larva-derived antibodies were fully functional when tested in vitro and in vivo, neutralizing Group A rotaviruses and protecting offspring mice against rotavirus-induced diarrhea. Conclusions Our results open up the possibility of using insects as living biofactories (IBES® technology) for the cost-efficient production of these and other fully functional VHHs to be used for diagnostic or therapeutic purposes, thereby eliminating concerns regarding the use of bacterial or mammalian cells. To the best of our knowledge, this is the first time that insects have been used as living biofactories to produce a VHH molecule. PMID:22953695

  9. Harnessing the immune system's arsenal: producing human monoclonal antibodies for therapeutics and investigating immune responses

    PubMed Central

    Sullivan, Meghan; Kaur, Kaval; Pauli, Noel

    2011-01-01

    Monoclonal antibody technology has undergone rapid and innovative reinvention over the last 30 years. Application of these technologies to human samples revealed valuable therapeutic and experimental insights. These technologies, each with their own benefits and flaws, have proven indispensable for immunological research and in our fight to provide new treatments and improved vaccines for infectious disease. PMID:21876728

  10. The Presence, Persistence and Functional Properties of Plasmodium vivax Duffy Binding Protein II Antibodies Are Influenced by HLA Class II Allelic Variants

    PubMed Central

    Torres, Leticia M.; Lima, Barbara A. S.; Sousa, Taís N.; Alves, Jéssica R. S.; Rocha, Roberto S.; Fontes, Cor J. F.; Sanchez, Bruno A. M.; Adams, John H.; Brito, Cristiana F. A.; Pires, Douglas E. V.; Ascher, David B.; Sell, Ana Maria; Carvalho, Luzia H.

    2016-01-01

    Background The human malaria parasite Plasmodium vivax infects red blood cells through a key pathway that requires interaction between Duffy binding protein II (DBPII) and its receptor on reticulocytes, the Duffy antigen/receptor for chemokines (DARC). A high proportion of P. vivax-exposed individuals fail to develop antibodies that inhibit DBPII-DARC interaction, and genetic factors that modulate this humoral immune response are poorly characterized. Here, we investigate if DBPII responsiveness could be HLA class II-linked. Methodology/Principal Findings A community-based open cohort study was carried out in an agricultural settlement of the Brazilian Amazon, in which 336 unrelated volunteers were genotyped for HLA class II (DRB1, DQA1 and DQB1 loci), and their DBPII immune responses were monitored over time (baseline, 6 and 12 months) by conventional serology (DBPII IgG ELISA-detected) and functional assays (inhibition of DBPII–erythrocyte binding). The results demonstrated an increased susceptibility of the DRB1*13:01 carriers to develop and sustain an anti-DBPII IgG response, while individuals with the haplotype DRB1*14:02-DQA1*05:03-DQB1*03:01 were persistent non-responders. HLA class II gene polymorphisms also influenced the functional properties of DBPII antibodies (BIAbs, binding inhibitory antibodies), with three alleles (DRB1*07:01, DQA1*02:01 and DQB1*02:02) comprising a single haplotype linked with the presence and persistence of the BIAbs response. Modelling the structural effects of the HLA-DRB1 variants revealed a number of differences in the peptide-binding groove, which is likely to lead to altered antigen binding and presentation profiles, and hence may explain the differences in subject responses. Conclusions/Significance The current study confirms the heritability of the DBPII antibody response, with genetic variation in HLA class II genes influencing both the development and persistence of IgG antibody responses. Cellular studies to increase

  11. Haitian variant ctxB producing Vibrio cholerae O1 with reduced susceptibility to ciprofloxacin is persistent in Yavatmal, Maharashtra, India, after causing a cholera outbreak.

    PubMed

    Kumar, P; Mishra, D K; Deshmukh, D G; Jain, M; Zade, A M; Ingole, K V; Yadava, P K

    2014-05-01

    Vibrio cholerae O1 biotype El Tor producing Haitian variant Cholera Toxin (HCT) and showing reduced susceptibility to ciprofloxacin caused a cholera outbreak associated with a high case fatality rate (4.5) in India. HCT-secreting strains responsible for severe cholera epidemics in Orissa (India), Western Africa and Haiti were associated with increased mortality. There is a pressing need for an integrated multidisciplinary approach to combat further spread of newly emerging variant strains. The therapeutic effect of ciprofloxacin was diminished whereas use of doxycycline in moderate to severe cholera patients was found to be effective in outbreak management.

  12. Detailed functional characterization of glycosylated and nonglycosylated variants of malaria vaccine candidate PfAMA1 produced in Nicotiana benthamiana and analysis of growth inhibitory responses in rabbits.

    PubMed

    Boes, Alexander; Spiegel, Holger; Edgue, Gueven; Kapelski, Stephanie; Scheuermayer, Matthias; Fendel, Rolf; Remarque, Edmond; Altmann, Friedrich; Maresch, Daniel; Reimann, Andreas; Pradel, Gabriele; Schillberg, Stefan; Fischer, Rainer

    2015-02-01

    One of the most promising malaria vaccine candidate antigens is the Plasmodium falciparum apical membrane antigen 1 (PfAMA1). Several studies have shown that this blood-stage antigen can induce strong parasite growth inhibitory antibody responses. PfAMA1 contains up to six recognition sites for N-linked glycosylation, a post-translational modification that is absent in P. falciparum. To prevent any potential negative impact of N-glycosylation, the recognition sites have been knocked out in most PfAMA1 variants expressed in eukaryotic hosts. However, N-linked glycosylation may increase efficacy by improving immunogenicity and/or focusing the response towards relevant epitopes by glycan masking. We describe the production of glycosylated and nonglycosylated PfAMA1 in Nicotiana benthamiana and its detailed characterization in terms of yield, integrity and protective efficacy. Both PfAMA1 variants accumulated to high levels (>510 μg/g fresh leaf weight) after transient expression, and high-mannose-type N-glycans were confirmed for the glycosylated variant. No significant differences between the N. benthamiana and Pichia pastoris PfAMA1 variants were detected in conformation-sensitive ligand-binding studies. Specific titres of >2 × 10(6) were induced in rabbits, and strong reactivity with P. falciparum schizonts was observed in immunofluorescence assays, as well as up to 100% parasite growth inhibition for both variants, with IC₅₀ values of ~35 μg/mL. Competition assays indicated that a number of epitopes were shielded from immune recognition by N-glycans, warranting further studies to determine how glycosylation can be used for the directed targeting of immune responses. These results highlight the potential of plant transient expression systems as a production platform for vaccine candidates.

  13. Reliability of the nanopheres-DNA immunization technology to produce polyclonal antibodies directed against human neogenic proteins.

    PubMed

    Arnaoty, Ahmed; Gouilleux-Gruart, Valérie; Casteret, Sophie; Pitard, Bruno; Bigot, Yves; Lecomte, Thierry

    2013-08-01

    The molecular domestication of several DNA transposons that occurred during the evolution of the mammalian lineage, has led to the emergence of at least 43 genes, known as neogenes. To date, the limited availability of efficient commercial antibodies directed against most of their protein isoforms hampers investigation of their expression in vitro and in situ. Since immunization protocols using peptides or recombinant proteins have revealed that it is difficult to recover antibodies, we planned to produce antisera in mice using a new technique of nanopheres/DNA immunization, the ICANtibodies™ technology. Here, we investigate the possibilities of obtaining polyclonal antibodies for 24 proteins or protein domains using this immunization strategy. We successfully obtained 13 antisera that were able to detect neogenic proteins by Western blotting and ELISA in protein extracts of transiently-transfected cells and various cancer cell lines, plus another two that only detected the in ELISA and in in situ hybridizations. The features required for the production of these antibodies are analyzed and discussed, and examples are given of the advantages they offer for the study of neogenic proteins.

  14. Production of specific IgY antibody to the recombinant FanC protein produced in Escherichia coli

    PubMed Central

    Nasiri, Khadijeh; Zibaee, Saeed; Nassiri, Mohammadreza; Tahmoorespur, Mojtaba; Haghparast, Alireza

    2016-01-01

    Objective(s): Enterotoxigenic Escherichia coli (ETEC) strains are one of the primary causes of diarrhea in newborn calves and in humans, pigs, and sheep. IgY technology has been identified as a promising alternative to generating a mass amount of specific antibody for use in immunotherapy and immunodiagnostics. The purpose of this study was to produce specific antibody by egg yolk antibody (IgY) to recombinant FanC protein from ETEC. Materials and Methods: FanC (K99) gene was amplified from ETEC by specific primers and polymerase chain reaction. The gene was cloned and subcloned into pTZ57R/T and pET32a (+) vectors, respectively. Recombinant vector was transferred into E. coli BL21 CodonPlus (DE3). Protein expression was investigated by 1 mM IPTG induction. Hens were immunized by the purified recombinant FanC protein. The activity and specificity of the IgY antibody were detected by dot-blotting, Western blotting, and indirect ELISA. Results: We obtained FanC specific IgYs by immunizing the hens with the recombinant FanC protein. The anti-FanC IgY showed binding specifically to the FanC protein of ETEC. Conclusion: The results emphasize that specific IgY against the recombinant FanC protein could be recommended as a candidate for passive immunization against ETEC infection in animals and humans. PMID:27746871

  15. Chromosome-Based blaOXA-48-Like Variants in Shewanella Species Isolates from Food-Producing Animals, Fish, and the Aquatic Environment.

    PubMed

    Ceccarelli, Daniela; van Essen-Zandbergen, Alieda; Veldman, Kees T; Tafro, Nedzib; Haenen, Olga; Mevius, Dik J

    2017-02-01

    Carbapenems are considered last-resort antibiotics in health care. Increasing reports of carbapenemase-producing bacteria in food-producing animals and in the environment indicate the importance of this phenomenon in public health. Surveillance for carbapenemase genes and carbapenemase-producing bacteria in Dutch food-producing animals, environmental freshwater, and imported ornamental fish revealed several chromosome-based blaOXA-48-like variants in Shewanella spp., including two new alleles, blaOXA-514 and blaOXA-515 Carbapenemase genes were not associated with mobile genetic elements or Enterobacteriaceae.

  16. Coexistence of hepatitis B surface antigen (HBs Ag) and anti-HBs antibodies in chronic hepatitis B virus carriers: influence of "a" determinant variants.

    PubMed

    Lada, Olivier; Benhamou, Yves; Poynard, Thierry; Thibault, Vincent

    2006-03-01

    In chronic hepatitis B (CHB), the persistence of hepatitis B surface antigen (HBs Ag) is sometimes associated with antibodies (Ab) to HBs (anti-HBs). To assess the hypothesis of the selection of HBs Ag immune escape variants in CHB patients, the variability of the HBV S gene was determined for patients persistently carrying both HBs Ag and anti-HBs antibodies and patients solely positive for HBs Ag. We selected 14 patients who presented both markers (group I) in several consecutive samples and 12 patients positive for HBs Ag only (group II). The HBs Ag-encoding gene was amplified and cloned, and at least 15 clones per patient were sequenced and analyzed. The number of residue changes within the S protein was 2.7 times more frequent for group I than for group II patients and occurred mostly in the "a" determinant of the major hydrophilic region (MHR), with 9.52 versus 2.43 changes per 100 residues (P = 0.009), respectively. Ten patients (71%) from group I, but only three (25%) from group II, presented at least two residue changes in the MHR. The most frequent changes in group I patients were located at positions s145, s129, s126, s144, and s123, as described for immune escape variants. In CHB patients, the coexistence of HBs Ag and anti-HBs Ab is associated with an increase of "a" determinant variability, suggesting a selection of HBV immune escape mutants during chronic carriage. The consequences of this selection process with regard to vaccine efficacy, diagnosis, and clinical evolution remain partially unknown.

  17. Variant RH alleles and Rh immunisation in patients with sickle cell disease

    PubMed Central

    Sippert, Emilia; Fujita, Claudia R.; Machado, Debora; Guelsin, Glaucia; Gaspardi, Ane C.; Pellegrino, Jordão; Gilli, Simone; Saad, Sara S.T.O.; Castilho, Lilian

    2015-01-01

    Background Alloimmunisation is a major complication in patients with sickle cell disease (SCD) receiving red blood cell (RBC) transfusions and despite provision of Rh phenotyped RBC units, Rh antibodies still occur. These antibodies in patients positive for the corresponding Rh antigen are considered autoantibodies in many cases but variant RH alleles found in SCD patients can also contribute to Rh alloimmunisation. In this study, we characterised variant RH alleles in 31 SCD patients who made antibodies to Rh antigens despite antigen-positive status and evaluated the clinical significance of the antibodies produced. Materials and methods RHD and RHCE BeadChip™ from BioArray Solutions and/or amplification and sequencing of exons were used to identify the RH variants. The serological features of all Rh antibodies in antigen-positive patients were analysed and the clinical significance of the antibodies was evaluated by retrospective analysis of the haemoglobin (Hb) levels before and after transfusion; the change from baseline pre-transfusion Hb and the percentage of HbS were also determined. Results We identified variant RH alleles in 31/48 (65%) of SCD patients with Rh antibodies. Molecular analyses revealed the presence of partial RHD alleles and variant RHCE alleles associated with altered C and e antigens. Five patients were compound heterozygotes for RHD and RHCE variants. Retrospective analysis showed that 42% of antibodies produced by the patients with RH variants were involved in delayed haemolytic transfusion reactions or decreased survival of transfused RBC. Discussion In this study, we found that Rh antibodies in SCD patients with RH variants can be clinically significant and, therefore, matching patients based on RH variants should be considered. PMID:24960646

  18. Relevance of biallelic versus monoallelic TNFRSF13B mutations in distinguishing disease-causing from risk-increasing TNFRSF13B variants in antibody deficiency syndromes

    PubMed Central

    Salzer, Ulrich; Bacchelli, Chiara; Buckridge, Sylvie; Pan-Hammarström, Qiang; Jennings, Stephanie; Lougaris, Vassilis; Bergbreiter, Astrid; Hagena, Tina; Birmelin, Jennifer; Plebani, Alessandro; Webster, A. David B.; Peter, Hans-Hartmut; Suez, Daniel; Chapel, Helen; McLean-Tooke, Andrew; Spickett, Gavin P.; Anover-Sombke, Stephanie; Ochs, Hans D.; Urschel, Simon; Belohradsky, Bernd H.; Ugrinovic, Sanja; Kumararatne, Dinakantha S.; Lawrence, Tatiana C.; Holm, Are M.; Franco, Jose L.; Schulze, Ilka; Schneider, Pascal; Gertz, E. Michael; Schäffer, Alejandro A.; Hammarström, Lennart; Thrasher, Adrian J.; Gaspar, H. Bobby

    2009-01-01

    TNFRSF13B encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), a B cell– specific tumor necrosis factor (TNF) receptor superfamily member. Both biallelic and monoallelic TNFRSF13B mutations were identified in patients with common variable immunodeficiency disorders. The genetic complexity and variable clinical presentation of TACI deficiency prompted us to evaluate the genetic, immunologic, and clinical condition in 50 individuals with TNFRSF13B alterations, following screening of 564 unrelated patients with hypogammaglobulinemia. We identified 13 new sequence variants. The most frequent TNFRSF13B variants (C104R and A181E; n = 39; 6.9%) were also present in a heterozygous state in 2% of 675 controls. All patients with biallelic mutations had hypogammaglobulinemia and nearly all showed impaired binding to a proliferation-inducing ligand (APRIL). However, the majority (n = 41; 82%) of the pa-tients carried monoallelic changes in TNFRSF13B. Presence of a heterozygous mutation was associated with antibody deficiency (P <.001, relative risk 3.6). Heterozygosity for the most common mutation, C104R, was associated with disease (P < .001, relative risk 4.2). Furthermore, heterozygosity for C104R was associated with low numbers of IgD−CD27+ B cells (P = .019), benign lymphoproliferation (P < .001), and autoimmune complications (P = .001). These associations indicate that C104R heterozygosity increases the risk for common variable immunodeficiency disorders and influences clinical presentation. PMID:18981294

  19. Characterization of drug-product-related impurities and variants of a therapeutic monoclonal antibody by higher energy C-trap dissociation mass spectrometry.

    PubMed

    Wang, Deyun; Wynne, Colin; Gu, Flora; Becker, Chris; Zhao, Jia; Mueller, Hans-Martin; Li, Huijuan; Shameem, Mohammed; Liu, Yan-Hui

    2015-01-20

    Mass spectrometry (MS) characterization of recombinant monoclonal antibody (mAb) drugs and their degraded and/or post-translationally modified counterparts, drug-product-related impurities and variants, is critical for successful development of biotherapeutics. Specifically in this study, drug-product-related impurities of an anti-Clostridium difficile IgG1 mAb drug substance were profiled by cation-exchange liquid chromatography (CEX) followed by the CEX peaks being fraction-collected for MS characterization. A reversed-phase liquid chromatography/mass spectrometry (LC/MS) methodology was developed on a Thermo Q-Exactive orbitrap mass spectrometer for (1) accurate mass measurements of the mAb, its CEX fractionated impurities, and their respective heavy chains and light chains and (2) middle-down LC/MS/MS of the light chains and the heavy chains using higher energy C-trap dissociation (HCD). The accurate mass measurements and the HCD middle-down MS/MS experiments identify that major impurities and variants of the anti-C. difficile mAb are degradation species of the heavy chains at residue Asn101 as well as at the hinge region amino acids, including Cys222, Lys224, His226, and Thr227, with levels ranging from 0.3% to 6.2% of the total drug substance. Additional impurities were identified as light chain C-terminal truncation at Gly93 and oxidized heavy chains at Met40, Met93, and Met430. Our impurity characterization results demonstrate that the middle-down MS method allows direct and accurate identification of drug-product-related impurities of therapeutic mAbs. It is particularly useful for those low-level impurities and variants that are not suitable for further fractionation and characterization by bottom-up MS.

  20. Multiproduct high-resolution monoclonal antibody charge variant separations by pH gradient ion-exchange chromatography.

    PubMed

    Farnan, Dell; Moreno, G Tony

    2009-11-01

    In the biotechnology industry, ion-exchange chromatography is widely used for profiling the charge heterogeneity of proteins, including monoclonal antibodies. Ionic strength based ion exchange separations, while having excellent resolving power and robustness, are product specific and time-consuming to develop. In the present work, a pH gradient based separation using a cation exchange column is described and shown to be a multiproduct charge sensitive separation method for monoclonal antibodies. Simple mixtures of defined buffer components were used to generate the pH-gradients that separate closely related antibody species. The form of the pH gradient was controlled and optimized by the pump as well as the buffer composition if necessary. During this work, the buffer compositions for the separation were optimized in parallel for several MAbs. The data shows that the multiproduct method is optimal for all of the MAbs studied. Operational aspects of the separation such as column chemistry, column length, and sample matrix indicate a very robust method. The pH gradient ion-exchange method is demonstrated to have significant resolving power and peak capacities far in excess of what we would expect for ionic strength elution ion-exchange. Data obtained demonstrates that the separation is relatively insensitive to column length. Direct analysis (no buffer exchange) of samples in matrixes consistent with in-process manufacturing pools is demonstrated. Such a capability is extremely useful for the high throughput evaluation of in-process and final product samples.

  1. Specific recognition pattern of IgM and IgG antibodies produced in the course of experimental paracoccidioidomycosis.

    PubMed Central

    Vaz, C A; Mackenzie, D W; Hearn, V M; Camargo, Z P; Singer-Vermes, L M; Burger, E; Calich, V L

    1992-01-01

    Specific IgM and IgG responses to Paracoccidioides brasiliensis produced in resistant and susceptible mice during experimental paracoccidioidomycosis were examined by the immunoblotting procedure. Sera from infected mice recognized 51 antigen bands with apparent molecular masses from 8 to 86 kD. Sixteen of these were defined as major antigen bands because of almost universal presence of antibodies to them, and their intense staining. All sera, including those from normal control mice, tested for both IgM and IgG antibody reacted with the major E antigen which appeared as a large diffuse band from 43 to 47 kD. Comparisons between resistant and susceptible mice showed some significant differences in IgM responses to many antigen bands. While IgG responses were quite similar for both strains, differences were apparent in the response to the antigens at 62 and 68 kD. Images Fig. 1 Fig. 2 Fig. 3 PMID:1563097

  2. CD27− B-Cells Produce Class Switched and Somatically Hyper-Mutated Antibodies during Chronic HIV-1 Infection

    PubMed Central

    Cagigi, Alberto; Du, Likun; Dang, Linh Vu Phuong; Grutzmeier, Sven; Atlas, Ann; Chiodi, Francesca

    2009-01-01

    Class switch recombination and somatic hypermutation occur in mature B-cells in response to antigen stimulation. These processes are crucial for the generation of functional antibodies. During HIV-1 infection, loss of memory B-cells, together with an altered differentiation of naïve B-cells result in production of low quality antibodies, which may be due to impaired immunoglobulin affinity maturation. In the current study, we evaluated the effect of HIV-1 infection on class switch recombination and somatic hypermutation by studying the expression of activation-induced cytidine deaminase (AID) in peripheral B-cells from a cohort of chronically HIV-1 infected patients as compared to a group of healthy controls. In parallel, we also characterized the phenotype of B-cells and their ability to produce immunoglobulins in vitro. Cells from HIV-1 infected patients showed higher baseline levels of AID expression and increased IgA production measured ex-vivo and upon CD40 and TLR9 stimulation in vitro. Moreover, the percentage of CD27−IgA+ and CD27−IgG+ B-cells in blood was significantly increased in HIV-1 infected patients as compared to controls. Interestingly, our results showed a significantly increased number of somatic hypermutations in the VH genes in CD27− cells from patients. Taken together, these results show that during HIV-1 infection, CD27− B-cells can also produce class switched and somatically hypermutated antibodies. Our data add important information for the understanding of the mechanisms underlying the loss of specific antibody production observed during HIV-1 infection. PMID:19412542

  3. Enzyme-labeled Antigen Method: Development and Application of the Novel Approach for Identifying Plasma Cells Locally Producing Disease-specific Antibodies in Inflammatory Lesions

    PubMed Central

    Mizutani, Yasuyoshi; Shiogama, Kazuya; Onouchi, Takanori; Sakurai, Kouhei; Inada, Ken-ichi; Tsutsumi, Yutaka

    2016-01-01

    In chronic inflammatory lesions of autoimmune and infectious diseases, plasma cells are frequently observed. Antigens recognized by antibodies produced by the plasma cells mostly remain unclear. A new technique identifying these corresponding antigens may give us a breakthrough for understanding the disease from a pathophysiological viewpoint, simply because the immunocytes are seen within the lesion. We have developed an enzyme-labeled antigen method for microscopic identification of the antigen recognized by specific antibodies locally produced in plasma cells in inflammatory lesions. Firstly, target biotinylated antigens were constructed by the wheat germ cell-free protein synthesis system or through chemical biotinylation. Next, proteins reactive to antibodies in tissue extracts were screened and antibody titers were evaluated by the AlphaScreen method. Finally, with the enzyme-labeled antigen method using the biotinylated antigens as probes, plasma cells producing specific antibodies were microscopically localized in fixed frozen sections. Our novel approach visualized tissue plasma cells that produced 1) autoantibodies in rheumatoid arthritis, 2) antibodies against major antigens of Porphyromonas gingivalis in periodontitis or radicular cyst, and 3) antibodies against a carbohydrate antigen, Strep A, of Streptococcus pyogenes in recurrent tonsillitis. Evaluation of local specific antibody responses expectedly contributes to clarifying previously unknown processes in inflammatory disorders. PMID:27006517

  4. Monoclonal neutralizing antibodies against EV71 screened from mice immunized with yeast-produced virus-like particles.

    PubMed

    Lin, Tao; Xianyu, Lingzhi; Lyu, Songya

    2015-06-01

    Periodic outbreaks of hand, foot and mouth disease (HFMD) occur in children under 5 years old, and can cause death in some cases. The C4 strain of enterovirus 71 (EV71) is the main pathogen that causes HFMD in China. Although no drugs against EV71 are available, some studies have shown that candidate vaccines or viral capsid proteins can produce anti-EV71 immunity. In this study, female BABL/c mice (6-8 weeks old) were immunized with virus-like particles (VLPs) of EV71 produced in yeast to screen for anti-EV71 antibodies. Two hybridomas that could produce neutralizing antibodies against EV71 were obtained. Both neutralizing mAbs (D4 and G12) were confirmed to bind the VP1 capsid protein of EV71, and could protect >95% cells from 100 TCID50 EV71 infection at 25 µg/mL solution (lowest concentration). Those two neutralizing mAbs identified in the study may be promising candidates in development for mAbs to treat EV71 infection, and utilized as suitable reagents for use in diagnostic tests and biological studies.

  5. Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.

    PubMed

    Sakudo, Akikazu; Chou, Han; Nagatsu, Masaaki

    2015-03-01

    Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella.

  6. An In Vitro Combined Antibiotic-Antibody Treatment Eliminates Toxicity from Shiga Toxin-Producing Escherichia coli

    PubMed Central

    Skinner, Craig; Zhang, Guodong; Patfield, Stephanie

    2015-01-01

    Treating Shiga toxin-producing Escherichia coli (STEC) gastrointestinal infections is difficult. The utility of antibiotics for STEC treatment is controversial, since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase the expression of Shiga toxins (Stxs), which are some of the most important virulence factors in STEC. Stxs contribute to life-threatening hemolytic uremic syndrome (HUS), which develops in considerable proportions of patients with STEC infections. Understanding the antibiotic resistance profiles of STEC isolates and the Stx induction potential of promising antibiotics is essential for evaluating any antibiotic treatment of STEC. In this study, 42 O157:H7 or non-O157 STEC isolates (including the “big six” serotypes) were evaluated for their resistance against 22 antibiotics by using an antibiotic array. Tigecycline inhibited the growth of all of the tested STEC isolates and also inhibited the production of Stxs (Stx2 in particular). In combination with neutralizing antibodies to Stx1 and Stx2, the tigecycline-antibody treatment fully protected Vero cells from Stx toxicity, even when the STEC bacteria and the Vero cells were cultured together. The combination of an antibiotic such as tigecycline with neutralizing antibodies presents a promising strategy for future STEC treatments. PMID:26100707

  7. Antibody-producing cells correlated to body weight in juvenile chinook salmon (Oncorhynchus tshawytscha) acclimated to optimal and elevated temperatures

    USGS Publications Warehouse

    Harrahy, L.N.M.; Schreck, C.B.; Maule, A.G.

    2001-01-01

    The immune response of juvenile chinook salmon (Oncorhynchus tshawytscha) ranging in weight from approximately 10 to 55 g was compared when the fish were acclimated to either 13 or 21?? C. A haemolytic plaque assay was conducted to determine differences in the number of antibody-producing cells (APC) among fish of a similar age but different body weights. Regression analyses revealed significant increases in the number of APC with increasing body weight when fish were acclimated to either water temperature. These results emphasise the importance of standardising fish weight in immunological studies of salmonids before exploring the possible effects of acclimation temperatures. ?? 2001 Academic Press.

  8. Structural insight in the inhibition of adherence of F4 fimbriae producing enterotoxigenic Escherichia coli by llama single domain antibodies.

    PubMed

    Moonens, Kristof; Van den Broeck, Imke; Okello, Emmanuel; Pardon, Els; De Kerpel, Maia; Remaut, Han; De Greve, Henri

    2015-02-24

    Enterotoxigenic Escherichia coli that cause neonatal and post-weaning diarrhea in piglets express F4 fimbriae to mediate attachment towards host receptors. Recently we described how llama single domain antibodies (VHHs) fused to IgA, produced in Arabidopsis thaliana seeds and fed to piglets resulted in a progressive decline in shedding of F4 positive ETEC bacteria. Here we present the structures of these inhibiting VHHs in complex with the major adhesive subunit FaeG. A conserved surface, distant from the lactose binding pocket, is targeted by these VHHs, highlighting the possibility of targeting epitopes on single-domain adhesins that are non-involved in receptor binding.

  9. Human Memory B Cells Producing Potent Cross-Neutralizing Antibodies against Human Parechovirus: Implications for Prevalence, Treatment, and Diagnosis

    PubMed Central

    Benschop, K. S. M.; Koen, G.; Claassen, Y. B.; Wagner, K.; Bakker, A. Q.; Wolthers, K. C.

    2015-01-01

    ABSTRACT The family Picornaviridae is a large and diverse group of positive-sense RNA viruses, including human enteroviruses (EVs) and human parechoviruses (HPeVs). The human immune response against EVs and HPeVs is thought to be mainly humoral, and an insufficient neutralizing antibody (Ab) response during infection is a risk factor and can ultimately be life threatening. The accessibility of different antigenic sites and observed cross-reactivity make HPeVs a good target for development of therapeutic human monoclonal antibodies (MAbs). In this study, we generated two different human MAbs specific for HPeV by screening culture supernatants of Ab-producing human B cell cultures for direct neutralization of HPeV1. Both MAbs showed HPeV1-specific neutralization as well as neutralization of HPeV2. One antibody, AM18, cross-neutralized HPeV4, -5, and -6 and coxsackievirus A9 (CV-A9). VP1 capsid protein-specific assays confirmed that AM18 bound VP1 of HPeV1, -2, and -4 with high affinity (11.5 pM). In contrast, the HPeV1-specific MAb AM28, which neutralized HPeV1 even more efficiently than did AM18, showed no cross-reactivity with HPeV3 to -6 or other EVs and did not bind any of the capsid proteins, suggesting that AM28 is specific for a conformation-dependent, nonlinear epitope on the virus. The discovery of MAbs that are cross-reactive between HPeVs may help development of HPeV treatment options with antibodies and vaccine design based on epitopes recognized by these antibodies. IMPORTANCE HPeV infections are widespread among young children and adults, causing a broad range of disease. Infections can be severe and life threatening, while no antiviral treatment is available. Given that the absence of neutralizing Abs is a risk factor for severe disease in infants, treatment of picornavirus infections with MAbs would be a therapeutic option. To study antibody neutralization of HPeV in more detail, we generated two different HPeV1-specific human MAbs. Both MAbs show HPe

  10. Natural killer cells produce T cell-recruiting chemokines in response to antibody-coated tumor cells.

    PubMed

    Roda, Julie M; Parihar, Robin; Magro, Cynthia; Nuovo, Gerard J; Tridandapani, Susheela; Carson, William E

    2006-01-01

    In the current report, we have examined the ability of natural killer (NK) cells to produce T cell-recruiting chemokines following dual stimulation with interleukin (IL)-2 or IL-12 and human breast cancer cells coated with an antitumor antibody (trastuzumab). NK cells stimulated in this manner secreted an array of T cell-recruiting chemotactic factors, including IL-8, macrophage-derived chemokine, macrophage inflammatory protein 1alpha (MIP-1alpha), monocyte chemoattractant protein 1, and regulated on activation, normal T-cell expressed and secreted (RANTES), whereas stimulation of NK cells with either agent alone had minimal effect. Furthermore, these factors were functional for T-cell chemotaxis as culture supernatants derived from costimulated NK cells induced migration of both naïve and activated T cells in an in vitro chemotaxis assay. T-cell migration was significantly reduced when neutralizing antibodies to IL-8, MIP-1alpha, or RANTES were added to culture supernatants before their use in the chemotaxis assay. In addition, coadministration of trastuzumab-coated tumor cells and IL-12 to mice led to enhanced serum MIP-1alpha. As a clinical correlate, we examined the chemokine content of serum samples from breast cancer patients enrolled on a phase I trial of trastuzumab and IL-12, and found elevated levels of IL-8, RANTES, IFN-gamma inducible protein 10, monokine induced by IFN-gamma, and MIP-1alpha, specifically in those patients that experienced a clinical benefit. Sera from these patients exhibited the ability to direct T-cell migration in a chemotaxis assay, and neutralization of chemokines abrogated this effect. These data are the first to show chemokine production by NK cells, specifically in response to stimulation with antibody-coated tumor cells, and suggest a potential role for NK cell-derived chemokines in patients receiving therapeutic monoclonal antibodies.

  11. Neutralization of Clostridium difficile Toxin B Mediated by Engineered Lactobacilli That Produce Single-Domain Antibodies

    PubMed Central

    Andersen, Kasper Krogh; Strokappe, Nika M.; Hultberg, Anna; Truusalu, Kai; Smidt, Imbi; Mikelsaar, Raik-Hiio; Mikelsaar, Marika; Verrips, Theo; Hammarström, Lennart

    2015-01-01

    Clostridium difficile is the primary cause of nosocomial antibiotic-associated diarrhea in the Western world. The major virulence factors of C. difficile are two exotoxins, toxin A (TcdA) and toxin B (TcdB), which cause extensive colonic inflammation and epithelial damage manifested by episodes of diarrhea. In this study, we explored the basis for an oral antitoxin strategy based on engineered Lactobacillus strains expressing TcdB-neutralizing antibody fragments in the gastrointestinal tract. Variable domain of heavy chain-only (VHH) antibodies were raised in llamas by immunization with the complete TcdB toxin. Four unique VHH fragments neutralizing TcdB in vitro were isolated. When these VHH fragments were expressed in either secreted or cell wall-anchored form in Lactobacillus paracasei BL23, they were able to neutralize the cytotoxic effect of the toxin in an in vitro cell-based assay. Prophylactic treatment with a combination of two strains of engineered L. paracasei BL23 expressing two neutralizing anti-TcdB VHH fragments (VHH-B2 and VHH-G3) delayed killing in a hamster protection model where the animals were challenged with spores of a TcdA− TcdB+ strain of C. difficile (P < 0.05). Half of the hamsters in the treated group survived until the termination of the experiment at day 5 and showed either no damage or limited inflammation of the colonic mucosa despite having been colonized with C. difficile for up to 4 days. The protective effect in the hamster model suggests that the strategy could be explored as a supplement to existing therapies for patients. PMID:26573738

  12. IgA and IgG antineutrophil cytoplasmic antibody engagement of Fc receptor genetic variants influences granulomatosis with polyangiitis.

    PubMed

    Kelley, James M; Monach, Paul A; Ji, Chuanyi; Zhou, Yebin; Wu, Jianming; Tanaka, Sumiaki; Mahr, Alfred D; Johnson, Sharleen; McAlear, Carol; Cuthbertson, David; Carette, Simon; Davis, John C; Dellaripa, Paul F; Hoffman, Gary S; Khalidi, Nader; Langford, Carol A; Seo, Phillip; St Clair, E William; Specks, Ulrich; Stone, John H; Spiera, Robert F; Ytterberg, Steven R; Merkel, Peter A; Edberg, Jeffrey C; Kimberly, Robert P

    2011-12-20

    Granulomatosis with polyangiitis (Wegener's) is a rare autoimmune neutrophil-mediated vasculitis that can cause renal disease and mucosal manifestations. Antineutrophil cytoplasmic antibodies (ANCA) are present in many patients, vary in level over time, and induce neutrophil activation through engagement with Fc receptors (FcRs). Given roles for FcRs in ANCA-mediated neutrophil activation and IgA antibodies in mucosal immunity, we hypothesized that FcR genetics and previously unappreciated IgA ANCA affect clinical presentation. We assembled a total of 673 patients and 413 controls from two multicenter cohorts, performed ELISA and immunofluorescence assays to determine IgA and IgG ANCA positivity, and used Illumina, TaqMan, or Pyrosequencing to genotype eight haplotype-tagging SNPs in the IgA FcR (FCAR) and to determine NA1/NA2 genotype of FCGR3B, the most prevalent neutrophil IgG FcR. We evaluated neutrophil activation by measuring degranulation marker CD11b with flow cytometry or neutrophil extracellcular trap formation with confocal microscopy. Functional polymorphisms in FCGR3B and FCAR differed between patient groups stratified by renal involvement. IgA ANCA were found in ∼30% of patients and were less common in patients with severe renal disease. Neutrophil stimulation by IgA or IgG ANCA led to degranulation and neutrophil extracellcular trap formation in a FcR allele-specific manner (IgA:FCAR P = 0.008; IgG:FCGR3B P = 0.003). When stimulated with IgA and IgG ANCA together, IgG ANCA induced neutrophil activation was reduced (P = 0.0001). FcR genotypes, IgA ANCA, and IgG ANCA are potential prognostic and therapeutic targets for understanding the pathogenesis and presentation of granulomatosis with polyangiitis (Wegener's).

  13. High-antibody-producing Chinese hamster ovary cells up-regulate intracellular protein transport and glutathione synthesis.

    PubMed

    Orellana, Camila A; Marcellin, Esteban; Schulz, Benjamin L; Nouwens, Amanda S; Gray, Peter P; Nielsen, Lars K

    2015-02-06

    Chinese hamster ovary (CHO) cells are the preferred production host for therapeutic monoclonal antibodies (mAb) due to their ability to perform post-translational modifications and their successful approval history. The completion of the genome sequence for CHO cells has reignited interest in using quantitative proteomics to identify markers of good production lines. Here we applied two different proteomic techniques, iTRAQ and SWATH, for the identification of expression differences between a high- and low-antibody-producing CHO cell lines derived from the same transfection. More than 2000 proteins were quantified with 70 of them classified as differentially expressed in both techniques. Two biological processes were identified as differentially regulated by both methods: up-regulation of glutathione biosynthesis and down-regulation of DNA replication. Metabolomic analysis confirmed that the high producing cell line displayed higher intracellular levels of glutathione. SWATH further identified up-regulation of actin filament processes and intracellular transport and down regulation of several growth-related processes. These processes may be important for conferring high mAb production and as such are promising candidates for targeted engineering of high-expression cell lines.

  14. Association of the interleukin-12 polymorphic variants with the development of antibodies to surface antigen of hepatitis B virus in hemodialysis patients in response to vaccination or infection.

    PubMed

    Grzegorzewska, Alicja E; Wobszal, Piotr M; Sowińska, Anna; Mostowska, Adrianna; Jagodziński, Paweł P

    2013-12-01

    Cytokines, involved in the T-helper 1 system, play a role in the regulation of hepatitis B virus (HBV) clearance and the immune response to HBV antigens during natural infection or planned vaccination. Our aim was to examine whether the polymorphic variants of IL-12 are equally associated with development of antibodies to HBV surface antigen (anti-HBs) in hemodialysis (HD) patients in the case of HBV vaccination or HBV infection. The IL-12A rs568408 and IL-12B rs3212227 polymorphisms were analyzed in relation to anti-HBs development in 602 HD patients with negative antibodies to HBV core antigen (anti-HBc) who were hepatitis B vaccinated (group I) as well as in 237 anti-HBc positive HD patients who were infected with HBV in the past (group II). In group I, 199 patients did not develop an anti-HBs titre >10 IU/L (subgroup Ia), whereas in group II, 55 patients did not develop an anti-HBs titre >10 IU/L (subgroup IIa). Patients of groups I and II that developed an anti-HBs >10 IU/L were included into subgroups Ib and IIb, respectively. In hepatitis B vaccinated HD patients, development of a protective anti-HBs titre was positively associated with vintage of renal replacement therapy (RRT), chronic glomerulonephritis as a cause of RRT, and GA rs 568408 IL-12A (OR 1.6, 95 % CI 1.0-2.5, P = 0.035), but a frequency distribution of this genotype between responders and non-responders was not significant when the Bonferroni correction was applied. In HBV infected HD patients, anti-HBs development was positively associated with AC rs3212227 IL-12B (OR 8.0, 95 % CI 2.6-24.9, P < 0.001), whereas HBsAg positivity, AA rs3212227 IL-12B (OR 0.3, 95 % CI 0.1-0.7, P = 0.007), and CC rs3212227 IL-12B (OR 0.1, 95 % CI 0.03-0.6, P = 0.011) were negative predictors of positive anti-HBs phenotype. When the Bonferroni correction was applied, if appropriate, these associations remained significant. In HD patients, the studied IL-12 polymorphic variants seem to be associated

  15. Taking advantage of unspecific interactions to produce highly active magnetic nanoparticle-antibody conjugates.

    PubMed

    Puertas, Sara; Batalla, Pilar; Moros, María; Polo, Ester; Del Pino, Pablo; Guisan, José M; Grazú, Valeria; de la Fuente, Jesús M

    2011-06-28

    Several strategies for linking antibodies (Abs) through their Fc region in an oriented manner have been proposed at the present time. By using these strategies, the Fab region of the Ab is available for antigen molecular recognition, leading to a more efficient interaction. Most of these strategies are complex processes optimized mainly for the functionalization of surfaces or microbeads. These methodologies imply though the Ab modification through several steps of purification or the use of expensive immobilized proteins. Besides, the functionalization of magnetic nanoparticles (MNPs) turned out to be much more complex than expected due to the lack of stability of most MNPs at high ionic strength and non-neutral pH values. Therefore, there is still missing an efficient, easy and universal methodology for the immobilization of nonmodified Abs onto MNPs without involving their Fab regions during the immobilization process. Herein, we propose the functionalization of MNPs via a two-steps strategy that takes advantage of the ionic reversible interactions between the Ab and the MNP. These interactions make possible the orientation of the Ab on the MNP surface before being attached in an irreversible way via covalent bonds. Three Abs (Immunoglobulin G class) with very different isoelectric points (against peroxidase, carcinoembryonic antigen, and human chorionic gonadotropin hormone) were used to prove the general applicability of the strategy here proposed and its utility for the development of more bioactive NPs.

  16. Monoclonal antibodies of three different immunoglobulin G isotypes produced by immunization with a synthetic peptide or native protein protect mice against challenge with Plasmodium yoelii sporozoites.

    PubMed

    Ak, M; Bower, J H; Hoffman, S L; Sedegah, M; Lees, A; Carter, M; Beaudoin, R L; Charoenvit, Y

    1993-06-01

    Passive transfer of monoclonal antibodies (MAbs) against malaria circumsporozoite (CS) proteins protects animals against malaria. Active immunization with synthetic or recombinant peptides induces a level of polyclonal antibodies to sporozoites comparable to those found after passive immunization but does not provide comparable protection. In the Plasmodium yoelii system, synthetic or recombinant peptide-induced antibodies have never been shown to protect. The current studies were designed to determine whether immunogen structure (native protein versus synthetic peptide) or immunoglobulin G (IgG) subclass of antibodies was responsible for the absolute differences between protective, passively transferred MAbs and nonprotective, actively induced polyclonal antibodies. In this study we produced two MAbs, QGP-S1 (IgG1) and QGP-S2 (IgG2b), by immunization with a synthetic peptide based on the P. yoelii CS major repeat, (QGPGAP)4, conjugated to keyhole limpet hemocyanin. These MAbs were compared tp NYS1 (IgG3), an anti-CS protein MAb previously produced by immunization with irradiated P. yoelii sporozoites, which recognizes (QGP GAP)2. QGP-S1 and QGP-S2 passively transferred protection. However, when compared with NYS1, there was a hierarchy of protection, NYS1 > QGP-S1 > QGP-S2. There was no correlation between antibody level at challenge as determined by immunofluorescent antibody test against sporozoites or enzyme-linked immunosorbent assay against (QGPGAP)2 or apparent antibody avidity for (QGPGAP)2 by sodium thiocyanate elution assay. The data demonstrate that a synthetic peptide can induce protective antibodies and that a specific antibody subclass is not required for protection. Work to determine whether antibody affinity or fine specificity can explain the hierarchy of protection among the MAbs is under way.

  17. Scaled-up manufacturing of recombinant antibodies produced by plant cells in a 200-L orbitally-shaken disposable bioreactor.

    PubMed

    Raven, Nicole; Rasche, Stefan; Kuehn, Christoph; Anderlei, Tibor; Klöckner, Wolf; Schuster, Flora; Henquet, Maurice; Bosch, Dirk; Büchs, Jochen; Fischer, Rainer; Schillberg, Stefan

    2015-02-01

    Tobacco BY-2 cells have emerged as a promising platform for the manufacture of biopharmaceutical proteins, offering efficient protein secretion, favourable growth characteristics and cultivation in containment under a controlled environment. The cultivation of BY-2 cells in disposable bioreactors is a useful alternative to conventional stainless steel stirred-tank reactors, and orbitally-shaken bioreactors could provide further advantages such as simple bag geometry, scalability and predictable process settings. We carried out a scale-up study, using a 200-L orbitally-shaken bioreactor holding disposable bags, and BY-2 cells producing the human monoclonal antibody M12. We found that cell growth and recombinant protein accumulation were comparable to standard shake flask cultivation, despite a 200-fold difference in cultivation volume. Final cell fresh weights of 300-387 g/L and M12 yields of ∼20 mg/L were achieved with both cultivation methods. Furthermore, we established an efficient downstream process for the recovery of M12 from the culture broth. The viscous spent medium prevented clarification using filtration devices, but we used expanded bed adsorption (EBA) chromatography with SP Sepharose as an alternative for the efficient capture of the M12 antibody. EBA was introduced as an initial purification step prior to protein A affinity chromatography, resulting in an overall M12 recovery of 75-85% and a purity of >95%. Our results demonstrate the suitability of orbitally-shaken bioreactors for the scaled-up cultivation of plant cell suspension cultures and provide a strategy for the efficient purification of antibodies from the BY-2 culture medium.

  18. Theoretical study of catalytic efficiency of a Diels-Alderase catalytic antibody: an indirect effect produced during the maturation process.

    PubMed

    Martí, Sergio; Andrés, Juan; Moliner, Vicent; Silla, Estanislao; Tuñón, Iñaki; Bertrán, Juan

    2008-01-01

    The Diels-Alder reaction is one of the most important and versatile transformations available to organic chemists for the construction of complex natural products, therapeutics agents, and synthetic materials. Given the lack of efficient enzymes capable of catalyzing this kind of reaction, it is of interest to ask whether a biological catalyst could be designed from an antibody-combining site. In the present work, a theoretical study of the different behavior of a germline catalytic antibody (CA) and its matured form, 39 A-11, that catalyze a Diels-Alder reaction has been carried out. A free-energy perturbation technique based on a hybrid quantum-mechanics/molecular-mechanics scheme, together with internal energy minimizations, has allowed free-energy profiles to be obtained for both CAs. The profiles show a smaller barrier for the matured form, which is in agreement with the experimental observation. Free-energy profiles were obtained with this methodology, thereby avoiding the much more demanding two-dimensional calculations of the energy surfaces that are normally required to study this kind of reaction. Structural analysis and energy evaluations of substrate-protein interactions have been performed from averaged structures, which allows understanding of how the single mutations carried out during the maturation process can be responsible for the observed fourfold enhancement of the catalytic rate constant. The conclusion is that the mutation effect in this studied germline CA produces a complex indirect effect through coupled movements of the backbone of the protein and the substrate.

  19. Changes of the immune reactivities of antibodies produced against gamma-irradiated antigen

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Lee, Ju-Woon; Seo, Ji-Hyun; Kim, Jae-Hun; Jo, Cheorun; Kim, Dong-Ho; Chung, Hyung-Wook

    2004-09-01

    To observe the changes of immunogenicity and antigenicity of gamma-irradiated ovalbumin (OVA), an antigen (Ag) solution (2.0 mg/ml) was prepared and irradiated with the absorbed doses of 3 and 10 kGy. Immunoglobulin G (IgG) was produced for each Ag. 0, 3 and 10 kGy-IgG were individually reacted against 3 Ags in an ELISA cross reactivity test. Cross reactivity of each IgG was significantly different for each Ag. Especially the 10 kGy-irradiated OVA lost most antigenicity compared to the 0 kGy-IgG.

  20. Antibody response against plasmid-encoded toxin (Pet) and the protein involved in intestinal colonization (Pic) in children with diarrhea produced by enteroaggregative Escherichia coli.

    PubMed

    Bellini, Estela M; Elias, Waldir P; Gomes, Tânia A T; Tanaka, Tânia L; Taddei, Carla R; Huerta, Rocio; Navarro-Garcia, Fernando; Martinez, Marina B

    2005-02-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging cause of pediatric and adult travellers diarrhea. The mechanism by which EAEC induce diarrhea is not completely known. Two serine protease autotransporter proteins, named Pet and Pic have been identified in EAEC strains. Pet has enterotoxic and cytotoxic activities, while the role of Pic in pathogenesis may lie on its mucinolytic activity. Little is known about Pet and Pic biological activities in vivo. In this study the antibody responses against these autotransporter proteins in convalescent children is investigated. Fifteen (83%) children showed specific antibodies against Pet or Pic in their sera. IgG and IgM antibodies were the main isotype found. Specific antibodies against Pic, but not against Pet, were detected in sera from age-matched control group. These data show that specific anti-Pet and anti-Pic antibodies are produced during the course of a natural EAEC infection in children.

  1. Efficient generation in vitro, from human peripheral blood cells, of monoclonal Epstein-Barr virus transformants producing specific antibody to a variety of antigens without prior deliberate immunization.

    PubMed Central

    Winger, L; Winger, C; Shastry, P; Russell, A; Longenecker, M

    1983-01-01

    This paper describes a simple protocol for the efficient generation of large numbers of human monoclonal antibody-producing cells. This system is based on initial limiting-dilution culture after Epstein-Barr virus exposure of highly enriched precursors selected from peripheral blood mononuclear cells. Precursors can be enriched by using rosetting or panning approaches. Antibodies to erythrocytes, a mouse mammary carcinoma, DNA, and sperm antigens, produced without any deliberate immunization, are described. Large-scale human monoclonal antibody production may be facilitated by a combination of this protocol with a human cellular fusion system. For efficient precursor analysis and short-term (2 months or more) monoclonal antibody production, however, the system described here may be sufficient. Images PMID:6308627

  2. Effector properties and glycosylation patterns of recombinant human anti-D-IgG1 antibodies produced by human PER.C6(®) cells.

    PubMed

    Olovnikova, N I; Grigorieva, O V; Petrov, A V

    2012-12-01

    Creation of effective monoclonal anti-D immunoglobulin for prevention of hemolytic disease of the newborn remains an unsolved problem because there is still no producer cell strain providing stable production and adequate glycosylation of antibodies. Recombinant anti-D have been obtained on the basis of human PER.C6(®) cells and characterized. Anti-D antibodies expressed in PER.C6(®) exhibited lower hemolytic activity in antibody-dependent cytotoxicity (ADCC) reaction mediated by low-affinity Fcγ receptors in comparison with identical antibodies of lymphoblastoid origin. Monoclonal antibodies produced by PER.C6(®) are completely fucosylated and desialylated, i.e. are characterized by abnormal glycosylation. Addition of kifunensine (α-mannosidase I inhibitor) to the medium led to production of antibodies with high hemolytic activity. Reduced activity of monoclonal antibodies in PER.C6(®) cells and the effect of kifunensine (causing synthesis of defucosylated glycans) suggest that the absence of fucose is the key factor responsible for Fc affinity for low-affinity receptors.

  3. Establishment of hybridomas producing cancer specific human antibodies from B cell line derived from PBL of a patient with adult T cell leukemia.

    PubMed

    Kawahara, T; Ichikawa, A; Katakura, Y; Teruya, K; Yoshida, T; Kikuchi, M; Kamei, M; Hashizume, S; Shirahata, S

    2001-07-01

    Adult T cell leukemia (ATL) is a malignant disease characterized by tumorous proliferation of CD4(+) T cells infected with retrovirus human T cell leukemia virus Type-I (HTLV-I) and concurs with an autoimmune disease and cancer due to attenuated immune response. In this study, we established ATL patient derived B-cell line TM-1 producing cancer-specific IgM antibodies, and further characterized its antigen specificity by establishing hybridomas fused with human-mouse origin hetero-myeloma cell line RF-S1. We established three hybridoma cell lines termed 2E12, 3E9, and 3E10, which continuously secreted human IgM antibodies. Immunohistochemical staining of formalin-fixed tissue section using antibodies secreted from these hybridomas showed that these antibodies specifically recognized tumor sites of human colon adenocarcinomas. Antibody produced from hybridoma 3E9 bound to some of leukemic cell lines, but not to normal human PBL, which was evidenced by the flow cytometric analysis, indicating that antibody produced from 3E9 recognizes cell surface antigen specifically expressed in the leukemic cells.

  4. Analyzing Clonal Variation of Monoclonal Antibody-Producing CHO Cell Lines Using an In Silico Metabolomic Platform

    PubMed Central

    Ghorbaniaghdam, Atefeh; Chen, Jingkui; Henry, Olivier; Jolicoeur, Mario

    2014-01-01

    Monoclonal antibody producing Chinese hamster ovary (CHO) cells have been shown to undergo metabolic changes when engineered to produce high titers of recombinant proteins. In this work, we have studied the distinct metabolism of CHO cell clones harboring an efficient inducible expression system, based on the cumate gene switch, and displaying different expression levels, high and low productivities, compared to that of the parental cells from which they were derived. A kinetic model for CHO cell metabolism was further developed to include metabolic regulation. Model calibration was performed using intracellular and extracellular metabolite profiles obtained from shake flask batch cultures. Model simulations of intracellular fluxes and ratios known as biomarkers revealed significant changes correlated with clonal variation but not to the recombinant protein expression level. Metabolic flux distribution mostly differs in the reactions involving pyruvate metabolism, with an increased net flux of pyruvate into the tricarboxylic acid (TCA) cycle in the high-producer clone, either being induced or non-induced with cumate. More specifically, CHO cell metabolism in this clone was characterized by an efficient utilization of glucose and a high pyruvate dehydrogenase flux. Moreover, the high-producer clone shows a high rate of anaplerosis from pyruvate to oxaloacetate, through pyruvate carboxylase and from glutamate to α-ketoglutarate, through glutamate dehydrogenase, and a reduced rate of cataplerosis from malate to pyruvate, through malic enzyme. Indeed, the increase of flux through pyruvate carboxylase was not driven by an increased anabolic demand. It is in fact linked to an increase of the TCA cycle global flux, which allows better regulation of higher redox and more efficient metabolic states. To the best of our knowledge, this is the first time a dynamic in silico platform is proposed to analyze and compare the metabolomic behavior of different CHO clones. PMID

  5. Binding specificities of eight monoclonal antibodies to human glycophorin A - studies with M/sup c/M, and M/sub k/En(UK) variant human erythrocytes and M- and MN/sup V/-type chimpanzee erythrocytes

    SciTech Connect

    Bigbee, W.L.; Langlois, R.G.; Vanderlaan, M.; Jensen, R.H.

    1984-12-01

    Four newly derived mouse monoclonal antibodies to human glycophorin A are described. Three of these antibodies bind preferentially to the N form of glycophorin A; the fourth recognizes a shared determinant of the M and N forms. All four antibodies are directed toward the 39 amino acid, amino-terminal portion of the protein, and the N-specific antibodies require for binding the presence of N-acetyl-neuraminic acid on the glycosidically linked oligosaccharides. Cross-reaction of the N-specific antibodies to homozygous MM erythrocytes appears to result from binding to glycophorin B. In addition, these antibodies together with four previously reported glycophorin monoclonal antibodies, including two that specifically recognize the M form of glycophorin A, were tested for binding to M/sup c/M and M/sup k/En(UK) variant human erythrocytes. Results obtained for five of the six M- or N-specific monoclonal antibodies point to the general immunodominance of the amino-terminal serine-leucine polymorphism and the requirement for sialic acid. The epitopes for all three N-specific monoclonal antibodies include the amino terminal leucine that occurs in the N form of glycophorin A and may also include the glutamic acid that occurs at position five. Their studies support the proposed Lepore-type glycophorin A-B hybrid gene rearrangement for the En(UK) allele found in the English En(a-) family. The data also confirm the expression of the M-like glycoprotein on chimpanzee erythrocytes and the presence of a human glycophorin B-like antigen on the MN/sup V/-type cells.

  6. Antithyroglobulin antibody

    MedlinePlus

    Thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Hypothyroidism - thyroglobulin antibody; Thyroiditis - thyroglobulin antibody; Graves disease - thyroglobulin antibody; Underactive thyroid - thyroglobulin antibody

  7. Cell lines for the production of monoclonal antibodies to human glycophorin A

    DOEpatents

    Bigbee, William L.; Fong, Stella S. N.; Jensen, Ronald H.; Vanderlaan, Martin; Langlois, Richard G.

    1988-01-01

    Cloned mouse hybridoma cell lines have been established which continuously produce antibodies that differentiate between the M and N forms of human glycophorin A. These antibodies have potential application as human blood group reagents, as markers for terminally differentiated erythroid cells and as immunofluorescent labels of somatically variant human erythrocytes.

  8. Method and cell lines for the production of monoclonal antibodies to human glycophorin A

    DOEpatents

    Bigbee, W.L.; Fong, S.S.N.; Jensen, R.H.; Vanderlaan, M.

    Cloned mouse hybridoma cell lines have been established which continuously produce antibodies that differentiate between the M and N forms of human glycophorin A. These antibodies have potential application as human blood group reagents, as markers for terminally differentiated erythroid cells and as immunofluorescent labels of somatically variant human erythrocytes.

  9. Antibody-producing cell responses to an isolated outer membrane protein and to complexes of this antigen with lipopolysaccharide or with vesicles of phospholipids from Proteus mirabilis.

    PubMed Central

    Karch, H; Nixdorff, K

    1981-01-01

    Antibody-producing cell responses of mice to a protein isolated from the outer membrane of Proteus mirabilis were typical of the responses to a thymus-dependent antigen. The immunoglobulin G antibody-producing cell responses to the protein were increased after administration of the antigen complexed with either lipopolysaccharide or with vesicles of phospholipids extracted from P. mirabilis. The protein in turn significantly increased the immune response to lipopolysaccharide and also converted this response from predominantly immunoglobulin M to predominantly immunoglobulin G. PMID:6164651

  10. ELPylated haemagglutinins produced in tobacco plants induce potentially neutralizing antibodies against H5N1 viruses in mice.

    PubMed

    Phan, Hoang T; Pohl, Julia; Floss, Doreen M; Rabenstein, Frank; Veits, Jutta; Le, Binh T; Chu, Ha H; Hause, Gerd; Mettenleiter, Thomas; Conrad, Udo

    2013-06-01

    Reducing the cost of vaccine production is a key priority for veterinary research, and the possibility of heterologously expressing antigen in plants provides a particularly attractive means of achieving this. Here, we report the expression of the avian influenza virus haemagglutinin (AIV HA) in tobacco, both as a monomer and as a trimer in its native and its ELPylated form. We firstly presented evidence to produce stabilized trimers of soluble HA in plants. ELPylation of these trimers does not influence the trimerization. Strong expression enhancement in planta caused by ELPylation was demonstrated for trimerized H5-ELP. ELPylated trimers could be purified by a membrane-based inverse transition cycling procedure with the potential of successful scale-up. The trimeric form of AIV HA was found to enhance the HA-specific immune response compared with the monomeric form. Plant-derived AIV HA trimers elicited potentially neutralizing antibodies interacting with both homologous virus-like particles from plants and heterologous inactivated AIV. ELPylation did not influence the functionality and the antigenicity of the stabilized H5 trimers. These data allow further developments including scale-up of production, purification and virus challenge experiments with the final goal to achieve suitable technologies for efficient avian flu vaccine production.

  11. Human macrophages produce dimeric forms of IL-18 which can be detected with monoclonal antibodies specific for inactive IL-18.

    PubMed

    Kikkawa, S; Matsumoto, M; Shida, K; Fukumori, Y; Toyoshima, K; Seya, T

    2001-02-23

    We established two monoclonal antibodies (mAbs) which specifically recognize human 'functionally inactive' recombinant IL-18, and IL-18 protein polymorphism was examined using human monocytes and macrophages (M phi). In 6 day GM-CSF-treated M phi, an 'inactive' IL-18-recognizing mAb 21 detected the IL-18 proform (24 kDa) and a 48-kDa protein, which were gradually increased concomitant with maturation stage. Majority of the 24- and 48-kDa forms were barely detectable with other mAbs recognizing 'active' IL-18. No reagents including Toll stimulators up-regulated these IL-18 populations in M phi. The 21-recognizable IL-18 species were separated using an anion-exchanger column and their IFN gamma-inducing activity was assessed with human lymphocytes plus IL-12. Virtually no as yet known activity was detected with these IL-18 species. After processed with M phi proteases, an 18-kDa form was generated to express the IFN gamma-inducing activity, although the activity was far weaker than that of control 'active' IL-18. These observations suggested that large amounts of various IL-18 species are produced with monocyte-M phi differentiation and most of these IL-18 species are functionally 'inactive' in terms of the reported IL-18 function even after proteolytic 18-kDa conversion.

  12. Automated in situ measurement of cell-specific antibody secretion and laser-mediated purification for rapid cloning of highly-secreting producers.

    PubMed

    Hanania, Elie G; Fieck, Annabeth; Stevens, Janine; Bodzin, Leon J; Palsson, Bernhard Ø; Koller, Manfred R

    2005-09-30

    Cloning of highly-secreting recombinant cells is critical for biopharmaceutical manufacturing, but faces numerous challenges including the fact that secreted protein does not remain associated with the producing cell. A fundamentally new approach was developed combining in situ capture and measurement of individual cell protein secretion followed by laser-mediated elimination of all non- and poorly-secreting cells, leaving only the highest-secreting cell in a well. Recombinant cells producing humanized antibody were cultured serum-free on a capture matrix, followed by staining with fluorescently-labeled anti-human antibody fragment. A novel, automated, high-throughput instrument (called LEAP) was used to image and locate every cell, quantify the cell-associated and secreted antibody (surrounding each cell), eliminate all undesired cells from a well via targeted laser irradiation, and then track clone outgrowth and stability. Temporarily sparing an island of helper cells around the clone of interest improved cloning efficiency (particularly when using serum-free medium), and helper cells were easily eliminated with the laser after several days. The in situ nature of this process allowed several serial sub-cloning steps to be performed within days of one another, resulting in rapid generation of clonal populations with significantly increased and more stable, homogeneous antibody secretion. Cell lines with specific antibody secretion rates of > 50 pg/cell per day (in static batch culture) were routinely obtained as a result of this cloning approach, often times representing up to 20% of the clones screened.

  13. Different inhibition of Gβγ-stimulated class IB phosphoinositide 3-kinase (PI3K) variants by a monoclonal antibody. Specific function of p101 as a Gβγ-dependent regulator of PI3Kγ enzymatic activity.

    PubMed

    Shymanets, Aliaksei; Prajwal; Vadas, Oscar; Czupalla, Cornelia; LoPiccolo, Jaclyn; Brenowitz, Michael; Ghigo, Alessandra; Hirsch, Emilio; Krause, Eberhard; Wetzker, Reinhard; Williams, Roger L; Harteneck, Christian; Nürnberg, Bernd

    2015-07-01

    Class IB phosphoinositide 3-kinases γ (PI3Kγ) are second-messenger-generating enzymes downstream of signalling cascades triggered by G-protein-coupled receptors (GPCRs). PI3Kγ variants have one catalytic p110γ subunit that can form two different heterodimers by binding to one of a pair of non-catalytic subunits, p87 or p101. Growing experimental data argue for a different regulation of p87-p110γ and p101-p110γ allowing integration into distinct signalling pathways. Pharmacological tools enabling distinct modulation of the two variants are missing. The ability of an anti-p110γ monoclonal antibody [mAb(A)p110γ] to block PI3Kγ enzymatic activity attracted us to characterize this tool in detail using purified proteins. In order to get insight into the antibody-p110γ interface, hydrogen-deuterium exchange coupled to MS (HDX-MS) measurements were performed demonstrating binding of the monoclonal antibody to the C2 domain in p110γ, which was accompanied by conformational changes in the helical domain harbouring the Gβγ-binding site. We then studied the modulation of phospholipid vesicles association of PI3Kγ by the antibody. p87-p110γ showed a significantly reduced Gβγ-mediated phospholipid recruitment as compared with p101-p110γ. Concomitantly, in the presence of mAb(A)p110γ, Gβγ did not bind to p87-p110γ. These data correlated with the ability of the antibody to block Gβγ-stimulated lipid kinase activity of p87-p110γ 30-fold more potently than p101-p110γ. Our data argue for differential regulatory functions of the non-catalytic subunits and a specific Gβγ-dependent regulation of p101 in PI3Kγ activation. In this scenario, we consider the antibody as a valuable tool to dissect the distinct roles of the two PI3Kγ variants downstream of GPCRs.

  14. DARPA Antibody Technology Program Standardized Test Bed for Antibody Characterization: Characterization of an MS2 sdAb Produced by U.S. Naval Research Laboratory

    DTIC Science & Technology

    2016-10-01

    Biosurveillance (JPMO BSV), Critical Reagents Program instituted a quality program for the standardization of test methods to support more...standardization of antibody testing provides JPMO BSV with an invaluable platform for providing consistent, high- quality assays and reagents for current...Program (ATP) Quality MS2 coat protein (MS2CP) Enzyme-linked immunosorbent assay (ELISA) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  15. Association of high levels of serum antibody to staphylococcal toxic shock antigen with nasal carriage of toxic shock antigen-producing strains of Staphylococcus aureus.

    PubMed Central

    Ritz, H L; Kirkland, J J; Bond, G G; Warner, E K; Petty, G P

    1984-01-01

    Forty-four asymptomatic male subjects were examined for their nasal carriage of strains of Staphylococcus aureus capable of producing staphylococcal toxic shock antigen (TSA), an exotoxin implicated in the pathogenesis of toxic shock syndrome. In addition, the levels of antibody to TSA in sera from these subjects were determined by an enzyme-linked immunosorbent assay. S. aureus was isolated from the anterior nares of 23 subjects. Of those 23 isolates of S. aureus, 9 were found to produce TSA. All individuals carrying strains of S. aureus capable of producing TSA had high to moderate levels of antibody to TSA. In contrast, those individuals carrying strains not producing TSA had levels of antibody to TSA ranging from high to nondetectable. A second examination of nasal samples from 42 of these subjects revealed that 86% of those carrying S. aureus initially still carried S. aureus after a period of 3 months; all subjects found to carry TSA-producing strains initially and that were examined a second time yielded TSA-producing strains once again. PMID:6698614

  16. Naturally produced opsonizing antibodies restrict the survival of Mycobacterium tuberculosis in human macrophages by augmenting phagosome maturation

    PubMed Central

    Kumar, Shashi Kant; Singh, Padam; Sinha, Sudhir

    2015-01-01

    This study investigated the hypothesis that serum antibodies against Mycobacterium tuberculosis present in naturally infected healthy subjects of a tuberculosis (TB) endemic area could create and/or sustain the latent form of infection. All five apparently healthy Indian donors showed high titres of serum antibodies against M. tuberculosis cell membrane antigens, including lipoarabinomannan and alpha crystallin. Uptake and killing of bacilli by the donor macrophages was significantly enhanced following their opsonization with antibody-rich, heat-inactivated autologous sera. However, the capability to opsonize was apparent for antibodies against some and not other antigens. High-content cell imaging of infected macrophages revealed significantly enhanced colocalization of the phagosome maturation marker LAMP-1, though not of calmodulin, with antibody-opsonized compared with unopsonized M. tuberculosis. Key enablers of macrophage microbicidal action—proinflammatory cytokines (IFN-γ and IL-6), phagosome acidification, inducible NO synthase and nitric oxide—were also significantly enhanced following antibody opsonization. Interestingly, heat-killed M. tuberculosis also elevated these mediators to the levels comparable to, if not higher than, opsonized M. tuberculosis. Results of the study support the emerging view that an efficacious vaccine against TB should, apart from targeting cell-mediated immunity, also generate ‘protective’ antibodies. PMID:26674415

  17. Clonal analysis of a human antibody response. Quantitation of precursors of antibody-producing cells and generation and characterization of monoclonal IgM, IgG, and IgA to rabies virus

    PubMed Central

    1990-01-01

    We quantitated and characterized the changes in the human B cell repertoire, at the clonal level, before and after immunization with rabies virus. Moreover, we generated 10 monoclonal cell lines producing IgM, IgG, and IgA antibodies to the virus. We found that in healthy subjects, not previously exposed to the virus, nearly 2% of the circulating B lymphocytes were committed to the production of antibodies that bound the virus. These B cells expressed the surface CD5 molecule. The antibodies they produced were polyreactive IgM that displayed a relatively low affinity for the virus components (Kd, 1.0- 2.4 x 10(-6) g/microliters). After immunization, different anti-virus (IgG and IgA) antibody-producing cells consistently appeared in the circulation and increased from less than 0.005% to greater than 10% of the total B cells committed to the production of IgG and IgA, respectively. Most of such B cells do not express CD5 and produce monoreactive antibodies of high affinity for rabies virus (Kd, 6.5 x 10(-9) to 1.2 x 10(-10) g/microliters). One of these IgG mAbs efficiently neutralized rabies virus in vitro and in vivo, as detailed elsewhere (Dietzschold, B., P. Casali, Y. Ueki, M. Gore, C. E. Rupprecht, A. L. Notkins, and H. Koprowski, manuscript submitted for publication). Hybridization experiments using probes specific for the different human V gene segment families revealed that cell precursors producing low affinity IgM binding to rabies virus utilized a restricted number of VH gene segments (i.e., only members of the VHIIIb subfamily), whereas cell precursors producing high affinity IgG and IgA to rabies virus utilized an assortment of different VH gene segments (i.e., members of the VHI, VHIII, VHIV, and VHVI families and VHIIIb subfamily). In conclusion, our studies show that EBV transformation in conjunction with limiting dilution technology and somatic cell hybridization techniques are useful methods for quantitating, at the B cell clonal level, the human

  18. Aging-dependent decline of IL-10 producing B cells coincides with production of antinuclear antibodies but not rheumatoid factors.

    PubMed

    van der Geest, Kornelis S M; Lorencetti, Pedro G; Abdulahad, Wayel H; Horst, Gerda; Huitema, Minke; Roozendaal, Caroline; Kroesen, Bart-Jan; Brouwer, Elisabeth; Boots, Annemieke M H

    2016-03-01

    Aging is associated with development of autoimmunity. Loss of B cell tolerance in the elderly is suggested by an increased prevalence of anti-nuclear antibodies (ANAs) and rheumatoid factors (RFs). Accumulating evidence indicates that B cells also impact autoimmunity via secretion of cytokines. So far, few studies have directly assessed the effect of aging on the latter B cell function. Here, we determined if and how human aging influences the production of cytokines by B cells. In a cross-sectional study, we found that absolute numbers of circulating B cells were similar in 31 young (ages 19-39) and 73 old (age ≥ 60) individuals. Numbers of transitional B cells (CD19(+)CD27(-)CD38(High)CD24(High)) were decreased in old individuals, whereas numbers of naive and memory B cell subsets were comparable in young and old individuals. Short-term in vitro stimulation of whole blood samples revealed that numbers of B cells capable of producing TNF-α were similar in young and old individuals. In contrast, B cells capable of IL-10 production were decreased in old subjects. This decline of IL-10(+) B cells was observed in old individuals that were ANA positive, and in those that were negative for both ANAs and RFs. However, IL-10(+) B cells were remarkably well retained in the circulation of old subjects that were RF positive. Thus, pro-inflammatory TNF-α(+) B cells are retained in the elderly, whereas IL-10(+) B cells generally decline. In addition, our findings indicate that IL-10(+) B cells may differentially impact the development of ANAs and RFs in the elderly.

  19. A Recombinant Human Anti-Platelet scFv Antibody Produced in Pichia pastoris for Atheroma Targeting

    PubMed Central

    Vallet-Courbin, Amelie; Larivière, Mélusine; Hocquellet, Agnès; Hemadou, Audrey; Parimala, Sarjapura-Nagaraja; Laroche-Traineau, Jeanny; Santarelli, Xavier; Clofent-Sanchez, Gisèle; Jacobin-Valat, Marie-Josée; Noubhani, Abdelmajid

    2017-01-01

    Cells of the innate and adaptive immune system are key factors in the progression of atherosclerotic plaque, leading to plaque instability and rupture, potentially resulting in acute atherothrombotic events such as coronary artery disease, cerebrovascular disease and peripheral arterial disease. Here, we describe the cloning, expression, purification, and immunoreactivity assessment of a recombinant single-chain variable fragment (scFv) derived from a human anti-αIIbβ3 antibody (HuAb) selected to target atheromatous lesions for the presence of platelets. Indeed, platelets within atheroma plaques have been shown to play a role in inflammation, in platelet-leucocyte aggregates and in thrombi formation and might thus be considered relevant biomarkers of atherosclerotic progression. The DNA sequence that encodes the anti-αIIbβ3 TEG4 scFv previously obtained from a phage-display selection on activated platelets, was inserted into the eukaryote vector (pPICZαA) in fusion with a tag sequence encoding 2 cysteines useable for specific probes grafting experiments. The recombinant protein was expressed at high yields in Pichia pastoris (30 mg/L culture). The advantage of P. pastoris as an expression system is the production and secretion of recombinant proteins in the supernatant, ruling out the difficulties encountered when scFv are produced in the cytoplasm of bacteria (low yield, low solubility and reduced affinity). The improved conditions allowed for the recovery of highly purified and biologically active scFv fragments ready to be grafted in a site-directed way to nanoparticles for the imaging of atherosclerotic plaques involving inflammatory processes and thus at high risk of instability. PMID:28125612

  20. Outbreak Caused by an Ertapenem-Resistant, CTX-M-15-Producing Klebsiella pneumoniae Sequence Type 101 Clone Carrying an OmpK36 Porin Variant

    PubMed Central

    Poulou, Aggeliki; Voulgari, Evangelia; Vrioni, Georgia; Koumaki, Vasiliki; Xidopoulos, Grigorios; Chatzipantazi, Vasiliki; Markou, Fani

    2013-01-01

    Although numerous studies have documented outbreaks of carbapenem-resistant Klebsiella pneumoniae (CRKP) possessing various carbapenemases, reports on outbreaks due to CRKP possessing extended-spectrum β-lactamases (ESBLs) and/or AmpCs with porin lesions have been limited. Here, we describe an outbreak caused by an ertapenem-resistant, CTX-M-15-producing clonal K. pneumoniae strain expressing an OmpK36 porin variant. From May 2012 to November 2012, 37 ertapenem-resistant K. pneumoniae isolates phenotypically negative for carbapenemase production were recovered from 19 patients hospitalized in the intensive care unit of a Greek hospital. The isolates were either susceptible or intermediate to other carbapenems and resistant to all remaining β-lactams but cefotetan. Phenotypic and molecular analysis revealed the presence in all isolates of the blaCTX-M-15 gene on a conjugative 100-kb plasmid, disruption in the expression of the ompK35 gene, and the production of an Ompk36 porin variant. The index case was a patient admitted from another hospital. Active surveillance upon admission and on a weekly basis was immediately initiated; environmental samples were also periodically tested. Molecular typing showed that all clinical isolates as well as two ertapenem-resistant environmental K. pneumoniae isolates belonged to the same clonal type and were assigned to multilocus sequence typing (MLST) sequence type 101 (ST101). As all colonized/infected patients were hospitalized during overlapping periods, cross-infection was considered the main route for the dissemination of the outbreak strain. Despite reinforcement of infection control measures and active surveillance, the outbreak lasted approximately 7 months. Identification of hidden carriers upon admission and by screening on a weekly basis was found valuable for early recognition and subsequent successful management of the outbreak. PMID:23850951

  1. Efficient In Vitro and In Vivo Activity of Glyco-Engineered Plant-Produced Rabies Monoclonal Antibodies E559 and 62-71-3

    PubMed Central

    Tsekoa, Tsepo Lebiletsa; Lotter-Stark, Therese; Buthelezi, Sindisiwe; Chakauya, Ereck; Stoychev, Stoyan H.; Sabeta, Claude; Shumba, Wonderful; Phahladira, Baby; Hume, Steve; Morton, Josh; Rupprecht, Charles E.; Steinkellner, Herta; Pauly, Michael; Zeitlin, Larry; Whaley, Kevin; Chikwamba, Rachel

    2016-01-01

    Rabies is a neglected zoonotic disease that has no effective treatment after onset of illness. However the disease can be prevented effectively by prompt administration of post exposure prophylaxis which includes administration of passive immunizing antibodies (Rabies Immune Globulin, RIG). Currently, human RIG suffers from many restrictions including limited availability, batch-to batch inconsistencies and potential for contamination with blood-borne pathogens. Anti-rabies monoclonal antibodies (mAbs) have been identified as a promising alternative to RIG. Here, we applied a plant-based transient expression system to achieve rapid, high level production and efficacy of the two highly potent anti-rabies mAbs E559 and 62-71-3. Expression levels of up to 490 mg/kg of recombinant mAbs were obtained in Nicotiana benthamiana glycosylation mutants by using a viral based transient expression system. The plant-made E559 and 62-71-3, carrying human-type fucose-free N-glycans, assembled properly and were structurally sound as determined by mass spectrometry and calorimetric density measurements. Both mAbs efficiently neutralised diverse rabies virus variants in vitro. Importantly, E559 and 62-71-3 exhibited enhanced protection against rabies virus compared to human RIG in a hamster model post-exposure challenge trial. Collectively, our results provide the basis for the development of a multi-mAb based alternative to RIG. PMID:27427976

  2. Efficient In Vitro and In Vivo Activity of Glyco-Engineered Plant-Produced Rabies Monoclonal Antibodies E559 and 62-71-3.

    PubMed

    Tsekoa, Tsepo Lebiletsa; Lotter-Stark, Therese; Buthelezi, Sindisiwe; Chakauya, Ereck; Stoychev, Stoyan H; Sabeta, Claude; Shumba, Wonderful; Phahladira, Baby; Hume, Steve; Morton, Josh; Rupprecht, Charles E; Steinkellner, Herta; Pauly, Michael; Zeitlin, Larry; Whaley, Kevin; Chikwamba, Rachel

    2016-01-01

    Rabies is a neglected zoonotic disease that has no effective treatment after onset of illness. However the disease can be prevented effectively by prompt administration of post exposure prophylaxis which includes administration of passive immunizing antibodies (Rabies Immune Globulin, RIG). Currently, human RIG suffers from many restrictions including limited availability, batch-to batch inconsistencies and potential for contamination with blood-borne pathogens. Anti-rabies monoclonal antibodies (mAbs) have been identified as a promising alternative to RIG. Here, we applied a plant-based transient expression system to achieve rapid, high level production and efficacy of the two highly potent anti-rabies mAbs E559 and 62-71-3. Expression levels of up to 490 mg/kg of recombinant mAbs were obtained in Nicotiana benthamiana glycosylation mutants by using a viral based transient expression system. The plant-made E559 and 62-71-3, carrying human-type fucose-free N-glycans, assembled properly and were structurally sound as determined by mass spectrometry and calorimetric density measurements. Both mAbs efficiently neutralised diverse rabies virus variants in vitro. Importantly, E559 and 62-71-3 exhibited enhanced protection against rabies virus compared to human RIG in a hamster model post-exposure challenge trial. Collectively, our results provide the basis for the development of a multi-mAb based alternative to RIG.

  3. Regulatory approval and a first-in-human phase I clinical trial of a monoclonal antibody produced in transgenic tobacco plants.

    PubMed

    Ma, Julian K-C; Drossard, Jürgen; Lewis, David; Altmann, Friedrich; Boyle, Julia; Christou, Paul; Cole, Tom; Dale, Philip; van Dolleweerd, Craig J; Isitt, Valerie; Katinger, Dietmar; Lobedan, Martin; Mertens, Hubert; Paul, Mathew J; Rademacher, Thomas; Sack, Markus; Hundleby, Penelope A C; Stiegler, Gabriela; Stoger, Eva; Twyman, Richard M; Vcelar, Brigitta; Fischer, Rainer

    2015-10-01

    Although plant biotechnology has been widely investigated for the production of clinical-grade monoclonal antibodies, no antibody products derived from transgenic plants have yet been approved by pharmaceutical regulators for clinical testing. In the Pharma-Planta project, the HIV-neutralizing human monoclonal antibody 2G12 was expressed in transgenic tobacco (Nicotiana tabacum). The scientific, technical and regulatory demands of good manufacturing practice (GMP) were addressed by comprehensive molecular characterization of the transgene locus, confirmation of genetic and phenotypic stability over several generations of transgenic plants, and by establishing standard operating procedures for the creation of a master seed bank, plant cultivation, harvest, initial processing, downstream processing and purification. The project developed specifications for the plant-derived antibody (P2G12) as an active pharmaceutical ingredient (API) based on (i) the guidelines for the manufacture of monoclonal antibodies in cell culture systems; (ii) the draft European Medicines Agency Points to Consider document on quality requirements for APIs produced in transgenic plants; and (iii) de novo guidelines developed with European national regulators. From the resulting process, a GMP manufacturing authorization was issued by the competent authority in Germany for transgenic plant-derived monoclonal antibodies for use in a phase I clinical evaluation. Following preclinical evaluation and ethical approval, a clinical trial application was accepted by the UK national pharmaceutical regulator. A first-in-human, double-blind, placebo-controlled, randomized, dose-escalation phase I safety study of a single vaginal administration of P2G12 was carried out in healthy female subjects. The successful completion of the clinical trial marks a significant milestone in the commercial development of plant-derived pharmaceutical proteins.

  4. Capture of dengue viruses using antibody-integrated graphite-encapsulated magnetic beads produced using gas plasma technology

    PubMed Central

    SAKUDO, AKIKAZU; VISWAN, ANCHU; CHOU, HAN; SASAKI, TADAHIRO; IKUTA, KAZUYOSHI; NAGATSU, MASAAKI

    2016-01-01

    Despite significant advances in medicine, global health is threatened by emerging infectious diseases caused by a number of viruses. Dengue virus (DENV) is a mosquito-borne virus, which can be transmitted to humans via mosquito vectors. Previously, the Ministry of Health, Labour and Welfare in Japan reported the country's first domestically acquired case of dengue fever for almost 70 years. To address this issue, it is important to develop novel technologies for the sensitive detection of DENV. The present study reported on the development of plasma-functionalized, graphite-encapsulated magnetic nanoparticles (GrMNPs) conjugated with anti-DENV antibody for DENV capture. Radiofrequency wave-excited inductively-coupled Ar and ammonia gas plasmas were used to introduce amino groups onto the surface of the GrMNPs. The GrMNPs were then conjugated with an antibody against DENV, and the antibody-integrated magnetic beads were assessed for their ability to capture DENV. Beads incubated in a cell culture medium of DENV-infected mosquito cells were separated from the supernatant by applying a magnetic field and were then washed. The adsorption of DENV serotypes 1–4 onto the beads was confirmed using reverse transcription-polymerase chain reaction, which detected the presence of DENV genomic RNA on the GrMNPs. The methodology described in the present study, which employed the plasma-functionalization of GrMNPs to enable antibody-integration, represents a significant improvement in the detection of DENV. PMID:27221214

  5. High-level carbapenem-resistant OXA-48-producing Klebsiella pneumoniae with a novel OmpK36 variant and low-level, carbapenem-resistant, non-porin-deficient, OXA-181-producing Escherichia coli from Thailand.

    PubMed

    Lunha, Kamonwan; Chanawong, Aroonwadee; Lulitanond, Aroonlug; Wilailuckana, Chotechana; Charoensri, Nicha; Wonglakorn, Lumyai; Saenjamla, Pimjai; Chaimanee, Prajuab; Angkititrakul, Sunpetch; Chetchotisakd, Ploenchan

    2016-06-01

    Five blaOXA-48-like-carrying Enterobacteriaceae isolates collected from two Thai patients in December 2012 were characterized. Three Klebsiella pneumoniae isolates giving two different pulsed-field gel electrophoresis patterns and sequence types (ST11 and ST37) from patient 1 harbored blaOXA-48 locating on Tn1999.2, whereas two Escherichia coli isolates with the same pulsotype and ST5 from Patient 2 carried ISEcp1-associated blaOXA-181. One K. pneumoniae strain had blaSHV-12, blaDHA-1, qnrB, and qnrS, while another strain harbored blaCTX-M-15, qnrS and aac(6')-Ib-cr. The E. coli strain contained blaCTX-M-15, blaCMY-2, qnrS, and aac(6')-Ib-cr. Interestingly, the OXA-48 producers with a novel OmpK36 variant by a substitution of Gly to Asp in the L3 loop-borne PEFXG motif exhibited high-level resistance to ertapenem, imipenem, and meropenem. In contrast, the OXA-181 producer with non-porin-deficient background showed low-level resistance to ertapenem only. Both patients died because of either septic shock or pneumonia. This study showed the impact of OXA-48-like carbapenemases in porin-defective clinical isolate background, which may lead to serious therapeutic problems in the near future.

  6. Cross-Neutralizing Antibodies in HIV-1 Individuals Infected by Subtypes B, F1, C or the B/Bbr Variant in Relation to the Genetics and Biochemical Characteristics of the env Gene

    PubMed Central

    de Almeida, Dalziza Victalina; Macieira, Karine Venegas; Grinsztejn, Beatriz Gilda Jegerhorn; Veloso dos Santos, Valdiléa Gonçalves; Guimarães, Monick Lindenmeyer

    2016-01-01

    Various HIV-1 env genetic and biochemical features impact the elicitation of cross-reactive neutralizing antibodies in natural infections. Thus, we aimed to investigate cross-neutralizing antibodies in individuals infected with HIV-1 env subtypes B, F1, C or the B/Bbr variant as well as env characteristics. Therefore, plasma samples from Brazilian chronically HIV-1 infected individuals were submitted to the TZM-bl neutralization assay. We also analyzed putative N-glycosylation sites (PNGLs) and the size of gp120 variable domains in the context of HIV-1 subtypes prevalent in Brazil. We observed a greater breadth and potency of the anti-Env neutralizing response in individuals infected with the F1 or B HIV-1 subtypes compared with the C subtype and the variant B/Bbr. We observed greater V1 B/Bbr and smaller V4 F1 than those of other subtypes (p<0.005), however neither was there a correlation verified between the variable region length and neutralization potency, nor between PNLG and HIV-1 subtypes. The enrichment of W at top of V3 loop in weak neutralizing response viruses and the P in viruses with higher neutralization susceptibility was statistically significant (p = 0.013). Some other signatures sites were associated to HIV-1 subtype-specific F1 and B/Bbr samples might influence in the distinct neutralizing response. These results indicate that a single amino acid substitution may lead to a distinct conformational exposure or load in the association domain of the trimer of gp120 and interfere with the induction power of the neutralizing response, which affects the sensitivity of the neutralizing antibody and has significant implications for vaccine design. PMID:27936047

  7. Polymorphisms in the F8 Gene and MHC-II Variants as Risk Factors for the Development of Inhibitory Anti-Factor VIII Antibodies during the Treatment of Hemophilia A: A Computational Assessment

    PubMed Central

    Pandey, Gouri Shankar; Yanover, Chen; Howard, Tom E.; Sauna, Zuben E.

    2013-01-01

    The development of neutralizing anti-drug-antibodies to the Factor VIII protein-therapeutic is currently the most significant impediment to the effective management of hemophilia A. Common non-synonymous single nucleotide polymorphisms (ns-SNPs) in the F8 gene occur as six haplotypes in the human population (denoted H1 to H6) of which H3 and H4 have been associated with an increased risk of developing anti-drug antibodies. There is evidence that CD4+ T-cell response is essential for the development of anti-drug antibodies and such a response requires the presentation of the peptides by the MHC-class-II (MHC-II) molecules of the patient. We measured the binding and half-life of peptide-MHC-II complexes using synthetic peptides from regions of the Factor VIII protein where ns-SNPs occur and showed that these wild type peptides form stable complexes with six common MHC-II alleles, representing 46.5% of the North American population. Next, we compared the affinities computed by NetMHCIIpan, a neural network-based algorithm for MHC-II peptide binding prediction, to the experimentally measured values and concluded that these are in good agreement (area under the ROC-curve of 0.778 to 0.972 for the six MHC-II variants). Using a computational binding predictor, we were able to expand our analysis to (a) include all wild type peptides spanning each polymorphic position; and (b) consider more MHC-II variants, thus allowing for a better estimation of the risk for clinical manifestation of anti-drug antibodies in the entire population (or a specific sub-population). Analysis of these computational data confirmed that peptides which have the wild type sequence at positions where the polymorphisms associated with haplotypes H3, H4 and H5 occur bind MHC-II proteins significantly more than a negative control. Taken together, the experimental and computational results suggest that wild type peptides from polymorphic regions of FVIII constitute potential T-cell epitopes and thus

  8. Anti-ICOS Monoclonal Antibody MEDI-570 in Treating Patients With Relapsed or Refractory Peripheral T-cell Lymphoma Follicular Variant or Angioimmunoblastic T-cell Lymphoma

    ClinicalTrials.gov

    2017-03-16

    Follicular Variant Peripheral T-Cell Lymphoma; Recurrent Angioimmunoblastic T-cell Lymphoma; Recurrent Mature T- and NK-Cell Non-Hodgkin Lymphoma; Refractory Angioimmunoblastic T-cell Lymphoma; Refractory Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma

  9. RNA interference-mediated phosphodiesterase 4D splice variants knock-down in the prefrontal cortex produces antidepressant-like and cognition-enhancing effects

    PubMed Central

    Wang, Zhen-Zhen; Zhang, Yi; Liu, Yan-Qin; Zhao, Nan; Zhang, You-Zhi; Yuan, Li; An, Lei; Li, Jing; Wang, Xiao-Yun; Qin, Juan-Juan; Wilson, Steven P; O'Donnell, James M; Zhang, Han-Ting; Li, Yun-Feng

    2013-01-01

    Background and Purpose Phosphodiesterase 4 (PDE4) inhibitors produce potent antidepressant-like and cognition-enhancing effects. However, their clinical utility is limited by the major side effect of emesis, which appears to be PDE4 isoform-specific. Although PDE4D subtype plays the pivotal role in these therapeutic profiles, it is also the primary subtype responsible for emesis. Therefore, the aim of present research was to investigate whether long-form PDE4D variants mediate antidepressant-like and cognition-enhancing effects, but are irrespective with emesis. Experimental Approach In mice microinfused with lentiviral vectors that contained shRNA-mir hairpin structure targeting long-form PDE4Ds into bilateral prefrontal cortices, the tail-suspension and forced-swim tests were used to measure antidepressant-like effects; novel object recognition and Morris water-maze tasks were used to determine cognition-enhancing effects. The emetic potential was assessed by alpha2 adrenergic receptor-mediated anaesthesia, a surrogate measure of emesis. Intracellular cAMP signalling was analysed by time-resolved FRET immunoassay and Western-blot. Dendritic complexity was assessed by Golgi staining. Key Results Microinfusions of lentiviral PDE4D-shRNA down-regulated PDE4D4 and PDE4D5, and imitated the antidepressant-like and cognition-enhancing effects of the prototypical PDE4 inhibitor rolipram. The behavioural effects were related to dendritic complexity and mediated by the increased cAMP signalling. In addition, these effects were not enhanced in the presence of rolipram. Finally, while rolipram shortened the duration of combined anaesthesia, RNA interference-mediated PDE4D knock-down in the prefrontal cortex did not. Conclusion and Implications These data suggest that long-form PDE4Ds, at least PDE4D4 and PDE4D5, may be the promising targets for the development of PDE4 variant-selective inhibitors as the new pharmacotherapies for depressive disorders and neurodegenerative

  10. T cells produce an antigen-binding factor with in vivo activity analogous to IgE antibody

    PubMed Central

    1983-01-01

    T cell-dependent activation of resident tissue mast cells is required for the elicitation of delayed-type hypersensitivity skin reactions in mice. A T cell-derived antigen-binding factor that transfers the ability to elicit an immediate hypersensitivity-like skin reaction is described and compared with a hybridoma IgE antibody. Both the T cell factor and IgE mediate reactions with increased vascular permeability and both are mast cell dependent, as they are inactive in two different types of mast cell deficient mice (W/Wv and Sl/Sld). The T cell factor was distinguished from IgE by affinity chromatography using specific anti-IgE and anti-factor antibodies and by a shorter duration of passive sensitization. The T cell factor is a suitable candidate for participation in the mechanism by which T cells activate mast cells in delayed-type hypersensitivity. PMID:6187880

  11. Large-Scale Purification of r28M: A Bispecific scFv Antibody Targeting Human Melanoma Produced in Transgenic Cattle

    PubMed Central

    Spiesberger, Katrin; Paulfranz, Florian; Egger, Anton; Reiser, Judith; Vogl, Claus; Rudolf-Scholik, Judith; Mayrhofer, Corina; Grosse-Hovest, Ludger; Brem, Gottfried

    2015-01-01

    Background 30 years ago, the potential of bispecific antibodies to engage cytotoxic T cells for the lysis of cancer cells was discovered. Today a variety of bispecific antibodies against diverse cell surface structures have been developed, the majority of them produced in mammalian cell culture systems. Beside the r28M, described here, no such bispecific antibody is known to be expressed by transgenic livestock, although various biologicals for medical needs are already harvested—mostly from the milk—of these transgenics. In this study we investigated the large-scale purification and biological activity of the bispecific antibody r28M, expressed in the blood of transgenic cattle. This tandem single-chain variable fragment antibody is designed to target human CD28 and the melanoma/glioblastoma-associated cell surface chondroitin sulfate proteoglycan 4 (CSPG4). Results With the described optimized purification protocol an average yield of 30 mg enriched r28M fraction out of 2 liters bovine plasma could be obtained. Separation of this enriched fraction by size exclusion chromatography into monomers, dimers and aggregates and further testing regarding the biological activity revealed the monomer fraction as being the most appropriate one to continue working with. The detailed characterization of the antibody’s activity confirmed its high specificity to induce the killing of CSPG4 positive cells. In addition, first insights into tumor cell death pathways mediated by r28M-activated peripheral blood mononuclear cells were gained. In consideration of possible applications in vivo we also tested the effect of the addition of different excipients to r28M. Conclusion Summing up, we managed to purify monomeric r28M from bovine plasma in a large-scale preparation and could prove that its biological activity is unaffected and still highly specific and thus, might be applicable for the treatment of melanoma. PMID:26469402

  12. An ultra scale-down approach identifies host cell protein differences across a panel of mAb producing CHO cell line variants.

    PubMed

    Hogwood, Catherine E M; Ahmad, Shahina S; Tarrant, Richard D; Bracewell, Daniel G; Smales, C Mark

    2016-03-01

    During the manufacture of biopharmaceutical products, the final product must lie within strict pre-set specifications, for example the host cell protein (HCP) content. A number of specific HCPs have been identified in particular products and the interactions between product/HCPs have also been recently investigated; however, a comparison of the HCP dynamics between related cell lines and their response to early downstream processing to aid process development and cell line selection has not been published. We have utilised a proteomic approach coupled with an ultra scale-down study to determine the HCP profile dynamics, at harvest and during early downstream processing, across a panel of recombinant GS-CHOK1SV antibody producing cell lines. The results reveal that cell culture viability upon harvest has the greatest impact upon shear sensitivity and HCP concentration. Whilst the general HCP population/profile was broadly similar across the cell lines, the actual amounts of some specific HCPs in the supernatant differed and a number of cell line specific differences in the response to early downstream processing were observed. We anticipate that such knowledge can now be applied to cell line selection and downstream processing development to target reduction/removal of general and specific problematic HCPs before and during downstream processing.

  13. mcr-1.2, a New mcr Variant Carried on a Transferable Plasmid from a Colistin-Resistant KPC Carbapenemase-Producing Klebsiella pneumoniae Strain of Sequence Type 512

    PubMed Central

    Di Pilato, Vincenzo; Arena, Fabio; Tascini, Carlo; Cannatelli, Antonio; Henrici De Angelis, Lucia; Fortunato, Simona; Giani, Tommaso; Menichetti, Francesco

    2016-01-01

    A novel mcr variant, named mcr-1.2, encoding a Gln3-to-Leu functional variant of MCR-1, was detected in a KPC-3-producing ST512 Klebsiella pneumoniae isolate collected in Italy from a surveillance rectal swab from a leukemic child. The mcr-1.2 gene was carried on a transferable IncX4 plasmid whose structure was very similar to that of mcr-1-bearing plasmids previously found in Escherichia coli and K. pneumoniae strains from geographically distant sites (Estonia, China, and South Africa). PMID:27401575

  14. mcr-1.2, a New mcr Variant Carried on a Transferable Plasmid from a Colistin-Resistant KPC Carbapenemase-Producing Klebsiella pneumoniae Strain of Sequence Type 512.

    PubMed

    Di Pilato, Vincenzo; Arena, Fabio; Tascini, Carlo; Cannatelli, Antonio; Henrici De Angelis, Lucia; Fortunato, Simona; Giani, Tommaso; Menichetti, Francesco; Rossolini, Gian Maria

    2016-09-01

    A novel mcr variant, named mcr-1.2, encoding a Gln3-to-Leu functional variant of MCR-1, was detected in a KPC-3-producing ST512 Klebsiella pneumoniae isolate collected in Italy from a surveillance rectal swab from a leukemic child. The mcr-1.2 gene was carried on a transferable IncX4 plasmid whose structure was very similar to that of mcr-1-bearing plasmids previously found in Escherichia coli and K. pneumoniae strains from geographically distant sites (Estonia, China, and South Africa).

  15. Validation of a pH gradient-based ion-exchange chromatography method for high-resolution monoclonal antibody charge variant separations.

    PubMed

    Rea, Jennifer C; Moreno, G Tony; Lou, Yun; Farnan, Dell

    2011-01-25

    Ion-exchange chromatography is widely used for profiling the charge heterogeneity of proteins, including monoclonal antibodies. Despite good resolving power and robustness, ionic strength-based ion-exchange separations are product-specific and time-consuming to develop. We have previously reported a novel pH-based separation of proteins by cation exchange chromatography that was multi-product, high-resolution, and robust against variations in sample matrix salt concentration and pH. In this study, a pH gradient-based separation method using cation exchange chromatography was evaluated in a mock validation. This method was shown to be robust for monoclonal antibodies and suitable for its intended purpose of charge heterogeneity analysis. Simple mixtures of defined buffer components were used to generate the pH gradients that separated closely related antibody species. Validation characteristics, such as precision and linearity, were evaluated. Robustness to changes in protein load, buffer pH and column oven temperature was demonstrated. The stability-indicating capability of this method was determined using thermally stressed antibody samples. In addition, intermediate precision was demonstrated using multiple instruments, multiple analysts, multiple column lots, and different column manufacturers. Finally, the precision for this method was compared to conventional ion-exchange chromatography and imaged capillary isoelectric focusing. These results demonstrate the superior precision and robustness of this multi-product method, which can be used for the high-throughput evaluation of in-process and final product samples.

  16. De Novo Assembly of the Complete Genome of an Enhanced Electricity-Producing Variant of Geobacter sulfurreducens Using Only Short Reads

    PubMed Central

    Nagarajan, Harish; Butler, Jessica E.; Klimes, Anna; Qiu, Yu; Zengler, Karsten; Ward, Joy; Young, Nelson D.; Methé, Barbara A.; Palsson, Bernhard Ø.; Lovley, Derek R.; Barrett, Christian L.

    2010-01-01

    State-of-the-art DNA sequencing technologies are transforming the life sciences due to their ability to generate nucleotide sequence information with a speed and quantity that is unapproachable with traditional Sanger sequencing. Genome sequencing is a principal application of this technology, where the ultimate goal is the full and complete sequence of the organism of interest. Due to the nature of the raw data produced by these technologies, a full genomic sequence attained without the aid of Sanger sequencing has yet to be demonstrated. We have successfully developed a four-phase strategy for using only next-generation sequencing technologies (Illumina and 454) to assemble a complete microbial genome de novo. We applied this approach to completely assemble the 3.7 Mb genome of a rare Geobacter variant (KN400) that is capable of unprecedented current production at an electrode. Two key components of our strategy enabled us to achieve this result. First, we integrated the two data types early in the process to maximally leverage their complementary characteristics. And second, we used the output of different short read assembly programs in such a way so as to leverage the complementary nature of their different underlying algorithms or of their different implementations of the same underlying algorithm. The significance of our result is that it demonstrates a general approach for maximizing the efficiency and success of genome assembly projects as new sequencing technologies and new assembly algorithms are introduced. The general approach is a meta strategy, wherein sequencing data are integrated as early as possible and in particular ways and wherein multiple assembly algorithms are judiciously applied such that the deficiencies in one are complemented by another. PMID:20544019

  17. Characterization of anti-P monoclonal antibodies directed against the ribosomal protein-RNA complex antigen and produced using Murphy Roths large autoimmune-prone mice.

    PubMed

    Sato, H; Onozuka, M; Hagiya, A; Hoshino, S; Narita, I; Uchiumi, T

    2015-02-01

    Autoantibodies, including anti-ribosomal P proteins (anti-P), are thought to be produced by an antigen-driven immune response in systemic lupus erythematosus (SLE). To test this hypothesis, we reconstituted the ribosomal antigenic complex in vitro using human P0, phosphorylated P1 and P2 and a 28S rRNA fragment covering the P0 binding site, and immunized Murphy Roths large (MRL)/lrp lupus mice with this complex without any added adjuvant to generate anti-P antibodies. Using hybridoma technology, we subsequently obtained 34 clones, each producing an anti-P monoclonal antibody (mAb) that recognized the conserved C-terminal tail sequence common to all three P proteins. We also obtained two P0-specific monoclonal antibodies, but no antibody specific to P1, P2 or rRNA fragment. Two types of mAbs were found among these anti-P antibodies: one type (e.g. 9D5) reacted more strongly with the phosphorylated P1 and P2 than that with their non-phosphorylated forms, whereas the other type (e.g. 4H11) reacted equally with both phosphorylated and non-phosphorylated forms of P1/P2. Both 9D5 and 4H11 inhibited the ribosome/eukaryotic elongation factor-2 (eEF-2)-coupled guanosine triphosphate (GTP)ase activity. However, preincubation with a synthetic peptide corresponding to the C-terminal sequence common to all three P proteins, but not the peptide that lacked the last three C-terminal amino acids, mostly prevented the mAb-induced inhibition of GTPase activity. Thus, at least two types of anti-P were produced preferentially following the immunization of MRL mice with the reconstituted antigenic complex. Presence of multiple copies of the C-termini, particularly that of the last three C-terminal amino acid residues, in the antigenic complex appears to contribute to the immunogenic stimulus.

  18. Characterization of anti-P monoclonal antibodies directed against the ribosomal protein–RNA complex antigen and produced using Murphy Roths large autoimmune-prone mice

    PubMed Central

    Sato, H; Onozuka, M; Hagiya, A; Hoshino, S; Narita, I; Uchiumi, T

    2015-01-01

    Autoantibodies, including anti-ribosomal P proteins (anti-P), are thought to be produced by an antigen-driven immune response in systemic lupus erythematosus (SLE). To test this hypothesis, we reconstituted the ribosomal antigenic complex in vitro using human P0, phosphorylated P1 and P2 and a 28S rRNA fragment covering the P0 binding site, and immunized Murphy Roths large (MRL)/lrp lupus mice with this complex without any added adjuvant to generate anti-P antibodies. Using hybridoma technology, we subsequently obtained 34 clones, each producing an anti-P monoclonal antibody (mAb) that recognized the conserved C-terminal tail sequence common to all three P proteins. We also obtained two P0-specific monoclonal antibodies, but no antibody specific to P1, P2 or rRNA fragment. Two types of mAbs were found among these anti-P antibodies: one type (e.g. 9D5) reacted more strongly with the phosphorylated P1 and P2 than that with their non-phosphorylated forms, whereas the other type (e.g. 4H11) reacted equally with both phosphorylated and non-phosphorylated forms of P1/P2. Both 9D5 and 4H11 inhibited the ribosome/eukaryotic elongation factor-2 (eEF-2)-coupled guanosine triphosphate (GTP)ase activity. However, preincubation with a synthetic peptide corresponding to the C-terminal sequence common to all three P proteins, but not the peptide that lacked the last three C-terminal amino acids, mostly prevented the mAb-induced inhibition of GTPase activity. Thus, at least two types of anti-P were produced preferentially following the immunization of MRL mice with the reconstituted antigenic complex. Presence of multiple copies of the C-termini, particularly that of the last three C-terminal amino acid residues, in the antigenic complex appears to contribute to the immunogenic stimulus. PMID:25255895

  19. [Immunization experiments for producing antibody-like substances in caterpillars of Mamestra brassicae L. (Insecta, Lepid., Noct.)].

    PubMed

    Luther, P; Otto, D; Köhler, W; Fischer, G

    1975-01-01

    The agglutinins against human blood cells described in caterpillars of Mamestra brassicae L. were not demonstrable when feeding the animals with a semisynthetic food. After injection or oral intake of certain bacteria (E. coli or streptococci of group C) or even Pope's broth the "antibody-like substances" known from feeding with natural food are being formed, and they agglutinated all human blood cells. The individual animals showed differences regarding the strength of agglutinin formation. The immune reactions observed possibly indicate the existence of a primitive immune system in these species (arthropods).

  20. Maternal autism-associated IgG antibodies delay development and produce anxiety in a mouse gestational transfer model.

    PubMed

    Braunschweig, Daniel; Golub, Mari S; Koenig, Claire M; Qi, Lihong; Pessah, Isaac N; Van de Water, Judy; Berman, Robert F

    2012-11-15

    A murine passive transfer model system was employed to ascertain the effects of gestational exposure to a single, intravenous dose of purified, brain-reactive IgG antibodies from individual mothers of children with autism (MAU) or mothers with typically developing children (MTD). Growth and behavioral outcomes in offspring were measured from postnatal days 8 to 65 in each group. Comparisons revealed alterations in early growth trajectories, significantly impaired motor and sensory development, and increased anxiety. This report demonstrates for the first time the effects of a single, low dose gestational exposure of IgG derived from individual MAU on their offspring's physical and social development.

  1. Anti-malaria antibody-producing B cell frequencies in adults after a Plasmodium falciparum outbreak in Madagascar.

    PubMed Central

    Migot, F; Chougnet, C; Henzel, D; Dubois, B; Jambou, R; Fievet, N; Deloron, P

    1995-01-01

    The central highlands of Madagascar offer a unique opportunity to explore the malaria immune memory, as the last murderous epidemic in the study area occurred 8 years ago. Quantification of the circulating memory B lymphocytes reacting to Plasmodium falciparum was assessed among 14 Madagascans by using a limiting dilution assay, applied to the EL4 culture system, which leads to activation, proliferation and differentiation into antibody-secreting cells (ASC) of most peripheral B cells. This system allowed us to observe, without any malaria-specific restimulation, a geometric mean frequency of one anti-P. falciparum ASC among 2992 circulating B cells, except for one Madagascan who did not have any detectable ASC. A geometric mean frequency of one anti-P. falciparum ASC among 1403 was obtained for six malaria hyperimmune Cameroonians, but conversely, no anti-malaria ASC was detected in the blood of six malaria non-immune French control subjects. Anti-P. falciparum ASC frequencies and serum specific antibodies were strongly related. Our results indicate that anti-malaria ASC are still present in peripheral blood of Madagascan subjects, who have not been exposed to P. falciparum for several years. These responder B cells reflect the malaria B cell memory acquired during the last epidemic. PMID:8536368

  2. Capture of dengue viruses using antibody-integrated graphite-encapsulated magnetic beads produced using gas plasma technology.

    PubMed

    Sakudo, Akikazu; Viswan, Anchu; Chou, Han; Sasaki, Tadahiro; Ikuta, Kazuyoshi; Nagatsu, Masaaki

    2016-07-01

    Despite significant advances in medicine, global health is threatened by emerging infectious diseases caused by a number of viruses. Dengue virus (DENV) is a mosquito‑borne virus, which can be transmitted to humans via mosquito vectors. Previously, the Ministry of Health, Labour and Welfare in Japan reported the country's first domestically acquired case of dengue fever for almost 70 years. To address this issue, it is important to develop novel technologies for the sensitive detection of DENV. The present study reported on the development of plasma-functionalized, graphite-encapsulated magnetic nanoparticles (GrMNPs) conjugated with anti-DENV antibody for DENV capture. Radiofrequency wave‑excited inductively‑coupled Ar and ammonia gas plasmas were used to introduce amino groups onto the surface of the GrMNPs. The GrMNPs were then conjugated with an antibody against DENV, and the antibody‑integrated magnetic beads were assessed for their ability to capture DENV. Beads incubated in a cell culture medium of DENV‑infected mosquito cells were separated from the supernatant by applying a magnetic field and were then washed. The adsorption of DENV serotypes 1‑4 onto the beads was confirmed using reverse transcription‑polymerase chain reaction, which detected the presence of DENV genomic RNA on the GrMNPs. The methodology described in the present study, which employed the plasma-functionalization of GrMNPs to enable antibody‑integration, represents a significant improvement in the detection of DENV.

  3. Enhanced transport of plant-produced rabies single chain antibody-RVG peptide fusion protein across an in cellulo blood-brain barrier device.

    PubMed

    Phoolcharoen, Waranyoo; Prehaud, Christophe; van Dolleweerd, Craig J; Both, Leonard; da Costa, Anaelle; Lafon, Monique; Ma, Julian K-C

    2017-03-08

    The biomedical applications of antibody engineering are developing rapidly and have been expanded to plant expression platforms. In the present study, we have generated a novel antibody molecule in planta for targeted delivery across the blood-brain barrier (BBB). Rabies virus (RABV) is a neurotropic virus for which there is no effective treatment after entry into the central nervous system (CNS). This study investigated the use of a RABV glycoprotein peptide sequence to assist delivery of a rabies neutralising single-chain antibody (ScFv) across an in cellulo model of human BBB. The 29 amino acid rabies virus peptide (RVG) recognises the nicotinic acetylcholine receptor (nAchR) at neuromuscular junctions and the BBB. ScFv and ScFv-RVG fusion proteins were produced in Nicotiana benthamiana by transient expression. Both molecules were successfully expressed and purified, but the ScFv expression level was significantly higher than that of ScFv-RVG fusion. Both ScFv and ScFv-RVG fusion molecules had potent neutralisation activity against RABV in cellulo. The ScFv-RVG fusion demonstrated increased binding to nAchR and entry into neuronal cells, compared to ScFv alone. Additionally, a human brain endothelial cell line BBB model was used to demonstrate that plant-produced ScFv-RVG(P) fusion could translocate across the cells. This study indicates that the plant-produced ScFv-RVG(P) fusion protein was able to cross the in cellulo BBB and neutralise RABV. This article is protected by copyright. All rights reserved.

  4. Differential analyses of major allergen proteins in wild-type rice and rice producing a fragment of anti-rotavirus antibody.

    PubMed

    Yuki, Yoshikazu; Kurokawa, Shiho; Kozuka-Hata, Hiroko; Tokuhara, Daisuke; Mejima, Mio; Kuroda, Masaharu; Oyama, Masaaki; Nishimaki-Mogami, Tomoko; Teshima, Reiko; Kiyono, Hiroshi

    2016-04-01

    To develop oral antibody therapy against rotavirus infection, we previously produced a recombinant fragment of llama heavy-chain antibody to rotavirus (ARP1) in rice seeds (MucoRice-ARP1). We intend to use a purification-free rice powder for clinical application but needed to check whether MucoRice-ARP1 had increased levels of known allergen proteins. For this purpose, we used two-dimensional fluorescence difference gel electrophoresis to compare the allergen protein levels in MucoRice-ARP1 and wild-type rice. We detected no notable differences, except in the levels of α-amylase/trypsin inhibitor-like family proteins. Because by this approach we could not completely separate ARP1 from the proteins of this family, we confirmed the absence of changes in the levels of these allergens by using shotgun mass spectrometry as well as immunoblot. By using immunoelectron microscopy, we also showed that RAG2, a member of the α-amylase/trypsin inhibitor-like protein family, was relocated from protein bodies II to the plasma membrane or cell wall in MucoRice-ARP1 seed. The relocation did not affect the level of RAG2. We demonstrated that most of the known rice allergens were not considerably upregulated by the genetic modification in MucoRice-ARP1. Our data suggest that MucoRice-ARP1 is a potentially safe oral antibody for clinical application.

  5. Intrahippocampal administration of a domain antibody that binds aggregated amyloid-β reverses cognitive deficits produced by diet-induced obesity

    PubMed Central

    Osborne, Danielle M.; Fitzgerald, Dennis P.; O’Leary, Kelsey E.; Anderson, Brian M.; Lee, Christine C.; Tessier, Peter M.; McNay, Ewan C.

    2016-01-01

    Background The prevalence of high fat diets (HFD), diet-induced obesity (DIO) and Type 2 diabetes continues to increase, associated with cognitive impairment in both humans and rodent models. Mechanisms transducing these impairments remain largely unknown: one possibility is that a common mechanism may be involved in the cognitive impairment seen in obese and/or diabetic states and in dementia, specifically Alzheimer’s disease (AD). DIO is well established as a risk factor for development of AD. Oligomeric amyloid-β (Aβ) is neurotoxic, and we showed that intrahippocampal oligomeric Aβ produces cognitive and metabolic dysfunction similar to that seen in DIO or diabetes. Moreover, animal models of DIO show elevated brain Aβ, a hallmark of AD, suggesting that this may be one source of cognitive impairment in both conditions. Methods Intrahippocampal administration of a novel anti-Aβ domain antibody for aggregated Aβ, or a control domain antibody, to control or HFD-induced DIO rats. Spatial learning measured in a conditioned contextual fear (CCF) task after domain antibody treatment; postmortem, hippocampal NMDAR and AMPAR were measured. Results DIO caused impairment in CCF, and this impairment was eliminated by intrahippocampal administration of the active domain antibody. Measurement of hippocampal proteins suggests that DIO causes dysregulation of hippocampal AMPA receptors, which is also reversed by acute domain antibody administration. Conclusions Our findings support the concept that oligomeric Aβ within the hippocampus of DIO animals may not only be a risk factor for development of AD but may also cause cognitive impairment before the development of dementia. General Significance and Interest Our work integrates the engineering of domain antibodies with conformational-and sequence-specificity for oligomeric amyloid beta with a clinically relevant model of diet-induced obesity in order to demonstrate not only the pervasive effects of obesity on several

  6. Top-down and middle-down approach by fraction collection enrichment using off-line capillary electrophoresis - mass spectrometry coupling: Application to monoclonal antibody Fc/2 charge variants.

    PubMed

    Biacchi, Michael; Said, Nassur; Beck, Alain; Leize-Wagner, Emmanuelle; François, Yannis-Nicolas

    2017-02-27

    The characterization of complex protein mixtures represents one of the biggest challenge in many research fields such as biological or biopharmaceutical sciences. Out of all categories, monoclonal antibodies (mAbs) and related products drawn the most interest due to their strong therapeutic potency and specificity. Because of their intrinsic complexity due to a large number of micro-heterogeneities, there is a crucial need for analytical methods to provide comprehensive in-depth characterization of these proteins. In this work, we developed a methodology using CE-UV/MALDI-MS to perform top-down or middle-down characterization after fraction collection enrichment applied to intact protein and mAbs samples. The performance of the method was evaluated with the rapid separation of three intact protein mixture. Good robustness of CZE separation and quality of MALDI-MS spectra and MALDI-ISD spectra of each protein confirms the usefulness of sample enrichment to obtain adequate quantity of deposed protein for top-down analysis and the proof of principle of the method. In a second step, the method was applied to the middle-down characterization of Fc/2 cetuximab variants. Identification of around 9% sequence coverage of Fc/2 cetuximab fragments allows to conclude on the feasibility of the strategy for middle-down characterization of Fc/2 cetuximab variants using CE-UV/MALDI-MS. Moreover, MALDI-ISD fragmentation of Fc/2 cetuximab variants confirm separation phenomenon based on the formation of Fc/2 dimers with and without C-terminal truncation.

  7. Human Polyclonal Antibodies Produced through DNA Vaccination of Transchromosomal Cattle Provide Mice with Post-Exposure Protection against Lethal Zaire and Sudan Ebolaviruses

    PubMed Central

    Bounds, Callie E.; Kwilas, Steven A.; Kuehne, Ana I.; Brannan, Jennifer M.; Bakken, Russell R.; Dye, John M.; Hooper, Jay W.; Dupuy, Lesley C.; Ellefsen, Barry; Hannaman, Drew; Wu, Hua; Jiao, Jin-an; Sullivan, Eddie J.; Schmaljohn, Connie S.

    2015-01-01

    DNA vaccination of transchromosomal bovines (TcBs) with DNA vaccines expressing the codon-optimized (co) glycoprotein (GP) genes of Ebola virus (EBOV) and Sudan virus (SUDV) produce fully human polyclonal antibodies (pAbs) that recognize both viruses and demonstrate robust neutralizing activity. Each TcB was vaccinated by intramuscular electroporation (IM-EP) a total of four times and at each administration received 10 mg of the EBOV-GPco DNA vaccine and 10 mg of the SUDV-GPco DNA vaccine at two sites on the left and right sides, respectively. After two vaccinations, robust antibody responses (titers > 1000) were detected by ELISA against whole irradiated EBOV or SUDV and recombinant EBOV-GP or SUDV-GP (rGP) antigens, with higher titers observed for the rGP antigens. Strong, virus neutralizing antibody responses (titers >1000) were detected after three vaccinations when measured by vesicular stomatitis virus-based pseudovirion neutralization assay (PsVNA). Maximal neutralizing antibody responses were identified by traditional plaque reduction neutralization tests (PRNT) after four vaccinations. Neutralizing activity of human immunoglobulins (IgG) purified from TcB plasma collected after three vaccinations and injected intraperitoneally (IP) into mice at a 100 mg/kg dose was detected in the serum by PsVNA up to 14 days after administration. Passive transfer by IP injection of the purified IgG (100 mg/kg) to groups of BALB/c mice one day after IP challenge with mouse adapted (ma) EBOV resulted in 80% protection while all mice treated with non-specific pAbs succumbed. Similarly, interferon receptor 1 knockout (IFNAR -/-) mice receiving the purified IgG (100 mg/kg) by IP injection one day after IP challenge with wild type SUDV resulted in 89% survival. These results are the first to demonstrate that filovirus GP DNA vaccines administered to TcBs by IM-EP can elicit neutralizing antibodies that provide post-exposure protection. Additionally, these data describe

  8. Human Polyclonal Antibodies Produced through DNA Vaccination of Transchromosomal Cattle Provide Mice with Post-Exposure Protection against Lethal Zaire and Sudan Ebolaviruses.

    PubMed

    Bounds, Callie E; Kwilas, Steven A; Kuehne, Ana I; Brannan, Jennifer M; Bakken, Russell R; Dye, John M; Hooper, Jay W; Dupuy, Lesley C; Ellefsen, Barry; Hannaman, Drew; Wu, Hua; Jiao, Jin-an; Sullivan, Eddie J; Schmaljohn, Connie S

    2015-01-01

    DNA vaccination of transchromosomal bovines (TcBs) with DNA vaccines expressing the codon-optimized (co) glycoprotein (GP) genes of Ebola virus (EBOV) and Sudan virus (SUDV) produce fully human polyclonal antibodies (pAbs) that recognize both viruses and demonstrate robust neutralizing activity. Each TcB was vaccinated by intramuscular electroporation (IM-EP) a total of four times and at each administration received 10 mg of the EBOV-GPco DNA vaccine and 10 mg of the SUDV-GPco DNA vaccine at two sites on the left and right sides, respectively. After two vaccinations, robust antibody responses (titers > 1000) were detected by ELISA against whole irradiated EBOV or SUDV and recombinant EBOV-GP or SUDV-GP (rGP) antigens, with higher titers observed for the rGP antigens. Strong, virus neutralizing antibody responses (titers >1000) were detected after three vaccinations when measured by vesicular stomatitis virus-based pseudovirion neutralization assay (PsVNA). Maximal neutralizing antibody responses were identified by traditional plaque reduction neutralization tests (PRNT) after four vaccinations. Neutralizing activity of human immunoglobulins (IgG) purified from TcB plasma collected after three vaccinations and injected intraperitoneally (IP) into mice at a 100 mg/kg dose was detected in the serum by PsVNA up to 14 days after administration. Passive transfer by IP injection of the purified IgG (100 mg/kg) to groups of BALB/c mice one day after IP challenge with mouse adapted (ma) EBOV resulted in 80% protection while all mice treated with non-specific pAbs succumbed. Similarly, interferon receptor 1 knockout (IFNAR(-/-)) mice receiving the purified IgG (100 mg/kg) by IP injection one day after IP challenge with wild type SUDV resulted in 89% survival. These results are the first to demonstrate that filovirus GP DNA vaccines administered to TcBs by IM-EP can elicit neutralizing antibodies that provide post-exposure protection. Additionally, these data describe

  9. Human anti-varicella-zoster virus (VZV) recombinant monoclonal antibody produced after Zostavax immunization recognizes the gH/gL complex and neutralizes VZV infection.

    PubMed

    Birlea, Marius; Owens, Gregory P; Eshleman, Emily M; Ritchie, Alanna; Traktinskiy, Igor; Bos, Nathan; Seitz, Scott; Azarkh, Yevgeniy; Mahalingam, Ravi; Gilden, Don; Cohrs, Randall J

    2013-01-01

    Varicella-zoster virus (VZV) is a ubiquitous, highly cell-associated, and exclusively human neurotropic alphaherpesvirus. VZV infection is initiated by membrane fusion, an event dependent in part on VZV glycoproteins gH and gL. Consistent with its location on the virus envelope, the gH/gL complex is a target of neutralizing antibodies produced after virus infection. One week after immunizing a 59-year-old VZV-seropositive man with Zostavax, we sorted his circulating blood plasma blasts and amplified expressed immunoglobulin variable domain sequences by single-cell PCR. Sequence analysis identified two plasma blast clones, one of which was used to construct a recombinant monoclonal antibody (rec-RC IgG). The rec-RC IgG colocalized with VZV gE on the membranes of VZV-infected cells and neutralized VZV infection in tissue culture. Mass spectrometric analysis of proteins immunoprecipitated by rec-RC IgG identified both VZV gH and gL. Transfection experiments showed that rec-RC IgG recognized a VZV gH/gL protein complex but not individual gH or gL proteins. Overall, our recombinant monoclonal anti-VZV antibody effectively neutralizes VZV and recognizes a conformational epitope within the VZV gH/L protein complex. An unlimited supply of this antibody provides the opportunity to analyze membrane fusion events that follow virus attachment and to identify multiple epitopes on VZV-specific proteins.

  10. A trial with IgY chicken antibodies to eradicate faecal carriage of Klebsiella pneumoniae and Escherichia coli producing extended-spectrum beta-lactamases

    PubMed Central

    Jonsson, Anna-Karin; Larsson, Anders; Tängdén, Thomas; Melhus, Åsa; Lannergård, Anders

    2015-01-01

    Background Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae is an emerging therapeutic challenge, especially in the treatment of urinary tract infections. Following an outbreak of CTX-M-15 Klebsiella pneumoniae in Uppsala, Sweden, an orphan drug trial on IgY chicken antibodies was undertaken in an attempt to eradicate faecal carriage of ESBL-producing K. pneumoniae and Escherichia coli. Methods Hens were immunised with epitopes from freeze-dried, whole-cell bacteria (ESBL-producing K. pneumoniae and E. coli) and recombinant proteins of two K. pneumoniae fimbriae subunits (fimH and mrkD). The egg yolks were processed according to good manufacturing practice and the product was stored at−20°C until used. Using an internal database from the outbreak and the regular laboratory database, faecal carriers were identified and recruited from May 2005 to December 2013. The participants were randomised in a placebo-controlled 1:1 manner. Results From 749 eligible patients, 327 (44%) had deceased, and only 91 (12%) were recruited and signed the informed consent. In the initial screening performed using the polymerase chain reaction, 24 participants were ESBL positive and subsequently randomised and treated with either the study drug or a placebo. The study was powered for 124 participants. Because of a very high dropout rate, the study was prematurely terminated. From the outbreak cohort (n=247), only eight patients were screened, and only one was positive with the outbreak strain in faeces. Conclusions The present study design, using IgY chicken antibodies for the eradication of ESBL-producing K. pneumonia and E. coli, was ineffective in reaching its goal due to high mortality and other factors resulting in a low inclusion rate. Spontaneous eradication of ESBL-producing bacteria was frequently observed in recruited participants, which is consistent with previous reports. PMID:26560861

  11. An in vitro combined antibiotic/antibody treatment eliminates toxicity from Shiga toxin-producing E. coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Treating Shiga toxin-producing Escherichia coli (STEC) gastrointestinal infections is a difficult endeavor. The utility of antibiotics as an STEC treatment is controversial since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase express...

  12. Versuche zur Gewinnung von katalytischen Antikörpern zur Hydrolyse von Arylcarbamaten und Arylharnstoffen. (English Title: Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas)

    NASA Astrophysics Data System (ADS)

    Werner, Deljana

    2002-05-01

    Umsatzgeschwindigkeit eine lineare Abhängigkeit festgestellt. Die thermodynamische Gleichtgewichtsdissoziationskonstante KD des Abzyms von 2,6 nM zeugt von einer sehr guten Affinität zum ÜZA. Hydrolytisch aktiv waren nur Antikörper, die gegen das Übergangszustandsanalogon Hei3 hergestellt worden waren. Es wird vermutet, dass die Hydrolyse der Benzylphenylcarbamate über einen Additions-Eliminierungsmechanismus unter Ausbildung eines tetraedrischen Übergangszustandes verläuft, dessen analoge Verbindung Hei3 ist. Im Rahmen der Generierung von Nachweisantikörpern zur Detektion der Substratabnahme bei der Hydrolyse wurden Anti-Diuron-Antikörper hergestellt. Einer der Antikörper (B91-CG5) ist spezifisch für das Herbizid Diuron und hat einen IC50-Wert von 0,19 µg/l und eine untere Nachweisgrenze von 0,04 µg/l. Ein anderer Antikörper (B91-KF5) reagiert kreuz mit einer Palette ähnlicher Herbizide. Mit diesen Antikörpern wurde ein empfindlicher Labortest, der ein Monitoring von Diuron auf Grundlage des durch die Trinkwasserverordnung festgeschriebenen Wertes für Pflanzenschutzmittel von 0,1 µg/l erlaubt, aufgebaut. Der Effekt der Anti-Diuron-Antikörper auf die Diuron-inhibierte Photosynthese wurde in vitro und in vivo untersucht. Es wurde nachgewiesen, dass sowohl in isolierten Thylakoiden, als auch in intakten Algen eine Vorinkubation der Anti-Diuron-Antikörper mit Diuron zur Inaktivierung seiner Photosynthese-hemmenden Wirkung führt. Wurde der Elektronentransport in den isolierten Thylakoiden oder in Algen durch Diuron unterbrochen, so führte die Zugabe der Anti-Diuron-Antikörper zur Reaktivierung der Elektronenübertragung. Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas: The aim of the investigations was to produce antibodies which are able to cleave herbicides resistant to naturally occuring enzymes. Structurally similar carbamate and urea derivatives were chosen for the experiments. Phosphonate derivatives were synthesized

  13. Cellulase variants

    DOEpatents

    Blazej, Robert; Toriello, Nicholas; Emrich, Charles; Cohen, Richard N.; Koppel, Nitzan

    2015-07-14

    This invention provides novel variant cellulolytic enzymes having improved activity and/or stability. In certain embodiments the variant cellulotyic enzymes comprise a glycoside hydrolase with or comprising a substitution at one or more positions corresponding to one or more of residues F64, A226, and/or E246 in Thermobifida fusca Cel9A enzyme. In certain embodiments the glycoside hydrolase is a variant of a family 9 glycoside hydrolase. In certain embodiments the glycoside hydrolase is a variant of a theme B family 9 glycoside hydrolase.

  14. Generation of human hybridomas producing migration inhibitory factor (MIF) and of murine hybridomas secreting monoclonal antibodies to human MIF.

    PubMed

    Weiser, W Y; Remold, H G; David, J R

    1985-01-01

    Human T-cell hybridomas were established by hybridization of concanavalin A (Con A)-stimulated human peripheral blood T lymphocytes with cells from a 6-thioguanine-resistant, aminopterin-sensitive mutant line designated CEM-WH4, derived from the continuously growing human T cell line, CEM. High levels of MIF activity were demonstrated in the supernatants of two hybridoma lines, T-CEMA and T-CEMB but not of CEM-WH4 when stimulated with phorbol myristate acetate and phytohemagglutinin. In comparison, MIF derived from Con A-stimulated peripheral blood mononuclear cells showed 100 times less activity. Upon isoelectrofocusing, MIF activity of T-CEMB was found exclusively between pH 4.6 and 5.3 whereas MIF derived from T-CEMA showed heterogeneity with a major peak of MIF recovered at pH 4.6-5.3 and a minor peak at pH 2.4-3.3. These molecules, however, were all found to have an apparent MW of 68,000 and were resistant to trypsin. Most of these characteristics are in accordance with second day pH 3- and pH 5-MIF derived from peripheral blood mononuclear cells. When spleen cells from BALB/c mice immunized with T-CEMB-MIF were used to fuse with NS-1 mouse myeloma cells, nine hybridomas secreting antibodies to human MIF were obtained. Clone D112 which demonstrated the highest MIF-neutralizing activity was found to neutralize MIF derived from T-CEMA, peripheral blood mononuclear cells, and a T cell line, Mo.

  15. A direct qPCR method for residual DNA quantification in monoclonal antibody drugs produced in CHO cells.

    PubMed

    Hussain, Musaddeq

    2015-11-10

    Chinese hamster ovary (CHO) cells are the host cell of choice for manufacturing of monoclonal antibody (mAb) drugs in the biopharmaceutical industry. Host cell DNA is an impurity of such manufacturing process and must be controlled and monitored in order to ensure drug purity and safety. A conventional method for quantification of host residual DNA in drug requires extraction of DNA from the mAb drug substance with subsequent quantification of the extracted DNA using real-time PCR (qPCR). Here we report a method where the DNA extraction step is eliminated prior to qPCR. In this method, which we have named 'direct resDNA qPCR', the mAb drug substance is digested with a protease called KAPA in a 96-well PCR plate, the protease in the digest is then denatured at high temperature, qPCR reagents are added to the resultant reaction wells in the plate along with standards and controls in other wells of the same plate, and the plate subjected to qPCR for analysis of residual host DNA in the samples. This direct resDNA qPCR method for CHO is sensitive to 5.0fg of DNA with high precision and accuracy and has a wide linear range of determination. The method has been successfully tested with four mAbs drug, two IgG1 and two IgG4. Both the purified drug substance as well as a number of process intermediate samples, e.g., bioreactor harvest, Protein A column eluate and ion-exchange column eluates were tested. This method simplifies the residual DNA quantification protocol, reduces time of analysis and leads to increased assay sensitivity and development of automated high-throughput methods.

  16. Exploring the capabilities of fluorometric online monitoring on chinese hamster ovary cell cultivations producing a monoclonal antibody.

    PubMed

    Schwab, Karen; Amann, Thomas; Schmid, Jakob; Handrick, René; Hesse, Friedemann

    2016-11-01

    Online monitoring of Chinese hamster ovary fed-batch cell cultures via two-dimensional fluorescence spectroscopy (2DFS) was evaluated in this work. Particular attention was directed toward different process strategies regarding the use of nutrient-rich feed media and temperature shifts. These intentionally performed process manipulations broadened the variances in the obtained fluorescence spectra and this was suspected to hamper the generation of reliable soft sensors. Principal component analysis of the obtained fluorescence data showed that temperature shift and feeding strategy had a considerable impact on the fluorescence signals. Partial least square regression models were calculated for the prediction of glucose, lactate, monoclonal antibody (mAb), and viable cell concentrations (VCC). It was aimed to integrate all 2DFS datasets in the respective calibration models regardless of the process-strategy-dependent diversity. Contrary to the expectations, it was feasible to calibrate soft sensors for the online prediction of glucose (7 latent variables (LVs), Rcal2 = 0.97, rout mean squared error of prediction (RMSEP) = 1.1 g L(-1) ), lactate (5 LV; Rcal2 = 0.96; RMSEP = 0.5 g L(-1) ) and mAb concentrations (4 LV; Rcal2 = 0.99; RMSEP = 11.4 mg L(-1) ). Feeding and temperature shifts had the highest impact on the VCC model (3 LV; Rcal2 = 0.94; RMSEP 3.8 × 10(5) mL(-1) ), nevertheless the prediction of VCC from the fed-batch 2DFS data was feasible. The results strongly indicate that variances in the datasets due to the process strategy can be tolerated to some extent by the respective soft sensors. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1592-1600, 2016.

  17. Antibodies binding granulocyte-macrophage colony stimulating factor produced by cord blood-derived B cell lines immortalized by Epstein-Barr virus in vitro.

    PubMed

    Revoltella, R P; Laricchia Robbio, L; Liberati, A M; Reato, G; Foa, R; Funaro, A; Vinante, F; Pizzolo, G

    2000-09-15

    We detected natural antibodies (auto-Abs) binding human granulocyte-macrophage colony stimulating factor (GM-CSF) in umbilical cord blood (CB) (23 of 94 samples screened) and peripheral blood of women at the end of pregnancy (6 of 42 samples tested). To demonstrate that Abs detected in CB were produced by the fetus, CB mononuclear cells were infected with Epstein-Barr virus in vitro. Ten cell lines producing constitutively anti-recombinant human GM-CSF (rhGM-CSF) Abs were isolated and characterized. These cells displayed a male karyotype, an early activated B cell phenotype, coexpressed surface IgM and IgD, and secreted only IgM with prevailing lambda clonal restriction. Specific cell surface binding of biotinylated rhGM-CSF and high-level anti-rhGM-CSF IgM Ab production were typical features of early cell cultures. In late cell passages the frequency of more undifferentiated B cells increased. Serum Abs of either maternal or fetal origin or Abs produced in culture did not affect the granulocyte and macrophage colony stimulating activity of rhGM-CSF from bone marrow progenitors in soft agar, suggesting that the Abs produced were nonneutralizing.

  18. A non-glycosylated, plant-produced human monoclonal antibody against anthrax protective antigen protects mice and non-human primates from B. anthracis spore challenge.

    PubMed

    Mett, Vadim; Chichester, Jessica A; Stewart, Michelle L; Musiychuk, Konstantin; Bi, Hong; Reifsnyder, Carolyn J; Hull, Anna K; Albrecht, Mark T; Goldman, Stanley; Baillie, Les W J; Yusibov, Vidadi

    2011-01-01

    The health and economic burden of infectious diseases in general and bioterrorism in particular necessitate the development of medical countermeasures. One proven approach to reduce the disease burden and spread of pathogen is treatment with monoclonal antibodies (mAb). mAbs can prevent or reduce severity of the disease by variety of mechanisms, including neutralizing pathogen growth, limiting its spread from infected to adjacent cells, or by inhibiting biological activity of toxins, such as anthrax lethal toxin. Here, we report the production of glycosylated (pp-mAb (PA) ) and non-glycosylated (pp-mAb (PANG) ) versions of a plant-derived mAb directed against protective antigen (PA) of Bacillus anthracis in Nicotiana benthamiana plants using agroinfiltration. Both forms of the antibody were able to neutralize anthrax lethal toxin activity in vitro and protect mice against an intraperitoneal challenge with spores of B. anthracis Sterne strain. A single 180 µg intraperitoneal dose of pp-mAb (PA) or pp-mAb (PANG) provided 90% and 100% survival, respectively. When tested in non-human primates, pp-mAb (PANG) was demonstrated to be superior to pp-mAb (PA) in that it had a significantly longer terminal half-life and conferred 100% protection against a lethal dose of aerosolized anthrax spore challenge after a single 5 mg/kg intravenous dose compared to a 40% survival rate conferred by pp-mAb (PA) . This study demonstrates the potential of a plant-produced non-glycosylated antibody as a useful tool for the treatment of inhalation anthrax.

  19. Double-peak elution profile of a monoclonal antibody in cation exchange chromatography is caused by histidine-protonation-based charge variants.

    PubMed

    Luo, Haibin; Cao, Mingyan; Newell, Kelcy; Afdahl, Christopher; Wang, Jihong; Wang, William K; Li, Yuling

    2015-12-11

    We have systemically investigated unusual elution behaviors of an IgG4 (mAb A) in cation exchange chromatography (CEX). This mAb A exhibited two elution peaks under certain conditions when being purified by several strong CEX columns. When either of the two peaks was isolated and re-injected on the same column, the similar pattern was observed again during elution. The protein distribution between the two peaks could be altered by NaCl concentration in the feed, or NaCl concentration in wash buffer, or elution pH, suggesting two pH-associated strong-and-weak binding configurations. The protein distributions under different pH values showed good correlation with protonated/un-protonated fractions of a histidine residue. These results suggest that the double-peak elution profile associates with histidine-protonation-based charge variants. By conducting pepsin digestion, amino-acid specific chemical modifications, peptide mapping, and measuring the effects of elution residence time, a histidine in the variable fragment (Fab) was identified to be the root cause. Besides double-peak pattern, mAb A can also exhibit peak-shouldering or single elution peak on different CEX resins, reflecting different resins' resolving capability on protonated/un-protonated forms. This work characterizes a novel cause for unusual elution behaviors in CEX and also provides alternative avenues of purification development for mAbs with similar behaviors.

  20. Characterization of N-Linked Glycosylation in a Monoclonal Antibody Produced in NS0 Cells Using Capillary Electrophoresis with Laser-Induced Fluorescence Detection

    PubMed Central

    Hamm, Melissa; Wang, Yang; Rustandi, Richard R.

    2013-01-01

    The N-linked glycosylation in recombinant monoclonal antibodies (mAb) occurs at Asn297 on the Fc region in the CH2 domain. Glycosylation heterogeneities have been well documented to affect biological activities such as antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) through their interaction with Fc-receptors. Hence, it is critical to monitor and characterize the N-linked glycosylation profile in a therapeutic protein such as a mAb for product consistency. In one approach, the glycans are first released from the mAb using an enzyme specific digestion, such as Protein N-Glycosidase F (PNGase) and subsequently they are labeled using a fluorophore, for example, 8-aminopyrene-1,3,6-trisulfonic acid (APTS) . Here we have applied this approach and used Capillary Electrophoresis with Laser-Induced Fluorescence detection (CE-LIF) to analyze a recombinant mAb produced in murine myeloma (NS0) cells. The technique provides short analysis times, efficient separations, and high sensitivity. CE-LIF peak identification was done by a combination of glycan standards and treatment with various exoglycosidases. Furthermore, the APTS-labeled glycans were also analyzed using hydrophilic interaction chromatography (HILIC) high performance liquid chromatography (HPLC) to aid identification of minor peaks by sample collection and off-line mass spectrometry (MS) analysis. PMID:24276024

  1. Polymorphisms of the Hepatitis A Virus Cellular Receptor 1 in African Green Monkey Kidney Cells Result in Antigenic Variants That Do Not React with Protective Monoclonal Antibody 190/4

    PubMed Central

    Feigelstock, Dino; Thompson, Peter; Mattoo, Pravina; Kaplan, Gerardo G.

    1998-01-01

    Monoclonal antibody (MAb) 190/4 blocks binding of hepatitis A virus (HAV) to the HAV cellular receptor 1 (havcr-1) and protects African green monkey kidney (AGMK) clone GL37 cells (GL37 cells) against HAV infection. BS-C-1 and CV-1 cells, two widely used AGMK cell lines, did not react with MAb 190/4 but expressed havcr-1, as judged by Western blot analysis. The cDNA coding for havcr-1 was amplified from BS-C-1 and CV-1 total cellular RNA by reverse transcription-PCR. Alignment of the amino acid sequences inferred from the cDNA nucleotide sequences showed that BS-C-1 and CV-1 havcr-1 differed from GL37 havcr-1 by having two substitutions in the Cys-rich region, N48H and K108Q, and 10 to 11 additional substitutions plus the insertion of 18 to 22 amino acids in the mucin-like region. Studies with chimeras of GL37 havcr-1 and BS-C-1 havcr-1 showed that the K108Q substitution was responsible for the lack of reaction of MAb 190/4 with BS-C-1 and CV-1 cells. Binding studies indicated that HAV bound to dog cell transfectants expressing the BS-C-1 havcr-1 as well as the GL37/BS-C-1 havcr-1 chimeras. These results indicate that antigenic variants of havcr-1 are expressed in AGMK cells and that binding of HAV to these havcr-1 variants tolerates changes in protective epitope 190/4. PMID:9621093

  2. Polymorphisms of the hepatitis A virus cellular receptor 1 in African green monkey kidney cells result in antigenic variants that do not react with protective monoclonal antibody 190/4.

    PubMed

    Feigelstock, D; Thompson, P; Mattoo, P; Kaplan, G G

    1998-07-01

    Monoclonal antibody (MAb) 190/4 blocks binding of hepatitis A virus (HAV) to the HAV cellular receptor 1 (havcr-1) and protects African green monkey kidney (AGMK) clone GL37 cells (GL37 cells) against HAV infection. BS-C-1 and CV-1 cells, two widely used AGMK cell lines, did not react with MAb 190/4 but expressed havcr-1, as judged by Western blot analysis. The cDNA coding for havcr-1 was amplified from BS-C-1 and CV-1 total cellular RNA by reverse transcription-PCR. Alignment of the amino acid sequences inferred from the cDNA nucleotide sequences showed that BS-C-1 and CV-1 havcr-1 differed from GL37 havcr-1 by having two substitutions in the Cys-rich region, N48H and K108Q, and 10 to 11 additional substitutions plus the insertion of 18 to 22 amino acids in the mucin-like region. Studies with chimeras of GL37 havcr-1 and BS-C-1 havcr-1 showed that the K108Q substitution was responsible for the lack of reaction of MAb 190/4 with BS-C-1 and CV-1 cells. Binding studies indicated that HAV bound to dog cell transfectants expressing the BS-C-1 havcr-1 as well as the GL37/BS-C-1 havcr-1 chimeras. These results indicate that antigenic variants of havcr-1 are expressed in AGMK cells and that binding of HAV to these havcr-1 variants tolerates changes in protective epitope 190/4.

  3. A novel hemagglutinin protein produced in bacteria protects chickens against H5N1 highly pathogenic avian influenza viruses by inducing H5 subtype-specific neutralizing antibodies

    PubMed Central

    Sączyńska, Violetta; Romanik, Agnieszka; Florys, Katarzyna; Cecuda-Adamczewska, Violetta; Kęsik-Brodacka, Małgorzata; Śmietanka, Krzysztof; Olszewska, Monika; Domańska-Blicharz, Katarzyna; Minta, Zenon; Szewczyk, Bogusław; Płucienniczak, Grażyna; Płucienniczak, Andrzej

    2017-01-01

    The highly pathogenic (HP) H5N1 avian influenza viruses (AIVs) cause a mortality rate of up to 100% in infected chickens and pose a permanent pandemic threat. Attempts to obtain effective vaccines against H5N1 HPAIVs have focused on hemagglutinin (HA), an immunodominant viral antigen capable of eliciting neutralizing antibodies. The vast majority of vaccine projects have been performed using eukaryotic expression systems. In contrast, we used a bacterial expression system to produce vaccine HA protein (bacterial HA) according to our own design. The HA protein with the sequence of the H5N1 HPAIV strain was efficiently expressed in Escherichia coli, recovered in the form of inclusion bodies and refolded by dilution between two chromatographic purification steps. Antigenicity studies showed that the resulting antigen, referred to as rH5-E. coli, preserves conformational epitopes targeted by antibodies specific for H5-subtype HAs, inhibiting hemagglutination and/or neutralizing influenza viruses in vitro. The proper conformation of this protein and its ability to form functional oligomers were confirmed by a hemagglutination test. Consistent with the biochemical characteristics, prime-boost immunizations with adjuvanted rH5-E. coli protected 100% and 70% of specific pathogen-free, layer-type chickens against challenge with homologous and heterologous H5N1 HPAIVs, respectively. The observed protection was related to the positivity in the FluAC H5 test (IDVet) but not to hemagglutination-inhibiting antibody titers. Due to full protection, the effective contact transmission of the homologous challenge virus did not occur. Survivors from both challenges did not or only transiently shed the viruses, as established by viral RNA detection in oropharyngeal and cloacal swabs. Our results demonstrate that vaccination with rH5-E. coli could confer control of H5N1 HPAIV infection and transmission rates in chicken flocks, accompanied by reduced virus shedding. Moreover, the role of

  4. A novel antibody engineering strategy for making monovalent bispecific heterodimeric IgG antibodies by electrostatic steering mechanism.

    PubMed

    Liu, Zhi; Leng, Esther C; Gunasekaran, Kannan; Pentony, Martin; Shen, Min; Howard, Monique; Stoops, Janelle; Manchulenko, Kathy; Razinkov, Vladimir; Liu, Hua; Fanslow, William; Hu, Zhonghua; Sun, Nancy; Hasegawa, Haruki; Clark, Rutilio; Foltz, Ian N; Yan, Wei

    2015-03-20

    Producing pure and well behaved bispecific antibodies (bsAbs) on a large scale for preclinical and clinical testing is a challenging task. Here, we describe a new strategy for making monovalent bispecific heterodimeric IgG antibodies in mammalian cells. We applied an electrostatic steering mechanism to engineer antibody light chain-heavy chain (LC-HC) interface residues in such a way that each LC strongly favors its cognate HC when two different HCs and two different LCs are co-expressed in the same cell to assemble a functional bispecific antibody. We produced heterodimeric IgGs from transiently and stably transfected mammalian cells. The engineered heterodimeric IgG molecules maintain the overall IgG structure with correct LC-HC pairings, bind to two different antigens with comparable affinity when compared with their parental antibodies, and retain the functionality of parental antibodies in biological assays. In addition, the bispecific heterodimeric IgG derived from anti-HER2 and anti-EGF receptor (EGFR) antibody was shown to induce a higher level of receptor internalization than the combination of two parental antibodies. Mouse xenograft BxPC-3, Panc-1, and Calu-3 human tumor models showed that the heterodimeric IgGs strongly inhibited tumor growth. The described approach can be used to generate tools from two pre-existent antibodies and explore the potential of bispecific antibodies. The asymmetrically engineered Fc variants for antibody-dependent cellular cytotoxicity enhancement could be embedded in monovalent bispecific heterodimeric IgG to make best-in-class therapeutic antibodies.

  5. Antibody humanization by structure-based computational protein design.

    PubMed

    Choi, Yoonjoo; Hua, Casey; Sentman, Charles L; Ackerman, Margaret E; Bailey-Kellogg, Chris

    2015-01-01

    Antibodies derived from non-human sources must be modified for therapeutic use so as to mitigate undesirable immune responses. While complementarity-determining region (CDR) grafting-based humanization techniques have been successfully applied in many cases, it remains challenging to maintain the desired stability and antigen binding affinity upon grafting. We developed an alternative humanization approach called CoDAH ("Computationally-Driven Antibody Humanization") in which computational protein design methods directly select sets of amino acids to incorporate from human germline sequences to increase humanness while maintaining structural stability. Retrospective studies show that CoDAH is able to identify variants deemed beneficial according to both humanness and structural stability criteria, even for targets lacking crystal structures. Prospective application to TZ47, a murine anti-human B7H6 antibody, demonstrates the approach. Four diverse humanized variants were designed, and all possible unique VH/VL combinations were produced as full-length IgG1 antibodies. Soluble and cell surface expressed antigen binding assays showed that 75% (6 of 8) of the computationally designed VH/VL variants were successfully expressed and competed with the murine TZ47 for binding to B7H6 antigen. Furthermore, 4 of the 6 bound with an estimated KD within an order of magnitude of the original TZ47 antibody. In contrast, a traditional CDR-grafted variant could not be expressed. These results suggest that the computational protein design approach described here can be used to efficiently generate functional humanized antibodies and provide humanized templates for further affinity maturation.

  6. Prevention and treatment of Clostridium perfringens epsilon toxin intoxication in mice with a neutralizing monoclonal antibody (c4D7) produced in Nicotiana benthamiana

    PubMed Central

    Garcia, J.P.; Beingesser, J.; Bohorov, O.; Bohorova, N.; Goodman, C.; Kim, D.; Pauly, M.; Velasco, J.; Whaley, K.; Zeitlin, L.; Roy, C.J.; Uzal, F.A.

    2014-01-01

    Epsilon toxin (ETX), produced by Clostridium perfringens types B and D, is among the most lethal toxins known. ETX is a potential bioterrorism threat that was listed as a Category B agent by the U.S. Centers for Disease Control until 2012 and it still remains a toxin of interest for several government agencies. We produced a monoclonal antibody (MAb) against ETX (ETX MAb c4D7) in Nicotiana benthamiana and characterized its preventive and therapeutic efficacy in mice. The ETX preparation used was highly lethal for mice (LD50 =1.6 μg/kg) and resulted in a mean time from inoculation to death of 18 and 180 minutes when administered intravenously or intraperitoneally, respectively. High lethal challenge resulted in dramatic increases of a variety of pro-inflammatory cytokines in serum, while lower, but still lethal doses, did not elicit such responses. ETX MAb c4D7 was highly effective prophylactically (ED50 = 0.3 mg/kg; ED100 = 0.8 mg/kg) and also provided protection when delivered 15-30 minutes post-ETX intoxication. These data suggest that ETX MAb c4D7 may have use as a pre- and post-exposure treatment for ETX intoxication. PMID:24950050

  7. A novel approach for the simultaneous quantification of a therapeutic monoclonal antibody in serum produced from two distinct host cell lines

    PubMed Central

    Geist, Brian J.; Davis, Darryl; McIntosh, Thomas; Yang, Tong-Yuan; Goldberg, Kenneth; Han, Chao; Pendley, Charles; Davis, Hugh M.

    2013-01-01

    Therapeutic monoclonal antibodies (mAbs) possess a high degree of heterogeneity associated with the cell expression system employed in manufacturing, most notably glycosylation. Traditional immunoassay formats used to quantify therapeutic mAbs are unable to discriminate between different glycosylation patterns that may exist on the same protein amino acid sequence. Mass spectrometry provides a technique to distinguish specific glycosylation patterns of the therapeutic antibody within the same sample, thereby allowing for simultaneous quantification of the same mAb with different glycosylation patterns. Here we demonstrate a two-step approach to successfully differentiate and quantify serum mixtures of a recombinant therapeutic mAb produced in two different host cell lines (CHO vs. Sp2/0) with distinct glycosylation profiles. Glycosylation analysis of the therapeutic mAb, CNTO 328 (siltuximab), was accomplished through sample pretreatment consisting of immunoaffinity purification (IAP) and enrichment, followed by liquid chromatography (LC) and mass spectrometry (MS). LC-MS analysis was used to determine the percentage of CNTO 328 in the sample derived from either cell line based on the N-linked G1F oligosaccharide on the mAb. The relative amount of G1F derived from each cell line was compared with ratios of CNTO 328 reference standards prepared in buffer. Glycoform ratios were converted to concentrations using an immunoassay measuring total CNTO 328 that does not distinguish between the different glycoforms. Validation of the IAP/LC-MS method included intra-run and inter-run variability, method sensitivity and freeze-thaw stability. The method was accurate (%bias range = -7.30–13.68%) and reproducible (%CV range = 1.49–10.81%) with a LOQ of 2.5 μg/mL. PMID:23182963

  8. Binding of monoclonal antibody AA4 to gangliosides on rat basophilic leukemia cells produces changes similar to those seen with Fc epsilon receptor activation

    PubMed Central

    1992-01-01

    The mAb AA4 binds to novel derivatives of the ganglioside Gd1b on rat basophilic leukemia (RBL-2H3) cells. Some of the gangliosides are located close to the high affinity IgE receptor (Fc epsilon RI), and binding of mAb AA4 inhibits Fc epsilon RI-mediated histamine release. In the present study, mAb AA4 was found to bind exclusively to mast cells in all rat tissues examined. In vitro, within 1 min of mAb AA4 binding, the cells underwent striking morphologic changes. They lost their normal spindle shaped appearance, increased their ruffling, and spread over the surface of the culture dish. These changes were accompanied by a redistribution of the cytoskeletal elements, actin, tubulin, and vimentin, but only the actin was associated with the membrane ruffles. Binding of mAb AA4 also induces a rise in intracellular calcium, stimulates phosphatidyl inositol breakdown, and activates PKC. However, the extent of these changes was less than that observed when the cells were stimulated with antigen or antibody directed against the Fc epsilon RI. None of these changes associated with mAb AA4 binding were seen when the cells were exposed to nonspecific IgG, IgE, or four other anti-cell surface antibodies, nor were the changes induced by binding mAb AA4 at 4 degrees C or in the absence of extracellular calcium. Although mAb AA4 does not stimulate histamine release, it enhances the effect of the calcium ionophore A23187 mediated release. The morphological and biochemical effects produced by mAb AA4 are similar to those seen following activation of the cell through the IgE receptor. Therefore, the surface gangliosides which bind mAb AA4 may function in modulating secretory events. PMID:1370498

  9. Using simple models to describe the kinetics of growth, glucose consumption, and monoclonal antibody formation in naive and infliximab producer CHO cells.

    PubMed

    López-Meza, Julián; Araíz-Hernández, Diana; Carrillo-Cocom, Leydi Maribel; López-Pacheco, Felipe; Rocha-Pizaña, María Del Refugio; Alvarez, Mario Moisés

    2016-08-01

    Despite their practical and commercial relevance, there are few reports on the kinetics of growth and production of Chinese hamster ovary (CHO) cells-the most frequently used host for the industrial production of therapeutic proteins. We characterize the kinetics of cell growth, substrate consumption, and product formation in naive and monoclonal antibody (mAb) producing recombinant CHO cells. Culture experiments were performed in 125 mL shake flasks on commercial culture medium (CD Opti CHO™ Invitrogen, Carlsbad, CA, USA) diluted to different glucose concentrations (1.2-4.8 g/L). The time evolution of cell, glucose, lactic acid concentration and monoclonal antibody concentrations was monitored on a daily basis for mAb-producing cultures and their naive counterparts. The time series were differentiated to calculate the corresponding kinetic rates (rx = d[X]/dt; rs = d[S]/dt; rp = d[mAb]/dt). Results showed that these cell lines could be modeled by Monod-like kinetics if a threshold substrate concentration value of [S]t = 0.58 g/L (for recombinant cells) and [S]t = 0.96 g/L (for naïve cells), below which growth is not observed, was considered. A set of values for μmax, and Ks was determined for naive and recombinant cell cultures cultured at 33 and 37 °C. The yield coefficient (Yx/s) was observed to be a function of substrate concentration, with values in the range of 0.27-1.08 × 10(7) cell/mL and 0.72-2.79 × 10(6) cells/mL for naive and recombinant cultures, respectively. The kinetics of mAb production can be described by a Luedeking-Piret model (d[mAb]/dt = αd[X]/dt + β[X]) with values of α = 7.65 × 10(-7) µg/cell and β = 7.68 × 10(-8) µg/cell/h for cultures conducted in batch-agitated flasks and batch and instrumented bioreactors operated in batch and fed-batch mode.

  10. The new allelic variant of the subtilase cytotoxin (subAB2) is common among Shiga toxin-producing Escherichia coli strains from large game animals and their meat and meat products.

    PubMed

    Sánchez, Sergio; Díaz-Sánchez, Sandra; Martínez, Remigio; Llorente, María Teresa; Herrera-León, Silvia; Vidal, Dolors

    2013-10-25

    Subtilase cytotoxin (SubAB) is an AB5 toxin produced by Shiga toxin (Stx)-producing Escherichia coli (STEC) strains usually lacking the eae gene product intimin. Two allelic variants of SubAB encoding genes have been described: subAB1, located on a plasmid, and subAB2, located on a pathogenicity island (PAI) together with tia gene. While subAB1 has been reported to be more frequent among bovine strains, subAB2 has been mainly associated with strains from small ruminants. We investigated the presence of the two variants of subAB among 59 eae-negative STEC from large game animals (deer and wild boar) and their meat and meat products in order to assess the role of other species in the epidemiology of subAB-positive, eae-negative STEC. For this approach, the strains were PCR-screened for the presence of subAB, including the specific detection of both allelic variants, for the presence of saa, tia and sab, and for stx subtyping. Overall, subAB genes were detected in 71.2% of the strains: 84.1% of the strains from deer and 33.3% of the strains from wild boar. Most of them (97.6%) possessed subAB2 and most of these subAB2-positive strains (92.7%) were also positive for tia and negative for saa, suggesting the presence of the subAB2-harbouring PAI. Subtype stx2b was present in most of the strains (67.8%) and a statistically significant association could be established between subAB2 and stx2b. Our results suggest that large game animals, mainly deer, may represent an important animal reservoir of subAB2-positive, eae-negative STEC, and also highlight the risk of human infection posed by the consumption of large game meat and meat products.

  11. The impact of cell adaptation to serum-free conditions on the glycosylation profile of a monoclonal antibody produced by Chinese hamster ovary cells.

    PubMed

    Costa, Ana Rita; Withers, Joanne; Rodrigues, Maria Elisa; McLoughlin, Niaobh; Henriques, Mariana; Oliveira, Rosário; Rudd, Pauline M; Azeredo, Joana

    2013-06-25

    N-glycosylation is one of the most crucial parameters affecting the biological activity of therapeutic monoclonal antibodies (mAbs), and should therefore be closely monitored and controlled to guarantee a consistent and high-quality product in biopharmaceutical processes. In the present work, the effect of the time-consuming step of gradual cell adaptation to serum-free conditions on the glycosylation profile of a mAb produced by CHO-K1 cells was evaluated. High-performance liquid chromatography analysis revealed important changes in mAb glycosylation patterns in all steps of serum reduction. These changes could be grouped in two distinct phases of the process of adaptation: middle (2.5 to 0.15% serum) and final (0.075 and 0% serum). For intermediate levels of serum, a desirable increase of galactosylation and decrease of fucosylation, but an undesirable increase in sialylation were observed; while the inverse was obtained at the final stages of adaptation. These divergences may be related to the reduction of serum supplementation, to variations in the levels of cell density and viability achieved at these stages, and to the natural shift of the cell growth mode during adaptation from adherent to suspended. The divergent glycan profiles obtained in this study demonstrate a strong influence of the adaptation process on mAb glycosylation, suggesting that control and monitoring of product quality should be implemented at the early stages of process development.

  12. Immunodetection of Triticum mosaic virus by DAS- and DAC-ELISA using antibodies produced against coat protein expressed in Escherichia coli: potential for high-throughput diagnostic methods.

    PubMed

    Tatineni, Satyanarayana; Sarath, Gautam; Seifers, Dallas; French, Roy

    2013-04-01

    Triticum mosaic virus (TriMV), an economically important virus infecting wheat in the Great Plains region of the USA, is the type species of the Poacevirus genus in the family Potyviridae. Sensitive and high-throughput serology-based detection methods are crucial for the management of TriMV and germplasm screening in wheat breeding programs. In this study, TriMV coat protein (CP) was expressed in Escherichia coli, and polyclonal antibodies were generated against purified soluble native form recombinant CP (rCP) in rabbits. Specificity and sensitivity of resulting antibodies were tested in Western immuno-blot and enzyme-linked immunosorbent assays (ELISA). In direct antigen coating (DAC)-ELISA, antibodies reacted specifically, beyond 1:20,000 dilution with TriMV in crude sap, but not with healthy extracts, and antiserum at a 1:10,000 dilution detected TriMV in crude sap up to 1:4860 dilution. Notably, rabbit anti-TriMV IgG and anti-TriMV IgG-alkaline phosphatase conjugate reacted positively with native virions in crude sap in a double antibody sandwich-ELISA, suggesting that these antibodies can be used as coating antibodies which is crucial for any 'sandwich' type of assays. Finally, the recombinant antibodies reacted positively in ELISA with representative TriMV isolates collected from fields, suggesting that antibodies generated against rCP can be used for sensitive, large-scale, and broad-spectrum detection of TriMV.

  13. Platelet transfusion refractoriness attributable to HLA antibodies produced by donor-derived cells after allogeneic bone marrow transplantation from one HLA-antigen-mismatched mother.

    PubMed

    Hatakeyama, Naoki; Hori, Tsukasa; Yamamoto, Masaki; Inazawa, Natsuko; Iesato, Kotoe; Miyazaki, Toru; Ikeda, Hisami; Tsutsumi, Hiroyuki; Suzuki, Nobuhiro

    2011-12-01

    PTR is a serious problem in patients being treated for hematologic disorders. Two patients with acute leukemia developed PTR after allogeneic BMT from one HLA-antigen-mismatched mother attributable to HLA antibodies, which could not be detected in their serum before BMT. HLA antibodies, whose specificity resembled that of each patient, were detected in each donor's serum. Each donor had probably been immunized during pregnancy by their partner's HLA antigens expressed by the fetus, consequently, transplanted donor-derived cells provoked HLA antibodies in each recipient early after BMT, and those HLA antibodies induced PTR. If the mothers are selected as donors for their children, they should be tested for the presence of HLA antibodies.

  14. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2011-08-16

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  15. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2011-05-31

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  16. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits [Vlaardingen, NL; Gualfetti, Peter [San Francisco, CA; Mitchinson, Colin [Half Moon Bay, CA; Larenas, Edmund [Moss Beach, CA

    2012-08-07

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  17. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2008-12-02

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  18. DHAD variants and methods of screening

    DOEpatents

    Kelly, Kristen J.; Ye, Rick W.

    2017-02-28

    Methods of screening for dihydroxy-acid dehydratase (DHAD) variants that display increased DHAD activity are disclosed, along with DHAD variants identified by these methods. Such enzymes can result in increased production of compounds from DHAD requiring biosynthetic pathways. Also disclosed are isolated nucleic acids encoding the DHAD variants, recombinant host cells comprising the isolated nucleic acid molecules, and methods of producing butanol.

  19. Variant humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Edmund, Larenas

    2014-09-09

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  20. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegeburr, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2013-02-19

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  1. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2014-03-18

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  2. Developing recombinant antibodies for biomarker detection

    SciTech Connect

    Baird, Cheryl L.; Fischer, Christopher J.; Pefaur, Noah B.; Miller, Keith D.; Kagen, Jacob; Srivastava, Sudhir; Rodland, Karin D.

    2010-10-01

    Monoclonal antibodies (mAbs) have an essential role in biomarker validation and diagnostic assays. A barrier to pursuing these applications is the reliance on immunization and hybridomas to produce mAbs, which is time-consuming and may not yield the desired mAb. We recommend a process flow for affinity reagent production that utilizes combinatorial protein display systems (eg, yeast surface display or phage display) rather than hybridomas. These systems link a selectable phenotype-binding conferred by an antibody fragment-with a means for recovering the encoding gene. Recombinant libraries obtained from immunizations can produce high-affinity antibodies (<10 nM) more quickly than other methods. Non-immune libraries provide an alternate route when immunizations are not possible, or when suitable mAbs are not recovered from an immune library. Directed molecular evolution (DME) is an integral part of optimizing mAbs obtained from combinatorial protein display, but can also be used on hybridoma-derived mAbs. Variants can easily be obtained and screened to increase the affinity of the parent mAb (affinity maturation). We discuss examples where DME has been used to tailor affinity reagents to specific applications. Combinatorial protein display also provides an accessible method for identifying antibody pairs, which are necessary for sandwich-type diagnostic assays.

  3. Top-down proteomic identification of Shiga toxin 2 variants from Shiga toxin-producing Escherichia coli (STEC) using MALDI-TOF-TOF-MS/MS-PSD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) are increasingly linked to severe outbreaks of foodborne illness throughout the world, e.g. Germany and France in 2011. STEC infections can result in bloody diarrhea, hemolytic uremic syndrome, kidney failure and death. New analytical techniques are ne...

  4. Characterization of shiga toxin-producing Escherichia coli recovered from domestic animals to determine stx variants, virulence genes, and cytotoxicity in mammalian cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to severe diseases such as hemorrhagic colitis (HC), and hemolytic uremic syndrome (HUS) in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in mammal...

  5. Detection of Shiga toxin variants, virulence genes and the relationship to cytotoxicity in Shiga toxin-producing Escherichia coli (STEC) from domestic farm animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to life-threating diseases such as hemorrhagic colitis, and hemolytic uremic syndrome in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in STEC stra...

  6. Monoclonal antibody that inhibits infection of HeLa and rhabdomyosarcoma cells by selected enteroviruses through receptor blockade

    SciTech Connect

    Crowell, R.L.; Field, A.K.; Schleif, W.A.; Long, W.L.; Colonno, R.J.; Mapoles, J.E.; Emini, E. A.

    1986-02-01

    BALB/c mice were immunized with HeLa cells, and their spleen cells were fused with myeloma cells to produce hybridomas. Initial screening of culture fluids from 800 fusion products in a cell protection assay against coxsackievirus B3 (CB3) and the CB3-RD virus variant yielded five presumptive monoclonal antibodies with three specificities: (i) protection against CB3 on HeLa, (ii) protection against CB3-RD on rhabdomyosarcoma (RD) cells, and (iii) protection against both viruses on the respective cells. Only one of the monoclonal antibodies (with dual specificity) survived two subclonings and was studied in detail. The antibody was determined to have an immunoglobulin G2a isotype and protected cells by blockade of cellular receptors, since attachment of (/sup 35/S)methionine-labeled CB3 was inhibited by greater than 90%. The monoclonal antibody protected HeLa cells against infection by CB1, CB3, CB5, echovirus 6, and coxsackievirus A21 and RD cells against CB1-RD, CB3-RD, and CB5-Rd virus variants. The monoclonal antibody did not protect either cell type against 16 other immunotypes of picornaviruses. The monoclonal antibody produced only positive fluorescence on those cells which were protected against infection, and /sup 125/I-labeled antibody confirmed the specific binding to HeLa and RD cells. The results suggest that this monoclonal antibody possesses some of the receptor specificity of the group B coxsackieviruses.

  7. Characterization of N-glycan structures and biofunction of anti-colorectal cancer monoclonal antibody CO17-1A produced in baculovirus-insect cell expression system.

    PubMed

    Song, Mira; Park, Da-Young; Kim, Youngkwan; Lee, Kyung-Jin; Lu, Zhe; Ko, Kinarm; Choo, Young Kug; Han, Yeon Soo; Ahn, Mi-Hyun; Oh, Doo-Byoung; Ko, Kisung

    2010-08-01

    Advantages of the baculovirus insect cell expression system for production of recombinant proteins include high capacity, flexibility, and glycosylation capability. In this study, this expression system was exploited to produce anti-cancer monoclonal antibody (mAb) CO17-1A, which recognizes the antigen GA733. The heavy chain (HC) and light chain (LC) genes of mAb CO17-1A were cloned under the control of P(10) and Polyhedrin promoters in the pFastBac dual vector, respectively. Gene expression cassettes carrying the HC and LC genes were transposed into a bacmid in Escherichia coli (DH10Bac). The transposed bacmid was transfected to Sf9 insect cells to generate baculovirus expressing mAb CO17-1A. Confocal immunofluorescence and Western blot analyses confirmed expression of mAb CO17-1A in baculovirus-infected insect cells. The optimum conditions for mAb expression were evaluated at 24, 48, and 72 h after the virus infection at an optimum virus multiplicity of infection of 1. Expression of mAb CO17-1A in insect cells significantly increased at 72 h after infection. HPLC analysis of glycosylation status revealed that the insect-derived mAb (mAb(I)) CO17-1A had insect specific glycan structures. ELISA showed that the purified mAb(I) from cell culture supernatant specifically bound to SW948 human colorectal cancer cells. Fluorescence-activated cell sorting analysis showed that, although mAb(I) had insect specific glycan structures that differed from their mammalian counterparts, mAb(I) similarly interacted with CD64 (FcgammaRI) and Fc of IgG, compared to the interactions of mammalian-derived mAb. These results suggest that the baculovirus insect cell expression system is able to express, assemble, and secrete biofunctional full size mAb.

  8. NNKTT120, an anti-iNKT cell monoclonal antibody, produces rapid and sustained iNKT cell depletion in adults with sickle cell disease

    PubMed Central

    Majerus, Elaine; Ataga, Kenneth I.; Vichinsky, Elliot P.; Schaub, Robert; Mashal, Robert; Nathan, David G.

    2017-01-01

    Invariant NKT (iNKT) cells can be activated to stimulate a broad inflammatory response. In murine models of sickle cell disease (SCD), interruption of iNKT cell activity prevents tissue injury from vaso-occlusion. NKTT120 is an anti-iNKT cell monoclonal antibody that has the potential to rapidly and specifically deplete iNKT cells and, potentially, prevent vaso-occlusion. We conducted an open-label, multi-center, single-ascending-dose study of NKTT120 to determine its pharmacokinetics, pharmacodynamics and safety in steady-state patients with SCD. Doses were escalated in a 3+3 study design over a range from 0.001 mg/kg to 1.0 mg/kg. Twenty-one adults with SCD were administered NKTT120 as part of 7 dose cohorts. Plasma levels of NKTT120 predictably increased with higher doses. Median half-life of NKTT120 was 263 hours. All subjects in the higher dose cohorts (0.1 mg/kg, 0.3 mg/kg, and 1 mg/kg) demonstrated decreased iNKT cells below the lower limit of quantification within 6 hours after infusion, the earliest time point at which they were measured. In those subjects who received the two highest doses of NKTT120 (0.3, 1 mg/kg), iNKT cells were not detectable in the peripheral blood for a range of 2 to 5 months. There were no serious adverse events in the study deemed to be related to NKTT120. In adults with SCD, NKTT120 produced rapid, specific and sustained iNKT cell depletion without any infusional toxicity or attributed serious adverse events. The next step is a trial to determine NKTT120’s ability to decrease rate of vaso-occlusive pain episodes. Trial Registration: clinicaltrials.gov NCT01783691. PMID:28152086

  9. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells

    PubMed Central

    Desin, Taseen S.; Townsend, Hugh G.; Potter, Andrew A.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  10. Synthetic nanoparticle vaccines produced by layer-by-layer assembly of artificial biofilms induce potent protective T-cell and antibody responses in vivo.

    PubMed

    Powell, Thomas J; Palath, Naveen; DeRome, Mary E; Tang, Jie; Jacobs, Andrea; Boyd, James G

    2011-01-10

    Nanoparticle vaccines induce potent immune responses in the absence of conventional adjuvant due to the recognition by immune cells of the particle structures, which mimic natural pathogens such as viruses and bacteria. Nanoparticle vaccines were fabricated by constructing artificial biofilms using layer-by-layer (LbL) deposition of oppositely charged polypeptides and target designed peptides on CaCO(3) cores. LbL nanoparticles were efficiently internalized by dendritic cells in vitro by a mechanism that was at least partially phagocytic, and induced DC maturation without triggering secretion of inflammatory cytokines. LbL nanoparticle delivery of designed peptides to DC resulted in potent cross-presentation to CD8+ T-cells and more efficient presentation to CD4+ T-cells compared to presentation of soluble peptide. A single immunization of mice with LbL nanoparticles containing designed peptide induced vigorous T-cell responses characterized by a balanced effector (IFNγ) and Th2 (IL-4) ELISPOT profile and in vivo CTL activity. Mice immunized with LbL nanoparticles bearing ovalbumin-derived designed peptides were protected from challenge with Listeria monocytogenes ectopically expressing ovalbumin, confirming the relevance of the CTL/effector T-cell responses. LbL nanoparticles also elicited antibody responses to the target epitope but not to the matrix components of the nanoparticle, avoiding the vector or carrier affect that hampers utility of other vaccine platforms. The potency and efficacy of LbL nanoparticles administered in aqueous suspension without adjuvant or other formulation additive, and the absence of immune responses to the matrix components, suggest that this strategy may be useful in producing novel vaccines against multiple diseases.

  11. Antibody discovery: sourcing of monoclonal antibody variable domains.

    PubMed

    Strohl, William R

    2014-03-01

    Historically, antibody variable domains for therapeutic antibodies have been sourced primarily from the mouse IgG repertoire, and typically either chimerized or humanized. More recently, human antibodies from transgenic mice producing human IgG, phage display libraries, and directly from human B lymphocytes have been used more broadly as sources of antibody variable domains for therapeutic antibodies. Of the total 36 antibodies approved by major maket regulatory agencies, the variable domain sequences of 26 originate from the mouse. Of these, four are marketed as murine antibodies (of which one is a mouse-rat hybrid IgG antibody), six are mouse-human chimeric antibodies, and 16 are humanized. Ten marketed antibodies have originated from human antibody genes, three isolated from phage libraries of human antibody genes and seven from transgenic mice producing human antibodies. Five antibodies currently in clinical trials have been sourced from camelids, as well as two from non-human primates, one from rat, and one from rabbit. Additional sources of antibody variable domains that may soon find their way into the clinic are potential antibodies from sharks and chickens. Finally, the various methods for retrieval of antibodies from humans, mouse and other sources, including various display technologies and amplification directly from B cells, are described.

  12. Molecular characterization of high-level-cholera-toxin-producing El Tor variant Vibrio cholerae strains in the Zanzibar Archipelago of Tanzania.

    PubMed

    Naha, A; Chowdhury, G; Ghosh-Banerjee, J; Senoh, M; Takahashi, T; Ley, B; Thriemer, K; Deen, J; Seidlein, L V; Ali, S M; Khatib, A; Ramamurthy, T; Nandy, R K; Nair, G B; Takeda, Y; Mukhopadhyay, A K

    2013-03-01

    Analysis of 1,180 diarrheal stool samples in Zanzibar detected 247 Vibrio cholerae O1, Ogawa strains in 2009. Phenotypic traits and PCR-based detection of rstR, rtxC, and tcpA alleles showed that they belonged to the El Tor biotype. Genetic analysis of ctxB of these strains revealed that they were classical type, and production of classical cholera toxin B (CTB) was confirmed by Western blotting. These strains produced more CT than the prototype El Tor and formed a separate cluster by pulsed-field gel electrophoresis (PFGE) analysis.

  13. Molecular Characterization of High-Level-Cholera-Toxin-Producing El Tor Variant Vibrio cholerae Strains in the Zanzibar Archipelago of Tanzania

    PubMed Central

    Naha, A.; Chowdhury, G.; Ghosh-Banerjee, J.; Senoh, M.; Takahashi, T.; Ley, B.; Thriemer, K.; Deen, J.; Seidlein, L. V.; Ali, S. M.; Khatib, A.; Ramamurthy, T.; Nandy, R. K.; Nair, G. B.; Takeda, Y.

    2013-01-01

    Analysis of 1,180 diarrheal stool samples in Zanzibar detected 247 Vibrio cholerae O1, Ogawa strains in 2009. Phenotypic traits and PCR-based detection of rstR, rtxC, and tcpA alleles showed that they belonged to the El Tor biotype. Genetic analysis of ctxB of these strains revealed that they were classical type, and production of classical cholera toxin B (CTB) was confirmed by Western blotting. These strains produced more CT than the prototype El Tor and formed a separate cluster by pulsed-field gel electrophoresis (PFGE) analysis. PMID:23325815

  14. A standard immunoglobulin preparation produced from bovine colostra shows antibody reactivity and neutralization activity against Shiga-like toxins and EHEC-hemolysin of Escherichia coli O157:H7.

    PubMed

    Lissner, R; Schmidit, H; Karch, H

    1996-01-01

    Enterohemorrhagic Escherichia coli (EHEC) causes a variety of clinical conditions, the most important being hemorrhagic colitis and hemolytic uremic syndrome. A curative therapy of EHEC diseases is not yet feasible. This study investigates the antibody reactivity of Lactobin, a standardized immunoglobulin (Ig) preparation, obtained from the colostra of non-immunized cows. Three different batches of Lactobin exhibited equally high titers of specific antibodies against Shiga-like toxins (SLTs, verocytotoxins) and EHEC hemolysin (EHEC-Hly) produced by E. coli O157. In addition, Lactobin blocked the cytotoxic effect of SLT-I and SLT-II on Vero cell monolayers and inhibited the cytolytic effects of EHEC-Hly on human erythrocytes. Since Lactobin contains high levels of antibodies and neutralizing activity against important virulence factors of EHEC O157, this drug has potential use in the treatment of diarrhea and the prevention of EHEC-associated hemolytic uremic syndrome.

  15. Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry

    PubMed Central

    Sanz, Miriam; Andreote, Ana Paula Dini; Fiore, Marli Fatima; Dörr, Felipe Augusto; Pinto, Ernani

    2015-01-01

    Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins) were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp.). PMID:26096276

  16. Tissue distribution of mucosal antibody-producing cells specific for respiratory syncytial virus in severe combined immune deficiency (SCID) mice engrafted with human tonsils.

    PubMed Central

    Nadal, D; Albini, B; Schläpfer, E; Chen, C; Brodsky, L; Ogra, P L

    1991-01-01

    Groups of C.B-17 SCID mice were reconstituted intraperitoneally with human tonsillar mononuclear cells (hu-TMC) from children seropositive for antibody to respiratory syncytial virus (RSV) and subsequently challenged intraperitoneally with inactivated RSV or sham-immunized. The synthesis and the distribution characteristics of human antibody to RSV in various murine tissues were studied using an enzyme-linked immunospot assay (ELISPOT). No specific antibody was observed in sham-immunized animals. In contrast, mice engrafted with hu-TMC exhibited the appearance of specific human antibody secreting cells (hu-ASC) after i.p. immunization with inactivated RSV. RSV-specific hu-ASC were detected only in animals engrafted with cells from donors seropositive for antibodies to Epstein-Barr virus. Hu-TMC engrafted mice showed RSV-specific IgM and, in lower numbers, IgG hu-ASC in several tissues including the lungs. Numbers of RSV-specific IgA hu-ASC were low, however, and detected only in the lung. No RSV-specific hu-ASC were detected in the intestine. These data demonstrate for the first time that hu-TMC-SCID chimeras respond to immunization with viral antigen. Furthermore, the results suggest that hu-TMC engraft in lungs but not in the intestinal tissue. PMID:1893614

  17. [New antibodies in cancer treatment].

    PubMed

    Pestalozzi, B C; Knuth, A

    2004-09-22

    Since the development of hybridoma technology in 1975 monoclonal antibodies with pre-defined specificity can be produced. Only twenty years later did it become possible to make therapeutic use of monoclonal antibodies in oncology. To this end it was necessary to attach the antigen-binding site of a mouse antibody onto the scaffold of a human antibody molecule. Such chimeric or "humanized" antibodies may be used in passive immunotherapy without eliciting an immune response. Rituximab and trastuzumab are such humanized antibodies. They are used today routinely in the treatment of malignant lymphoma and breast cancer, respectively. These antibodies are usually used in combination with conventional cytostatic anticancer drugs.

  18. Transcriptome and proteome analysis of antibody-producing mouse myeloma NS0 cells cultivated at different cell densities in perfusion culture.

    PubMed

    Krampe, Britta; Swiderek, Halina; Al-Rubeai, Mohamed

    2008-07-01

    A combined gene and protein expression profiling was performed to gain a deeper insight into the intracellular response of the antibody-producing GS-NS0 cell line in continuous perfusion culture. Growth rate, production rate, metabolic activity and viability declined with increasing cell density, dilution rate and time. Transcriptome and proteome analyses of cells at three different densities revealed 53 genes and 47 proteins as having significantly altered expression levels at HCD (high cell density). The results showed an increased up-regulation of genes/proteins involved in cellular energy production with increasing cell density. Furthermore, the intensified process triggered a cellular response to external stress stimuli, revealed by an overexpression of the genes/proteins implicated in cell-cycle arrest [e.g. Rb1 (retinoblastoma 1 gene) and Cdkn1b (cyclin-dependent kinase inhibitor 1B gene)] and in the induction of pro-apoptotic genes/proteins [e.g. Tnfrsf (tumour necrosis factor receptor superfamily gene), Nfkappa bia (gene coding for nuclear factor-kappaB inhibitor), HSP60 (heat-shock protein of molecular mass 60 kDa) and heterogeneous nuclear ribonucleoprotein K]. Interestingly, we observed a down-regulation of the transcription factor interferon regulatory factor 4 involved in the unfolded-protein-response process and protein disulfide-isomerase family members responsible for protein folding and assembly. Additionally, subunits of proteasome complex were highly expressed at HCD. Microarray, real-time quantitative reverse-transcription PCR and Western-blot analyses demonstrated a consistent trend of decrease in IgG heavy-chain level with increasing cell density. HSP60, which inhibits apoptosis by complexing with pro-apoptotic proteins such as Bax and Bak, was repressed at HCD. Overall, the data suggested that the balance among several factors involved in energy metabolism might be essential for fine-tuning the cell choice between survival and apoptosis

  19. 21 CFR 866.5090 - Antimitochondrial antibody immunological test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... immunochemical techniques the antimitochondrial antibodies in human serum. The measurements aid in the diagnosis of diseases that produce a spectrum of autoantibodies (antibodies produced against the body's...

  20. Antimitochondrial antibody

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/003529.htm Antimitochondrial antibody To use the sharing features on this page, please enable JavaScript. Antimitochondrial antibodies (AMA) are substances ( antibodies ) that form against mitochondria. ...

  1. Vaccination of rhesus macaques with the anthrax vaccine adsorbed vaccine produces a serum antibody response that effectively neutralizes receptor-bound protective antigen in vitro.

    PubMed

    Clement, Kristin H; Rudge, Thomas L; Mayfield, Heather J; Carlton, Lena A; Hester, Arelis; Niemuth, Nancy A; Sabourin, Carol L; Brys, April M; Quinn, Conrad P

    2010-11-01

    Anthrax toxin (ATx) is composed of the binary exotoxins lethal toxin (LTx) and edema toxin (ETx). They have separate effector proteins (edema factor and lethal factor) but have the same binding protein, protective antigen (PA). PA is the primary immunogen in the current licensed vaccine anthrax vaccine adsorbed (AVA [BioThrax]). AVA confers protective immunity by stimulating production of ATx-neutralizing antibodies, which could block the intoxication process at several steps (binding of PA to the target cell surface, furin cleavage, toxin complex formation, and binding/translocation of ATx into the cell). To evaluate ATx neutralization by anti-AVA antibodies, we developed two low-temperature LTx neutralization activity (TNA) assays that distinguish antibody blocking before and after binding of PA to target cells (noncomplexed [NC] and receptor-bound [RB] TNA assays). These assays were used to investigate anti-PA antibody responses in AVA-vaccinated rhesus macaques (Macaca mulatta) that survived an aerosol challenge with Bacillus anthracis Ames spores. Results showed that macaque anti-AVA sera neutralized LTx in vitro, even when PA was prebound to cells. Neutralization titers in surviving versus nonsurviving animals and between prechallenge and postchallenge activities were highly correlated. These data demonstrate that AVA stimulates a myriad of antibodies that recognize multiple neutralizing epitopes and confirm that change, loss, or occlusion of epitopes after PA is processed from PA83 to PA63 at the cell surface does not significantly affect in vitro neutralizing efficacy. Furthermore, these data support the idea that the full-length PA83 monomer is an appropriate immunogen for inclusion in next-generation anthrax vaccines.

  2. The germinal center antibody response in health and disease.

    PubMed

    DeFranco, Anthony L

    2016-01-01

    The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells or into a broad diversity of mutated memory B cells; the former secrete the improved antibodies to fight an infection and to provide continuing protection from re-infection, whereas the latter may jumpstart immune responses to subsequent infections with related but distinct infecting agents. Our understanding of the molecules involved in the germinal center reaction has been informed by studies of human immunodeficiency patients with selective defects in the production of antibodies. Recent studies have begun to reveal how innate immune recognition via Toll-like receptors can enhance the magnitude and selective properties of the germinal center, leading to more effective control of infection by a subset of viruses. Just as early insights into the nature of the germinal center found application in the development of the highly successful conjugate vaccines, more recent insights may find application in the current efforts to develop new generations of vaccines, including vaccines that can induce broadly protective neutralizing antibodies against influenza virus or HIV-1.

  3. New engineered antibodies against prions

    PubMed Central

    Škrlj, Nives; Dolinar, Marko

    2014-01-01

    A number of recently developed and approved therapeutic agents based on highly specific and potent antibodies have shown the potential of antibody therapy. As the next step, antibody-based therapeutics will be bioengineered in a way that they not only bind pathogenic targets but also address other issues, including drug targeting and delivery. For antibodies that are expected to act within brain tissue, like those that are directed against the pathogenic prion protein isoform, one of the major obstacles is the blood-brain barrier which prevents efficient transfer of the antibody, even of the engineered single-chain variants. We recently demonstrated that a specific prion-specific antibody construct which was injected into the murine tail vein can be efficiently transported into brain tissue. The novelty of the work was in that the cell penetrating peptide was used as a linker connecting both specificity-determining domains of the antibody peptide, thus eliminating the need for the standard flexible linker, composed of an arrangement of three consecutive (Gly4Ser) repeats. This paves the road toward improved bioengineered antibody variants that target brain antigens. PMID:23941991

  4. Purification of HBsAg produced by the human hepatoma cell line PLC/PRE/5 by affinity chromatography using monoclonal antibodies and application for ELISA diagnostic.

    PubMed

    Merten, O W; Reiter, S; Scheirer, W; Katinger, H

    1983-01-01

    The human cell line PLC/PRF/5 (5) was used for the production of hepatitis B surface antigen subtype ad (HBsAg ad) and purified by affinity chromatography (AC) with monoclonal antibodies (mAb). mAb to HBsAg from mouse ascites have been purified by Protein A - AC prior coupling to AH-Sepharose 4B (Pharmacia). The combined procedure of ammonium-sulphate-precipitation of HBsAg from culture supernatants and immunosorbent-AC leads to approx. 700-fold purification. ELISA results using the mAb and the HBsAg for diagnostics of human serum, positive for anti-HBsAg-antibodies correlate with the RIA (AUSAB, Abbott).

  5. AA479 antiserum: new reagent for the serotype characterization of atypical variants of Shigella flexneri.

    PubMed

    van der Ploeg, Claudia A; Rogé, Ariel D; Bordagorria, Ximena L; de Urquiza, María T; Viñas, María R; Pichel, Mariana G; Bruno, Susana B

    2015-01-01

    Shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the O-antigen. A new O-antigen modification with phosphoethanolamine has been identified. The presence of this antigenic determinant (called E1037) is recognized by monoclonal antibody MASF IV-1. Given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (AA479) through immunization with a S. flexneri Xv strain. The antiserum specificity was assessed by slide agglutination against isolates from clinical cases and a culture collection representing all Shigella serotypes. The results obtained demonstrated a 100% correlation between AA479 absorbed antiserum and monoclonal antibody MASF IV-1. The availability of AA479 antiserum in every public hospital in Argentina will allow us to identify atypical S. flexneri isolates in order to strengthen Shigella surveillance in our country and to compare with global epidemiological data.

  6. Variant Calling From Next Generation Sequence Data.

    PubMed

    Hansen, Nancy F

    2016-01-01

    The use of next generation nucleotide sequencing to discover and genotype small sequence variants has led to numerous insights into the molecular causes of various diseases. This chapter describes the use of freely available software to align next generation sequencing reads to a reference and then to use the resulting alignments to call, annotate, view, and filter small sequence variants. The suggested variant calling workflow includes read alignment with novoalign, the removal of polymerase chain reaction duplicate sequences with samtools or bamUtils, and the detection of variants with Freebayes or bam2mpg software. ANNOVAR is then used to annotate the predicted variants using gene models, population frequencies, and predicted mutation severity, producing variant files which can be viewed and filtered with the variant display tool VarSifter.

  7. Investigation of protein selectivity in multimodal chromatography using in silico designed Fab fragment variants.

    PubMed

    Karkov, Hanne Sophie; Krogh, Berit Olsen; Woo, James; Parimal, Siddharth; Ahmadian, Haleh; Cramer, Steven M

    2015-11-01

    In this study, a unique set of antibody Fab fragments was designed in silico and produced to examine the relationship between protein surface properties and selectivity in multimodal chromatographic systems. We hypothesized that multimodal ligands containing both hydrophobic and charged moieties would interact strongly with protein surface regions where charged groups and hydrophobic patches were in close spatial proximity. Protein surface property characterization tools were employed to identify the potential multimodal ligand binding regions on the Fab fragment of a humanized antibody and to evaluate the impact of mutations on surface charge and hydrophobicity. Twenty Fab variants were generated by site-directed mutagenesis, recombinant expression, and affinity purification. Column gradient experiments were carried out with the Fab variants in multimodal, cation-exchange, and hydrophobic interaction chromatographic systems. The results clearly indicated that selectivity in the multimodal system was different from the other chromatographic modes examined. Column retention data for the reduced charge Fab variants identified a binding site comprising light chain CDR1 as the main electrostatic interaction site for the multimodal and cation-exchange ligands. Furthermore, the multimodal ligand binding was enhanced by additional hydrophobic contributions as evident from the results obtained with hydrophobic Fab variants. The use of in silico protein surface property analyses combined with molecular biology techniques, protein expression, and chromatographic evaluations represents a previously undescribed and powerful approach for investigating multimodal selectivity with complex biomolecules.

  8. Development and characterization of antibodies specific to caspase-3-produced alpha II-spectrin 120 kDa breakdown product: marker for neuronal apoptosis.

    PubMed

    Nath, R; Huggins, M; Glantz, S B; Morrow, J S; McGinnis, K; Nadimpalli, R; Wanga, K K

    2000-10-01

    Alpha II-spectrin (alpha-fodrin) is a demonstrated endogenous substrate for caspase-3 in neurons undergoing unscheduled apoptotic death. We have previously identified the caspase cleavage site that yields the distinctive 120 kDa spectrin breakdown product (SBDP120) as (DSLD(1478)*SVEAL). Here, by using a synthetic peptide (NH(2)-SVEALC) mimicking the neo-N-terminal of SBDP120 as antigen, we report the development of chicken antibodies that specifically recognize the SBDP120 generated by in vitro caspase-3 digestion of bovine alpha-spectrin on Western blot. These anti-SBDP120 antibodies recognize SBDP120 generated by two apoptotic challenges (staurosporine, EGTA) to human neuroblastoma SH-SY5Y cells. Yet they neither react with intact alpha-spectrin nor its other fragments on Western blots. These anti-SBDP120 work equally well in detecting SBDP120 generated in rat cerebellar granule neurons undergoing potassium withdrawal-induced apoptosis. In immunocytochemical studies, these antibodies also specifically stained apoptotic SH-SY5Y or CGN's undergoing apoptosis in a caspase- inhibitor-sensitive manner. These anti-SBDP120s might become powerful markers for apoptotic neurons in various neurological or neurodegenerative conditions in vivo.

  9. [Progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases].

    PubMed

    Yao, Yuan; Yu, Chuan-xin

    2013-08-01

    Antibody has extensive application prospects in the biomedical field. The inherent disadvantages of traditional polyclonal antibody and monoclonal antibody limit their application values. The humanized and fragmented antibody remodeling has given a rise to a series of genetic engineered antibody variant. This paper reviews the progress of research on genetic engineering antibody and its application in prevention and control of parasitic diseases.

  10. Expression of recombinant antibodies.

    PubMed

    Frenzel, André; Hust, Michael; Schirrmann, Thomas

    2013-01-01

    Recombinant antibodies are highly specific detection probes in research, diagnostics, and have emerged over the last two decades as the fastest growing class of therapeutic proteins. Antibody generation has been dramatically accelerated by in vitro selection systems, particularly phage display. An increasing variety of recombinant production systems have been developed, ranging from Gram-negative and positive bacteria, yeasts and filamentous fungi, insect cell lines, mammalian cells to transgenic plants and animals. Currently, almost all therapeutic antibodies are still produced in mammalian cell lines in order to reduce the risk of immunogenicity due to altered, non-human glycosylation patterns. However, recent developments of glycosylation-engineered yeast, insect cell lines, and transgenic plants are promising to obtain antibodies with "human-like" post-translational modifications. Furthermore, smaller antibody fragments including bispecific antibodies without any glycosylation are successfully produced in bacteria and have advanced to clinical testing. The first therapeutic antibody products from a non-mammalian source can be expected in coming next years. In this review, we focus on current antibody production systems including their usability for different applications.

  11. Expression of Recombinant Antibodies

    PubMed Central

    Frenzel, André; Hust, Michael; Schirrmann, Thomas

    2013-01-01

    Recombinant antibodies are highly specific detection probes in research, diagnostics, and have emerged over the last two decades as the fastest growing class of therapeutic proteins. Antibody generation has been dramatically accelerated by in vitro selection systems, particularly phage display. An increasing variety of recombinant production systems have been developed, ranging from Gram-negative and positive bacteria, yeasts and filamentous fungi, insect cell lines, mammalian cells to transgenic plants and animals. Currently, almost all therapeutic antibodies are still produced in mammalian cell lines in order to reduce the risk of immunogenicity due to altered, non-human glycosylation patterns. However, recent developments of glycosylation-engineered yeast, insect cell lines, and transgenic plants are promising to obtain antibodies with “human-like” post-translational modifications. Furthermore, smaller antibody fragments including bispecific antibodies without any glycosylation are successfully produced in bacteria and have advanced to clinical testing. The first therapeutic antibody products from a non-mammalian source can be expected in coming next years. In this review, we focus on current antibody production systems including their usability for different applications. PMID:23908655

  12. Incidence of Lettuce mosaic virus in lettuce and its detection by polyclonal antibodies produced against recombinant coat protein expressed in Escherichia coli.

    PubMed

    Sharma, Prachi; Sharma, Susheel; Singh, Jasvir; Saha, Swati; Baranwal, V K

    2016-04-01

    Lettuce mosaic virus (LMV), a member of the genus Potyvirus of family Potyviridae, causes mosaic disease in lettuce has recently been identified in India. The virus is seed borne and secondary infection occurs through aphids. To ensure virus freedom in seeds it is important to develop diagnostic tools, for serological methods the production of polyclonal antibodies is a prerequisite. The coat protein (CP) gene of LMV was amplified, cloned and expressed using pET-28a vector in Escherichia coli BL21DE3 competent cells. The LMV CP was expressed as a fusion protein containing a fragment of the E. coli His tag. The LMV CP/His protein reacted positively with a commercial antiserum against LMV in an immunoblot assay. Polyclonal antibodies purified from serum of rabbits immunized with the fusion protein gave positive results when LMV infected lettuce (Lactuca sativa) was tested at 1:1000 dilution in PTA-ELISA. These were used for specific detection of LMV in screening lettuce accessions. The efficacy of the raised polyclonal antiserum was high and it can be utilized in quarantine and clean seed production.

  13. Novel Epitopes Identified by Anti-PrP Monoclonal Antibodies Produced Following Immunization of Prnp0/0 Balb/cJ Mice with Purified Scrapie Prions

    PubMed Central

    Stanker, Larry H.; Scotcher, Miles C.; Lin, Alice; McGarvey, Jeffery; Prusiner, Stanley B.

    2012-01-01

    Prions, or infectious proteins, cause a class of uniformly fatal neurodegenerative diseases. Prions are composed solely of an aberrantly folded isoform (PrPSc) of a normal cellular protein (PrPC). Shared sequence identity of PrPSc with PrPC has limited the detection sensitivity of immunochemical assays, as antibodies specific for the disease-causing PrPSc isoform have not been developed. Here we report the generation of three new monoclonal antibodies (MAbs) to PrP, which were isolated following immunization of Prnp0/0 Balb/cJ mice with highly purified PrPSc isolated from brain lipid rafts. Epitope mapping using synthetic PrP peptides revealed that the three MAbs bind different epitopes of PrP. The DRM1-31 MAb has a conformational epitope at the proposed binding site for the putative prion conversion co-factor “protein X.” The DRM1-60 MAb binds a single linear epitope localized to the β2–α2 loop region of PrP, whereas DRM2-118 binds an epitope that includes sequences within the octarepeat region and near the site of N-terminal truncation of PrPSc by proteinase K. Our novel anti-PrP MAbs with defined PrP epitopes may be useful in deciphering the conformational conversion of PrPC into PrPSc. PMID:23098297

  14. Swine-origin pandemic H1N1 influenza virus-like particles produced in insect cells induce hemagglutination inhibiting antibodies in BALB/c mice

    PubMed Central

    Krammer, Florian; Nakowitsch, Sabine; Messner, Paul; Palmberger, Dieter; Ferko, Boris; Grabherr, Reingard

    2015-01-01

    Recent outbreaks of influenza A highlight the importance of rapid and sufficient supply for pandemic and inter-pandemic vaccines. Classical manufacturing methods for influenza vaccines fail to satisfy this demand. Alternatively, cell culture-based production systems and virus-like particle (VLP)-based technologies have been established. We developed swine-origin pandemic H1N1 influenza VLPs consisting of hemagglutinin (A/California/04/2009) and matrix protein. Hemagglutinin and matrix protein were co-expressed in insect cells by the baculovirus expression system. VLPs were harvested from infection supernatants, purified and used for intraperitoneal immunization of BALB/c mice. Immunization induced high serum antibody titers against A/California/04/2009 as well as hemagglutination inhibiting antibodies. Additionally, we compared VLP production in two different insect cell lines, Sf9 and BTI-TN5B1-4 (High Five™). Taken together VLPs represent a potential strategy for the fight against new pandemic influenza viruses. PMID:20041443

  15. Establishment of a sandwich enzyme-linked immunosorbent assay for specific detection of Bacillus thuringiensis (Bt) Cry1Ab toxin utilizing a monoclonal antibody produced with a novel hapten designed with molecular model.

    PubMed

    Dong, Sa; Zhang, Xiao; Liu, Yuan; Zhang, Cunzheng; Xie, Yajing; Zhong, Jianfeng; Xu, Chongxin; Liu, Xianjin

    2017-03-01

    Cry1Ab toxin is commonly expressed in genetically modified crops in order to control chewing pests. At present, the detection method with enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibody cannot specifically detect Cry1Ab toxin for Cry1Ab's amino acid sequence and spatial structure are highly similar to Cry1Ac toxin. In this study, based on molecular design, a novel hapten polypeptide was synthesized and conjugated to keyhole limpet hemocyanin (KLH). Then, through animal immunization with this antigen, a monoclonal antibody named 2C12, showing high affinity to Cry1Ab and having no cross reaction with Cry1Ac, was produced. The equilibrium dissociation constant (K D) value of Cry1Ab toxin with MAb 2C12 was 1.947 × 10(-8) M. Based on this specific monoclonal antibody, a sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was developed for the specific determination of Cry1Ab toxin and the LOD and LOQ values were determined as 0.47 ± 0.11 and 2.43 ± 0.19 ng mL(-1), respectively. The average recoveries of Cry1Ab from spiked rice leaf and rice flour samples ranged from 75 to 115%, with coefficient of variation (CV) less than 8.6% within the quantitation range (2.5-100 ng mL(-1)), showing good accuracy for the quantitative detection of Cry1Ab toxin in agricultural samples. In conclusion, this study provides a new approach for the production of high specific antibody and the newly developed DAS-ELISA is a useful method for Cry1Ab monitoring in agriculture products. Graphical Abstract Establishment of a DAS-ELISA for the specific detecting of Bacillus thuringiensis (Bt) Cry1Ab toxin.

  16. Monoclonal Antibodies.

    ERIC Educational Resources Information Center

    Killington, R. A.; Powell, K. L.

    1984-01-01

    Monoclonal antibodies have provided an exciting addition to the "armory" of the molecular biologist and immunologist. This article discusses briefly the concept of, techniques available for, production of, and possible uses of monoclonal antibodies. (Author)

  17. Antithyroid microsomal antibody

    MedlinePlus

    Thyroid antimicrosomal antibody; Antimicrosomal antibody; Microsomal antibody; Thyroid peroxidase antibody; TPOAb ... Granulomatous thyroiditis Hashimoto thyroiditis High levels of these antibodies have also been linked with an increased risk ...

  18. Immunogenic variants obtained by mutagenesis of mouse mastocytoma P815. V. H-2 associativity of variant-specific antigens.

    PubMed

    Van Snick, J; Maryanski, J; Van Pel, A; Parmiani, G; Boon, T

    1982-11-01

    By in vitro mutagenesis of mastocytoma P815, it is possible to obtain tumor cell variants that are rejected by syngeneic mice (tum-). Most of these variants carry new individual antigens and stimulate a specific cytolytic T cell (CTL) response in mixed leukocyte tumor cell culture (MLTC). The H-2 associativity of this response was examined for six different variants by measuring the inhibition of cell-mediated cytolysis by antibodies directed against products of the K or the D end of the H-2d complex. The lysis was either not inhibited (variants P91 and P116) or inhibited selectively by anti-Kd (variants P21, P32 and P198) or anti-Dd antibodies (variant P35). All these tum- variants expressed Kd and Dd antigens as measured by absorption of H-2 alloantisera. Long-term CTL clones can be obtained that are specific for individual tum- antigens. The pattern of H-2 associativity obtained with MLTC-derived CTL against four tum- variants was verified with CTL clones directed against the specific antigens of these variants. Concordant results were observed in all cases. In addition to CTL clones specific for tum- antigens, it is possible to isolate clones against a P815 tumor-associated antigen found on all P815 tum- variants. For these clones no clear associativity with either Kd or Dd products was found.

  19. Humanized Antibodies for Antiviral Therapy

    NASA Astrophysics Data System (ADS)

    Co, Man Sung; Deschamps, Marguerite; Whitley, Richard J.; Queen, Cary

    1991-04-01

    Antibody therapy holds great promise for the treatment of cancer, autoimmune disorders, and viral infections. Murine monoclonal antibodies are relatively easy to produce but are severely restricted for therapeutic use by their immunogenicity in humans. Production of human monoclonal antibodies has been problematic. Humanized antibodies can be generated by introducing the six hypervariable regions from the heavy and light chains of a murine antibody into a human framework sequence and combining it with human constant regions. We humanized, with the aid of computer modeling, two murine monoclonal antibodies against herpes simplex virus gB and gD glycoproteins. The binding, virus neutralization, and cell protection results all indicate that both humanized antibodies have retained the binding activities and the biological properties of the murine monoclonal antibodies.

  20. Evaluation of options for harvest of a recombinant E. Coli fermentation producing a domain antibody using ultra scale‐down techniques and pilot‐scale verification

    PubMed Central

    Voulgaris, Ioannis; Chatel, Alex; Finka, Gary; Uden, Mark

    2016-01-01

    Ultra scale‐down (USD) methods operating at the millilitre scale were used to characterise full‐scale processing of E. coli fermentation broths autolysed to different extents for release of a domain antibody. The focus was on the primary clarification stages involving continuous centrifugation followed by depth filtration. The performance of this sequence was predicted by USD studies to decrease significantly with increased extents of cell lysis. The use of polyethyleneimine reagent was studied to treat the lysed cell broth by precipitation of soluble contaminants such as DNA and flocculation of cell debris material. The USD studies were used to predict the impact of this treatment on the performance and here it was found that the fermentation could be run to maximum productivity using an acceptable clarification process (e.g., a centrifugation stage operating at 0.11 L/m2 equivalent gravity settling area per hour followed by a resultant required depth filter area of 0.07 m2/L supernatant). A range of USD predictions was verified at the pilot scale for centrifugation followed by depth filtration. © 2016 The Authors Biotechnology Progress published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers Biotechnol. Prog., 32:382–392, 2016 PMID:26698375

  1. New monoclonal antibodies against a novel subtype of Shiga toxin 1 produced by Enterobacter cloacae and their use in analysis of human serum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin (Stx) is a major virulence factor for several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges in clinical diagnosis of infections caused by Shiga toxin-producing org...

  2. A polyclonal antibody based immunoassay detects seven subtypes of Shiga toxin 2 produced by escherichia coli in human and environmental samples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increase of outbreaks and illnesses linked to Shiga toxin-producing Escherichia coli (STEC) has necessitated the development of effective detection methods for these pathogens in various matrices. The best way to determine if a bacterial strain is a STEC is to examine the production of Shiga tox...

  3. Comparison of antibody- versus pcr-based assays for serotyping shiga toxin-producing escherichia coli recovered from various cattle operations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serotyping of Shiga toxin-producing Escherichia coli (STEC) strains is contingent upon the availability of quality antisera. In this study, the serogroup of 161 STEC strains typed by conventional antisera and isolated from the fecal samples of California cattle were compared to two newly developed ...

  4. Glycan modulation and sulfoengineering of anti–HIV-1 monoclonal antibody PG9 in plants

    PubMed Central

    Loos, Andreas; Gach, Johannes S.; Hackl, Thomas; Maresch, Daniel; Henkel, Theresa; Porodko, Andreas; Bui-Minh, Duc; Sommeregger, Wolfgang; Wozniak-Knopp, Gordana; Forthal, Donald N.; Altmann, Friedrich; Steinkellner, Herta; Mach, Lukas

    2015-01-01

    Broadly neutralizing anti–HIV-1 monoclonal antibodies, such as PG9, and its derivative RSH hold great promise in AIDS therapy and prevention. An important feature related to the exceptional efficacy of PG9 and RSH is the presence of sulfated tyrosine residues in their antigen-binding regions. To maximize antibody functionalities, we have now produced glycan-optimized, fucose-free versions of PG9 and RSH in Nicotiana benthamiana. Both antibodies were efficiently sulfated in planta on coexpression of an engineered human tyrosylprotein sulfotransferase, resulting in antigen-binding and virus neutralization activities equivalent to PG9 synthesized by mammalian cells (CHOPG9). Based on the controlled production of both sulfated and nonsulfated variants in plants, we could unequivocally prove that tyrosine sulfation is critical for the potency of PG9 and RSH. Moreover, the fucose-free antibodies generated in N. benthamiana are capable of inducing antibody-dependent cellular cytotoxicity, an activity not observed for CHOPG9. Thus, tailoring of the antigen-binding site combined with glycan modulation and sulfoengineering yielded plant-produced anti–HIV-1 antibodies with effector functions superior to PG9 made in CHO cells. PMID:26417081

  5. Characterization of C69R variant HBsAg: effect on binding to anti-HBs and the structure of virus-like particles.

    PubMed

    Hadiji-Abbes, Nadia; Mihoubi, Wafa; Martin, Marta; Karakasyan-Dia, Carole; Frikha, Fakher; Gergely, Csilla; Jouenne, Thierry; Gargouri, Ali; Mokdad-Gargouri, Raja

    2015-10-01

    Several variants of the major "a" determinant of the HBsAg, the main target of HBV neutralization by antibodies, have been described. However, mutations outside this region have not been as thoroughly investigated. During the genotyping of HBV from Tunisian patients with chronic hepatitis B, we identified a variant with a C69R substitution in the cytosolic loop of the S protein, resulting in a change in the hydrophobicity profile compared to the wild-type HBsAg. Wild-type and mutant HBsAgs were produced in Saccharomyces cerevisiae and recombinant proteins were tested for their ability to correctly self-assemble into virus-like particles (VLPs), and their ability to bind to HBs antibodies. The C69R substitution resulted in a decrease in binding to commercial anti-HBs antibodies, and although the variant appeared to assemble properly into VLPs, the average size of the particles was larger than that of the wild-type HBsAg. Prediction of the tertiary structure of the C69R mutant revealed a change in the first (aa 60-70) and the second loop (aa 110 to 120) compared to the wild-type protein. Furthermore, we showed by an isothermal titration calorimetry assay that the interaction between the wild-type HBsAg and the anti-HBs antibody was exothermic, whereas that with the mutant C69R was endothermic, indicating an effect on the binding affinity.

  6. 2H-WS2 Quantum Dots Produced by Modulating the Dimension and Phase of 1T-Nanosheets for Antibody-Free Optical Sensing of Neurotransmitters.

    PubMed

    Kim, Man-Jin; Jeon, Su-Ji; Kang, Tae Woog; Ju, Jong-Min; Yim, DaBin; Kim, Hye-In; Park, Jung Hyun; Kim, Jong-Ho

    2017-03-28

    Modulating the dimensions and phases of transition metal dichalcogenides is of great interest to enhance their intrinsic properties or to create new physicochemical properties. Herein, we report an effective approach to synthesize 2H-WS2 quantum dots (QDs) via the dimension and phase engineering of 1T-WS2 nanosheets. The solvothermal reaction of chemically exfoliated 1T-WS2 nanosheets in N-methyl-2-pyrrolidone (NMP) under an N2 atmosphere induced their chopping and phase transition at lower temperature to produce 2H-WS2 QDs with a high quantum yield (5.5 ± 0.3%). Interestingly, this chopping and phase transition process showed strong dependency on solvent; WS2 QDs were not produced in other solvents such as 1,4-dioxane and dimethyl sulfoxide. Mechanistic investigations suggested that NMP radicals played a crucial role in the effective production of 2H-WS2 QDs from 1T-WS2 nanosheets. WS2 QDs were successfully applied for the selective, sensitive, and rapid detection of dopamine in human serum (4 min, as low as 23.8 nM). The intense fluorescence of WS2 QDs was selectively quenched upon the addition of dopamine and Au(3+) ions due to fluorescence resonance energy transfer between WS2 QDs and the quickly formed Au nanoparticles. This new sensing principle enabled us to discriminate dopamine from dopamine-derivative neurotransmitters including epinephrine and norepinephrine, as well as other interference compounds.

  7. Charge variant analysis of proposed biosimilar to Trastuzumab.

    PubMed

    Dakshinamurthy, Pravinkumar; Mukunda, Pavithra; Prasad Kodaganti, Bhargav; Shenoy, Bharath Ravindra; Natarajan, Bairavabalakumar; Maliwalave, Amol; Halan, Vivek; Murugesan, Sathyabalan; Maity, Sunit

    2017-03-01

    Trastuzumab is a humanized monoclonal antibody (mAb) employed for the treatment of HER2 Positive Breast Cancer. A HER2 overexpressing tumor cell binds to Trastuzumab and attracts immune cells which lead to induction of Antibody Dependent Cellular Cytotoxicity (ADCC) by binding to Fc receptors (CD16a or FcγRIIIa) on an effector cell, such as natural killer (NK) cells. The most commonly expressed receptor on NK cell is CD16a which binds to the Fc portion of Trastuzumab. The ligand-independent HER2-HER3 dimerization is the most potent stimulator of downstream pathways for regulation of cell growth and survival. An attempt has been made in this study to understand the impact of charge heterogeneity on the binding kinetics and potency of the monoclonal antibody. Trastuzumab has a pI range of 8.7-8.9 and is composed of mixture of acidic and basic variants beside the main peak. Ion exchange chromatography was used to isolate the acidic, basic, and main peak fractions from in-house proposed biosimilar to Trastuzumab and their activities were compared to the Innovator Trastuzumab Herclon(®). Data from the mass analysis confirmed the potential modifications in both acidic and basic variant. Binding activity studies performed using Surface Plasmon Resonance (SPR) revealed that acidic variants had lesser binding to HER2 in comparison to the basic variants. Both acidic and basic variant showed no significant changes in their binding to soluble CD16a receptors. In vitro assay studies using a breast cancer cell line (BT-474) confirmed the binding potency of acidic variant to be lesser than basic variant, along with reduced anti-proliferative activity for the acidic variant of Trastuzumab. Overall, these data has provided meaningful insights to the impact of antibody charge variants on in vitro potency and CD16 binding affinity of trastuzumab.

  8. Monoclonal antibody heterogeneity analysis and deamidation monitoring with high-performance cation-exchange chromatofocusing using simple, two component buffer systems.

    PubMed

    Kang, Xuezhen; Kutzko, Joseph P; Hayes, Michael L; Frey, Douglas D

    2013-03-29

    The use of either a polyampholyte buffer or a simple buffer system for the high-performance cation-exchange chromatofocusing of monoclonal antibodies is demonstrated for the case where the pH gradient is produced entirely inside the column and with no external mixing of buffers. The simple buffer system used was composed of two buffering species, one which becomes adsorbed onto the column packing and one which does not adsorb, together with an adsorbed ion that does not participate in acid-base equilibrium. The method which employs the simple buffer system is capable of producing a gradual pH gradient in the neutral to acidic pH range that can be adjusted by proper selection of the starting and ending pH values for the gradient as well as the buffering species concentration, pKa, and molecular size. By using this approach, variants of representative monoclonal antibodies with isoelectric points of 7.0 or less were separated with high resolution so that the approach can serve as a complementary alternative to isoelectric focusing for characterizing a monoclonal antibody based on differences in the isoelectric points of the variants present. Because the simple buffer system used eliminates the use of polyampholytes, the method is suitable for antibody heterogeneity analysis coupled with mass spectrometry. The method can also be used at the preparative scale to collect highly purified isoelectric variants of an antibody for further study. To illustrate this, a single isoelectric point variant of a monoclonal antibody was collected and used for a stability study under forced deamidation conditions.

  9. Application of histone modification-specific interaction domains as an alternative to antibodies

    PubMed Central

    Kungulovski, Goran; Kycia, Ina; Tamas, Raluca; Jurkowska, Renata Z.; Kudithipudi, Srikanth; Henry, Chisato; Reinhardt, Richard; Labhart, Paul

    2014-01-01

    Post-translational modifications (PTMs) of histones constitute a major chromatin indexing mechanism, and their proper characterization is of highest biological importance. So far, PTM-specific antibodies have been the standard reagent for studying histone PTMs despite caveats such as lot-to-lot variability of specificity and binding affinity. Herein, we successfully employed naturally occurring and engineered histone modification interacting domains for detection and identification of histone PTMs and ChIP-like enrichment of different types of chromatin. Our results demonstrate that histone interacting domains are robust and highly specific reagents that can replace or complement histone modification antibodies. These domains can be produced recombinantly in Escherichia coli at low cost and constant quality. Protein design of reading domains allows for generation of novel specificities, addition of affinity tags, and preparation of PTM binding pocket variants as matching negative controls, which is not possible with antibodies. PMID:25301795

  10. Plasma proteomics, the Human Proteome Project, and cancer-associated alternative splice variant proteins.

    PubMed

    Omenn, Gilbert S

    2014-05-01

    This article addresses three inter-related subjects: the development of the Human Plasma Proteome Peptide Atlas, the launch of the Human Proteome Project, and the emergence of alternative splice variant transcripts and proteins as important features of evolution and pathogenesis. The current Plasma Peptide Atlas provides evidence on which peptides have been detected for every protein confidently identified in plasma; there are links to their spectra and their estimated abundance, facilitating the planning of targeted proteomics for biomarker studies. The Human Proteome Project (HPP) combines a chromosome-centric C-HPP with a biology and disease-driven B/D-HPP, upon a foundation of mass spectrometry, antibody, and knowledgebase resource pillars. The HPP aims to identify the approximately 7000 "missing proteins" and to characterize all proteins and their many isoforms. Success will enable the larger research community to utilize newly-available peptides, spectra, informative MS transitions, and databases for targeted analyses of priority proteins for each organ and disease. Among the isoforms of proteins, splice variants have the special feature of greatly enlarging protein diversity without enlarging the genome; evidence is accumulating of striking differential expression of splice variants in cancers. In this era of RNA-sequencing and advanced mass spectrometry, it is no longer sufficient to speak simply of increased or decreased expression of genes or proteins without carefully examining the splice variants in the protein mixture produced from each multi-exon gene. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge.

  11. Charge variants in IgG1

    PubMed Central

    Goswami, Sirj; Hutchinson, Ryan; Kwong, Zephania W; Yang, Jihong; Wang, Xiangdan; Yao, Zhenling; Sreedhara, Alavattam; Cano, Tony; Tesar, Devin; Nijem, Ihsan; Allison, David E; Wong, Pin Yee; Kao, Yung-Hsiang; Quan, Cynthia; Joshi, Amita; Harris, Reed J; Motchnik, Paul

    2010-01-01

    Antibody charge variants have gained considerable attention in the biotechnology industry due to their potential influence on stability and biological activity. Subtle differences in the relative proportions of charge variants are often observed during routine biomanufacture or process changes and pose a challenge to demonstrating product comparability. To gain further insights into the impact on biological activity and pharmacokinetics (PK) of monoclonal antibody (mAb) charge heterogeneity, we isolated the major charge forms of a recombinant humanized IgG1 and compared their in vitro properties and in vivo PK. The mAb starting material had a pI range of 8.7–9.1 and was composed of about 20% acidic variants, 12% basic variants and 68% main peak. Cation exchange displacement chromatography was used to isolate the acidic, basic and main peak fractions for animal studies. Detailed analyses were performed on the isolated fractions to identify specific chemical modification contributing to the charge differences and were also characterized for purity and in vitro potency prior to being administered either subcutaneously (SC) or intravenously (IV) in rats. All isolated materials had similar potency and rat FcRn binding relative to the starting material. Following IV or SC administration (10 mg/kg) in rats, no difference in serum PK was observed, indicating that physiochemical modifications and pI differences among charge variants were not sufficient to result in PK changes. Thus, these results provided meaningful information for the comparative evaluation of charge-related heterogeneity of mAbs and suggested that charge variants of IgGs do not affect the in vitro potency, FcRn binding affinity or the PK properties in rats. PMID:20818176

  12. Evaluation of selectivity in homologous multimodal chromatographic systems using in silico designed antibody fragment libraries.

    PubMed

    Karkov, Hanne Sophie; Woo, James; Krogh, Berit Olsen; Ahmadian, Haleh; Cramer, Steven M

    2015-12-24

    This study describes the in silico design, surface property analyses, production and chromatographic evaluations of a diverse set of antibody Fab fragment variants. Based on previous findings, we hypothesized that the complementarity-determining regions (CDRs) constitute important binding sites for multimodal chromatographic ligands. Given that antibodies are highly diversified molecules and in particular the CDRs, we set out to examine the generality of this result. For this purpose, four different Fab fragments with different CDRs and/or framework regions of the variable domains were identified and related variants were designed in silico. The four Fab variant libraries were subsequently generated by site-directed mutagenesis and produced by recombinant expression and affinity purification to enable examination of their chromatographic retention behavior. The effects of geometric re-arrangement of the functional moieties on the multimodal resin ligands were also investigated with respect to Fab variant retention profiles by comparing two commercially available multimodal cation-exchange ligands, Capto MMC and Nuvia cPrime, and two novel multimodal ligand prototypes. Interestingly, the chromatographic data demonstrated distinct selectivity trends between the four Fab variant libraries. For three of the Fab libraries, the CDR regions appeared as major binding sites for all multimodal ligands. In contrast, the fourth Fab library displayed a distinctly different chromatographic behavior, where Nuvia cPrime and related multimodal ligand prototypes provided markedly improved selectivity over Capto MMC. Clearly, the results illustrate that the discriminating power of multimodal ligands differs between different Fab fragments. The results are promising indications that multimodal chromatography using the appropriate multimodal ligands can be employed in downstream bioprocessing for challenging selective separation of product related variants.

  13. HHF35, a muscle-actin-specific monoclonal antibody. I. Immunocytochemical and biochemical characterization.

    PubMed

    Tsukada, T; Tippens, D; Gordon, D; Ross, R; Gown, A M

    1987-01-01

    A monoclonal antibody to muscle cell actin isotypes was produced and characterized. Immunocytochemical analysis of methanol-Carnoy's-fixed, paraffin-embedded human tissue revealed that this antibody, termed HHF35, reacts with skeletal muscle cells, cardiac muscle cells, smooth muscle cells, pericytes, and myoepithelial cells, but is nonreactive with endothelial, epithelial, neural, or connective tissue cells. When assayed by indirect immunofluorescence, HHF35 reacts with microfilament bundles from various cultured mammalian smooth muscle cells, but does not react with cultured human dermal fibroblasts or various epithelial tumor cell lines. In one-dimensional gel electrophoresis immunoblot experiments this antibody detects a 42-kd polypeptide from tissue extracts of uterus, ileum, aorta, diaphragm, and heart and extract from smooth muscle cells. The antibody also reacts with a comigrating 42-kd band of highly purified rabbit skeletal muscle actin. HHF35 is nonreactive on immunoblots of extracts from all tested nonmuscle cell extracts. Immunoelectrophoresis followed by immunoblotting performed in the presence of urea and reducing agents reveals recognition of the alpha isoelectrophoretic variant of actin from skeletal, cardiac, and smooth muscle sources and of the gamma variant from smooth muscle sources. Because HHF35 reacts with virtually all muscle cells, it will be useful as a marker for muscle and muscle-derived cells.

  14. Monoclonal Antibodies against Pectin

    PubMed Central

    Liners, Françoise; Letesson, Jean-Jacques; Didembourg, Christian; Van Cutsem, Pierre

    1989-01-01

    Monoclonal antibodies have been produced that recognize a conformation of homopolygalacturonic acid (pectic acid) induced by an optimum concentration of calcium and sodium of about 1 and 150 millinormal, respectively. The epitope recognized is probably part of the dimers of pectin chains associated according to the `egg box' model. Images Figure 2 PMID:16667195

  15. Microbials for the production of monoclonal antibodies and antibody fragments

    PubMed Central

    Spadiut, Oliver; Capone, Simona; Krainer, Florian; Glieder, Anton; Herwig, Christoph

    2014-01-01

    Monoclonal antibodies (mAbs) and antibody fragments represent the most important biopharmaceutical products today. Because full length antibodies are glycosylated, mammalian cells, which allow human-like N-glycosylation, are currently used for their production. However, mammalian cells have several drawbacks when it comes to bioprocessing and scale-up, resulting in long processing times and elevated costs. By contrast, antibody fragments, that are not glycosylated but still exhibit antigen binding properties, can be produced in microbial organisms, which are easy to manipulate and cultivate. In this review, we summarize recent advances in the expression systems, strain engineering, and production processes for the three main microbials used in antibody and antibody fragment production, namely Saccharomyces cerevisiae, Pichia pastoris, and Escherichia coli. PMID:24183828

  16. Monoclonal Antibodies.

    PubMed

    Geskin, Larisa J

    2015-10-01

    Use of monoclonal antibodies (mAbs) has revolutionized cancer therapy. Approaches targeting specific cellular targets on the malignant cells and in tumor microenvironment have been proved to be successful in hematologic malignancies, including cutaneous lymphomas. mAb-based therapy for cutaneous T-cell lymphoma has demonstrated high response rates and a favorable toxicity profile in clinical trials. Several antibodies and antibody-based conjugates are approved for use in clinical practice, and many more are in ongoing and planned clinical trials. In addition, these safe and effective drugs can be used as pillars for sequential therapies in a rational stepwise manner.

  17. Development and Evaluation of an Ovine Antibody-Based Platform for Treatment of Clostridium difficile Infection

    PubMed Central

    Roberts, April; McGlashan, Joanna; Al-Abdulla, Ibrahim; Ling, Roger; Denton, Harriet; Green, Steve; Coxon, Ruth; Landon, John

    2012-01-01

    Treatment of Clostridium difficile is a major problem as a hospital-associated infection which can cause severe, recurrent diarrhea. The currently available antibiotics are not effective in all cases and alternative treatments are required. In the present study, an ovine antibody-based platform for passive immunotherapy of C. difficile infection is described. Antibodies with high toxin-neutralizing titers were generated against C. difficile toxins A and B and were shown to neutralize three sequence variants of these toxins (toxinotypes) which are prevalent in human C. difficile infection. Passive immunization of hamsters with a mixture of toxin A and B antibodies protected them from a challenge with C. difficile spores in a dose-dependent manner. Antibodies to both toxins A and B were required for protection. The administration of toxin A and B antibodies up to 24 h postchallenge was found to reduce significantly the onset of C. difficile infection compared to nonimmunized controls. Protection from infection was also demonstrated with key disease isolates (ribotypes 027 and 078), which are members of the hypervirulent C. difficile clade. The ribotype 027 and 078 strains also have the capacity to produce an active binary toxin and these data suggest that neutralization of this toxin is unnecessary for the management of infection induced by these strains. In summary, the data suggest that ovine toxin A and B antibodies may be effective in the treatment of C. difficile infection; their potential use for the management of severe, fulminant cases is discussed. PMID:22144483

  18. Histone Variants and Epigenetics

    PubMed Central

    Henikoff, Steven; Smith, M. Mitchell

    2015-01-01

    Histones package and compact DNA by assembling into nucleosome core particles. Most histones are synthesized at S phase for rapid deposition behind replication forks. In addition, the replacement of histones deposited during S phase by variants that can be deposited independently of replication provide the most fundamental level of chromatin differentiation. Alternative mechanisms for depositing different variants can potentially establish and maintain epigenetic states. Variants have also evolved crucial roles in chromosome segregation, transcriptional regulation, DNA repair, and other processes. Investigations into the evolution, structure, and metabolism of histone variants provide a foundation for understanding the participation of chromatin in important cellular processes and in epigenetic memory. PMID:25561719

  19. A novel multi-epitope vaccine based on Dipeptidyl Peptidase 4 prevents streptozotocin-induced diabetes by producing anti-DPP4 antibody and immunomodulatory effect in C57BL/6J mice.

    PubMed

    Li, Zhixin; Fang, Jinzhi; Jiao, Rui; Wei, Xiaomin; Ma, Yanjie; Liu, Xiaoran; Cheng, Peng; Li, Taiming

    2017-03-31

    Type 1 diabetes is a chronic organ-specific autoimmune disease in which selective destruction of insulin-producing β-cells leads to impaired glucose metabolism and its attendant complications. A series of Dipeptidyl peptidase 4 (DPP4) inhibitors have been developed and granted approval in the treatment of type 2 diabetes mellitus by inhibiting the enzymatic degradation of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). An increasing number of studies have shown the potential benefits of DPP4 inhibitors for type 1 diabetes. In this report, we describe a novel multi-epitope vaccine comprising a B cell epitope of DPP4, an anti-diabetic B cell epitope of Insulinoma antigen-2 (IA-2) and a Th2 epitope of P277 peptide in human heat shock protein 60 (HSP60). Immunization with the multi-epitope vaccine in streptozotocin (STZ) treated mice successfully induced specific anti-DPP4 antibody and increased serum GLP-1 level. Moreover, this antibody lasted for more than 7 weeks. Inoculation of this vaccine in C57BL/6J mice significantly reduced blood glucose level, improved glucose excursion and increased plasma insulin concentration. Consistent with a lower diabetic and insulitis incidence, induced splenic T cell proliferation and tolerance were observed. IFN-γ and IL-2 secretion reduced, but IL-10 and IL-4 increased significantly in the Dipeptidyl Peptidase 41-Insulinoma antigen-2(5)-P2-1 (D41-IP) treated mice compared to the Insulinoma antigen-2(5)-P2-1 (IA2(5)P2-1) and control group due to the potential immunomodulatory effect of the epitopes in the vaccine. Our results demonstrate that this multi-epitope vaccine may serve as a promising therapeutic approach against type 1 diabetes.

  20. Different roles played by periostin splice variants in retinal neovascularization.

    PubMed

    Nakama, Takahito; Yoshida, Shigeo; Ishikawa, Keijiro; Kobayashi, Yoshiyuki; Abe, Takaya; Kiyonari, Hiroshi; Shioi, Go; Katsuragi, Naruto; Ishibashi, Tatsuro; Morishita, Ryuichi; Taniyama, Yoshiaki

    2016-12-01

    Retinal neovascularization (NV) due to retinal ischemia is one of the major causes of vision reduction in patients with different types of retinal diseases although anti-vascular endothelial growth factor (anti-VEGF) therapy can partially reduce the size of the retinal NV. We recently reported that periostin plays an important role in the development of NV and the formation of preretinal fibrovascular membranes, but the role of the splice variants of periostin on retinal NV has not been determined. We examined the expressions of periostin splice variants in the ischemic retinas of a mouse model of oxygen-induced retinal NV. We also studied the function of periostin splice variants on retinal NV using periostin knock out mice, and the effects of anti-periostin antibodies on retinal NV. Our results showed that the expressions of the periostin splice variants were increased in ischemic retinas. The degree of increase of periostin lacking exon 17 was the highest among the periostin splice variants examined. Both genetic ablation of periostin exons 17 and 21 and antibodies for periostin exons 17 and 21 affected preretinal pathological NV. Inhibition of exon 17 of periostin had the greatest effect in reducing preretinal pathological NV. These findings suggest a causal link between periostin splice variants and retinal NV, and an intravitreal injection of antibody for exon 17 and exon 21 of periostin should be considered to inhibit preretinal pathological NV.

  1. Effect of ambient light on monoclonal antibody product quality during small-scale mammalian cell culture process in clear glass bioreactors.

    PubMed

    Mallaney, Mary; Wang, Szu-Han; Sreedhara, Alavattam

    2014-01-01

    During a small-scale cell culture process producing a monoclonal antibody, a larger than expected difference was observed in the charge variants profile of the harvested cell culture fluid (HCCF) between the 2 L and larger scales (e.g., 400 L and 12 kL). Small-scale studies performed at the 2 L scale consistently showed an increase in acidic species when compared with the material made at larger scale. Since the 2 L bioreactors were made of clear transparent glass while the larger scale reactors are made of stainless steel, the effect of ambient laboratory light on cell culture process in 2 L bioreactors as well as handling the HCCF was carefully evaluated. Photoreactions in the 2 L glass bioreactors including light mediated increase in acidic variants in HCCF and formulation buffers were identified and carefully analyzed. While the acidic variants comprised of a mixture of sialylated, reduced disulfide, crosslinked (nonreducible), glycated, and deamidated forms, an increase in the nonreducible forms, deamidation and Met oxidation was predominantly observed under light stress. The monoclonal antibody produced in glass bioreactors that were protected from light behaved similar to the one produced in the larger scale. Our data clearly indicate that care should be taken when glass bioreactors are used in cell culture studies during monoclonal antibody production.

  2. Polyclonal and monoclonal antibodies in clinic.

    PubMed

    Wootla, Bharath; Denic, Aleksandar; Rodriguez, Moses

    2014-01-01

    Immunoglobulins (Ig) or antibodies are heavy plasma proteins, with sugar chains added to amino-acid residues by N-linked glycosylation and occasionally by O-linked glycosylation. The versatility of antibodies is demonstrated by the various functions that they mediate such as neutralization, agglutination, fixation with activation of complement and activation of effector cells. Naturally occurring antibodies protect the organism against harmful pathogens, viruses and infections. In addition, almost any organic chemical induces antibody production of antibodies that would bind specifically to the chemical. These antibodies are often produced from multiple B cell clones and referred to as polyclonal antibodies. In recent years, scientists have exploited the highly evolved machinery of the immune system to produce structurally and functionally complex molecules such as antibodies from a single B clone, heralding the era of monoclonal antibodies. Most of the antibodies currently in the clinic, target components of the immune system, are not curative and seek to alleviate symptoms rather than cure disease. Our group used a novel strategy to identify reparative human monoclonal antibodies distinct from conventional antibodies. In this chapter, we discuss the therapeutic relevance of both polyclonal and monoclonal antibodies in clinic.

  3. Methods for engineering polypeptide variants via somatic hypermutation and polypeptide made thereby

    DOEpatents

    Tsien, Roger Y; Wang, Lei

    2015-01-13

    Methods using somatic hypermutation (SHM) for producing polypeptide and nucleic acid variants, and nucleic acids encoding such polypeptide variants are disclosed. Such variants may have desired properties. Also disclosed are novel polypeptides, such as improved fluorescent proteins, produced by the novel methods, and nucleic acids, vectors, and host cells comprising such vectors.

  4. Mucopolysaccharidosis: A New Variant?

    ERIC Educational Resources Information Center

    Primrose, D. A.

    1972-01-01

    Described is a possibly new variant of mucopolysaccharidosis characterized by progressive mental and motor deficiency, bone abnormalities, a generalized skin lesion, and abnormal mucopolysaccharides in the urine as seen in a 20-year-old female. (DB)

  5. Metrics for antibody therapeutics development.

    PubMed

    Reichert, Janice M

    2010-01-01

    A wide variety of full-size monoclonal antibodies (mAbs) and therapeutics derived from alternative antibody formats can be produced through genetic and biological engineering techniques. These molecules are now filling the preclinical and clinical pipelines of every major pharmaceutical company and many biotechnology firms. Metrics for the development of antibody therapeutics, including averages for the number of candidates entering clinical study and development phase lengths for mAbs approved in the United States, were derived from analysis of a dataset of over 600 therapeutic mAbs that entered clinical study sponsored, at least in part, by commercial firms. The results presented provide an overview of the field and context for the evaluation of on-going and prospective mAb development programs. The expansion of therapeutic antibody use through supplemental marketing approvals and the increase in the study of therapeutics derived from alternative antibody formats are discussed.

  6. Complete mapping of viral escape from neutralizing antibodies

    PubMed Central

    Hensley, Scott E.

    2017-01-01

    Identifying viral mutations that confer escape from antibodies is crucial for understanding the interplay between immunity and viral evolution. We describe a high-throughput approach to quantify the selection that monoclonal antibodies exert on all single amino-acid mutations to a viral protein. This approach, mutational antigenic profiling, involves creating all replication-competent protein variants of a virus, selecting with antibody, and using deep sequencing to identify enriched mutations. We use mutational antigenic profiling to comprehensively identify mutations that enable influenza virus to escape four monoclonal antibodies targeting hemagglutinin, and validate key findings with neutralization assays. We find remarkable mutation-level idiosyncrasy in antibody escape: for instance, at a single residue targeted by two antibodies, some mutations escape both antibodies while other mutations escape only one or the other. Because mutational antigenic profiling rapidly maps all mutations selected by an antibody, it is useful for elucidating immune specificities and interpreting the antigenic consequences of viral genetic variation. PMID:28288189

  7. Role of Human Immunodeficiency Virus Type 1 Envelope Structure in the Induction of Broadly Neutralizing Antibodies

    PubMed Central

    Benjelloun, F.; Lawrence, P.; Verrier, B.; Genin, C.

    2012-01-01

    Very soon after the discovery of neutralizing antibodies (NAbs) toward human immunodeficiency virus type 1 (HIV-1) infection, it became apparent that characterization of these NAbs would be an important step in finding a cure for or a vaccine to eradicate HIV-1. Since the initial description of broadly cross-clade NAbs naturally produced in HIV-1 patients, numerous studies have described new viral targets for these antibodies. More recently, studies concerning new groups of patients able to control their viremia, such as long-term nonprogressors (LTNPs) or elite controllers, have described the generation of numerous envelope-targeted NAbs. Recent studies have marked a new stage in research on NAbs with the description of antibodies obtained from a worldwide screening of HIV-positive patients. These studies have permitted the discovery of NAb families with great potential for both neutralization and neutralization breadth, such as PG, PGT, CH, and highly active agonistic anti-CD4 binding site antibodies (HAADs), of which VRC01 and its variants are members. These antibodies are able to neutralize more than 80% of circulating strains without any autoreactivity and can be rapidly integrated into clinical trials in order to test their protective potential. In this review, we will focus on new insights into HIV-1 envelope structure and their implications for the generation of potent NAbs. PMID:23015715

  8. Recombinant antibodies and their use in biosensors.

    PubMed

    Zeng, Xiangqun; Shen, Zhihong; Mernaugh, Ray

    2012-04-01

    Inexpensive, noninvasive immunoassays can be used to quickly detect disease in humans. Immunoassay sensitivity and specificity are decidedly dependent upon high-affinity, antigen-specific antibodies. Antibodies are produced biologically. As such, antibody quality and suitability for use in immunoassays cannot be readily determined or controlled by human intervention. However, the process through which high-quality antibodies can be obtained has been shortened and streamlined by use of genetic engineering and recombinant antibody techniques. Antibodies that traditionally take several months or more to produce when animals are used can now be developed in a few weeks as recombinant antibodies produced in bacteria, yeast, or other cell types. Typically most immunoassays use two or more antibodies or antibody fragments to detect antigens that are indicators of disease. However, a label-free biosensor, for example, a quartz-crystal microbalance (QCM) needs one antibody only. As such, the cost and time needed to design and develop an immunoassay can be substantially reduced if recombinant antibodies and biosensors are used rather than traditional antibody and assay (e.g. enzyme-linked immunosorbant assay, ELISA) methods. Unlike traditional antibodies, recombinant antibodies can be genetically engineered to self-assemble on biosensor surfaces, at high density, and correctly oriented to enhance antigen-binding activity and to increase assay sensitivity, specificity, and stability. Additionally, biosensor surface chemistry and physical and electronic properties can be modified to further increase immunoassay performance above and beyond that obtained by use of traditional methods. This review describes some of the techniques investigators have used to develop highly specific and sensitive, recombinant antibody-based biosensors for detection of antigens in simple or complex biological samples.

  9. CBH1 homologs and variant CBH1 cellulases

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Neefe, Paulien

    2008-11-18

    Disclosed are a number of homologs and variants of Hypocrea jecorina Cel7A (formerly Trichoderma reesei cellobiohydrolase I or CBH1), nucleic acids encoding the same and methods for producing the same. The homologs and variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted and/or deleted.

  10. CBH1 homologs and variant CBH1 cellulases

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Neefe, Paulien

    2011-05-31

    Disclosed are a number of homologs and variants of Hypocrea jecorina Cel7A (formerly Trichoderma reesei cellobiohydrolase I or CBH1), nucleic acids encoding the same and methods for producing the same. The homologs and variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted and/or deleted.

  11. Cellobiohydrolase I gene and improved variants

    DOEpatents

    Adney, William S.; Decker, Stephen R.; Mc Carter, Suzanne; Baker, John O.; Nieves, Raphael; Himmel, Michael E.; Vinzant, Todd B.

    2008-05-20

    The disclosure provides a method for preparing an active exoglucanase in a heterologous host of eukaryotic origin. The method includes mutagenesis to reduce glycosylation of the exoglucanase when expressed in a heterologous host. It is further disclosed a method to produce variant cellobiohydrolase that is stable at high temperature through mutagenesis.

  12. Reshaping Antibody Diversity

    PubMed Central

    Wang, Feng; Ekiert, Damian C.; Ahmad, Insha; Yu, Wenli; Zhang, Yong; Bazirgan, Omar; Torkamani, Ali; Raudsepp, Terje; Mwangi, Waithaka; Criscitiello, Michael F.; Wilson, Ian A.; Schultz, Peter G.; Smider, Vaughn V.

    2014-01-01

    Summary Unlike humans or mice, some species have limited genome encoded combinatorial diversity potential, yet mount a robust antibody response. Cows are unusual in having exceptionally long CDR H3 loops and few V-regions, but the mechanism for creating diversity is not understood. Deep sequencing revealed that ultralong CDR H3s contain a remarkable complexity of cysteines, suggesting that disulfide-bonded mini-domains may arise during repertoire development. Indeed, crystal structures of two cow antibodies reveal that these CDR H3s form a very unusual architecture composed of a β-strand “stalk” that supports a structurally diverse, disulfide-bonded, “knob” domain. Sequence analysis suggests that diversity arises from somatic hypermutation of an ultralong DH with a severe codon bias towards mutation to cysteine. These unusual antibodies can be elicited to recognize defined antigens through the knob domain. Thus, the bovine immune system produces an antibody repertoire composed of CDR H3s of unprecedented length that fold into a diversity of mini-domains generated through combinations of somatically generated disulfides. PMID:23746848

  13. Predictable removal of anticardiolipin antibody by therapeutic plasma exchange (TPE) in catastrophic antiphospholipid antibody syndrome (CAPS).

    PubMed

    Zar, T; Kaplan, A A

    2008-07-01

    Catastrophic antiphospholipid antibody syndrome (CAPS) is a rare life-threatening variant of antiphospholipid antibody syndrome (APS), with an associated mortality rate of > 50%. Treatment recommendations are aggressive and consist of intravenous heparin, steroids, immunoglobulins and/or therapeutic plasma exchange (TPE). At present, insufficient data exist to make precise recommendations regarding the most effective therapy for CAPS. Accumulating evidence over recent years is encouraging and may lead to future guidelines. We report predictive and effective removal of pathological anticardiolipin antibody (aCL AB) in a patient with CAPS. The case report and discussion provide valuable insight into aCL AB production and its removal by first- order kinetics using TPE.

  14. Antibody i-Patch prediction of the antibody binding site improves rigid local antibody-antigen docking.

    PubMed

    Krawczyk, Konrad; Baker, Terry; Shi, Jiye; Deane, Charlotte M

    2013-10-01

    Antibodies are a class of proteins indispensable for the vertebrate immune system. The general architecture of all antibodies is very similar, but they contain a hypervariable region which allows millions of antibody variants to exist, each of which can bind to different molecules. This binding malleability means that antibodies are an increasingly important category of biopharmaceuticals and biomarkers. We present Antibody i-Patch, a method that annotates the most likely antibody residues to be in contact with the antigen. We show that our predictions correlate with energetic importance and thus we argue that they may be useful in guiding mutations in the artificial affinity maturation process. Using our predictions as constraints for a rigid-body docking algorithm, we are able to obtain high-quality results in minutes. Our annotation method and re-scoring system for docking achieve their predictive power by using antibody-specific statistics. Antibody i-Patch is available from http://www.stats.ox.ac.uk/research/proteins/resources.

  15. Human combinatorial autoantibodies and mouse monoclonal antibodies to PDC-E2 produce abnormal apical staining of salivary glands in patients with coexistent primary biliary cirrhosis and Sjögren's syndrome.

    PubMed

    Tsuneyama, K; Van de Water, J; Nakanuma, Y; Cha, S; Ansari, A; Coppel, R; Gershwin, M E

    1994-10-01

    An increase in the incidence of Sjögren's syndrome in patients with primary biliary cirrhosis has been noted. Indeed, primary biliary cirrhosis has been described as a ductal disease with involvement not only of the biliary tract but of epithelial ductal cells in other organs. We have previously reported the development of a panel of mouse monoclonal antibodies directed at PDC-E2, the major autoantigen of primary biliary cirrhosis. One such antibody, C355.1, but none of the other monoclonal antibodies, reacted not only with mitochondria but also with the apical region of biliary epithelium of patients with primary biliary cirrhosis but not in similar specimens from patients with other liver disease or normal human liver. In addition, we have reported the development of human combinatorial antibodies specific for PDC-E2; these reagents also reacted uniquely with the biliary epithelium of patients with primary biliary cirrhosis. In this paper, we have performed a similar study and have compared the staining of monoclonal antibody C355.1 and a human combinatorial antibody, SP4, with control monoclonal antibodies with respect to their reactivity of salivary glands in 9 patients with primary biliary cirrhosis associated with Sjögren's syndrome, 11 patients with Sjögren's syndrome alone and 7 control patients. Interestingly, the apical region of the salivary gland epithelial cells of approximately 50% of patients with coexisting primary biliary cirrhosis and Sjögren's syndrome had a staining pattern similar to that seen in primary biliary cirrhosis biliary epithelium. In contrast, we did not observe this reactivity in any patient with Sjögren's syndrome alone or in any control patient.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Development of Primer Pairs from Molecular Typing of Rabies Virus Variants Present in Mexico

    PubMed Central

    Ramírez-Hernández, Dolores G.; Lara-Padilla, Eleazar; Zárate-Segura, Paola

    2016-01-01

    Nucleoprotein (N) gene from rabies virus (RABV) is a useful sequence target for variant studies. Several specific RABV variants have been characterized in different mammalian hosts such as skunk, dog, and bats by using anti-nucleocapsid monoclonal antibodies (MAbs) via indirect fluorescent antibody (IFA) test, a technique not available in many laboratories in Mexico. In the present study, a total of 158 sequences of N gene from RABV were used to design eight pairs of primers (four external and four internal primers), for typing four different RABV variants (dog, skunk, vampire bat, and nonhematophagous bat) which are most common in Mexico. The results indicate that the primer and the typing variant from the brain samples, submitted to nested and/or real-time PCR, are in agreement in all four singleplex reactions, and the designed primer pairs are an alternative for use in specific variant RABV typing. PMID:27563666

  17. Development of Primer Pairs from Molecular Typing of Rabies Virus Variants Present in Mexico.

    PubMed

    Bastida-González, Fernando; Ramírez-Hernández, Dolores G; Chavira-Suárez, Erika; Lara-Padilla, Eleazar; Zárate-Segura, Paola

    2016-01-01

    Nucleoprotein (N) gene from rabies virus (RABV) is a useful sequence target for variant studies. Several specific RABV variants have been characterized in different mammalian hosts such as skunk, dog, and bats by using anti-nucleocapsid monoclonal antibodies (MAbs) via indirect fluorescent antibody (IFA) test, a technique not available in many laboratories in Mexico. In the present study, a total of 158 sequences of N gene from RABV were used to design eight pairs of primers (four external and four internal primers), for typing four different RABV variants (dog, skunk, vampire bat, and nonhematophagous bat) which are most common in Mexico. The results indicate that the primer and the typing variant from the brain samples, submitted to nested and/or real-time PCR, are in agreement in all four singleplex reactions, and the designed primer pairs are an alternative for use in specific variant RABV typing.

  18. Production and Purification of Antibodies Against Histone Modifications.

    PubMed

    Guillemette, Benoit; Hammond-Martel, Ian; Wurtele, Hugo; Verreault, Alain

    2017-01-01

    Antibodies that recognize specific histone modifications are invaluable tools to study chromatin structure and function. There are numerous commercially available antibodies that recognize a remarkable diversity of histone modifications. Unfortunately, many of them fail to work in certain applications or lack the high degree of specificity required of these reagents. The production of affinity-purified polyclonal antibodies against histone modifications demands a little effort but, in return, provides extremely valuable tools that overcome many of the concerns and limitations of commercial antibodies. We present a series of protocols and guidelines for the production and use of large amounts of polyclonal antibodies that recognize modifications of canonical histones. Our protocols can be applied to obtain antibodies that occur in histone variants and proteins other than histones. In addition, some of our protocols are compatible with the production of monoclonal or recombinant antibodies.

  19. Antibody Engineering and Therapeutics

    PubMed Central

    Almagro, Juan Carlos; Gilliland, Gary L; Breden, Felix; Scott, Jamie K; Sok, Devin; Pauthner, Matthias; Reichert, Janice M; Helguera, Gustavo; Andrabi, Raiees; Mabry, Robert; Bléry, Mathieu; Voss, James E; Laurén, Juha; Abuqayyas, Lubna; Barghorn, Stefan; Ben-Jacob, Eshel; Crowe, James E; Huston, James S; Johnston, Stephen Albert; Krauland, Eric; Lund-Johansen, Fridtjof; Marasco, Wayne A; Parren, Paul WHI; Xu, Kai Y

    2014-01-01

    The 24th Antibody Engineering & Therapeutics meeting brought together a broad range of participants who were updated on the latest advances in antibody research and development. Organized by IBC Life Sciences, the gathering is the annual meeting of The Antibody Society, which serves as the scientific sponsor. Preconference workshops on 3D modeling and delineation of clonal lineages were featured, and the conference included sessions on a wide variety of topics relevant to researchers, including systems biology; antibody deep sequencing and repertoires; the effects of antibody gene variation and usage on antibody response; directed evolution; knowledge-based design; antibodies in a complex environment; polyreactive antibodies and polyspecificity; the interface between antibody therapy and cellular immunity in cancer; antibodies in cardiometabolic medicine; antibody pharmacokinetics, distribution and off-target toxicity; optimizing antibody formats for immunotherapy; polyclonals, oligoclonals and bispecifics; antibody discovery platforms; and antibody-drug conjugates. PMID:24589717

  20. A phonetic explanation of pronunciation variant effects.

    PubMed

    Sumner, Meghan

    2013-07-01

    Effects of word-level phonetic variation on the recognition of words with different pronunciation variants (e.g., center produced with/(out) [t]) are investigated via the semantic- and pseudoword-priming paradigms. A bias favoring clearly articulated words with canonical variants ([nt]) is found. By reducing the bias, words with different variants show robust and equivalent lexical activation. The equivalence of different word forms highlights a snag for frequency-based theories of lexical access: How are words and word productions with vastly different frequencies recognized equally well by listeners? A process-based account is proposed, suggesting that careful speech induces bottom-up processing and casual speech induces top-down processing.

  1. Functional Characterization of Antibodies against Neisseria gonorrhoeae Opacity Protein Loops

    PubMed Central

    Cole, Jessica G.; Jerse, Ann E.

    2009-01-01

    Background The development of a gonorrhea vaccine is challenged by the lack of correlates of protection. The antigenically variable neisserial opacity (Opa) proteins are expressed during infection and have a semivariable (SV) and highly conserved (4L) loop that could be targeted in a vaccine. Here we compared antibodies to linear (Ablinear) and cyclic (Abcyclic) peptides that correspond to the SV and 4L loops and selected hypervariable (HV2) loops for surface-binding and protective activity in vitro and in vivo. Methods/Findings AbSV cyclic bound a greater number of different Opa variants than AbSV linear, including variants that differed by seven amino acids. Antibodies to the 4L peptide did not bind Opa-expressing bacteria. AbSV cyclic and AbHV2 cyclic, but not AbSV linear or AbHV2 linear agglutinated homologous Opa variants, and AbHV2BD cyclic but not AbHV2BD linear blocked the association of OpaB variants with human endocervical cells. Only AbHV2BD linear were bactericidal against the serum resistant parent strain. Consistent with host restrictions in the complement cascade, the bactericidal activity of AbHV2BD linear was increased 8-fold when rabbit complement was used. None of the antibodies was protective when administered vaginally to mice. Antibody duration in the vagina was short-lived, however, with <50% of the antibodies recovered 3 hrs post-administration. Conclusions We conclude that an SV loop-specific cyclic peptide can be used to induce antibodies that recognize a broad spectrum of antigenically distinct Opa variants and have agglutination abilities. HV2 loop-specific cyclic peptides elicited antibodies with agglutination and adherence blocking abilities. The use of human complement when testing the bactericidal activity of vaccine-induced antibodies against serum resistant gonococci is also important. PMID:19956622

  2. Avian Diagnostic and Therapeutic Antibodies

    SciTech Connect

    Bradley, David Sherman

    2012-12-31

    A number of infectious agents have the potential of causing significant clinical symptomology and even death, but dispite this, the number of incidence remain below the level that supports producing a vaccine. Therapeutic antibodies provide a viable treatment option for many of these diseases. We proposed that antibodies derived from West Nile Virus (WNV) immunized geese would be able to treat WNV infection in mammals and potential humans. We demonstrated that WNV specific goose antibodies are indeed successful in treating WNV infection both prophylactically and therapeutically in a golden hamster model. We demonstrated that the goose derived antibodies are non-reactogenic, i.e. do not cause an inflammatory response with multiple exposures in mammals. We also developed both a specific pathogen free facility to house the geese during the antibody production phase and a patent-pending purification process to purify the antibodies to greater than 99% purity. Therefore, the success of these study will allow a cost effective rapidly producible therapeutic toward clinical testing with the necessary infrastructure and processes developed and in place.

  3. Neutralising Antibodies against Ricin Toxin

    PubMed Central

    Prigent, Julie; Panigai, Laetitia; Lamourette, Patricia; Sauvaire, Didier; Devilliers, Karine; Plaisance, Marc; Volland, Hervé; Créminon, Christophe; Simon, Stéphanie

    2011-01-01

    The Centers for Disease Control and Prevention have listed the potential bioweapon ricin as a Category B Agent. Ricin is a so-called A/B toxin produced by plants and is one of the deadliest molecules known. It is easy to prepare and no curative treatment is available. An immunotherapeutic approach could be of interest to attenuate or neutralise the effects of the toxin. We sought to characterise neutralising monoclonal antibodies against ricin and to develop an effective therapy. For this purpose, mouse monoclonal antibodies (mAbs) were produced against the two chains of ricin toxin (RTA and RTB). Seven mAbs were selected for their capacity to neutralise the cytotoxic effects of ricin in vitro. Three of these, two anti-RTB (RB34 and RB37) and one anti-RTA (RA36), when used in combination improved neutralising capacity in vitro with an IC50 of 31 ng/ml. Passive administration of association of these three mixed mAbs (4.7 µg) protected mice from intranasal challenges with ricin (5 LD50). Among those three antibodies, anti-RTB antibodies protected mice more efficiently than the anti-RTA antibody. The combination of the three antibodies protected mice up to 7.5 hours after ricin challenge. The strong in vivo neutralising capacity of this three mAbs combination makes it potentially useful for immunotherapeutic purposes in the case of ricin poisoning or possibly for prevention. PMID:21633505

  4. Monoclonal antibodies: new agents for cancer detection and targeted therapy

    SciTech Connect

    Baldwin, R.W.; Byers, V.S. )

    1991-01-01

    Antibodies directed against markers on cancer cells are gaining in importance for the purpose of targeting diagnostic and therapeutic agents. In the past, this approach has had very limited success principally because the classical methods for producing antibodies from blood serum of animals immunized with cancer cells or extracts were unsatisfactory. The situation has changed dramatically since 1975 following the design of procedures for 'immortalizing' antibody-producing cells (lymphocytes) by fusing them with cultured myeloma cells to form hybridomas which continuously secrete antibodies. Since these hybridomas produce antibodies coded for by a single antibody-producing cell, the antibodies are called monoclonal. Building on these advances in biomedical research, it is now possible to reproducibly manufacture monoclonal antibodies on a scale suitable for use in cancer detection and therapy.

  5. HIV-1 resistance to neutralizing antibodies: Determination of antibody concentrations leading to escape mutant evolution.

    PubMed

    Magnus, Carsten; Reh, Lucia; Trkola, Alexandra

    2016-06-15

    Broadly neutralizing antibodies against human immunodeficiency virus type 1 (HIV-1) are considered vital components of novel therapeutics and blueprints for vaccine research. Yet escape to even the most potent of these antibodies is imminent in natural infection. Measures to define antibody efficacy and prevent mutant selection are thus urgently needed. Here, we derive a mathematical framework to predict the concentration ranges for which antibody escape variants can outcompete their viral ancestors, referred to as mutant selection window (MSW). When determining the MSW, we focus on the differential efficacy of neutralizing antibodies against HIV-1 in two canonical infection routes, free-virus infection and cell-cell transmission. The latter has proven highly effective in vitro suggesting its importance for both in vivo spread as well as for escaping targeted intervention strategies. We observed a range of MSW patterns that highlight the potential of mutants to arise in both transmission pathways and over wide concentration ranges. Most importantly, we found that only when the arising mutant has both, residual sensitivity to the neutralizing antibody and reduced infectivity compared to the parental virus, antibody dosing outside of the MSW to restrict mutant selection is possible. Emergence of mutants that provide complete escape and have no considerable fitness loss cannot be prevented by adjusting antibody doses. The latter may in part explain the ubiquitous resistance to neutralizing antibodies observed in natural infection and antibody treatment. Based on our findings, combinations of antibodies targeting different epitopes should be favored for antibody-based interventions as this may render complete resistance less likely to occur and also increase chances that multiple escapes result in severe fitness loss of the virus making longer-term antibody treatment more feasible.

  6. Quantitative cumulative biodistribution of antibodies in mice

    PubMed Central

    Yip, Victor; Palma, Enzo; Tesar, Devin B; Mundo, Eduardo E; Bumbaca, Daniela; Torres, Elizabeth K; Reyes, Noe A; Shen, Ben Q; Fielder, Paul J; Prabhu, Saileta; Khawli, Leslie A; Boswell, C Andrew

    2014-01-01

    The neonatal Fc receptor (FcRn) plays an important and well-known role in antibody recycling in endothelial and hematopoietic cells and thus it influences the systemic pharmacokinetics (PK) of immunoglobulin G (IgG). However, considerably less is known about FcRn’s role in the metabolism of IgG within individual tissues after intravenous administration. To elucidate the organ distribution and gain insight into the metabolism of humanized IgG1 antibodies with different binding affinities FcRn, comparative biodistribution studies in normal CD-1 mice were conducted. Here, we generated variants of herpes simplex virus glycoprotein D-specific antibody (humanized anti-gD) with increased and decreased FcRn binding affinity by genetic engineering without affecting antigen specificity. These antibodies were expressed in Chinese hamster ovary cell lines, purified and paired radiolabeled with iodine-125 and indium-111. Equal amounts of I-125-labeled and In-111-labeled antibodies were mixed and intravenously administered into mice at 5 mg/kg. This approach allowed us to measure both the real-time IgG uptake (I-125) and cumulative uptake of IgG and catabolites (In-111) in individual tissues up to 1 week post-injection. The PK and distribution of the wild-type IgG and the variant with enhanced binding for FcRn were largely similar to each other, but vastly different for the rapidly cleared low-FcRn-binding variant. Uptake in individual tissues varied across time, FcRn binding affinity, and radiolabeling method. The liver and spleen emerged as the most concentrated sites of IgG catabolism in the absence of FcRn protection. These data provide an increased understanding of FcRn’s role in antibody PK and catabolism at the tissue level. PMID:24572100

  7. SslE Elicits Functional Antibodies That Impair In Vitro Mucinase Activity and In Vivo Colonization by Both Intestinal and Extraintestinal Escherichia coli Strains

    PubMed Central

    Nesta, Barbara; Valeri, Maria; Spagnuolo, Angela; Rosini, Roberto; Mora, Marirosa; Donato, Paolo; Alteri, Christopher J.; Del Vecchio, Mariangela; Buccato, Scilla; Pezzicoli, Alfredo; Bertoldi, Isabella; Buzzigoli, Lapo; Tuscano, Giovanna; Falduto, Maria; Rippa, Valentina; Ashhab, Yaqoub; Bensi, Giuliano; Fontana, Maria Rita; Seib, Kate L.; Mobley, Harry L. T.; Pizza, Mariagrazia; Soriani, Marco; Serino, Laura

    2014-01-01

    SslE, the Secreted and surface-associated lipoprotein from Escherichia coli, has recently been associated to the M60-like extracellular zinc-metalloprotease sub-family which is implicated in glycan recognition and processing. SslE can be divided into two main variants and we recently proposed it as a potential vaccine candidate. By applying a number of in vitro bioassays and comparing wild type, knockout mutant and complemented strains, we have now demonstrated that SslE specifically contributes to degradation of mucin substrates, typically present in the intestine and bladder. Mutation of the zinc metallopeptidase motif of SslE dramatically impaired E. coli mucinase activity, confirming the specificity of the phenotype observed. Moreover, antibodies raised against variant I SslE, cloned from strain IHE3034 (SslEIHE3034), are able to inhibit translocation of E. coli strains expressing different variants through a mucin-based matrix, suggesting that SslE induces cross-reactive functional antibodies that affect the metallopeptidase activity. To test this hypothesis, we used well-established animal models and demonstrated that immunization with SslEIHE3034 significantly reduced gut, kidney and spleen colonization by strains producing variant II SslE and belonging to different pathotypes. Taken together, these data strongly support the importance of SslE in E. coli colonization of mucosal surfaces and reinforce the use of this antigen as a component of a broadly protective vaccine against pathogenic E. coli species. PMID:24809621

  8. Lack of in Vivo Antibody Dependent Cellular Cytotoxicity with Antibody Containing Gold Nanoparticles

    PubMed Central

    2016-01-01

    Antibody-dependent cellular cytotoxicity (ADCC) is a cytolytic mechanism that can elicit in vivo antitumor effects and can play a significant role in the efficacy of antibody treatments for cancer. Here, we prepared cetuximab, panitumumab, and rituximab containing gold nanoparticles and investigated their ability to produce an ADCC effect in vivo. Cetuximab treatment of EGFR-expressing H1975 tumor xenografts showed significant tumor regression due to the ADCC activity of the antibody in vivo, while the control antibody, panitumumab, did not. However, all three antibody containing nanoparticles are not able to suppress tumor growth in the same in vivo mouse model. The antibody containing nanoparticles localized in the tumors and did not suppress the immune function of the animals, so the lack of tumor growth suppression of the cetuximab containing nanoparticle suggests that immobilizing antibodies onto a nanoparticle significantly decreases the ability of the antibody to promote an ADCC response. PMID:25879583

  9. Protection against anthrax toxin by recombinant antibody fragments correlates with antigen affinity.

    PubMed

    Maynard, Jennifer A; Maassen, Catharina B M; Leppla, Stephen H; Brasky, Kathleen; Patterson, Jean L; Iverson, Brent L; Georgiou, George

    2002-06-01

    The tripartite toxin produced by Bacillus anthracis is the key determinant in the etiology of anthrax. We have engineered a panel of toxin-neutralizing antibodies, including single-chain variable fragments (scFvs) and scFvs fused to a human constant kappa domain (scAbs), that bind to the protective antigen subunit of the toxin with equilibrium dissociation constants (K(d)) between 63 nM and 0.25 nM. The entire antibody panel showed high serum, thermal, and denaturant stability. In vitro, post-challenge protection of macrophages from the action of the holotoxin correlated with the K(d) of the scFv variants. Strong correlations among antibody construct affinity, serum half-life, and protection were also observed in a rat model of toxin challenge. High-affinity toxin-neutralizing antibodies may be of therapeutic value for alleviating the symptoms of anthrax toxin in infected individuals and for medium-term prophylaxis to infection.

  10. Monoclonal antibodies reacting with murine teratocarcinoma cells.

    PubMed Central

    Goodfellow, P N; Levinson, J R; Williams, V E; McDevitt, H O

    1979-01-01

    Monoclonal antibodies were produced in vitro by fusing mouse myeloma cells with spleen cells from a rat immunized with the C3H mouse teratocarcinoma C86-S1. After the fusion two clones were chosen for further analysis. The first clone, 3C4-10, produced an antibody recognizing an antigen with a distribution restricted to teratocarcinoma cell lines, an endoderm cell line, and a neuroblastoma. The second clone, 4A1-9, produced an antibody that reacted with all cultured murine cells tested and adult brain. Neither antibody reacted with preimplantation embryos. The 3C4-10 antibody recognized an antigen associated with proteins. The apparent molecular weight of the 3C4-10 antigen was greater than 100,000. PMID:284353

  11. HIV-specific CD4-induced Antibodies Mediate Broad and Potent Antibody-dependent Cellular Cytotoxicity Activity and are Commonly Detected in Plasma from HIV-infected Humans

    PubMed Central

    Williams, Katherine L.; Cortez, Valerie; Dingens, Adam S.; Gach, Johannes S.; Rainwater, Stephanie; Weis, Julie F.; Chen, Xuemin; Spearman, Paul; Forthal, Donald N.; Overbaugh, Julie

    2015-01-01

    HIV-specific antibodies (Abs) can reduce viral burden by blocking new rounds of infection or by destroying infected cells via activation of effector cells through Fc–FcR interaction. This latter process, referred to as antibody-dependent cellular cytotoxicity (ADCC), has been associated with viral control and improved clinical outcome following both HIV and SIV infections. Here we describe an HIV viral-like particle (VLP)-based sorting strategy that led to identification of HIV-specific memory B cells encoding Abs that mediate ADCC from a subtype A-infected Kenyan woman at 914 days post-infection. Using this strategy, 12 HIV-envelope-specific monoclonal antibodies (mAbs) were isolated and three mediated potent ADCC activity when compared to well-characterized ADCC mAbs. The ADCC-mediating Abs also mediated antibody-dependent cell-mediated virus inhibition (ADCVI), which provides a net measure of Fc receptor-triggered effects against replicating virus. Two of the three ADCC-mediating Abs targeted a CD4-induced (CD4i) epitope also bound by the mAb C11; the third antibody targeted the N-terminus of V3. Both CD4i Abs identified here demonstrated strong cross-clade breadth with activity against 10 of 11 envelopes tested, including those from clades A, B, C, A/D and C/D, whereas the V3-specific antibody showed more limited breadth. Variants of these CD4i, C11-like mAbs engineered to interrupt binding to FcγRs inhibited a measurable percentage of the donor's ADCC activity starting as early as 189 days post-infection. C11-like antibodies also accounted for between 18–78% of ADCC activity in 9 chronically infected individuals from the same cohort study. Further, the two CD4i Abs originated from unique B cells, suggesting that antibodies targeting this epitope can be commonly produced. Taken together, these data provide strong evidence that CD4i, C11-like antibodies develop within the first 6 months of infection and they can arise from unique B-cell lineages in the

  12. Site-Specific Antibody Labeling by Covalent Photoconjugation of Z Domains Functionalized for Alkyne-Azide Cycloaddition Reactions.

    PubMed

    Perols, Anna; Arcos Famme, Melina; Eriksson Karlström, Amelie

    2015-11-01

    Antibodies are extensively used in research, diagnostics, and therapy, and for many applications the antibodies need to be labeled. Labeling is typically performed by using amine-reactive probes that target surface-exposed lysine residues, resulting in heterogeneously labeled antibodies. An alternative labeling strategy is based on the immunoglobulin G (IgG)-binding protein domain Z, which binds to the Fc region of IgG. Introducing the photoactivable amino acid benzoylphenylalanine (BPA) into the Z domain makes it possible for a covalent bond to be be formed between the Z domain and the antibody on UV irradiation, to produce a site-specifically labeled product. Z32 BPA was synthesized by solid-phase peptide synthesis and further functionalized to give alkyne-Z32 BPA and azide-Z32 BPA for Cu(I) -catalyzed cycloaddition, as well as DBCO-Z32 BPA for Cu-free strain-promoted cycloaddition. The Z32 BPA variants were conjugated to the human IgG1 antibody trastuzumab and site-specifically labeled with biotin or fluorescein. The fluorescently labeled trastuzumab showed specific staining of the membranes of HER2-expressing cells in immunofluorescence microscopy.

  13. Serum herpes simplex antibodies

    MedlinePlus

    ... gov/ency/article/003352.htm Serum herpes simplex antibodies To use the sharing features on this page, please enable JavaScript. Serum herpes simplex antibodies is a blood test that looks for antibodies ...

  14. Variants of Uncertainty

    DTIC Science & Technology

    1981-05-15

    Variants of Uncertainty Daniel Kahneman University of British Columbia Amos Tversky Stanford University DTI-C &%E-IECTE ~JUNO 1i 19 8 1j May 15, 1981... Dennett , 1979) in which different parts have ac- cess to different data, assign then different weights and hold different views of the situation...2robable and t..h1 provable. Oxford- Claredor Press, 1977. Dennett , D.C. Brainstorms. Hassocks: Harvester, 1979. Donchin, E., Ritter, W. & McCallum, W.C

  15. Variants of glycoside hydrolases

    DOEpatents

    Teter, Sarah; Ward, Connie; Cherry, Joel; Jones, Aubrey; Harris, Paul; Yi, Jung

    2013-02-26

    The present invention relates to variants of a parent glycoside hydrolase, comprising a substitution at one or more positions corresponding to positions 21, 94, 157, 205, 206, 247, 337, 350, 373, 383, 438, 455, 467, and 486 of amino acids 1 to 513 of SEQ ID NO: 2, and optionally further comprising a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2 a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2, wherein the variants have glycoside hydrolase activity. The present invention also relates to nucleotide sequences encoding the variant glycoside hydrolases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  16. Variants of glycoside hydrolases

    DOEpatents

    Teter, Sarah; Ward, Connie; Cherry, Joel; Jones, Aubrey; Harris, Paul; Yi, Jung

    2011-04-26

    The present invention relates to variants of a parent glycoside hydrolase, comprising a substitution at one or more positions corresponding to positions 21, 94, 157, 205, 206, 247, 337, 350, 373, 383, 438, 455, 467, and 486 of amino acids 1 to 513 of SEQ ID NO: 2, and optionally further comprising a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2 a substitution at one or more positions corresponding to positions 8, 22, 41, 49, 57, 113, 193, 196, 226, 227, 246, 251, 255, 259, 301, 356, 371, 411, and 462 of amino acids 1 to 513 of SEQ ID NO: 2, wherein the variants have glycoside hydrolase activity. The present invention also relates to nucleotide sequences encoding the variant glycoside hydrolases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  17. Antibody humanization methods - a review and update.

    PubMed

    Safdari, Yaghoub; Farajnia, Safar; Asgharzadeh, Mohammad; Khalili, Masoumeh

    2013-01-01

    This article reviews recent advances achieved during recent years on various aspects of antibody humanization theories and techniques. Common methods for producing humanized antibodies including framework-homology-based humanization, germline humanization, complementary determining regions (CDR)-homology-based humanization and specificity determining residues (SDR) grafting, as well as advantages and disadvantages of each of these methods and their applications are discussed.

  18. Paraneoplastic cerebellar degeneration with anti-Yo antibodies - a review.

    PubMed

    Venkatraman, Anand; Opal, Puneet

    2016-08-01

    The ataxic syndrome associated with Anti-Yo antibody, or Purkinje cell cytoplasmic antibody type 1 (PCA1), is the most common variant of paraneoplastic cerebellar degeneration (PCD). The typical presentation involves the subacute development of pancerebellar deficits with a clinical plateau within 6 months. The vast majority of cases have been reported in women with pelvic or breast tumors. Magnetic resonance imaging of the brain is often normal in the early stages, with cerebellar atrophy seen later. The underlying mechanism is believed to be an immunological reaction to cerebellar degeneration-related protein 2 (CDR2), a protein usually found in the cerebellum that is ectopically produced by tumor cells. Although both B- and T-cell abnormalities are seen, there is debate about the relative importance of the autoantibodies and cytotoxic T lymphocytes in the neuronal loss. Cerebrospinal fluid abnormalities, primarily elevated protein, lymphocytic pleocytosis, and oligoclonal bands, are common in the early stages. The low prevalence of this condition has not allowed for large-scale randomized controlled trials. Immunotherapies, such as steroids, intravenous immune globulins, and plasma exchange, have been extensively used in managing this condition, with limited success. Although some reports indicate benefit from antitumor therapies like surgery and chemotherapy, this has not been consistently observed. The prognosis for anti-Yo PCD is almost uniformly poor, with most patients left bedridden. Further studies are required to clarify the pathophysiology and provide evidence-based treatment options.

  19. A pilot study on an attenuated Chinese EIAV vaccine inducing broadly neutralizing antibodies.

    PubMed

    Meng, Qinglai; Lin, Yuezhi; Ma, Jian; Ma, Yan; Zhao, Liping; Li, Shenwei; Liang, Hua; Zhou, Jianhua; Shen, Rongxian; Zhang, Xiaoyan; Shao, Yiming

    2011-08-01

    The attenuated Chinese equine infectious anemia virus (EIAV) vaccine has successfully protected millions of equine animals from EIA disease in China. In this pilot study, to determine whether this attenuated vaccine can induce broadly neutralizing antibodies, we immunized four horses with the attenuated Chinese vaccine strain EIAVFDDV and then observed the evolution of neutralizing antibodies against different EIAV strains. During the vaccination phase, all vaccinees rapidly developed high levels of neutralizing antibodies against the homologous vaccine strain (pLGFD3V), and 3 out of 4 horses showed a gradual increase in serum neutralizing activity against two relatively heterologous virulent variants of the challenge strain (pLGFD3Mu12V and DLV34). After challenge, the three horses that had developed high levels of neutralizing antibodies against pLGFD3Mu12V and DLV34 did not show signs of infection, which was demonstrated by immune suppression, while the one horse producing serum that could only neutralize pLGFD3V developed a febrile episode during the 8-month observation period. To assess whether the broadly neutralizing activity is associated with immune protection, sera drawn on the day of challenge from these four vaccinees and an additional four EIAVFDDV-vaccinated horses were analyzed for neutralizing antibodies against pLGFD3V, pLGFD3Mu12V and DLV34. Although there was no significant correlation between protection from infection and serum neutralizing activity against any of these three viral strains, protection from infection was observed to correlate better with serum neutralizing activity against the two heterologous virulent strains than against the homologous vaccine strain. These data indicate that EIAVFDDV induced broadly neutralizing antibodies, which might confer enhanced protection of vaccinees from infection by the challenge virus.

  20. [Antinuclear antibodies].

    PubMed

    Cabiedes, Javier; Núñez-Álvarez, Carlos A

    2010-01-01

    Anti-nuclear antibodies (ANA) are immunoglobulin directed against autologous cell nuclear and cytoplasmic components. Besides the autoimmune ANA there are other ANA that can be detected in circulation, like natural and infectious ANA. Because of its high sensibility, detection of the ANA must be done by indirect immunofluorescence (IIF) as screening test and all of those positive samples are convenient to confirm its specificity by ELISA, western blot or other techniques. Positive ANA detected by IIF must be evaluated taking in to account the pattern and titer. The following recommended step is the specificity characterization (reactivity against extractable nuclear antigens [ENA], dsDNA, etc.) which is useful for the diagnosis and follow up of patients with autoimmune diseases, and by such reasoning, its detection must be performed in an orderly and reasonable way using guides or strategies focused to the good use and interpretation of the autoantibodies. The objective of this review is to present a compilation of the literature and our experience in the detection and study of the ANA.

  1. Thermolabile antifreeze protein produced in Escherichia coli for structural analysis.

    PubMed

    Lin, Feng-Hsu; Sun, Tianjun; Fletcher, Garth L; Davies, Peter L

    2012-03-01

    The only hyperactive antifreeze protein (AFP) found to date in fishes is an extreme variant of the 3-kDa, alpha-helical, alanine-rich type I AFP, which is referred to here as type Ih. Purification of the 33-kDa homodimeric AFP Ih from a natural source was hampered by its low levels in fish plasma; by the need to remove the more abundant smaller isoforms; and by its extreme thermolability. Moreover, ice affinity as a purification tool was spoiled by the tendency of fish IgM antibodies to bind to ice in the presence of AFPs. In order to produce enough protein for crystallography we expressed AFP Ih as a recombinant protein in the Arctic Express® strain of Escherichia coli at 12 °C, just below the thermal denaturation temperature of 16-18 °C. His-tags were not useful because they compromised the activity and yield of AFP Ih. But in the absence of fish antibodies we were able to recover 10-mg quantities of the antifreeze protein using two cycles of ice affinity purification followed by anion-exchange chromatography to remove contaminating chaperones. The purified recombinant AFP Ih yielded diffraction-quality crystals with an extremely asymmetrical unit cell. By transferring the genes of the chaperones into a methionine auxotroph we were able to grow this host at low temperatures and produce sufficient selenomethionine-labeled AFP Ih for crystallography.

  2. Human AZU-1 gene, variants thereof and expressed gene products

    DOEpatents

    Chen, Huei-Mei; Bissell, Mina

    2004-06-22

    A human AZU-1 gene, mutants, variants and fragments thereof. Protein products encoded by the AZU-1 gene and homologs encoded by the variants of AZU-1 gene acting as tumor suppressors or markers of malignancy progression and tumorigenicity reversion. Identification, isolation and characterization of AZU-1 and AZU-2 genes localized to a tumor suppressive locus at chromosome 10q26, highly expressed in nonmalignant and premalignant cells derived from a human breast tumor progression model. A recombinant full length protein sequences encoded by the AZU-1 gene and nucleotide sequences of AZU-1 and AZU-2 genes and variant and fragments thereof. Monoclonal or polyclonal antibodies specific to AZU-1, AZU-2 encoded protein and to AZU-1, or AZU-2 encoded protein homologs.

  3. Two distinct variants of erythrocyte spectrin beta IV domain.

    PubMed

    Pothier, B; Alloisio, N; Morlé, L; Maréchal, J; Barthélemy, H; Ducluzeau, M T; Dorier, A; Delaunay, J

    1989-11-01

    We report two distinct variants affecting the beta IV domain of erythrocyte spectrin, designated spectrin Saint-Chamond and spectrin Tlemcen. They were discovered in a French family and an Algerian individual, respectively. They appeared clinically and morphologically asymptomatic in the heterozygous state. In two-dimensional maps of spectrin partial digests, both mutants were manifested by cathodic shifts (with no change of the molecular weights) of the peptides that cover the N-terminal region of spectrin beta IV domain. The relevance of the abnormal peptides to the beta IV domain was established by quantitative analysis and by Western blotting using anti-beta IV domain-specific antibodies. These two variants are thus far the most distal variants of spectrin to be defined on an unequivocal structural basis.

  4. Oral immunization with xenogeneic antibodies stimulates the production of systemic and mucosal anti-idiotypic antibodies.

    PubMed Central

    Collins, A M; Roberton, D M; Hosking, C S; Flannery, G R

    1991-01-01

    The humoral and mucosal immune responses to oral immunization with xenogeneic antibodies were studied using an animal model in which female rabbits were fed daily doses of the MOPC-315 murine IgA antibody, and were mated during the course of the feeding programme. Serum and colostrum samples were assayed for the presence of anti-idiotypic antibodies by ELISA assay, before and after depletion of anti-IgA antibodies, by affinity chromatography using another murine IgA idiotype. It was shown that all animals responded to exposure to the MOPC-315 idiotype with the production of serum anti-murine immunoglobulin antibodies and that four of six animals produced serum anti-idiotypic antibodies. That the immune response included antibodies directed against the antigen-binding site was confirmed by competition ELISA assay. Mucosal IgG and IgA anti-immunoglobulin antibodies were present in milk from all antibody-fed rabbits tested, and IgA anti-idiotypic antibodies were detectable in the colostrum of one rabbit. The results provide some support for the hypothesis that human exposure to xenogeneic antibodies, most commonly bovine milk immunoglobulins, may provoke the production of anti-idiotypic antibodies, and that such exposure may lead to disturbances of immune regulation. PMID:1916890

  5. Selection of antibodies from synthetic antibody libraries.

    PubMed

    Harel Inbar, Noa; Benhar, Itai

    2012-10-15

    More than 2 dozen years had passed since the field of antibody engineering was established, with the first reports of bacterial [1-3] and mammalian cells [4] expression of recombinant antibody fragments, and in that time a lot of effort was dedicated to the development of efficient technological means, intended to assist in the creation of therapeutic monoclonal antibodies (mAbs). Research focus was given to two intertwined technological aspects: the selection platform and the recombinant antibody repertoires. In accordance with these areas of interest, it is the goal of this chapter to describe the various selection tools and antibody libraries existing, with emphasis on the later, and their applications. This chapter gives a far from exhaustive, subjective "historic account" of the field, describing the selection platforms, the different formats of antibody repertoires and the applications of both for selecting recombinant antibodies. Several excellent books provide detailed protocols for constructing antibody libraries and selecting antibodies from those libraries [5-13]. Such books may guide a newcomer to the field in the fine details of antibody engineering. We would like to offer advice to the novice: although seemingly simple, effective library construction and antibody isolation provide best benefits in the hands of professionals. It is an art as much as it is science.

  6. Peptide Antibodies: Past, Present, and Future.

    PubMed

    Houen, Gunnar

    2015-01-01

    Peptide antibodies recognize epitopes with amino acid residues adjacent in sequence ("linear" epitopes). Such antibodies can be made to virtually any sequence and have been immensely important in all areas of molecular biology and diagnostics due to their versatility and to the rapid growth in protein sequence information. Today, peptide antibodies can be routinely and rapidly made to large numbers of peptides, including peptides with posttranslationally modified residues, and are used for immunoblotting, immunocytochemistry, immunohistochemistry, and immunoassays. In the future, peptide antibodies will continue to be immensely important for molecular biology, TCR- and MHC-like peptide antibodies may be produced routinely, peptide antibodies with predetermined conformational specificities may be designed, and peptide-based vaccines may become part of vaccination programs.

  7. [Evolution of monoclonal antibodies in cancer treatment].

    PubMed

    Kubczak, Małgorzata; Rogalińska, Małgorzata

    2016-01-01

    Since late 90s of last century the new age of directed therapy began using mainly biological constructs produced in rodents called monoclonal antibodies. The side effects of monoclonal antibodies were a challenge for pharmaceutical companies to improve the biological properties of these biological drugs. The humanization of monoclonal constructs was an idea to improve monoclonal antibodies next generation activity cancer cell reduction in humans. Moreover for some other patients sensitive for monoclonal antibodies therapy could also potentially induce immunological differences that might imply on human health. The new idea related to monoclonal antibodies was to design a small molecule constructs of nanoantibodies with ability to enter into cells. Such small molecules could find their targets inside human cells, even in nuclei leading to differences in cancer cells expression. The existing knowledge on monoclonal antibodies as well as directed activity of nanoantibodies could improve anticancer treatment efficancy of diseases.

  8. VARIANT: Command Line, Web service and Web interface for fast and accurate functional characterization of variants found by Next-Generation Sequencing

    PubMed Central

    Medina, Ignacio; De Maria, Alejandro; Bleda, Marta; Salavert, Francisco; Alonso, Roberto; Gonzalez, Cristina Y.; Dopazo, Joaquin

    2012-01-01

    The massive use of Next-Generation Sequencing (NGS) technologies is uncovering an unexpected amount of variability. The functional characterization of such variability, particularly in the most common form of variation found, the Single Nucleotide Variants (SNVs), has become a priority that needs to be addressed in a systematic way. VARIANT (VARIant ANalyis Tool) reports information on the variants found that include consequence type and annotations taken from different databases and repositories (SNPs and variants from dbSNP and 1000 genomes, and disease-related variants from the Genome-Wide Association Study (GWAS) catalog, Online Mendelian Inheritance in Man (OMIM), Catalog of Somatic Mutations in Cancer (COSMIC) mutations, etc). VARIANT also produces a rich variety of annotations that include information on the regulatory (transcription factor or miRNA-binding sites, etc.) or structural roles, or on the selective pressures on the sites affected by the variation. This information allows extending the conventional reports beyond the coding regions and expands the knowledge on the contribution of non-coding or synonymous variants to the phenotype studied. Contrarily to other tools, VARIANT uses a remote database and operates through efficient RESTful Web Services that optimize search and transaction operations. In this way, local problems of installation, update or disk size limitations are overcome without the need of sacrifice speed (thousands of variants are processed per minute). VARIANT is available at: http://variant.bioinfo.cipf.es. PMID:22693211

  9. Soluble Envelope Glycoprotein Trimers from a CD4-Independent HIV-1 Elicit Antibody-Dependent Cellular Cytotoxicity-Mediating Antibodies in Guinea Pigs

    PubMed Central

    Murray, Marta K.; Teran, Victor A.; Chapleau, Jean-Philippe; Wang, Baomin; Kim, Su Hyon; LaBranche, Celia C.; Richard, Jonathan; Montefiori, David C.

    2015-01-01

    CD4-independent HIV-1 variants can infect coreceptor-expressing cells lacking CD4. The envelope (Env) glycoproteins on these HIV-1 variants expose a coreceptor binding site that overlaps some CD4-induced (CD4i) epitopes. Reports have demonstrated that CD4i antibodies mediate antibody-dependent cellular cytotoxicity (ADCC). Here we investigated the immunogenicity of soluble Env trimers (sgp140) from a CD4-independent HIV-1 in guinea pigs and found that the sgp140 elicited ADCC-mediating antibodies. Therefore, these sgp140 might be useful in vaccine regimens aimed at eliciting ADCC responses. PMID:26246571

  10. Nonencapsulated Variant of Cryptococcus neoformans I. Virulence Studies and Characterization of Soluble Polysaccharide

    PubMed Central

    Kozel, Thomas R.; Cazin, John

    1971-01-01

    A weakly virulent nonencapsulated variant of Cryptococcus neoformans is described. The chemical structure and antigenicity of the soluble polysaccharides produced by the variant strain and a typical virulent strain were compared. The soluble polysaccharides produced by both strains were composed of the same constituent monosaccharides; however, the virulent strain produced a polysaccharide having a greater uronic acid content and a larger molecular size than that of the variant strain. Soluble polysaccharides from the two strains are not closely related immunologically. Soluble polysaccharide obtained from the virulent strain did not affect persistence of the variant strain in mice. PMID:16557967

  11. The Polymorphic Aggregative Phenotype of Shiga Toxin-Producing Escherichia coli O111 Depends on RpoS and Curli

    PubMed Central

    Diodati, M. E.; Bates, A. H.; Miller, W. G.; Carter, M. Q.; Zhou, Y.

    2015-01-01

    Escherichia coli O111 is an emerging non-O157:H7 serotype of Shiga toxin-producing E. coli (STEC). We previously reported that outbreak and environmental, but not sporadic-case, strains of STEC O111 share a distinct aggregation phenotype (M. E. Diodati, A. H. Bates, M. B. Cooley, S. Walker, R. E. Mandrell, and M. T. Brandl, Foodborne Pathog Dis 12:235−243, 2015, http://dx.doi.org/10.1089/fpd.2014.1887). We show here the natural occurrence of nonaggregative variants in single STEC O111 strains. These variants do not produce curli fimbriae and lack RpoS function but synthesize cellulose. The deletion of csgBAC or rpoS in an aggregative outbreak strain abolished aggregate formation, which was rescued when curli biogenesis or RpoS function, respectively, was restored. Complementation of a nonaggregative variant with RpoS also conferred curli production and aggregation. These observations were supported by Western blotting with an anti-CsgA antibody. Immunomicroscopy revealed that curli were undetectable on the cells of the nonaggregative variant and the RpoS mutant but were present in large quantities in the intercellular matrix of the assemblages formed by aggregative strains. Sequence analysis of rpoS in the aggregative strain and its variant showed a single substitution of threonine for asparagine at amino acid 124. Our results indicate that the multicellular behavior of STEC O111 is RpoS dependent via positive regulation of curli production. Aggregation may confer a fitness advantage in O111 outbreak strains under stressful conditions in hydrodynamic environments along the food production chain and in the host, while the occurrence of nonaggregative variants may allow the cell population to adapt to conditions benefiting a planktonic lifestyle. PMID:26712542

  12. Monoclonal antibodies and method for detecting dioxins and dibenzofurans

    DOEpatents

    Vanderlaan, Martin; Stanker, Larry H.; Watkins, Bruce E.; Bailey, Nina R.

    1989-01-01

    Compositions of matter are described which include five monoclonal antibodies that react with dioxins and dibenzofurans, and the five hybridomas that produce these monoclonal antibodies. In addition, a method for the use of these antibodies in a sensitive immunoassay for dioxins and dibenzofurans is given, which permits detection of these pollutants in samples at concentrations in the range of a few parts per billion.

  13. 21 CFR 866.5110 - Antiparietal antibody immunological test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...), atrophic gastritis (inflammation of the stomach), and autoimmune connective tissue diseases (diseases resulting when the body produces antibodies against its own tissues). (b) Classification. Class...

  14. Tropomyosin variants describe distinct functional subcellular domains in differentiated vascular smooth muscle cells.

    PubMed

    Gallant, Cynthia; Appel, Sarah; Graceffa, Philip; Leavis, Paul; Lin, Jim Jung-Ching; Gunning, Peter W; Schevzov, Galina; Chaponnier, Christine; DeGnore, Jon; Lehman, William; Morgan, Kathleen G

    2011-06-01

    Tropomyosin (Tm) is known to be an important gatekeeper of actin function. Tm isoforms are encoded by four genes, and each gene produces several variants by alternative splicing, which have been proposed to play roles in motility, proliferation, and apoptosis. Smooth muscle studies have focused on gizzard smooth muscle, where a heterodimer of Tm from the α-gene (Tmsm-α) and from the β-gene (Tmsm-β) is associated with contractile filaments. In this study we examined Tm in differentiated mammalian vascular smooth muscle (dVSM). Liquid chromatography-tandem mass spectrometry (LC MS/MS) analysis and Western blot screening with variant-specific antibodies revealed that at least five different Tm proteins are expressed in this tissue: Tm6 (Tmsm-α) and Tm2 from the α-gene, Tm1 (Tmsm-β) from the β-gene, Tm5NM1 from the γ-gene, and Tm4 from the δ-gene. Tm6 is by far most abundant in dVSM followed by Tm1, Tm2, Tm5NM1, and Tm4. Coimmunoprecipitation and coimmunofluorescence studies demonstrate that Tm1 and Tm6 coassociate with different actin isoforms and display different intracellular localizations. Using an antibody specific for cytoplasmic γ-actin, we report here the presence of a γ-actin cortical cytoskeleton in dVSM cells. Tm1 colocalizes with cortical cytoplasmic γ-actin and coprecipitates with γ-actin. Tm6, on the other hand, is located on contractile bundles. These data indicate that Tm1 and Tm6 do not form a classical heterodimer in dVSM but rather describe different functional cellular compartments.

  15. A case report of patient with cerebellar variant of stiff person syndrome.

    PubMed

    Maludzińska, Ewa; Rudzińska, Monika; Stępień, Artur; Szczudlik, Andrzej

    2016-01-01

    Stiff person syndrome (SPS) is a rare autoimmune neurological disorder with antibodies against antigens involved in neurotransmission of gamma-aminobutyric acid (GABA). About 10% of patients with SPS may develop ataxia. This cerebellar variant is a distinct subset of SPS with more severe and complex clinical phenotype. We report the clinical, neuropsychological and neuroradiological findings in a 39-year-old female with cerebellar variant of SPS.

  16. Quantification and simultaneous evaluation of the bioactivity of antibody produced in CHO cell culture-The use of the ectodomain of FcγRI and surface plasmon resonance-based biosensor.

    PubMed

    Dorion-Thibaudeau, July; Durocher, Yves; De Crescenzo, Gregory

    2017-02-01

    A surface plasmon resonance (SPR)-based assay has been developed in order to quantify the monoclonal antibody (Mab) Trastuzumab within the supernatant of a mammalian cell culture using the ectodomain of FcγRI (CD64) and confirm Mab bioactivity, i.e. binding to its antigen Her2, in a single biosensing experiment. Under partial mass transport limitation, we were able to quantify Mab present in unpurified samples taken throughout the cell culture. While Mab capture on the biosensor surface confirmed the ability of its Fc region to bind to FcγRI, the binding activity of its Fab region was also tested by injecting increasing concentrations of the Mab antigen (Her2). The kinetics of the interactions we recorded from 48h post transfection until the end of the culture, were superimposable, which highly suggested that the quality attributes of the antibody were conserved throughout the process. This SPR methodology is thus of great interest for atline quality control analysis during Mab production campaign.

  17. Molecular-specific urokinase antibodies

    NASA Technical Reports Server (NTRS)

    Atassi, M. Zouhair (Inventor); Morrison, Dennis R. (Inventor)

    2009-01-01

    Antibodies have been developed against the different molecular forms of urokinase using synthetic peptides as immunogens. The peptides were synthesized specifically to represent those regions of the urokinase molecules which are exposed in the three-dimensional configuration of the molecule and are uniquely homologous to urokinase. Antibodies are directed against the lysine 158-isoleucine 159 peptide bond which is cleaved during activation from the single-chain (ScuPA) form to the bioactive double chain (54 KDa and 33 KDa) forms of urokinase and against the lysine 135 lysine 136 bond that is cleaved in the process of removing the alpha-chain from the 54 KDa form to produce the 33 KDa form of urokinase. These antibodies enable the direct measurement of the different molecular forms of urokinase from small samples of conditioned medium harvested from cell cultures.

  18. Back to the future: recombinant polyclonal antibody therapeutics

    PubMed Central

    Wang, Xian-zhe; Coljee, Vincent W.; Maynard, Jennifer A.

    2013-01-01

    Antibody therapeutics are one of the fastest growing classes of pharmaceuticals, with an annual US market over $20 billion, developed to treat a variety of diseases including cancer, auto-immune and infectious diseases. Most are currently administered as a single molecule to treat a single disease, however there is mounting evidence that cocktails of multiple antibodies, each with a unique binding specificity and protective mechanism, may improve clinical efficacy. Here, we review progress in the development of oligoclonal combinations of antibodies to treat disease, focusing on identification of synergistic antibodies. We then discuss the application of modern antibody engineering technologies to produce highly potent antibody preparations, including oligoclonal antibody cocktails and truly recombinant polyclonal antibodies. Specific examples illustrating the synergy conferred by multiple antibodies will be provided for diseases caused by botulinum toxin, cancer and immune thrombocytopenia. The bioprocessing and regulatory options for these preparations will be discussed. PMID:24443710

  19. An update on pathobiologic roles of anti-glycan antibodies in Guillain-Barré syndrome

    PubMed Central

    Zhang, Gang

    2010-01-01

    Anti-glycan antibodies directed against gangliosides are now considered the major immune effectors that induce damage to intact nerve fibers in some variants of the monophasic neuropathic disorders that comprise Guillain-Barré syndrome. Recent experimental studies elucidating the complexity of anti-glycan antibody-mediated pathobiologic effects on intact and injured nerves undergoing repair are discussed. PMID:20948812

  20. Group B streptococcal opacity variants.

    PubMed Central

    Pincus, S H; Cole, R L; Wessels, M R; Corwin, M D; Kamanga-Sollo, E; Hayes, S F; Cieplak, W; Swanson, J

    1992-01-01

    Colony opacity variants were detected for type III group B streptococci (GBS). Transparent colonies predominate in the parent GBS, with occasional colonies having opaque portions. Two stable opaque variants (1.1 and 1.5) were compared with three transparent clones (1.2, 1.3, and 1.4). All grew well on blood agar and on GC medium, but variant 1.1 failed to grow on Todd-Hewitt medium. Scanning and transmission electron microscopy demonstrated that colony opacity correlated with bacterial aggregation status, with opaque variants forming longer and more organized chains. Opaque-transparent switches were observed in both directions for most variants, with transparent to opaque noted most frequently, but 1.5 did not switch at all. Switching of the opacity phenotype was observed both in vitro and in neonatal mice. Relationships between colony opacity and several cell surface phenomena were explored. (i) Opaque variant 1.1 had two surface proteins (46 and 75 kDa) that were either unique or greatly overexpressed. (ii) Variant 1.1 was deficient in type III polysaccharide, while 1.5 lacked group B antigen. Diminished capsular polysaccharide of variant 1.1 was reflected in reduced negative electrophoretic mobility and in increased buoyant density. (iii) Transparent variant colonies growing closest to a penicillin disk were opaque, but colonial variants did not differ in their sensitivity to penicillin. These data indicate that GBS can exist in both opaque and transparent forms, with opaque appearance occurring by multiple routes. Opaque variants grow poorly on Todd-Hewitt medium generally used for isolation of GBS, so any possible relationships between opacity variation and pathogenesis of GBS infection are unknown. Images PMID:1592825

  1. Variants of windmill nystagmus.

    PubMed

    Choi, Kwang-Dong; Shin, Hae Kyung; Kim, Ji-Soo; Kim, Sung-Hee; Choi, Jae-Hwan; Kim, Hyo-Jung; Zee, David S

    2016-07-01

    Windmill nystagmus is characterized by a clock-like rotation of the beating direction of a jerk nystagmus suggesting separate horizontal and vertical oscillators, usually 90° out of phase. We report oculographic characteristics in three patients with variants of windmill nystagmus in whom the common denominator was profound visual loss due to retinal diseases. Two patients showed a clock-like pattern, while in the third, the nystagmus was largely diagonal (in phase or 180° out of phase) but also periodically changed direction by 180°. We hypothesize that windmill nystagmus is a unique manifestation of "eye movements of the blind." It emerges when the central structures, including the cerebellum, that normally keep eye movements calibrated and gaze steady can no longer perform their task, because they are deprived of the retinal image motion that signals a need for adaptive recalibration.

  2. Structural comparisons of two allelic variants of human placental alkaline phosphatase.

    PubMed

    Millán, J L; Stigbrand, T; Jörnvall, H

    1985-01-01

    A simple immunosorbent purification scheme based on monoclonal antibodies has been devised for human placental alkaline phosphatase. The two most common allelic variants, S and F, have similar amino acid compositions with identical N-terminal amino acid sequences through the first 13 residues. Both variants have identical lectin binding properties towards concanavalin A, lentil-lectin, wheat germ agglutinin, phytohemagglutinin and soybean agglutinin, and identical carbohydrate contents as revealed by methylation analysis. CNBr fragments of the variants demonstrate identical high performance liquid chromatography patterns. The carbohydrate containing fragment is different from the 32P-labeled active site fragment and the N-terminal fragment.

  3. Murine monoclonal antibodies against murine uPA receptor produced in gene-deficient mice: inhibitory effects on receptor-mediated uPA activity in vitro and in vivo.

    PubMed

    Pass, Jesper; Jögi, Annika; Lund, Ida K; Rønø, Birgitte; Rasch, Morten G; Gårdsvoll, Henrik; Lund, Leif R; Ploug, Michael; Rømer, John; Danø, Keld; Høyer-Hansen, Gunilla

    2007-06-01

    Binding of urokinase plasminogen activator (uPA) to its cellular receptor, uPAR, potentiates plasminogen activation and localizes it to the cell surface. Focal plasminogen activation is involved in both normal and pathological tissue remodeling processes including cancer invasion. The interaction between uPA and uPAR therefore represents a potential target for anti-invasive cancer therapy. Inhibitors of the human uPA-uPAR interaction have no effect in the murine system. To enable in-vivo studies in murine cancer models we have now generated murine monoclonal antibodies (mAbs) against murine uPAR (muPAR) by immunizing uPAR-deficient mice with recombinant muPAR and screened for antibodies, which inhibit the muPA-muPAR interaction. Two of the twelve mAbs obtained, mR1 and mR2, interfered with the interaction between muPAR and the amino-terminal fragment of muPA (mATF) when analyzed by surface plasmon resonance. The epitope for mR1 is located on domain I of muPAR, while that of mR2 is on domains (II-III). In cell binding experiments using radiolabelled mATF, the maximal inhibition obtained with mR1 was 85% while that obtained with mR2 was 50%. The IC(50) value for mR1 was 0.67 nM compared to 0.14 nM for mATF. In an assay based on modified anthrax toxins, requiring cell-bound muPA activity for its cytotoxity, an approximately 50% rescue of the cells could be obtained by addition of mR1. Importantly, in-vivo efficacy of mR1 was demonstrated by the ability of mR1 to rescue mice treated with a lethal dose of uPA-activatable anthrax toxins.

  4. Election 2016: Voting on Variants.

    PubMed

    Cho, Raymond J; Collisson, Eric A

    2016-07-01

    Genome sequencing studies increasingly identify variants of unknown significance in provocative genes. Kim and colleagues present a system with which to functionally annotate such variants in a high-throughput, biologically relevant series of assays. Cancer Discov; 6(7); 694-6. ©2016 AACRSee related article by Kim et al., p. 714.

  5. Harnessing gene conversion in chicken B cells to create a human antibody sequence repertoire.

    PubMed

    Schusser, Benjamin; Yi, Henry; Collarini, Ellen J; Izquierdo, Shelley Mettler; Harriman, William D; Etches, Robert J; Leighton, Philip A

    2013-01-01

    Transgenic chickens expressing human sequence antibodies would be a powerful tool to access human targets and epitopes that have been intractable in mammalian hosts because of tolerance to conserved proteins. To foster the development of the chicken platform, it is beneficial to validate transgene constructs using a rapid, cell culture-based method prior to generating fully transgenic birds. We describe a method for the expression of human immunoglobulin variable regions in the chicken DT40 B cell line and the further diversification of these genes by gene conversion. Chicken VL and VH loci were knocked out in DT40 cells and replaced with human VK and VH genes. To achieve gene conversion of human genes in chicken B cells, synthetic human pseudogene arrays were inserted upstream of the functional human VK and VH regions. Proper expression of chimeric IgM comprised of human variable regions and chicken constant regions is shown. Most importantly, sequencing of DT40 genetic variants confirmed that the human pseudogene arrays contributed to the generation of diversity through gene conversion at both the Igl and Igh loci. These data show that engineered pseudogene arrays produce a diverse pool of human antibody sequences in chicken B cells, and suggest that these constructs will express a functional repertoire of chimeric antibodies in transgenic chickens.

  6. High level transient production of recombinant antibodies and antibody fusion proteins in HEK293 cells

    PubMed Central

    2013-01-01

    Background The demand of monospecific high affinity binding reagents, particularly monoclonal antibodies, has been steadily increasing over the last years. Enhanced throughput of antibody generation has been addressed by optimizing in vitro selection using phage display which moved the major bottleneck to the production and purification of recombinant antibodies in an end-user friendly format. Single chain (sc)Fv antibody fragments require additional tags for detection and are not as suitable as immunoglobulins (Ig)G in many immunoassays. In contrast, the bivalent scFv-Fc antibody format shares many properties with IgG and has a very high application compatibility. Results In this study transient expression of scFv-Fc antibodies in human embryonic kidney (HEK) 293 cells was optimized. Production levels of 10-20 mg/L scFv-Fc antibody were achieved in adherent HEK293T cells. Employment of HEK293-6E suspension cells expressing a truncated variant of the Epstein Barr virus (EBV) nuclear antigen (EBNA) 1 in combination with production under serum free conditions increased the volumetric yield up to 10-fold to more than 140 mg/L scFv-Fc antibody. After vector optimization and process optimization the yield of an scFv-Fc antibody and a cytotoxic antibody-RNase fusion protein further increased 3-4-fold to more than 450 mg/L. Finally, an entirely new mammalian expression vector was constructed for single step in frame cloning of scFv genes from antibody phage display libraries. Transient expression of more than 20 different scFv-Fc antibodies resulted in volumetric yields of up to 600 mg/L and 400 mg/L in average. Conclusion Transient production of recombinant scFv-Fc antibodies in HEK293-6E in combination with optimized vectors and fed batch shake flasks cultivation is efficient and robust, and integrates well into a high-throughput recombinant antibody generation pipeline. PMID:23802841

  7. Antibodies and antibody-derived analytical biosensors

    PubMed Central

    Sharma, Shikha; Byrne, Hannah

    2016-01-01

    The rapid diagnosis of many diseases and timely initiation of appropriate treatment are critical determinants that promote optimal clinical outcomes and general public health. Biosensors are now being applied for rapid diagnostics due to their capacity for point-of-care use with minimum need for operator input. Antibody-based biosensors or immunosensors have revolutionized diagnostics for the detection of a plethora of analytes such as disease markers, food and environmental contaminants, biological warfare agents and illicit drugs. Antibodies are ideal biorecognition elements that provide sensors with high specificity and sensitivity. This review describes monoclonal and recombinant antibodies and different immobilization approaches crucial for antibody utilization in biosensors. Examples of applications of a variety of antibody-based sensor formats are also described. PMID:27365031

  8. Current status of radioligand antibodies in the treatment of malignancy

    SciTech Connect

    Maners, A.W.; Sanders, M.M.; Pappas, A.A.

    1988-01-01

    Monoclonal anti-tumor antibodies labeled with a radioactive moiety present an exciting new approach to cancer therapy. With the advent of hybridoma technology, monoclonal antibodies can now be produced in quantity. Indeed, antibodies against tumor-related and tumor-specific antigens have been produced, labeled with a radioactive substance, and used therapeutically. The rationale for this therapeutic approach and the results of human clinical trials will be reported herein.27 references.

  9. Platelet associated antibodies

    MedlinePlus

    ... medlineplus.gov/ency/article/003552.htm Platelet-associated antibodies blood test To use the sharing features on ... JavaScript. This blood test shows if you have antibodies against platelets in your blood. Platelets are a ...

  10. Lyme disease antibody

    MedlinePlus

    ... JavaScript. The Lyme disease blood test looks for antibodies in the blood to the bacteria that causes ... needed. A laboratory specialist looks for Lyme disease antibodies in the blood sample using the ELISA test . ...

  11. Antiparietal cell antibody test

    MedlinePlus

    ... Gastric ulcer - anti-gastric parietal cell antibody; Pernicious anemia - anti-gastric parietal cell antibody; Vitamin B12 - anti- ... may use this test to help diagnose pernicious anemia. Pernicious anemia is a decrease in red blood ...

  12. Cellobiohydrolase variants and polynucleotides encoding same

    DOEpatents

    Wogulis, Mark

    2013-09-24

    The present invention relates to variants of a parent cellobiohydrolase II. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.

  13. Cellobiohydrolase variants and polynucleotides encoding same

    DOEpatents

    Wogulis, Mark

    2014-10-14

    The present invention relates to variants of a parent cellobiohydrolase II. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.

  14. Cellobiohydrolase variants and polynucleotides encoding the same

    DOEpatents

    Wogulis, Mark

    2014-09-09

    The present invention relates to variants of a parent cellobiohydrolase. The present invention also relates to polynucleotides encoding the cellobiohydrolase variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the cellobiohydrolase variants.

  15. Macrophages are critical effectors of antibody therapies for cancer.

    PubMed

    Weiskopf, Kipp; Weissman, Irving L

    2015-01-01

    Macrophages are innate immune cells that derive from circulating monocytes, reside in all tissues, and participate in many states of pathology. Macrophages play a dichotomous role in cancer, where they promote tumor growth but also serve as critical immune effectors of therapeutic antibodies. Macrophages express all classes of Fcγ receptors, and they have immense potential to destroy tumors via the process of antibody-dependent phagocytosis. A number of studies have demonstrated that macrophage phagocytosis is a major mechanism of action of many antibodies approved to treat cancer. Consequently, a number of approaches to augment macrophage responses to therapeutic antibodies are under investigation, including the exploration of new targets and development of antibodies with enhanced functions. For example, the interaction of CD47 with signal-regulatory protein α (SIRPα) serves as a myeloid-specific immune checkpoint that limits the response of macrophages to antibody therapies, and CD47-blocking agents overcome this barrier to augment phagocytosis. The response of macrophages to antibody therapies can also be enhanced with engineered Fc variants, bispecific antibodies, or antibody-drug conjugates. Macrophages have demonstrated success as effectors of cancer immunotherapy, and further investigation will unlock their full potential for the benefit of patients.

  16. Prospects for engineering HIV-specific antibodies for enhanced effector function and half-life

    PubMed Central

    Boesch, Austin W.; Alter, Galit; Ackerman, Margaret E.

    2015-01-01

    Purpose of review A wealth of recent animal model data suggests that as exciting possibilities for the use of antibodies in passive immunotherapy strategies continue to develop, it will be important to broadly consider how antibodies achieve anti-HIV-1 effect in vivo. Recent findings Beyond neutralization breadth and potency, substantial evidence from natural infection, vaccination, and studies in animal models points to a critical role for antibody Fc receptor (FcR) engagement in reducing risk of infection, decreasing postinfection viremia, and delaying viral rebound. Supporting these findings in the setting of HIV, the clinical maturation of recombinant antibody therapeutics has reinforced the importance of Fc-driven activity in vivo across many disease settings, as well as opportunely resulted in the development and exploration of a number of engineered Fc sequence and glycosylation variants that possess differential binding to FcRs. Exploiting these variants as tools, the individual and concerted effects of antibody effector functions such as antibody-dependent cellular cytotoxicity, antibody-dependent cell-mediated virus inhibition, phagocytosis, complement-dependent cytotoxicity, antibody half-life, and compartmentalization are now being explored. As exciting molecular therapies are advanced, these studies promise to provide insight into optimal in-vivo antibody activity profiles. Summary Careful consideration of recent progress in understanding protective antibody activities in vivo can point toward how tailoring antibody activity via Fc domain modification may enable optimization of HIV prevention and eradication strategies. PMID:25700208

  17. Rare Copy Number Variants

    PubMed Central

    Grozeva, Detelina; Kirov, George; Ivanov, Dobril; Jones, Ian R.; Jones, Lisa; Green, Elaine K.; St Clair, David M.; Young, Allan H.; Ferrier, Nicol; Farmer, Anne E.; McGuffin, Peter; Holmans, Peter A.; Owen, Michael J.; O’Donovan, Michael C.; Craddock, Nick

    2015-01-01

    Context Recent studies suggest that copy number variation in the human genome is extensive and may play an important role in susceptibility to disease, including neuropsychiatric disorders such as schizophrenia and autism. The possible involvement of copy number variants (CNVs) in bipolar disorder has received little attention to date. Objectives To determine whether large (>100 000 base pairs) and rare (found in <1% of the population) CNVs are associated with susceptibility to bipolar disorder and to compare with findings in schizophrenia. Design A genome-wide survey of large, rare CNVs in a case-control sample using a high-density microarray. Setting The Wellcome Trust Case Control Consortium. Participants There were 1697 cases of bipolar disorder and 2806 nonpsychiatric controls. All participants were white UK residents. Main Outcome Measures Overall load of CNVs and presence of rare CNVs. Results The burden of CNVs in bipolar disorder was not increased compared with controls and was significantly less than in schizophrenia cases. The CNVs previously implicated in the etiology of schizophrenia were not more common in cases with bipolar disorder. Conclusions Schizophrenia and bipolar disorder differ with respect to CNV burden in general and association with specific CNVs in particular. Our data are consistent with the possibility that possession of large, rare deletions may modify the phenotype in those at risk of psychosis: those possessing such events are more likely to be diagnosed as having schizophrenia, and those without them are more likely to be diagnosed as having bipolar disorder. PMID:20368508

  18. Modeling Antibody Diversity.

    ERIC Educational Resources Information Center

    Baker, William P.; Moore, Cathy Ronstadt

    1998-01-01

    Understanding antibody structure and function is difficult for many students. The rearrangement of constant and variable regions during antibody differentiation can be effectively simulated using a paper model. Describes a hands-on laboratory exercise which allows students to model antibody diversity using readily available resources. (PVD)

  19. RBC Antibody Screen

    MedlinePlus

    ... Cell Antibody Screen Related tests: Direct Antiglobulin Test ; Blood Typing ; RBC Antibody Identification ; Type and Screen; Crossmatch All content on Lab Tests Online has been reviewed and approved by our Editorial Review Board . At a ... screen is used to screen an individual's blood for antibodies directed against red blood cell (RBC) ...

  20. Heteromorphic variants of chromosome 9

    PubMed Central

    2013-01-01

    Background Heterochromatic variants of pericentromere of chromosome 9 are reported and discussed since decades concerning their detailed structure and clinical meaning. However, detailed studies are scarce. Thus, here we provide the largest ever done molecular cytogenetic research based on >300 chromosome 9 heteromorphism carriers. Results In this study, 334 carriers of heterochromatic variants of chromosome 9 were included, being 192 patients from Western Europe and the remainder from Easter-European origin. A 3-color-fluorescence in situ hybridization (FISH) probe-set directed against for 9p12 to 9q13~21.1 (9het-mix) and 8 different locus-specific probes were applied for their characterization. The 9het-mix enables the characterization of 21 of the yet known 24 chromosome 9 heteromorphic patterns. In this study, 17 different variants were detected including five yet unreported; the most frequent were pericentric inversions (49.4%) followed by 9qh-variants (23.9%), variants of 9ph (11.4%), cenh (8.2%), and dicentric- (3.8%) and duplication-variants (3.3%). For reasons of simplicity, a new short nomenclature for the yet reported 24 heteromorphic patterns of chromosome 9 is suggested. Six breakpoints involved in four of the 24 variants could be narrowed down using locus-specific probes. Conclusions Based on this largest study ever done in carriers of chromosome 9 heteromorphisms, three of the 24 detailed variants were more frequently observed in Western than in Eastern Europe. Besides, there is no clear evidence that infertility is linked to any of the 24 chromosome 9 heteromorphic variants. PMID:23547710

  1. Gut Microbial Metabolites Fuel Host Antibody Responses.

    PubMed

    Kim, Myunghoo; Qie, Yaqing; Park, Jeongho; Kim, Chang H

    2016-08-10

    Antibody production is a metabolically demanding process that is regulated by gut microbiota, but the microbial products supporting B cell responses remain incompletely identified. We report that short-chain fatty acids (SCFAs), produced by gut microbiota as fermentation products of dietary fiber, support host antibody responses. In B cells, SCFAs increase acetyl-CoA and regulate metabolic sensors to increase oxidative phosphorylation, glycolysis, and fatty acid synthesis, which produce energy and building blocks supporting antibody production. In parallel, SCFAs control gene expression to express molecules necessary for plasma B cell differentiation. Mice with low SCFA production due to reduced dietary fiber consumption or microbial insufficiency are defective in homeostatic and pathogen-specific antibody responses, resulting in greater pathogen susceptibility. However, SCFA or dietary fiber intake restores this immune deficiency. This B cell-helping function of SCFAs is detected from the intestines to systemic tissues and conserved among mouse and human B cells, highlighting its importance.

  2. Solid phase synthesis of bifunctional antibodies.

    PubMed

    DeSilva, B S; Wilson, G S

    1995-12-15

    Bifunctional antibodies were prepared using the principle of solid-phase synthesis. The two Fab' fragments were chemically linked together via a bismaleimide crosslinking reagent. The F(ab')2 fragments from intact IgG were prepared using an immobilized pepsin column. Goat, mouse and human antibodies were digested completely within 4 h. The F(ab')2 fragments thus produced did not contain any IgG impurities. The Fab' fragments were produced by reducing the inter-heavy chain disulfide bonds using 2-mercaptoethylamine. The use of the solid-phase reactor in the preparation of the bifunctional antibodies eliminated many of the time-consuming separation steps between the fragmentation and conjugation steps. This procedure facilitates the automation of the bifunctional antibody preparation and the rapid optimization of reaction conditions.

  3. Synthesis of bifunctional antibodies for immunoassays.

    PubMed

    DeSilva, B S; Wilson, G S

    2000-09-01

    The synthesis of bifunctional antibodies using the principle of solid-phase synthesis is described. Two Fab' fragments were chemically linked together via a bismaleimide crosslinking reagent. The F(ab')(2) fragments from intact immunoglobulin G (IgG) were prepared using an immobilized pepsin column. Goat, mouse, and human antibodies were digested completely within 4 h. The F(ab')(2) fragments thus produced did not contain any IgG impurities. Fab' fragments were produced by reducing the heavy interchain disulfide bonds using 2-mercaptoethylamine. Use of the solid-phase reactor in the preparation of the bifunctional antibodies eliminated many of the time-consuming separation steps between the fragmentation and conjugation steps. This procedure facilitates the automation of bifunctional antibody preparation and the rapid optimization of reaction conditions.

  4. Primary Aldosteronism and ARMC5 Variants

    PubMed Central

    Zilbermint, Mihail; Xekouki, Paraskevi; Faucz, Fabio R.; Berthon, Annabel; Gkourogianni, Alexandra; Schernthaner-Reiter, Marie Helene; Batsis, Maria; Sinaii, Ninet; Quezado, Martha M.; Merino, Maria; Hodes, Aaron; Abraham, Smita B.; Libé, Rossella; Assié, Guillaume; Espiard, Stéphanie; Drougat, Ludivine; Ragazzon, Bruno; Davis, Adam; Gebreab, Samson Y.; Neff, Ryan; Kebebew, Electron; Bertherat, Jérôme; Lodish, Maya B.

    2015-01-01

    Context: Primary aldosteronism is one of the leading causes of secondary hypertension, causing significant morbidity and mortality. A number of genetic defects have recently been identified in primary aldosteronism, whereas we identified mutations in ARMC5, a tumor-suppressor gene, in cortisol-producing primary macronodular adrenal hyperplasia. Objective: We investigated a cohort of 56 patients who were referred to the National Institutes of Health for evaluation of primary aldosteronism for ARMC5 defects. Methods: Patients underwent step-wise diagnosis, with measurement of serum aldosterone and plasma renin activity followed by imaging, saline suppression and/or oral salt loading tests, plus adrenal venous sampling. Cortisol secretion was also evaluated; unilateral or bilateral adrenalectomy was performed, if indicated. DNA, protein, and transfection studies in H295R cells were conducted by standard methods. Results: We identified 12 germline ARMC5 genetic alterations in 20 unrelated and two related individuals in our cohort (39.3%). ARMC5 sequence changes in 6 patients (10.7%) were predicted to be damaging by in silico analysis. All affected patients carrying a variant predicted to be damaging were African Americans (P = .0023). Conclusions: Germline ARMC5 variants may be associated with primary aldosteronism. Additional cohorts of patients with primary aldosteronism and metabolic syndrome, particularly African Americans, should be screened for ARMC5 sequence variants because these may underlie part of the known increased predisposition of African Americans to low renin hypertension. PMID:25822102

  5. Variants of beta-glucosidases

    SciTech Connect

    Fidantsef, Ana; Lamsa, Michael; Gorre-Clancy, Brian

    2014-10-07

    The present invention relates to variants of a parent beta-glucosidase, comprising a substitution at one or more positions corresponding to positions 142, 183, 266, and 703 of amino acids 1 to 842 of SEQ ID NO: 2 or corresponding to positions 142, 183, 266, and 705 of amino acids 1 to 844 of SEQ ID NO: 70, wherein the variant has beta-glucosidase activity. The present invention also relates to nucleotide sequences encoding the variant beta-glucosidases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  6. Variants of beta-glucosidase

    SciTech Connect

    Fidantsef, Ana; Lamsa, Michael; Gorre-Clancy, Brian

    2015-07-14

    The present invention relates to variants of a parent beta-glucosidase, comprising a substitution at one or more positions corresponding to positions 142, 183, 266, and 703 of amino acids 1 to 842 of SEQ ID NO: 2 or corresponding to positions 142, 183, 266, and 705 of amino acids 1 to 844 of SEQ ID NO: 70, wherein the variant has beta-glucosidase activity. The present invention also relates to nucleotide sequences encoding the variant beta-glucosidases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  7. Variants of beta-glucosidase

    DOEpatents

    Fidantsef, Ana; Lamsa, Michael; Gorre-Clancy, Brian

    2009-12-29

    The present invention relates to variants of a parent beta-glucosidase, comprising a substitution at one or more positions corresponding to positions 142, 183, 266, and 703 of amino acids 1 to 842 of SEQ ID NO: 2 or corresponding to positions 142, 183, 266, and 705 of amino acids 1 to 844 of SEQ ID NO: 70, wherein the variant has beta-glucosidase activity. The present invention also relates to nucleotide sequences encoding the variant beta-glucosidases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  8. Variants of beta-glucosidases

    DOEpatents

    Fidantsef, Ana; Lamsa, Michael; Clancy, Brian Gorre

    2008-08-19

    The present invention relates to variants of a parent beta-glucosidase, comprising a substitution at one or more positions corresponding to positions 142, 183, 266, and 703 of amino acids 1 to 842 of SEQ ID NO: 2 or corresponding to positions 142, 183, 266, and 705 of amino acids 1 to 844 of SEQ ID NO: 70, wherein the variant has beta-glucosidase activity. The present invention also relates to nucleotide sequences encoding the variant beta-glucosidases and to nucleic acid constructs, vectors, and host cells comprising the nucleotide sequences.

  9. Anti-insulin antibody test

    MedlinePlus

    Insulin antibodies - serum; Insulin Ab test; Insulin resistance - insulin antibodies; Diabetes - insulin antibodies ... Normally, there are no antibodies against insulin in your blood. ... different laboratories. Some labs use different measurements or ...

  10. CHO expression of a novel human recombinant IgG1 anti-RhD antibody isolated by phage display.

    PubMed

    Miescher, S; Zahn-Zabal, M; De Jesus, M; Moudry, R; Fisch, I; Vogel, M; Kobr, M; Imboden, M A; Kragten, E; Bichler, J; Mermod, N; Stadler, B M; Amstutz, H; Wurm, F

    2000-10-01

    Replacement of the hyperimmune anti-Rhesus (Rh) D immunoglobulin, currently used to prevent haemolytic disease of the newborn, by fully recombinant human anti-RhD antibodies would solve the current logistic problems associated with supply and demand. The combination of phage display repertoire cloning with precise selection procedures enables isolation of specific genes that can then be inserted into mammalian expression systems allowing production of large quantities of recombinant human proteins. With the aim of selecting high-affinity anti-RhD antibodies, two human Fab libraries were constructed from a hyperimmune donor. Use of a new phage panning procedure involving bromelin-treated red blood cells enabled the isolation of two high-affinity Fab-expressing phage clones. LD-6-3 and LD-6-33, specific for RhD. These showed a novel reaction pattern by recognizing the D variants D(III), D(IVa), D(IVb), D(Va), D(VI) types I and II. D(VII), Rh33 and DFR. Full-length immunoglobulin molecules were constructed by cloning the variable regions into expression vectors containing genomic DNA encoding the immunoglobulin constant regions. We describe the first, stable, suspension growth-adapted Chinese hamster ovary (CHO) cell line producing a high affinity recombinant human IgG1 anti-RhD antibody adapted to pilot-scale production. Evaluation of the Fc region of this recombinant antibody by either chemiluminescence or antibody-dependent cell cytotoxicity (ADCC) assays demonstrated macrophage activation and lysis of red blood cells by human lymphocytes. A consistent source of recombinant human anti-RhD immunoglobulin produced by CHO cells is expected to meet the stringent safety and regulatory requirements for prophylactic application.

  11. Microscale purification of antigen-specific antibodies.

    PubMed

    Brown, Eric P; Normandin, Erica; Osei-Owusu, Nana Yaw; Mahan, Alison E; Chan, Ying N; Lai, Jennifer I; Vaccari, Monica; Rao, Mangala; Franchini, Genoveffa; Alter, Galit; Ackerman, Margaret E

    2015-10-01

    Glycosylation of the Fc domain is an important driver of antibody effector function. While assessment of antibody glycoform compositions observed across total plasma IgG has identified differences associated with a variety of clinical conditions, in many cases it is the glycosylation state of only antibodies against a specific antigen or set of antigens that may be of interest, for example, in defining the potential effector function of antibodies produced during disease or after vaccination. Historically, glycoprofiling such antigen-specific antibodies in clinical samples has been challenging due to their low prevalence, the high sample requirement for most methods of glycan determination, and the lack of high-throughput purification methods. New methods of glycoprofiling with lower sample requirements and higher throughput have motivated the development of microscale and automatable methods for purification of antigen-specific antibodies from polyclonal sources such as clinical serum samples. In this work, we present a robot-compatible 96-well plate-based method for purification of antigen-specific antibodies, suitable for such population level glycosylation screening. We demonstrate the utility of this method across multiple antibody sources, using both purified plasma IgG and plasma, and across multiple different antigen types, with enrichment factors greater than 1000-fold observed. Using an on-column IdeS protease treatment, we further describe staged release of Fc and Fab domains, allowing for glycoprofiling of each domain.

  12. Microscale purification of antigen-specific antibodies

    PubMed Central

    Brown, Eric P.; Normandin, Erica; Osei-Owusu, Nana Yaw; Mahan, Alison E.; Chan, Ying N.; Lai, Jennifer I.; Vaccari, Monica; Rao, Mangala; Franchini, Genoveffa; Alter, Galit; Ackerman, Margaret E.

    2015-01-01

    Glycosylation of the Fc domain is an important driver of antibody effector function. While assessment of antibody glycoform compositions observed across total plasma IgG has identified differences associated with a variety of clinical conditions, in many cases it is the glycosylation state of only antibodies against a specific antigen or set of antigens that may be of interest, for example, in defining the potential effector function of antibodies produced during disease or after vaccination. Historically, glycoprofiling such antigen-specific antibodies in clinical samples has been challenging due to their low prevalence, the high sample requirement for most methods of glycan determination, and the lack of high-throughput purification methods. New methods of glycoprofiling with lower sample requirements and higher throughput have motivated the development of microscale and automatable methods for purification of antigen-specific antibodies from polyclonal sources such as clinical serum samples. In this work, we present a robot-compatible 96-well plate-based method for purification of antigen-specific antibodies, suitable for such population level glycosylation screening. We demonstrate the utility of this method across multiple antibody sources, using both purified plasma IgG and plasma, and across multiple different antigen types, with enrichment factors greater than 1000-fold observed. Using an on-column IdeS protease treatment, we further describe staged release of Fc and Fab domains, allowing for glycoprofiling of each domain. PMID:26078040

  13. Meta-analysis of Gene-Level Associations for Rare Variants Based on Single-Variant Statistics

    PubMed Central

    Hu, Yi-Juan; Berndt, Sonja I.; Gustafsson, Stefan; Ganna, Andrea; Berndt, Sonja I.; Gustafsson, Stefan; Mägi, Reedik; Ganna, Andrea; Wheeler, Eleanor; Feitosa, Mary F.; Justice, Anne E.; Monda, Keri L.; Croteau-Chonka, Damien C.; Day, Felix R.; Esko, Tõnu; Fall, Tove; Ferreira, Teresa; Gentilini, Davide; Jackson, Anne U.; Luan, Jian’an; Randall, Joshua C.; Vedantam, Sailaja; Willer, Cristen J.; Winkler, Thomas W.; Wood, Andrew R.; Workalemahu, Tsegaselassie; Hu, Yi-Juan; Lee, Sang Hong; Liang, Liming; Lin, Dan-Yu; Min, Josine L.; Neale, Benjamin M.; Thorleifsson, Gudmar; Yang, Jian; Albrecht, Eva; Amin, Najaf; Bragg-Gresham, Jennifer L.; Cadby, Gemma; den Heijer, Martin; Eklund, Niina; Fischer, Krista; Goel, Anuj; Hottenga, Jouke-Jan; Huffman, Jennifer E.; Jarick, Ivonne; Johansson, Åsa; Johnson, Toby; Kanoni, Stavroula; Kleber, Marcus E.; König, Inke R.; Kristiansson, Kati; Kutalik, Zoltán; Lamina, Claudia; Lecoeur, Cecile; Li, Guo; Mangino, Massimo; McArdle, Wendy L.; Medina-Gomez, Carolina; Müller-Nurasyid, Martina; Ngwa, Julius S.; Nolte, Ilja M.; Paternoster, Lavinia; Pechlivanis, Sonali; Perola, Markus; Peters, Marjolein J.; Preuss, Michael; Rose, Lynda M.; Shi, Jianxin; Shungin, Dmitry; Smith, Albert Vernon; Strawbridge, Rona J.; Surakka, Ida; Teumer, Alexander; Trip, Mieke D.; Tyrer, Jonathan; Van Vliet-Ostaptchouk, Jana V.; Vandenput, Liesbeth; Waite, Lindsay L.; Zhao, Jing Hua; Absher, Devin; Asselbergs, Folkert W.; Atalay, Mustafa; Attwood, Antony P.; Balmforth, Anthony J.; Basart, Hanneke; Beilby, John; Bonnycastle, Lori L.; Brambilla, Paolo; Bruinenberg, Marcel; Campbell, Harry; Chasman, Daniel I.; Chines, Peter S.; Collins, Francis S.; Connell, John M.; Cookson, William; de Faire, Ulf; de Vegt, Femmie; Dei, Mariano; Dimitriou, Maria; Edkins, Sarah; Estrada, Karol; Evans, David M.; Farrall, Martin; Ferrario, Marco M.; Ferrières, Jean; Franke, Lude; Frau, Francesca; Gejman, Pablo V.; Grallert, Harald; Grönberg, Henrik; Gudnason, Vilmundur; Hall, Alistair S.; Hall, Per; Hartikainen, Anna-Liisa; Hayward, Caroline; Heard-Costa, Nancy L.; Heath, Andrew C.; Hebebrand, Johannes; Homuth, Georg; Hu, Frank B.; Hunt, Sarah E.; Hyppönen, Elina; Iribarren, Carlos; Jacobs, Kevin B.; Jansson, John-Olov; Jula, Antti; Kähönen, Mika; Kathiresan, Sekar; Kee, Frank; Khaw, Kay-Tee; Kivimaki, Mika; Koenig, Wolfgang; Kraja, Aldi T.; Kumari, Meena; Kuulasmaa, Kari; Kuusisto, Johanna; Laitinen, Jaana H.; Lakka, Timo A.; Langenberg, Claudia; Launer, Lenore J.; Lind, Lars; Lindström, Jaana; Liu, Jianjun; Liuzzi, Antonio; Lokki, Marja-Liisa; Lorentzon, Mattias; Madden, Pamela A.; Magnusson, Patrik K.; Manunta, Paolo; Marek, Diana; März, Winfried; Leach, Irene Mateo; McKnight, Barbara; Medland, Sarah E.; Mihailov, Evelin; Milani, Lili; Montgomery, Grant W.; Mooser, Vincent; Mühleisen, Thomas W.; Munroe, Patricia B.; Musk, Arthur W.; Narisu, Narisu; Navis, Gerjan; Nicholson, George; Nohr, Ellen A.; Ong, Ken K.; Oostra, Ben A.; Palmer, Colin N.A.; Palotie, Aarno; Peden, John F.; Pedersen, Nancy; Peters, Annette; Polasek, Ozren; Pouta, Anneli; Pramstaller, Peter P.; Prokopenko, Inga; Pütter, Carolin; Radhakrishnan, Aparna; Raitakari, Olli; Rendon, Augusto; Rivadeneira, Fernando; Rudan, Igor; Saaristo, Timo E.; Sambrook, Jennifer G.; Sanders, Alan R.; Sanna, Serena; Saramies, Jouko; Schipf, Sabine; Schreiber, Stefan; Schunkert, Heribert; Shin, So-Youn; Signorini, Stefano; Sinisalo, Juha; Skrobek, Boris; Soranzo, Nicole; Stančáková, Alena; Stark, Klaus; Stephens, Jonathan C.; Stirrups, Kathleen; Stolk, Ronald P.; Stumvoll, Michael; Swift, Amy J.; Theodoraki, Eirini V.; Thorand, Barbara; Tregouet, David-Alexandre; Tremoli, Elena; Van der Klauw, Melanie M.; van Meurs, Joyce B.J.; Vermeulen, Sita H.; Viikari, Jorma; Virtamo, Jarmo; Vitart, Veronique; Waeber, Gérard; Wang, Zhaoming; Widén, Elisabeth; Wild, Sarah H.; Willemsen, Gonneke; Winkelmann, Bernhard R.; Witteman, Jacqueline C.M.; Wolffenbuttel, Bruce H.R.; Wong, Andrew; Wright, Alan F.; Zillikens, M. Carola; Amouyel, Philippe; Boehm, Bernhard O.; Boerwinkle, Eric; Boomsma, Dorret I.; Caulfield, Mark J.; Chanock, Stephen J.; Cupples, L. Adrienne; Cusi, Daniele; Dedoussis, George V.; Erdmann, Jeanette; Eriksson, Johan G.; Franks, Paul W.; Froguel, Philippe; Gieger, Christian; Gyllensten, Ulf; Hamsten, Anders; Harris, Tamara B.; Hengstenberg, Christian; Hicks, Andrew A.; Hingorani, Aroon; Hinney, Anke; Hofman, Albert; Hovingh, Kees G.; Hveem, Kristian; Illig, Thomas; Jarvelin, Marjo-Riitta; Jöckel, Karl-Heinz; Keinanen-Kiukaanniemi, Sirkka M.; Kiemeney, Lambertus A.; Kuh, Diana; Laakso, Markku; Lehtimäki, Terho; Levinson, Douglas F.; Martin, Nicholas G.; Metspalu, Andres; Morris, Andrew D.; Nieminen, Markku S.; Njølstad, Inger; Ohlsson, Claes; Oldehinkel, Albertine J.; Ouwehand, Willem H.; Palmer, Lyle J.; Penninx, Brenda; Power, Chris; Province, Michael A.; Psaty, Bruce M.; Qi, Lu; Rauramaa, Rainer; Ridker, Paul M.; Ripatti, Samuli; Salomaa, Veikko; Samani, Nilesh J.; Snieder, Harold; Sørensen, Thorkild I.A.; Spector, Timothy D.; Stefansson, Kari; Tönjes, Anke; Tuomilehto, Jaakko; Uitterlinden, André G.; Uusitupa, Matti; van der Harst, Pim; Vollenweider, Peter; Wallaschofski, Henri; Wareham, Nicholas J.; Watkins, Hugh; Wichmann, H.-Erich; Wilson, James F.; Abecasis, Goncalo R.; Assimes, Themistocles L.; Barroso, Inês; Boehnke, Michael; Borecki, Ingrid B.; Deloukas, Panos; Fox, Caroline S.; Frayling, Timothy; Groop, Leif C.; Haritunian, Talin; Heid, Iris M.; Hunter, David; Kaplan, Robert C.; Karpe, Fredrik; Moffatt, Miriam; Mohlke, Karen L.; O’Connell, Jeffrey R.; Pawitan, Yudi; Schadt, Eric E.; Schlessinger, David; Steinthorsdottir, Valgerdur; Strachan, David P.; Thorsteinsdottir, Unnur; van Duijn, Cornelia M.; Visscher, Peter M.; Di Blasio, Anna Maria; Hirschhorn, Joel N.; Lindgren, Cecilia M.; Morris, Andrew P.; Meyre, David; Scherag, André; McCarthy, Mark I.; Speliotes, Elizabeth K.; North, Kari E.; Loos, Ruth J.F.; Ingelsson, Erik; Hirschhorn, Joel; North, Kari E.; Ingelsson, Erik; Lin, Dan-Yu

    2013-01-01

    Meta-analysis of genome-wide association studies (GWASs) has led to the discoveries of many common variants associated with complex human diseases. There is a growing recognition that identifying “causal” rare variants also requires large-scale meta-analysis. The fact that association tests with rare variants are performed at the gene level rather than at the variant level poses unprecedented challenges in the meta-analysis. First, different studies may adopt different gene-level tests, so the results are not compatible. Second, gene-level tests require multivariate statistics (i.e., components of the test statistic and their covariance matrix), which are difficult to obtain. To overcome these challenges, we propose to perform gene-level tests for rare variants by combining the results of single-variant analysis (i.e., p values of association tests and effect estimates) from participating studies. This simple strategy is possible because of an insight that multivariate statistics can be recovered from single-variant statistics, together with the correlation matrix of the single-variant test statistics, which can be estimated from one of the participating studies or from a publicly available database. We show both theoretically and numerically that the proposed meta-analysis approach provides accurate control of the type I error and is as powerful as joint analysis of individual participant data. This approach accommodates any disease phenotype and any study design and produces all commonly used gene-level tests. An application to the GWAS summary results of the Genetic Investigation of ANthropometric Traits (GIANT) consortium reveals rare and low-frequency variants associated with human height. The relevant software is freely available. PMID:23891470

  14. Meta-analysis of gene-level associations for rare variants based on single-variant statistics.

    PubMed

    Hu, Yi-Juan; Berndt, Sonja I; Gustafsson, Stefan; Ganna, Andrea; Hirschhorn, Joel; North, Kari E; Ingelsson, Erik; Lin, Dan-Yu

    2013-08-08

    Meta-analysis of genome-wide association studies (GWASs) has led to the discoveries of many common variants associated with complex human diseases. There is a growing recognition that identifying "causal" rare variants also requires large-scale meta-analysis. The fact that association tests with rare variants are performed at the gene level rather than at the variant level poses unprecedented challenges in the meta-analysis. First, different studies may adopt different gene-level tests, so the results are not compatible. Second, gene-level tests require multivariate statistics (i.e., components of the test statistic and their covariance matrix), which are difficult to obtain. To overcome these challenges, we propose to perform gene-level tests for rare variants by combining the results of single-variant analysis (i.e., p values of association tests and effect estimates) from participating studies. This simple strategy is possible because of an insight that multivariate statistics can be recovered from single-variant statistics, together with the correlation matrix of the single-variant test statistics, which can be estimated from one of the participating studies or from a publicly available database. We show both theoretically and numerically that the proposed meta-analysis approach provides accurate control of the type I error and is as powerful as joint analysis of individual participant data. This approach accommodates any disease phenotype and any study design and produces all commonly used gene-level tests. An application to the GWAS summary results of the Genetic Investigation of ANthropometric Traits (GIANT) consortium reveals rare and low-frequency variants associated with human height. The relevant software is freely available.

  15. Molecular stabilization effects of interactions between anti-metatype antibodies and liganded antibody.

    PubMed

    Weidner, K M; Denzin, L K; Voss, E W

    1992-05-25

    Anti-metatype antibodies have been described as antibodies which recognize ligand-induced conformational changes in the antibody variable region. Additionally, anti-metatype antibodies, produced by multiple immunizations with liganded high affinity monoclonal anti-fluorescein antibody 4-4-20, enhanced the lifetime of monoclonal antibody 4-4-20-fluorescein complex. To better understand the mechanism of the delayed dissociation rate, deuterium oxide was used to probe the liganded active site. The rate and extent of deuterium oxide-mediated fluorescence enhancement of bound ligand served to monitor the conformational dynamics of the active site in the presence and absence of anti-metatype antibodies. Results showed that anti-metatype antibodies reduced the rate and extent of deuterium oxide-mediated fluorescence enhancement of 4-4-20, a single-chain derivative of 4-4-20 (consisting of the variable domains and a polylinker), and idiotypically related monoclonal anti-fluorescein antibodies suggesting that anti-metatype stabilized the liganded active site. Size exclusion liquid chromatography was utilized to isolate the liganded antibody-anti-metatype complex. Liganded single chain antibody 4-4-20 was mixed with 10-fold molar excess anti-metatype Fab fragments, and a major complex eluted with an apparent M(r) 249,000. The apparent molecular weight of this complex inferred that one liganded single chain antibody was bound by five antimetatype Fab fragments. Spectral analysis confirmed these results and the characteristic delayed rate of ligand dissociation was also observed for the isolated complex. The results suggest that anti-metatype antibodies stabilize the liganded conformation by forming a large, stable, macromolecular complex.

  16. Cloning and characterization of functional subtype A HIV-1 envelope variants transmitted through breastfeeding.

    PubMed

    Rainwater, Stephanie M J; Wu, Xueling; Nduati, Ruth; Nedellec, Rebecca; Mosier, Donald; John-Stewart, Grace; Mbori-Ngacha, Dorothy; Overbaugh, Julie

    2007-03-01

    Previous studies of HIV-1 variants transmitted from mother-to-infant have focused primarily on computational analyses of partial envelope gene sequences, rather than analyses of functional envelope variants. There are very few examples of well-characterized functional envelope clones from mother-infant pairs, especially from envelope variants representing the most prevalent subtypes worldwide. To address this, we amplified the envelope variants present in 4 mother-infant transmission pairs, all of whom were infected with subtype A and three of whom presumably transmitted HIV-1 during the breastfeeding period. Functional envelope clones were constructed, either encoding full-length envelope sequences from the mother and baby or by making chimeric envelope clones in a common backbone sequence. The infant envelope sequences were genetically homogeneous compared to the maternal viruses, and pseudoviruses bearing these envelopes all used CCR5 as a coreceptor. The infant viruses were generally resistant to neutralization by maternal antibodies present near the time of transmission. There were no notable differences in sensitivity of the mother and infant envelope variants to neutralization by heterologous plasma or monoclonal antibodies 2G12 and b12, or to inhibition by sCD4, PSC-RANTES or TAK779. This collection of viral envelopes, which can be used for making pseudotyped viruses, may be useful for examining the efficacy of interventions to block mother-infant transmission, including sera from vaccine candidates, purified antibodies under consideration for passive immunization and viral entry inhibitors.

  17. Humoral Immune Pressure Selects for HIV-1 CXC-chemokine Receptor 4-using Variants.

    PubMed

    Lin, Nina; Gonzalez, Oscar A; Registre, Ludy; Becerril, Carlos; Etemad, Behzad; Lu, Hong; Wu, Xueling; Lockman, Shahin; Essex, Myron; Moyo, Sikhulile; Kuritzkes, Daniel R; Sagar, Manish

    2016-06-01

    Although both C-C chemokine receptor 5 (CCR5)- and CXC chemokine receptor 4 (CXCR4)-using HIV-1 strains cause AIDS, the emergence of CXCR4-utilizing variants is associated with an accelerated decline in CD4+ T cells. It remains uncertain if CXCR4-using viruses hasten disease or if these variants only emerge after profound immunological damage. We show that exclusively CXCR4- as compared to cocirculating CCR5-utilizing variants are less sensitive to neutralization by both contemporaneous autologous plasma and plasma pools from individuals that harbor only CCR5-using HIV-1. The CXCR4-utilizing variants, however, do not have a global antigenic change because they remain equivalently susceptible to antibodies that do not target coreceptor binding domains. Studies with envelope V3 loop directed antibodies and chimeric envelopes suggest that the neutralization susceptibility differences are potentially influenced by the V3 loop. In vitro passage of a neutralization sensitive CCR5-using virus in the presence of autologous plasma and activated CD4+ T cells led to the emergence of a CXCR4-utilizing virus in 1 of 3 cases. These results suggest that in some but not necessarily all HIV-1 infected individuals humoral immune pressure against the autologous virus selects for CXCR4-using variants, which potentially accelerates disease progression. Our observations have implications for using antibodies for HIV-1 immune therapy.

  18. Arenavirus Glycan Shield Promotes Neutralizing Antibody Evasion and Protracted Infection

    PubMed Central

    Malinge, Pauline; Magistrelli, Giovanni; Fischer, Nicolas; Sahin, Mehmet; Bergthaler, Andreas; Igonet, Sebastien; ter Meulen, Jan; Rigo, Dorothée; Meda, Paolo; Rabah, Nadia; Coutard, Bruno; Bowden, Thomas A.; Lambert, Paul-Henri; Siegrist, Claire-Anne; Pinschewer, Daniel D.

    2015-01-01

    Arenaviruses such as Lassa virus (LASV) can cause severe hemorrhagic fever in humans. As a major impediment to vaccine development, delayed and weak neutralizing antibody (nAb) responses represent a unifying characteristic of both natural infection and all vaccine candidates tested to date. To investigate the mechanisms underlying arenavirus nAb evasion we engineered several arenavirus envelope-chimeric viruses and glycan-deficient variants thereof. We performed neutralization tests with sera from experimentally infected mice and from LASV-convalescent human patients. NAb response kinetics in mice correlated inversely with the N-linked glycan density in the arenavirus envelope protein’s globular head. Additionally and most intriguingly, infection with fully glycosylated viruses elicited antibodies, which neutralized predominantly their glycan-deficient variants, both in mice and humans. Binding studies with monoclonal antibodies indicated that envelope glycans reduced nAb on-rate, occupancy and thereby counteracted virus neutralization. In infected mice, the envelope glycan shield promoted protracted viral infection by preventing its timely elimination by the ensuing antibody response. Thus, arenavirus envelope glycosylation impairs the protective efficacy rather than the induction of nAbs, and thereby prevents efficient antibody-mediated virus control. This immune evasion mechanism imposes limitations on antibody-based vaccination and convalescent serum therapy. PMID:26587982

  19. Arenavirus Glycan Shield Promotes Neutralizing Antibody Evasion and Protracted Infection.

    PubMed

    Sommerstein, Rami; Flatz, Lukas; Remy, Melissa M; Malinge, Pauline; Magistrelli, Giovanni; Fischer, Nicolas; Sahin, Mehmet; Bergthaler, Andreas; Igonet, Sebastien; Ter Meulen, Jan; Rigo, Dorothée; Meda, Paolo; Rabah, Nadia; Coutard, Bruno; Bowden, Thomas A; Lambert, Paul-Henri; Siegrist, Claire-Anne; Pinschewer, Daniel D

    2015-11-01

    Arenaviruses such as Lassa virus (LASV) can cause severe hemorrhagic fever in humans. As a major impediment to vaccine development, delayed and weak neutralizing antibody (nAb) responses represent a unifying characteristic of both natural infection and all vaccine candidates tested to date. To investigate the mechanisms underlying arenavirus nAb evasion we engineered several arenavirus envelope-chimeric viruses and glycan-deficient variants thereof. We performed neutralization tests with sera from experimentally infected mice and from LASV-convalescent human patients. NAb response kinetics in mice correlated inversely with the N-linked glycan density in the arenavirus envelope protein's globular head. Additionally and most intriguingly, infection with fully glycosylated viruses elicited antibodies, which neutralized predominantly their glycan-deficient variants, both in mice and humans. Binding studies with monoclonal antibodies indicated that envelope glycans reduced nAb on-rate, occupancy and thereby counteracted virus neutralization. In infected mice, the envelope glycan shield promoted protracted viral infection by preventing its timely elimination by the ensuing antibody response. Thus, arenavirus envelope glycosylation impairs the protective efficacy rather than the induction of nAbs, and thereby prevents efficient antibody-mediated virus control. This immune evasion mechanism imposes limitations on antibody-based vaccination and convalescent serum therapy.

  20. Localisation of malignant glioma by a radiolabelled human monoclonal antibody.

    PubMed Central

    Phillips, J; Alderson, T; Sikora, K; Watson, J

    1983-01-01

    Human monoclonal antibodies were produced by fusing intratumoral lymphocytes from patients with malignant gliomas with a human myeloma line. One antibody was selected for further study after screening for binding activity to glioma cell lines. The patient from whom it was derived developed recurrent glioma. 1 mg of antibody was purified, radiolabelled with 131I, and administered intravenously. The distribution of antibody was determined in the blood, CSF and tumour cyst fluid and compared with that of a control human monoclonal immunoglobulin. Antibody localisation in the tumour was observed and confirmed by external scintiscanning. Images PMID:6101173

  1. Pitfalls of formalin fixation for determination of antineutrophil cytoplasmic antibodies.

    PubMed

    Chowdhury, S M; Broomhead, V; Spickett, G P; Wilkinson, R

    1999-06-01

    Sera can produce nuclear or perinuclear immunofluorescence staining in neutrophils which may be caused by antibodies with differing antigenic specificities. These include perinuclear antineutrophil cytoplasmic antibodies (P-ANCA), granulocyte specific antinuclear antibody (GS-ANA), and antinuclear antibody (ANA). There is controversy over the value of formalin fixation of neutrophils in differentiating antibodies giving selective or preferential reaction with the nuclear or perinuclear area of neutrophils. In a comparative study of 77 sera, formalin fixation caused inconsistency, nonspecific effects, and false positivity owing to enhanced fluorescence. If formalin fixed neutrophils are used in the routine diagnostic laboratory, this will add confusion to the interpretation of the ANCA assay.

  2. Pitfalls of formalin fixation for determination of antineutrophil cytoplasmic antibodies.

    PubMed Central

    Chowdhury, S M; Broomhead, V; Spickett, G P; Wilkinson, R

    1999-01-01

    Sera can produce nuclear or perinuclear immunofluorescence staining in neutrophils which may be caused by antibodies with differing antigenic specificities. These include perinuclear antineutrophil cytoplasmic antibodies (P-ANCA), granulocyte specific antinuclear antibody (GS-ANA), and antinuclear antibody (ANA). There is controversy over the value of formalin fixation of neutrophils in differentiating antibodies giving selective or preferential reaction with the nuclear or perinuclear area of neutrophils. In a comparative study of 77 sera, formalin fixation caused inconsistency, nonspecific effects, and false positivity owing to enhanced fluorescence. If formalin fixed neutrophils are used in the routine diagnostic laboratory, this will add confusion to the interpretation of the ANCA assay. PMID:10562820

  3. Developing a DNA variant database.

    PubMed

    Fung, David C Y

    2008-01-01

    Disease- and locus-specific variant databases have been a valuable resource to clinical and research geneticists. With the recent rapid developments in technologies, the number of DNA variants detected in a typical molecular genetics laboratory easily exceeds 1,000. To keep track of the growing inventory of DNA variants, many laboratories employ information technology to store the data as well as distributing the data and its associated information to clinicians and researchers via the Web. While it is a valuable resource, the hosting of a web-accessible database requires collaboration between bioinformaticians and biologists and careful planning to ensure its usability and availability. In this chapter, a series of tutorials on building a local DNA variant database out of a sample dataset will be provided. However, this tutorial will not include programming details on building a web interface and on constructing the web application necessary for web hosting. Instead, an introduction to the two commonly used methods for hosting web-accessible variant databases will be described. Apart from the tutorials, this chapter will also consider the resources and planning required for making a variant database project successful.

  4. Entamoeba histolytica: expression and localization of Gal/GalNAc lectin in virulent and non-virulent variants from HM1:IMSS strain.

    PubMed

    López-Vancell, R; Arreguín Espinosa, R; González-Canto, A; Néquiz Avendaño, M; García de León, M C; Olivos-García, A; López-Vancell, D; Pérez-Tamayo, R

    2010-07-01

    We have purified Gal/GalNAc lectin from Entamoeba histolytica by electroelution. The purified protein was used to immunize rabbits and obtain polyclonal IgG's anti-lectin. These antibodies were used as tools to analyze the expression and localization of the amoebic lectin in both virulent (vEh) and non-virulent (nvEh) variants of axenically cultured HM1:IMSS strain. vEh is able to induce liver abscesses in hamsters, whereas nvEh has lost this ability. In vitro, amoebic trophozoites from both variants equally express this protein as shown by densitometric analysis of the corresponding band in Western blots from lysates. In both types of trophozoites, the pattern of distribution of the lectin was mainly on the surface. We have also compared by immunohistochemistry the presence and distribution of lectin in the in vivo liver lesions produced in hamsters. In order to prolong the survival of nvEh to analyze both variants in an in vivo model, hamsters inoculated with nvEh were treated with methyl prednisolone. Our results suggest that the Gal/GalNAc lectin is equally expressed in both nvEh and vEh.

  5. Engineering unnatural variants of plantazolicin through codon reprogramming

    PubMed Central

    Deane, Caitlin D.; Melby, Joel O.; Molohon, Katie J.; Susarrey, Aziz R.; Mitchell, Douglas A.

    2013-01-01

    Plantazolicin (PZN) is a polyheterocyclic natural product derived from a ribosomal peptide that harbors remarkable antibiotic selectivity for the causative agent of anthrax, Bacillus anthracis. To simultaneously establish the structure-activity relationship of PZN and the substrate tolerance of the biosynthetic pathway, an Escherichia coli expression strain was engineered to heterologously produce PZN analogs. Variant PZN precursor genes were produced by site-directed mutagenesis and later screened by mass spectrometry to assess posttranslational modification and export by E. coli. From a screen of 72 precursor peptides, 29 PZN variants were detected. This analog collection provided insight into the selectivity of the posttranslational modifying enzymes and established the boundaries of the natural biosynthetic pathway. Unlike other studied thiazole/oxazole-modified microcins, the biosynthetic machinery appeared to be finely tuned towards the production of PZN, such that the cognate enzymes did not process even other naturally occurring sequences from similar biosynthetic clusters. The modifying enzymes were exquisitely selective, installing heterocycles only at pre-defined positions within the precursor peptides while leaving neighboring residues unmodified. Nearly all substitutions at positions normally harboring heterocycles prevented maturation of a PZN variant, though some exceptions were successfully produced lacking a heterocycle at the penultimate residue. No variants containing additional heterocycles were detected, although several peptide sequences yielded multiple PZN variants as a result of varying oxidation states of select residues. Eleven PZN variants were produced in sufficient quantity to facilitate purification and assessment of their antibacterial activity, providing insight into the structure-activity relationship of PZN. PMID:23823732

  6. Antibody Therapeutics in Oncology

    PubMed Central

    Wold, Erik D; Smider, Vaughn V; Felding, Brunhilde H

    2016-01-01

    One of the newer classes of targeted cancer therapeutics is monoclonal antibodies. Monoclonal antibody therapeutics are a successful and rapidly expanding drug class due to their high specificity, activity, favourable pharmacokinetics, and standardized manufacturing processes. Antibodies are capable of recruiting the immune system to attack cancer cells through complement-dependent cytotoxicity or antibody dependent cellular cytotoxicity. In an ideal scenario the initial tumor cell destruction induced by administration of a therapeutic antibody can result in uptake of tumor associated antigens by antigen-presenting cells, establishing a prolonged memory effect. Mechanisms of direct tumor cell killing by antibodies include antibody recognition of cell surface bound enzymes to neutralize enzyme activity and signaling, or induction of receptor agonist or antagonist activity. Both approaches result in cellular apoptosis. In another and very direct approach, antibodies are used to deliver drugs to target cells and cause cell death. Such antibody drug conjugates (ADCs) direct cytotoxic compounds to tumor cells, after selective binding to cell surface antigens, internalization, and intracellular drug release. Efficacy and safety of ADCs for cancer therapy has recently been greatly advanced based on innovative approaches for site-specific drug conjugation to the antibody structure. This technology enabled rational optimization of function and pharmacokinetics of the resulting conjugates, and is now beginning to yield therapeutics with defined, uniform molecular characteristics, and unprecedented promise to advance cancer treatment. PMID:27081677

  7. Motor variant of chronic inflammatory demyelinating polyneuropathy in a child.

    PubMed

    Sinno, Durriyah D; Darras, Basil T; Yamout, Bassem I; Rebeiz, Jean G; Mikati, Mohamad A

    2008-06-01

    Only 2 cases of pure motor chronic demyelinating inflammatory polyneuropathy in the pediatric age group have been reported in the literature. We report on a motor variant of chronic demyelinating inflammatory polyneuropathy with anti-ganglioside antibodies, diagnosed in a 5-year-old girl who presented with progressive motor weakness over a period of 12 months with no sensory involvement. She initially responded partially to intravenous immunoglobulin therapy (1 gm/kg/month for 6 months), and then demonstrated sustained but incomplete improvement on chronic prednisone therapy (1-2 mg/kg/day), on which she has continued since 1 year and 4 months after her initial presentation 3 years ago.

  8. The VSG C-terminal domain is inaccessible to antibodies on live trypanosomes.

    PubMed

    Schwede, Angela; Jones, Nicola; Engstler, Markus; Carrington, Mark

    2011-02-01

    In the mammalian host, the Trypanosoma brucei cell surface is covered with a densely packed protein coat of a single protein, the variant surface glycoprotein (VSG). The VSG is believed to shield invariant surface proteins from host antibodies but there is limited information on how far antibodies can penetrate into the VSG monolayer. Here, the VSG surface coat was probed to determine whether it acts as a barrier to binding of antibodies to the membrane proximal VSG C-terminal domain. The binding of C-terminal domain antibodies to VSG221 or VSG118 was compared with antibodies recognising the cognate whole VSGs. The C-terminal VSG domain was inaccessible to antibodies on live cells but not on fixed cells. This provides further evidence that the VSG coat acts as a barrier and protects the cell from antibodies that would otherwise bind to some of the other externally disposed proteins.

  9. Optimizing selection of restriction enzymes in the search for DNA variants.

    PubMed Central

    Wijsman, E M

    1984-01-01

    A model is developed for predicting the relative efficiencies of different enzymes for detecting DNA variants when such variants are the result of single base-pair changes. 71 enzymes are analyzed for this ability in human DNA. Their relative ranked efficiencies are influenced by the sizes of the probes used, and the size of the smallest detectable fragment produced. PMID:6096823

  10. Clear Speech Variants: An Acoustic Study in Parkinson's Disease

    ERIC Educational Resources Information Center

    Lam, Jennifer; Tjaden, Kris

    2016-01-01

    Purpose: The authors investigated how different variants of clear speech affect segmental and suprasegmental acoustic measures of speech in speakers with Parkinson's disease and a healthy control group. Method: A total of 14 participants with Parkinson's disease and 14 control participants served as speakers. Each speaker produced 18 different…

  11. High Resolution Mapping of Bactericidal Monoclonal Antibody Binding Epitopes on Staphylococcus aureus Antigen MntC

    PubMed Central

    Gribenko, Alexey V.; Parris, Kevin; Mosyak, Lidia; Li, Sheng; Handke, Luke; Hawkins, Julio C.; Severina, Elena; Matsuka, Yury V.; Anderson, Annaliesa S.

    2016-01-01

    The Staphylococcus aureus manganese transporter protein MntC is under investigation as a component of a prophylactic S.aureus vaccine. Passive immunization with monoclonal antibodies mAB 305-78-7 and mAB 305-101-8 produced using MntC was shown to significantly reduce S. aureus burden in an infant rat model of infection. Earlier interference mapping suggested that a total of 23 monoclonal antibodies generated against MntC could be subdivided into three interference groups, representing three independent immunogenic regions. In the current work binding epitopes for selected representatives of each of these interference groups (mAB 305-72-5 – group 1, mAB 305-78-7 – group 2, and mAB 305-101-8 – group 3) were mapped using Hydrogen-Deuterium Exchange Mass Spectrometry (DXMS). All of the identified epitopes are discontinuous, with binding surface formed by structural elements that are separated within the primary sequence of the protein but adjacent in the context of the three-dimensional structure. The approach was validated by co-crystallizing the Fab fragment of one of the antibodies (mAB 305-78-7) with MntC and solving the three-dimensional structure of the complex. X-ray results themselves and localization of the mAB 305-78-7 epitope were further validated using antibody binding experiments with MntC variants containing substitutions of key amino acid residues. These results provided insight into the antigenic properties of MntC and how these properties may play a role in protecting the hostagainst S. aureus infection by preventing the capture and transport of Mn2+, a key element that the pathogen uses to evade host immunity. PMID:27689696

  12. [Autoimmune encephalitis induced by antibodies against GABA-A receptor].

    PubMed

    González R, Pablo; Hudson A, Lorena; Basáez M, Esteban; Miranda C, Marcelo

    2016-11-01

    Among autoimmune encephalitides, a prevalent group are those associated with antibodies against the N-Methyl-D-aspartate receptor, which present with behavior abnormalities, psychosis, seizures and abnormal movements. A new variant, mediated by antibodies against the GABA-A receptor, was recen-tly described. We report a 66-years-old female with this form of encephalitis whose main manifestation was the presence of severe seizures leading to status epilepticus. The patient had a good response to immunomodulatory therapy with intravenous methylprednisolone, azathioprine and anticonvulsants. The laboratory tests initially detected anti-thyroid peroxidase antibodies which lead to the misdiagnosis of Hashimoto Encephalitis, which was ruled out after the detection of antibodies against GABA-A receptor. No malignancy was detected.

  13. Prediction and reduction of the aggregation of monoclonal antibodies.

    PubMed

    van der Kant, Rob; Karow-Zwick, Anne R; Van Durme, Joost; Blech, Michaela; Gallardo, Rodrigo; Seeliger, Daniel; Aßfalg, Kerstin; Baatsen, Pieter; Compernolle, Griet; Gils, Ann; Studts, Joey M; Schulz, Patrick; Garidel, Patrick; Schymkowitz, Joost; Rousseau, Frederic

    2017-03-17

    Protein aggregation remains a major area of focus in the production of monoclonal antibodies. Improving the intrinsic properties of antibodies can improve manufacturability, attrition rates, safety, formulation, titers, immunogenicity and solubility. Here, we explore the potential of predicting and reducing the aggregation propensity of monoclonal antibodies, based on the identification of aggregation-prone regions (APRs) and their contribution to the thermodynamic stability of the protein. Although APRs are thought to occur in the antigen binding region to drive hydrophobic binding with antigen, we were able to rationally design variants that display a marked decrease in aggregation propensity while retaining antigen binding through the introduction of artificial aggregation gatekeeper residues. The reduction in aggregation propensity was accompanied by an increase in expression titer, showing that reducing protein aggregation is beneficial throughout the development process. The data presented show that this approach can significantly reduce liabilities in novel therapeutic antibodies and proteins, leading to a more efficient path to clinical studies.

  14. Antibodies in Transplantation

    PubMed Central

    Platt, Jeffrey L.

    2011-01-01

    Transplantation of cells, tissues, and organs from one individual to another can incite the production of antibodies specific for foreign antigens, especially major histocompatibility antigens, in the graft. Antibodies specific for a graft provide an index of immunity and a potential trigger for injury and rejection. However, the index of immunity can sometimes miss antibody-mediated rejection and besides causing injury the antibodies against a graft can also protect a graft from injury by blocking immune recognition, called enhancement, regulating activation of complement, and inducing changes in the graft that resist damage. Reviewed here are potential limitations in the use of antibodies as an index of immunity and the ways antibodies cause and/or prevent injury. PMID:20807473

  15. Determination of serum antibodies against swine-origin influenza A virus H1N1/09 by immunofluorescence, haemagglutination inhibition, and by neutralization tests: how is the prevalence rate of protecting antibodies in humans?

    PubMed

    Allwinn, Regina; Geiler, Janina; Berger, Annemarie; Cinatl, J; Doerr, H W

    2010-05-01

    In April 2009, a new variant of influenza A virus, subtype H1N1v emerged in Mexico and spread all over the world producing the H1N1 pandemic in mankind after 1918-1920 and 1978/1979. Obviously there was no herd immunity against this new virus variant. Mainly young people, but less elderly were affected and presented severe and even lethal courses of disease. Since virus-specific antibodies are commonly regarded as markers of partial or complete immunoprotection, we performed antibody determinations in serum samples obtained from people before and after the pandemic has arrived in our region (Frankfurt/M., Germany). The assays were done by indirect immunofluorescence, by neutralization test, and by a haemagglutination inhibition test (HI), which was established in a practical modification for general and easy use. Among 145 individuals, of whom serum specimens had been drawn before the onset of pandemic, 19 revealed humoral immunity, i.e. titres of H1N1v neutralizing antibodies (at least 1:64). Eleven were older than 60 years, one belonged to the age group 40-59 years, three to the age group 20-39 years, and two to the age group 15-19 years. After the onset of pandemic in Frankfurt, serum specimens drawn from n = 225 randomly selected patients of our local university hospital were investigated for antibodies against H1N1v by HI, which is generally recommended for routine check of immunity. Twenty-eight individuals revealed the protecting antibody titre of at least 1:40. The age distribution had moved to mean age groups. The results fit to the incidence of influenza A/H1N1(09) disease, as confirmed by RT-PCR in patients admitted to our hospital, peaking in the younger age groups up to 30 years (second affected group: 30-40 years). While commonly used solid-phase antibody tests (like immunofluorescence) are not suitable to diagnose passed H1N1(09) infection and acquired immunity, this can be easily done by HI. Expecting the next waves of influenza A/H1N1v infections

  16. Antibodies Targeting EMT

    DTIC Science & Technology

    2015-10-01

    AWARD NUMBER: W81XWH-14-1-0381 TITLE: Antibodies Targeting EMT PRINCIPAL INVESTIGATOR: Vaughn Smider CONTRACTING ORGANIZATION: The Scripps...REPORT DATE October 2015 2. REPORT TYPE Annual 3. DATES COVERED 30 Sep 2014 - 29 Sep 2015 4. TITLE AND SUBTITLE Antibodies Targeting EMT 5a. CONTRACT ...ABSTRACT Monoclonal antibodies are drugs that can specifically bind targets present on tumor cells. The highly aggressive triple-negative subtype of

  17. Metabolic engineering of monoclonal antibody carbohydrates for antibody-drug conjugation.

    PubMed

    Okeley, Nicole M; Toki, Brian E; Zhang, Xinqun; Jeffrey, Scott C; Burke, Patrick J; Alley, Stephen C; Senter, Peter D

    2013-10-16

    The role that carbohydrates play in antibody function and pharmacokinetics has made them important targets for modification. The terminal fucose of the N-linked glycan structure, which has been shown to be involved in modulation of antibody-directed cellular cytotoxicity, is a particularly interesting location for potential modification through incorporation of alternative sugar structures. A library of fucose analogues was evaluated for their ability to incorporate into antibody carbohydrates in place of the native fucose. A number of efficiently incorporated molecules were identified, demonstrating the ability of fucosyltransferase VIII to utilize a variety of non-natural sugars as substrates. Among these structures was a thiolated analogue, 6-thiofucose, which was incorporated into the antibody carbohydrate with good efficiency. This unnatural thio-sugar could then be used for conjugation using maleimide chemistry to produce antibody-drug conjugates with pronounced cytotoxic activities and improved homogeneity compared to drug attachment through hinge disulfides.

  18. A two-in-one antibody engineered from a humanized interleukin 4 antibody through mutation in heavy chain complementarity-determining regions.

    PubMed

    Lee, Chingwei V; Koenig, Patrick; Fuh, Germaine

    2014-01-01

    A mono-specific antibody may recruit a second antigen binding specificity, thus converting to a dual-specific Two-in-One antibody through mutation at the light chain complementarity-determining regions (CDRs). It is, however, unknown whether mutation at the heavy chain CDRs may evolve such dual specificity. Herein, we examined the CDRs of a humanized interleukin 4 (IL4) antibody using alanine scanning and structural modeling, designed libraries of mutants in regions that tolerate mutation, and isolated dual specific antibodies harboring mutation at the heavy chain CDRs only. We then affinity improved an IL4/IL5 dual specific antibody to variants with dissociation constants in the low nanomolar range for both antigens. The results demonstrate the full capacity of antibodies to evolve dual binding specificity.

  19. Computerized design and generation of space-variant holographic filters. II - Applications of space-variant filters to optical computing

    NASA Technical Reports Server (NTRS)

    Ambs, P.; Fainman, Y.; Esener, S.; Lee, S. H.

    1988-01-01

    Holographic optical elements (HOEs) of space-variant impulse response have been designed and generated using a computerized optical system. HOEs made of dichromated gelatin have been produced and used for spatial light modulator defect removal and optical interconnects. Experimental performance and characteristics are presented.

  20. Purification and properties of non-precipitating rabbit antibodies

    PubMed Central

    Margni, R.; Binaghi, R.

    1972-01-01

    Precipitating and non-precipitating anti-egg albumin and anti-dinitrophenyl rabbit antibodies were specifically purified from hyperimmunized sera. Both populations of antibody were similar with regard to electrophoretic mobility and molecular size. Non-precipitating antibodies brought about passive haemagglutination and PCA, although with less efficiency than precipitating antibodies. On the other hand, only precipitating antibodies fixed complement and produced a reverse Arthus reaction. The F(ab′)2 fragment obtained from non-precipitating antibody did not precipitate with antigen. These results are compatible with the hypothesis that non-precipitability is due to a particular configuration of the molecule that makes it impossible for one molecule of antibody to combine with two different molecules of antigen simultaneously. PMID:4259530

  1. Goat serums for fluorescent antibody conjugates to chlamydial antigens.

    PubMed Central

    Tessler, J

    1984-01-01

    Serums from goats hyperimmunized with Chlamydia psittaci consistently produce antichlamydial fluorescent antibody conjugate of high titer. The titer of the fluorescent antibody conjugate prepared from a given serum correlated well with the titer obtained by agar gel precipitin, but not with the complement fixation. The agar gel precipitin test can be used to predict whether a given serum is satisfactory for use in production of a conjugate for direct fluorescent antibody tests. Serums with an agar gel precipitin titer of 1/8 or higher generally produce a usable fluorescent antibody conjugate. Labeling gamma globulins with fluorescein isothiocyanate at a ratio of 1/150 resulted in satisfactory fluorescent antibody conjugates. Cultures of Vero cells infected with chlamydiae were found to be suitable for titration of the fluorescent antibody conjugates. PMID:6372973

  2. Variants of Aspergillus alutaceus var. alutaceus (formerly Aspergillus ochraceus) with altered ochratoxin a production

    SciTech Connect

    Chelack, W.S.; Borsa, J.; Szekely, J.G. ); Marquardt, R.R.; Frohlich, A.A. )

    1991-09-01

    The present studies, using Asperigillus alutaceus var. alutaceus Berkeley et Curtis (formerly A. ochraceus Wilhelm) NRRL 3174 along with three other wild-type strains, were undertaken in an attempt to understand the effects of irradiation and other treatments on mycotoxin production in grain. Bedford barley was inoculated with spores of NRRL 3174, gamma irradiated, and incubated at 28C and 25% moisture. After 10 days of incubation, two colony types, ocher (parental) and yellow (variant), were isolated from the grain. Further culturing of the yellow variant resulted in the spontaneous appearance of a white variant that exhibited greatly enhanced fluorescence under UV light. In subsequent work, we have also isolated variants producing a soluble red pigment. In addition, in model experiments involving irradiation (1 kGy) of pure cultures, induction frequencies ranging between 2 and 4% (survival basis) were observed for the yellow and red variants. Inoculation of these variants into wheat and incubation for 14 days at 28C and 32% moisture resulted in ochratoxin A production in the relative amounts of 0.09:1:4.6:9.3 for the red, ocher (parental), yellow, and white variants, respectively. Additional characteristics of these isolates are described. Confirmation that the white high-ochratoxin-A-producing variants were derived from the parental strain was demonstrated by obtaining revertant sectors in monoclonal cultures of the variants.

  3. Combined glyco- and protein-Fc engineering simultaneously enhance cytotoxicity and half-life of a therapeutic antibody

    PubMed Central

    Monnet, Céline; Jorieux, Sylvie; Souyris, Nathalie; Zaki, Ouafa; Jacquet, Alexandra; Fournier, Nathalie; Crozet, Fabien; de Romeuf, Christophe; Bouayadi, Khalil; Urbain, Rémi; Behrens, Christian K; Mondon, Philippe; Fontayne, Alexandre

    2014-01-01

    While glyco-engineered monoclonal antibodies (mAbs) with improved antibody-dependent cell-mediated cytotoxicity (ADCC) are reaching the market, extensive efforts have also been made to improve their pharmacokinetic properties to generate biologically superior molecules. Most therapeutic mAbs are human or humanized IgG molecules whose half-life is dependent on the neonatal Fc receptor FcRn. FcRn reduces IgG catabolism by binding to the Fc domain of endocytosed IgG in acidic lysosomal compartments, allowing them to be recycled into the blood. Fc-engineered mAbs with increased FcRn affinity resulted in longer in vivo half-life in animal models, but also in healthy humans. These Fc-engineered mAbs were obtained by alanine scanning, directed mutagenesis or in silico approach of the FcRn binding site. In our approach, we applied a random mutagenesis technology (MutaGenTM) to generate mutations evenly distributed over the whole Fc sequence of human IgG1. IgG variants with improved FcRn-binding were then isolated from these Fc-libraries using a pH-dependent phage display selection process. Two successive rounds of mutagenesis and selection were performed to identify several mutations that dramatically improve FcRn binding. Notably, many of these mutations were unpredictable by rational design as they were located distantly from the FcRn binding site, validating our random molecular approach. When produced on the EMABling® platform allowing effector function increase, our IgG variants retained both higher ADCC and higher FcRn binding. Moreover, these IgG variants exhibited longer half-life in human FcRn transgenic mice. These results clearly demonstrate that glyco-engineering to improve cytotoxicity and protein-engineering to increase half-life can be combined to further optimize therapeutic mAbs. PMID:24492301

  4. Sperm-immobilizing monoclonal antibody to human seminal plasma antigens.

    PubMed Central

    Shigeta, M; Watanabe, T; Maruyama, S; Koyama, K; Isojima, S

    1980-01-01

    Rat spleen cells immunized to human azoospermic semen (a mixture of seminal plasma components) and mouse myeloma cells (P3/X63 Ag8U1; P3U1) (Marguilies et al., 1976) were successfully fused with polyethylene glycol (PEG 1500) and 19 of 89 fused cell cultures were found to produce sperm-immobilizing antibody. The cells that produced antibody indicating the highest sperm-immobilizing activity were distributed into wells for further recloning and 10 clones producing sperm-immobilizing antibody were established. The clone (1C4) producing the highest antibody titre was found to produce a large amount of IgG in culture supernatants and to contain a mixture of rat and mouse chromosomes. It was proved by immunodiffusion test that the monoclonal antibody was produced to the human seminal plasma antigen No. 7 which is common to human milk protein. Using this hybridoma which produced a large amount of monoclonal sperm-immobilizing antibody, a new method could be developed for purifying human seminal plasma antigen by immunoaffinity chromatography with bound antibody from the hybridoma. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:6783353

  5. Cephalopod eye evolution was modulated by the acquisition of Pax-6 splicing variants

    PubMed Central

    Yoshida, Masa-aki; Yura, Kei; Ogura, Atsushi

    2014-01-01

    Previous studies have reported that the developmental processes of vertebrate eyes are controlled by four Pax-6 splicing variants, each modulating different downstream genes, whereas those of insect eyes are controlled by duplicated Pax-6 genes. Cephalopods belong to the Protostomes but possess a camera-type eye similar to those in vertebrates. We examined Pax-6 variations in the squid and found five types of Pax-6 splicing variants but no duplication of the Pax-6 gene. In the five splicing variants, the splicing patterns were produced by the combination of two additional exons to the ortholog and one jettisoned exon containing most of the Homeobox domain (HD). These five variants show spatio-temporal patterns of gene expression during development in the squid. Our study suggests that cephalopods acquired Pax-6 splicing variants independent of those in vertebrates and that these variants were similarly utilized in the development of the squid eye. PMID:24594543

  6. Cephalopod eye evolution was modulated by the acquisition of Pax-6 splicing variants.

    PubMed

    Yoshida, Masa-aki; Yura, Kei; Ogura, Atsushi

    2014-03-05

    Previous studies have reported that the developmental processes of vertebrate eyes are controlled by four Pax-6 splicing variants, each modulating different downstream genes, whereas those of insect eyes are controlled by duplicated Pax-6 genes. Cephalopods belong to the Protostomes but possess a camera-type eye similar to those in vertebrates. We examined Pax-6 variations in the squid and found five types of Pax-6 splicing variants but no duplication of the Pax-6 gene. In the five splicing variants, the splicing patterns were produced by the combination of two additional exons to the ortholog and one jettisoned exon containing most of the Homeobox domain (HD). These five variants show spatio-temporal patterns of gene expression during development in the squid. Our study suggests that cephalopods acquired Pax-6 splicing variants independent of those in vertebrates and that these variants were similarly utilized in the development of the squid eye.

  7. Mutations in the paralogous human alpha-globin genes yielding identical hemoglobin variants.

    PubMed

    Moradkhani, Kamran; Préhu, Claude; Old, John; Henderson, Shirley; Balamitsa, Vera; Luo, Hong-Yuan; Poon, Man-Chiu; Chui, David H K; Wajcman, Henri; Patrinos, George P

    2009-06-01

    The human alpha-globin genes are paralogues, sharing a high degree of DNA sequence similarity and producing an identical alpha-globin chain. Over half of the alpha-globin structural variants reported to date are only characterized at the amino acid level. It is likely that a fraction of these variants, with phenotypes differing from one observation to another, may be due to the same mutation but on a different alpha-globin gene. There have been very few previous examples of hemoglobin variants that can be found at both HBA1 and HBA2 genes. Here, we report the results of a systematic multicenter study in a large multiethnic population to identify such variants and to analyze their differences from a functional and evolutionary perspective. We identified 14 different Hb variants resulting from identical mutations on either one of the two human alpha-globin paralogue genes. We also showed that the average percentage of hemoglobin variants due to a HBA2 gene mutation (alpha2) is higher than the percentage of hemoglobin variants due to the same HBA1 gene mutation (alpha1) and that the alpha2/alpha1 ratio varied between variants. These alpha-globin chain variants have most likely occurred via recurrent mutations, gene conversion events, or both. Based on these data, we propose a nomenclature for hemoglobin variants that fall into this category.

  8. Adenosine and Preexcitation Variants: Reappraisal of Electrocardiographic Changes.

    PubMed

    Ali, Hussam; Lupo, Pierpaolo; Foresti, Sara; De Ambroggi, Guido; Epicoco, Gianluca; Fundaliotis, Angelica; Cappato, Riccardo

    2016-07-01

    Intravenous adenosine is a short-acting blocker of the atrioventricular node that has been used to unmask subtle or latent preexcitation, and also to enable catheter ablation in selected patients with absent or intermittent preexcitation. Depending on the accessory pathway characteristics, intravenous adenosine may produce specific electrocardiographic changes highly suggestive of the preexcitation variant. Herein, we view different ECG responses to this pharmacological test in various preexcitation patterns that were confirmed by electrophysiological studies. Careful analysis of electrocardiographic changes during adenosine test, with emphasis on P-delta interval, preexcitation degree, and atrioventricular block, can be helpful to diagnose the preexcitation variant/pattern.

  9. Enhancement of the in vitro antibody response by thyrotropin.

    PubMed

    Blalock, J E; Johnson, H M; Smith, E M; Torres, B A

    1984-11-30

    The pituitary hormone thyrotropin (TSH) has been shown to enhance in a dose dependent manner the in vitro antibody response. Highly purified preparations of bovine and human TSH enhanced up to 375% the number of cells producing antibody to sheep erythrocytes. TSH had to be present prior to 24-48h of the initiation of culture for enhancement of the antibody response. An analogy is discussed between TSH and B lymphocyte growth and differentiation factors.

  10. N-terminal or signal peptide sequence engineering prevents truncation of human monoclonal antibody light chains.

    PubMed

    Gibson, S J; Bond, N J; Milne, S; Lewis, A; Sheriff, A; Pettman, G; Pradhan, R; Higazi, D R; Hatton, D

    2017-03-28

    Monoclonal antibodies (mAbs) contain short N-terminal signal peptides on each individual polypeptide that comprises the mature antibody, targeting them for export from the cell in which they are produced. The signal peptide is cleaved from each heavy chain (Hc) and light chain (Lc) polypeptide after translocation to the ER and prior to secretion. This process is generally highly efficient, producing a high proportion of correctly cleaved Hc and Lc polypeptides. However, mis-cleavage of the signal peptide can occur, resulting in truncation or elongation at the N-terminus of the Hc or Lc. This is undesirable for antibody manufacturing as it can impact efficacy and can result in product heterogeneity. Here, we describe a truncated variant of the Lc that was detected during a routine developability assessment of the recombinant human IgG1 MEDI8490 in Chinese hamster ovary cells. We found that the truncation of the Lc was caused due to the use of the murine Hc signal peptide together with a lambda Lc containing an SYE amino acid motif at the N-terminus. This truncation was not caused by mis-processing of the mRNA encoding the Lc and was not dependent on expression platform (transient or stable), the scale of the fed-batch culture or clonal lineage. We further show that using alternative signal peptides or engineering the Lc SYE N-terminal motif prevented the truncation and that this strategy will improve Lc homogeneity of other SYE lambda Lc-containing mAbs. This article is protected by copyright. All rights reserved.

  11. Recombinant genetic libraries and human monoclonal antibodies.

    PubMed

    Adams, Jarrett J; Nelson, Bryce; Sidhu, Sachdev S

    2014-01-01

    In order to comprehensively manipulate the human proteome we require a vast repertoire of pharmacological reagents. To address these needs we have developed repertoires of synthetic antibodies by phage display, where diversified oligonucleotides are used to modify the complementarity-determining regions (CDRs) of a human antigen-binding fragment (Fab) scaffold. As diversity is produced outside the confines of the mammalian immune system, synthetic antibody libraries allow us to bypass several limitations of hybridoma technology while improving the experimental parameters under which pharmacological reagents are produced. Here we describe the methodologies used to produce synthetic antibody libraries from a single human framework with diversity restricted to four CDRs. These synthetic repertoires can be extremely functional as they produce highly selective, high affinity Fabs to the majority of soluble human antigens. Finally we describe selection methodologies that allow us to overcome immuno-dominance in our selections to target a variety of epitopes per antigen. Together these methodologies allow us to produce human monoclonal antibodies to manipulate the human proteome.

  12. Antibodies Against Three Forms of Urokinase

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R.; Atassi, M. Zouhair

    2007-01-01

    Antibodies that bind to preselected regions of the urokinase molecule have been developed. These antibodies can be used to measure small quantities of each of three molecular forms of urokinase that could be contained in microsamples or conditioned media harvested from cultures of mammalian cells. Previously available antibodies and assay techniques do not yield both clear distinctions among, and measurements of, all three forms. Urokinase is a zymogen that is synthesized in a single-chain form, called ScuPA, which is composed of 411 amino acid residues (see figure). ScuPA has very little enzyme activity, but it can be activated in two ways: (1) by cleavage of the peptide bond lysine 158/isoleucine 159 and the loss of lysine 158 to obtain the high molecular-weight (HMW) form of the enzyme or (2) by cleavage of the bond lysine 135/lysine 136 to obtain the low-molecular-weight (LMW) form of the enzyme. The antibodies in question were produced in mice and rabbits by use of peptides as immunogens. The peptides were selected to obtain antibodies that bind to regions of ScuPA that include the lysine 158/isoleucine 159 and the lysine 135/lysine 136 bonds. The antibodies include monoclonal and polyclonal ones that yield indications as to whether either of these bonds is intact. The polyclonal antibodies include ones that preferentially bind to the HMW or LMW forms of the urokinase molecule. The monoclonal antibodies include ones that discriminate between the ScuPA and the HMW form. A combination of these molecular-specific antibodies will enable simultaneous assays of the ScuPA, HMW, and LMW forms in the same specimen of culture medium.

  13. Canine Parvovirus (CPV) Vaccination: Comparison of Neutralizing Antibody Responses in Pups after Inoculation with CPV2 or CPV2b Modified Live Virus Vaccine

    PubMed Central

    Pratelli, Annamaria; Cavalli, Alessandra; Martella, Vito; Tempesta, Maria; Decaro, Nicola; Carmichael, Leland Eugene; Buonavoglia, Canio

    2001-01-01

    Canine parvovirus type 2 (CPV2) emerged in 1978 as causative agent of a new disease of dogs. New antigenic variants (biotypes), designated CPV2a and CPV2b, became widespread during 1979 to 1980 and 1984, respectively. At the present time the original CPV2 has disappeared in the dog population and has been replaced by the two new viruses. In the present study the comparison of neutralizing antibody titers in two groups of pups (18 pups in each group) inoculated with CPV2 and CPV2b modified live virus vaccines is reported. Using the hemagglutination inhibition (HI) test, relevant differences between antibody titers, against either the homologous or the heterologous virus, were not constantly observed. Using the neutralization (Nt) test, however, the pups inoculated with CPV2 had antibody titers which were approximately 30 times higher to the homologous virus (mean, 4,732) than to the heterologous virus (CPV2b) (mean, 162). The results of these experiments support two conclusions: (i) the HI test may not always accurately evaluate the true immune status of dogs with respect to CPV, and (ii) dogs inoculated with CPV2 vaccine develop relatively low Nt antibody titers against the heterologous virus (CPV2b). These data may suggest an advantage for new vaccines, considering that most presently licensed vaccines are produced with CPV2, which no longer exists in the dog population. PMID:11329467

  14. Recombinant renewable polyclonal antibodies.

    PubMed

    Ferrara, Fortunato; D'Angelo, Sara; Gaiotto, Tiziano; Naranjo, Leslie; Tian, Hongzhao; Gräslund, Susanne; Dobrovetsky, Elena; Hraber, Peter; Lund-Johansen, Fridtjof; Saragozza, Silvia; Sblattero, Daniele; Kiss, Csaba; Bradbury, Andrew R M

    2015-01-01

    Only a small fraction of the antibodies in a traditional polyclonal antibody mixture recognize the target of interest, frequently resulting in undesirable polyreactivity. Here, we show that high-quality recombinant polyclonals, in which hundreds of different antibodies are all directed toward a target of interest, can be easily generated in vitro by combining phage and yeast display. We show that, unlike traditional polyclonals, which are limited resources, recombinant polyclonal antibodies can be amplified over one hundred million-fold without losing representation or functionality. Our protocol was tested on 9 different targets to demonstrate how the strategy allows the selective amplification of antibodies directed toward desirable target specific epitopes, such as those found in one protein but not a closely related one, and the elimination of antibodies recognizing common epitopes, without significant loss of diversity. These recombinant renewable polyclonal antibodies are usable in different assays, and can be generated in high throughput. This approach could potentially be used to develop highly specific recombinant renewable antibodies against all human gene products.

  15. Therapeutic Recombinant Monoclonal Antibodies

    ERIC Educational Resources Information Center

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

  16. Affinity purification of antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibodies are provided in a variety of formats that includes antiserum, hybridoma culture supernatant or ascites. They can all be used successfully in crude form for the detection of target antigens by immunoassay. However, it is advantageous to use purified antibody in defined quantity to facil...

  17. Production Of Human Antibodies

    NASA Technical Reports Server (NTRS)

    Sammons, David W.; Neil, Garry A.

    1993-01-01

    Process for making human monoclonal antibodies based on combination of techniques. Antibodies made active against specific antigen. Process involves in vivo immunization of human B lymphocyte cells in mice. B cells of interest enriched in vitro before fusion. Method potentially applicable to any antigen. Does not rely on use of Epstein-Barr virus at any step. Human lymphocytes taken from any source.

  18. Antibodies for biodefense

    PubMed Central

    Froude, Jeffrey W; Stiles, Bradley; Pelat, Thibaut

    2011-01-01

    Potential bioweapons are biological agents (bacteria, viruses and toxins) at risk of intentional dissemination. Biodefense, defined as development of therapeutics and vaccines against these agents, has seen an increase, particularly in the US, following the 2001 anthrax attack. This review focuses on recombinant antibodies and polyclonal antibodies for biodefense that have been accepted for clinical use. These antibodies aim to protect against primary potential bioweapons or category A agents as defined by the Centers for Disease Control and Prevention (Bacillus anthracis, Yersinia pestis, Francisella tularensis, botulinum neurotoxins, smallpox virus and certain others causing viral hemorrhagic fevers) and certain category B agents. Potential for prophylactic use is presented, as well as frequent use of oligoclonal antibodies or synergistic effect with other molecules. Capacities and limitations of antibodies for use in biodefense are discussed, and are generally applicable to the field of infectious diseases. PMID:22123065

  19. In vivo emergence of enterotoxigenic Escherichia coli variants lacking genes for K99 fimbriae and heat-stable enterotoxin.

    PubMed Central

    Mainil, J G; Sadowski, P L; Tarsio, M; Moon, H W

    1987-01-01

    Neonatal pigs were inoculated with porcine enterotoxigenic Escherichia coli 431, which carries genes for K99 fimbriae and STaP enterotoxin. Colonies of strain 431 were recovered from feces of pigs for up to 17 days after inoculation and tested for hybridization with gene probes for K99 and STaP. Variants of strain 431 that did not hybridize with the probes were considered to have lost the genes. Variants were recovered from 10 of 13 suckling pigs that survived the infection. Only 0.4% of the isolates recovered during the first 2 days after inoculation were variants. Of the isolates recovered 3 to 5 days after inoculation, 20 to 36% were variants. Variant colonies were detected more frequently among pigs in some litters than in others. The litter with the highest number of variant-shedding pigs had the dam with the highest titer of K99 antibody in her colostrum. Variants also occurred in colostrum-deprived, artificially reared pigs. However, the number of variants detected was lower and they occurred later in the course of the infection in colostrum-deprived pigs than in suckling pigs. More variants were detected and they were detected earlier in colostrum-deprived pigs fed anti-K99 monoclonal antibody than in controls fed anti-K88 monoclonal antibody. Loss of STaP appeared to be secondary to loss of K99 in that some variants lacked only K99 (K99- STaP+) and some lacked both genes (K99- STaP-), but none was of the K99+ STaP- type. Our results confirmed reports of gene loss from enterotoxigenic E. coli during infection. They are consistent with the hypothesis that variants emerge under in vivo selection pressure of K99 antibody and with the speculation that gene loss may be an important component of protection in vaccinated populations. However, the emergence of variants did not appear to play a major role in the recovery of individual pigs from clinical disease. PMID:2890584

  20. Are natural antibodies involved in tumour defence?

    PubMed

    Bohn, J

    1999-09-01

    Natural antibodies (NAb) are found in the serum of healthy individuals. These antibodies are produced without any apparent specific antigenic stimulation. They are one part of the circulating immunoglobulins and are found in virtually all vertebrate species. NAb react to various self- and non-self antigens. A protective function in different infection models could be demonstrated. Several groups have reported the ability of NAb to bind to tumour cells. Their possible role in tumour defence is documented in mice. The present status of attempts to characterise the role of NAb in tumour defence is discussed, particularly as regards the human immune system. This paper focuses on antibody cell interactions and discusses the genetic background of the Nab-producing B-cells.

  1. Anti-DNA antibody mediated catalysis is isotype dependent.

    PubMed

    Xia, Yumin; Eryilmaz, Ertan; Zhang, Qiuting; Cowburn, David; Putterman, Chaim

    2016-01-01

    Anti-DNA antibodies are the serological hallmark of systemic lupus erythematosus, and participate in the pathogenesis of lupus nephritis by cross-reacting with multiple renal antigens. Previously, using a panel of murine anti-DNA IgGs that share identical variable regions but that differ in the constant regions, we demonstrated that the cross-reaction and renal pathogenicity of anti-DNA antibodies are isotype dependent. In this study, we investigated the catalytic potential of this anti-DNA antibody panel, and determined its isotype dependency. The three isotype switch variants (IgG1, IgG2a, IgG2b) and the parent IgG3 PL9-11 anti-DNA antibodies were compared in their catalysis of 500 base pair linear double stranded DNA and a 12-mer peptide (ALWPPNLHAWVP), by gel analysis, MALDI-TOF mass spectrometry, and nuclear magnetic resonance spectroscopy. The binding affinity of anti-DNA antibodies to double stranded DNA and peptide antigens were assessed by ELISA and surface plasmon resonance. We found that the PL9-11 antibody isotypes vary significantly in their potential to catalyze the cleavage of both linear and double stranded DNA and the proteolysis of peptides. The degree of the cleavage and proteolysis increases with the incubation temperature and time. While different PL9-11 isotypes have the same initial attack sites within the ALWPPNLHAWVP peptide, there was no correlation between binding affinity to the peptide and proteolysis rates. In conclusion, the catalytic properties of anti-DNA antibodies are isotype dependent. This finding provides further evidence that antibodies that share the same variable region, but which have different constant regions, are functionally distinct. The catalytic effects modulated by antibody constant regions need to be considered in the design of therapeutic antibodies (abzymes) and peptides designed to block pathogenic autoantibodies.

  2. Monoclonal antibodies against soman: Characterization of soman stereoisomers. (Reannouncement with new availability information)

    SciTech Connect

    Lenz, D.E.; Yourick, J.J.; Dawson, J.S.; Scott, J.

    1992-12-31

    Hybridomas were produced which expressed monoclonal anti-soman antibodies as determined by microtiter enzyme-linked-antibody immunoassay (EIA). Each of these antibodies was titrated using a competitive inhibition enzyme immunoassay (CIEIA) with a variety of test ligands. The ligands used included soman (a racemic mixture), sarin, tabun, and each of the four stereoisomers of soman(C+P+, C+P-, C-P+ and C-P-). In all cases the antibodies tested exhibited IC50 values of 10 - 4 - 5 X 10 - 6 M for soman. When sarin or tabun was used as a ligand, the antibodies exhibited no cross reactivity. All of the antibodies cross reacted with the four soman stereoisomers. A second group of hybridomas were produced which expressed monoclonal antibodies against CsPs-soman. These antibodies were used to make preliminary absolute chiral assignments to the four soman stereoisomers. Soman; Antibodies; Stereoisomers; Absolute configuration.

  3. An antibody to the aggregated synthetic prion protein peptide (PrP106-126) selectively recognizes disease-associated prion protein (PrP) from human brain specimens.

    PubMed

    Jones, Michael; Wight, Darren; McLoughlin, Victoria; Norrby, Katherine; Ironside, James W; Connolly, John G; Farquhar, Christine F; MacGregor, Ian R; Head, Mark W

    2009-04-01

    Human prion diseases are characterized by the conversion of the normal host cellular prion protein (PrP(C)) into an abnormal misfolded form [disease-associated prion protein (PrP(Sc))]. Antibodies that are capable of distinguishing between PrP(C) and PrP(Sc) may prove to be useful, not only for the diagnosis of these diseases, but also for a better understanding of the molecular mechanisms involved in disease pathogenesis. In an attempt to produce such antibodies, we immunized mice with an aggregated peptide spanning amino acid residues 106 to 126 of human PrP (PrP106-126). We were able to isolate and single cell clone a hybridoma cell line (P1:1) which secreted an IgM isotype antibody [monoclonal antibody (mAb P1:1)] that recognized the aggregated, but not the monomeric form of the immunogen. When used in immunoprecipitation assays, the antibody did not recognize normal PrP(C) from non-prion disease brain specimens, but did selectively immunoprecipitate full-length PrP(Sc) from cases of variant and sporadic Creutzfeldt-Jakob disease and Gerstmann-Straussler-Scheinker disease. These results suggest that P1:1 recognizes an epitope formed during the structural rearrangement or aggregation of the PrP that is common to the major PrP(Sc) types found in the most common forms of human prion disease.

  4. Selection of Recombinant Human Antibodies.

    PubMed

    Tomszak, Florian; Weber, Susanne; Zantow, Jonas; Schirrmann, Thomas; Hust, Michael; Frenzel, André

    2016-01-01

    Since the development of therapeutic antibodies the demand of recombinant human antibodies is steadily increasing. Traditionally, therapeutic antibodies were generated by immunization of rat or mice, the generation of hybridoma clones, cloning of the antibody genes and subsequent humanization and engineering of the lead candidates. In the last few years, techniques were developed that use transgenic animals with a human antibody gene repertoire. Here, modern recombinant DNA technologies can be combined with well established immunization and hybridoma technologies to generate already affinity maturated human antibodies. An alternative are in vitro technologies which enabled the generation of fully human antibodies from antibody gene libraries that even exceed the human antibody repertoire. Specific antibodies can be isolated from these libraries in a very short time and therefore reduce the development time of an antibody drug at a very early stage.In this review, we describe different technologies that are currently used for the in vitro and in vivo generation of human antibodies.

  5. Red Blood Cell Antibody Identification

    MedlinePlus

    ... name: Red Blood Cell Antibody Identification Related tests: Direct Antiglobulin Test ; RBC Antibody Screen ; Blood Typing ; Type ... a positive RBC antibody screen or a positive direct antiglobulin test (DAT) . It is used to identify ...

  6. Manipulating the selection forces during affinity maturation to generate cross-reactive HIV antibodies

    PubMed Central

    Wang, Shenshen; Mata-Fink, Jordi; Kriegsman, Barry; Hanson, Melissa; Irvine, Darrell J.; Eisen, Herman N.; Burton, Dennis R.; Wittrup, K. Dane; Kardar, Mehran; Chakraborty, Arup K.

    2015-01-01

    Summary Generation of potent antibodies by a mutation-selection process called affinity maturation is a key component of effective immune responses. Antibodies that protect against highly mutable pathogens must neutralize diverse strains. Developing effective immunization strategies to drive their evolution requires understanding how affinity maturation happens in an enviroment where variants of the same antigen are present. We present an in silico model of affinity maturation driven by antigen variants which reveals that induction of cross-reactive antibodies often occurs with low probability because conflicting selection forces, imposed by different antigen variants, can frustrate affinity maturation. We describe how variables such as temporal pattern of antigen administration influence the outcome of this frustrated evolutionary process. Our calculations predict, and experiments in mice with variant gp120 constructs of the HIV envelope protein confirm, that sequential immunization with antigen variants is preferred over a cocktail for induction of cross-reactive antibodies focused on the shared CD4 binding site epitope. PMID:25662010

  7. Production of site-specific antibody-drug conjugates using optimized non-natural amino acids in a cell-free expression system.

    PubMed

    Zimmerman, Erik S; Heibeck, Tyler H; Gill, Avinash; Li, Xiaofan; Murray, Christopher J; Madlansacay, Mary Rose; Tran, Cuong; Uter, Nathan T; Yin, Gang; Rivers, Patrick J; Yam, Alice Y; Wang, Willie D; Steiner, Alexander R; Bajad, Sunil U; Penta, Kalyani; Yang, Wenjin; Hallam, Trevor J; Thanos, Christopher D; Sato, Aaron K

    2014-02-19

    Antibody-drug conjugates (ADCs) are a targeted chemotherapeutic currently at the cutting edge of oncology medicine. These hybrid molecules consist of a tumor antigen-specific antibody coupled to a chemotherapeutic small molecule. Through targeted delivery of potent cytotoxins, ADCs exhibit improved therapeutic index and enhanced efficacy relative to traditional chemotherapies and monoclonal antibody therapies. The currently FDA-approved ADCs, Kadcyla (Immunogen/Roche) and Adcetris (Seattle Genetics), are produced by conjugation to surface-exposed lysines, or partial disulfide reduction and conjugation to free cysteines, respectively. These stochastic modes of conjugation lead to heterogeneous drug products with varied numbers of drugs conjugated across several possible sites. As a consequence, the field has limited understanding of the relationships between the site and extent of drug loading and ADC attributes such as efficacy, safety, pharmacokinetics, and immunogenicity. A robust platform for rapid production of ADCs with defined and uniform sites of drug conjugation would enable such studies. We have established a cell-free protein expression system for production of antibody drug conjugates through site-specific incorporation of the optimized non-natural amino acid, para-azidomethyl-l-phenylalanine (pAMF). By using our cell-free protein synthesis platform to directly screen a library of aaRS variants, we have discovered a novel variant of the Methanococcus jannaschii tyrosyl tRNA synthetase (TyrRS), with a high activity and specificity toward pAMF. We demonstrate that site-specific incorporation of pAMF facilitates near complete conjugation of a DBCO-PEG-monomethyl auristatin (DBCO-PEG-MMAF) drug to the tumor-specific, Her2-binding IgG Trastuzumab using strain-promoted azide-alkyne cycloaddition (SPAAC) copper-free click chemistry. The resultant ADCs proved highly potent in in vitro cell cytotoxicity assays.

  8. Detection of Specific Strains and Variants of Streptococcus cremoris in Mixed Cultures by Immunofluorescence

    PubMed Central

    Hugenholtz, Jeroen; Veldkamp, Hans; Konings, Wil N.

    1987-01-01

    Antisera against four different strains of Streptococcus cremoris were raised by injecting rabbits with washed suspensions of whole cells. These antisera interacted specifically with the corresponding strain in a mixture of up to nine different S. cremoris strains. The antisera could be used for analyzing the composition of mixed cultures containing these strains by immunofluorescence. Competition experiments were performed in batch and continuous cultures under amino acid limitation. A bacteriophage-sensitive variant of S. cremoris SK11 (SK1128) could be distinguished from a bacteriophage-resistant variant (SK1143) by the same immunofluorescence technique. The competition between the two variants and the stability of both variants in pure cultures were followed with the specific antibodies. Antibodies against the purified proteolytic system of S. cremoris Wg2 were used to determine the presence of proteases by immunofluorescence in several S. cremoris strains under different culture conditions. The described immunofluorescence methods can be used to analyze complex mixed starter cultures common in the dairy industry as the strains and variants present in these mixtures can be recognized microscopically. Images PMID:16347256

  9. Re-ranking sequencing variants in the post-GWAS era for accurate causal variant identification.

    PubMed

    Faye, Laura L; Machiela, Mitchell J; Kraft, Peter; Bull, Shelley B; Sun, Lei

    2013-01-01

    Next generation sequencing has dramatically increased our ability to localize disease-causing variants by providing base-pair level information at costs increasingly feasible for the large sample sizes required to detect complex-trait associations. Yet, identification of causal variants within an established region of association remains a challenge. Counter-intuitively, certain factors that increase power to detect an associated region can decrease power to localize the causal variant. First, combining GWAS with imputation or low coverage sequencing to achieve the large sample sizes required for high power can have the unintended effect of producing differential genotyping error among SNPs. This tends to bias the relative evidence for association toward better genotyped SNPs. Second, re-use of GWAS data for fine-mapping exploits previous findings to ensure genome-wide significance in GWAS-associated regions. However, using GWAS findings to inform fine-mapping analysis can bias evidence away from the causal SNP toward the tag SNP and SNPs in high LD with the tag. Together these factors can reduce power to localize the causal SNP by more than half. Other strategies commonly employed to increase power to detect association, namely increasing sample size and using higher density genotyping arrays, can, in certain common scenarios, actually exacerbate these effects and further decrease power to localize causal variants. We develop a re-ranking procedure that accounts for these adverse effects and substantially improves the accuracy of causal SNP identification, often doubling the probability that the causal SNP is top-ranked. Application to the NCI BPC3 aggressive prostate cancer GWAS with imputation meta-analysis identified a new top SNP at 2 of 3 associated loci and several additional possible causal SNPs at these loci that may have otherwise been overlooked. This method is simple to implement using R scripts provided on the author's website.

  10. Site-specific photoconjugation of antibodies using chemically synthesized IgG-binding domains.

    PubMed

    Perols, Anna; Karlström, Amelie Eriksson

    2014-03-19

    Site-specific labeling of antibodies can be performed using the immunoglobulin-binding Z domain, derived from staphylococcal protein A (SpA), which has a well-characterized binding site in the Fc region of antibodies. By introducing a photoactivable probe in the Z domain, a covalent bond can be formed between the Z domain and the antibody by irradiation with UV light. The aim of this study was to improve the conjugation yield for labeling of different subclasses of IgG having different sequence composition, using a photoactivated Z domain variant. Four different variants of the Z domain (Z5BPA, Z5BBA, Z32BPA, and Z32BBA) were synthesized to investigate the influence of the position of the photoactivable probe and the presence of a flexible linker between the probe and the protein. For two of the variants, the photoreactive benzophenone group was introduced as part of an amino acid side chain by incorporation of the unnatural amino acid benzoylphenylalanine (BPA) during peptide synthesis. For the other two variants, the photoreactive benzophenone group was attached via a flexible linker by coupling of benzoylbenzoic acid (BBA) to the ε-amino group of a selectively deprotected lysine residue. Photoconjugation experiments using human IgG1, mouse IgG1, and mouse IgG2A demonstrated efficient conjugation for all antibodies. It was shown that differences in linker length had a large impact on the conjugation efficiency for labeling of mouse IgG1, whereas the positioning of the photoactivable probe in the sequence of the protein had a larger effect for mouse IgG2A. Conjugation to human IgG1 was only to a minor extent affected by position or linker length. For each subclass of antibody, the best variant tested using a standard conjugation protocol resulted in conjugation efficiencies of 41-66%, which corresponds to on average approximately one Z domain attached to each antibody. As a combination of the two best performing variants, Z5BBA and Z32BPA, a Z domain variant with

  11. 9 CFR 113.450 - General requirements for antibody products.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... precise glycoprotein structure, produced by certain cells of the B lymphocyte lineage in response to... characterized by an abnormally low concentration of circulating maternal IgG. (b) Nomenclature. Antibody... “monoclonal” shall be used. Example: “Duck Virus Hepatitis Antibody, Duck Origin.” (2)...

  12. 9 CFR 113.450 - General requirements for antibody products.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... precise glycoprotein structure, produced by certain cells of the B lymphocyte lineage in response to... characterized by an abnormally low concentration of circulating maternal IgG. (b) Nomenclature. Antibody... “monoclonal” shall be used. Example: “Duck Virus Hepatitis Antibody, Duck Origin.” (2)...

  13. 9 CFR 113.450 - General requirements for antibody products.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... precise glycoprotein structure, produced by certain cells of the B lymphocyte lineage in response to... characterized by an abnormally low concentration of circulating maternal IgG. (b) Nomenclature. Antibody... “monoclonal” shall be used. Example: “Duck Virus Hepatitis Antibody, Duck Origin.” (2)...

  14. 9 CFR 113.450 - General requirements for antibody products.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... precise glycoprotein structure, produced by certain cells of the B lymphocyte lineage in response to... characterized by an abnormally low concentration of circulating maternal IgG. (b) Nomenclature. Antibody... “monoclonal” shall be used. Example: “Duck Virus Hepatitis Antibody, Duck Origin.” (2)...

  15. 9 CFR 113.450 - General requirements for antibody products.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... precise glycoprotein structure, produced by certain cells of the B lymphocyte lineage in response to... characterized by an abnormally low concentration of circulating maternal IgG. (b) Nomenclature. Antibody... “monoclonal” shall be used. Example: “Duck Virus Hepatitis Antibody, Duck Origin.” (2)...

  16. Characterization of Humanized Antibodies Secreted by Aspergillus niger

    PubMed Central

    Ward, Michael; Lin, Cherry; Victoria, Doreen C.; Fox, Bryan P.; Fox, Judith A.; Wong, David L.; Meerman, Hendrik J.; Pucci, Jeff P.; Fong, Robin B.; Heng, Meng H.; Tsurushita, Naoya; Gieswein, Christine; Park, Minha; Wang, Huaming

    2004-01-01

    Two different humanized immunoglobulin G1(κ) antibodies and an Fab′ fragment were produced by Aspergillus niger. The antibodies were secreted into the culture supernatant. Both light and heavy chains were initially synthesized as fusion proteins with native glucoamylase. After antibody assembly, cleavage by A. niger KexB protease allowed the release of free antibody. Purification by hydrophobic charge induction chromatography proved effective at removing any antibody to which glucoamylase remained attached. Glycosylation at N297 in the Fc region of the heavy chain was observed, but this site was unoccupied on approximately 50% of the heavy chains. The glycan was of the high-mannose type, with some galactose present, and the size ranged from Hex6GlcNAc2 to Hex15GlcNAc2. An aglycosyl mutant form of antibody was also produced. No significant difference between the glycosylated antibody produced by Aspergillus and that produced by mammalian cell cultures was observed in tests for affinity, avidity, pharmacokinetics, or antibody-dependent cellular cytotoxicity function. PMID:15128505

  17. A Recombinant Bispecific CD20×CD95 Antibody With Superior Activity Against Normal and Malignant B-cells

    PubMed Central

    Nalivaiko, Kristina; Hofmann, Martin; Kober, Karina; Teichweyde, Nadine; Krammer, Peter H; Rammensee, Hans-Georg; Grosse-Hovest, Ludger; Jung, Gundram

    2016-01-01

    Monoclonal antibodies directed to the B-cell-specific CD20-antigen are successfully used for the treatment of lymphomas and autoimmune diseases. Here, we compare the anti-B-cell activity of three different antibodies directed to CD20: (i) a chimeric, monospecific antibody, (ii) an Fc-optimized variant thereof, and (iii) a bispecific CD20×CD95-antibody in a newly developed recombinant format, termed Fabsc. The bispecific antibody specifically triggers the CD95 death receptor on malignant, as well as activated, normal B-cells. We found that the capability of this antibody to suppress the growth of malignant B-cells in vitro and in vivo and to specifically deplete normal, activated B-cells from peripheral blood mononuclear cell (PBMC) cultures was superior to that of the Fc-optimized monospecific antibody. This antibody in turn was more effective than its nonoptimized variant. Moreover, the bispecific antibody was the only reagent capable of significantly suppressing antibody production in vitro. Our findings imply that the bispecific CD20×CD95-antibody might become a new, prototypical reagent for the treatment of B-cell-mediated autoimmune disease. PMID:26581163

  18. Project Produce

    ERIC Educational Resources Information Center

    Wolfinger, Donna M.

    2005-01-01

    The grocery store produce section used to be a familiar but rather dull place. There were bananas next to the oranges next to the limes. Broccoli was next to corn and lettuce. Apples and pears, radishes and onions, eggplants and zucchinis all lay in their appropriate bins. Those days are over. Now, broccoli may be next to bok choy, potatoes beside…

  19. Production and characterization of a panel of monoclonal antibodies against native human cellular prion protein.

    PubMed

    Jones, Michael; McLoughlin, Victoria; Connolly, John G; Farquhar, Christine F; MacGregor, Ian R; Head, Mark W

    2009-02-01

    The human prion diseases, such as variant Creutzfeldt-Jakob disease (vCJD), are characterized by the conversion of the normal cellular prion protein (PrP(C)) into an abnormal disease associated form (PrP(Sc)). Monoclonal antibodies (MAbs) that recognize these different PrP isoforms are valuable reagents both in the diagnosis of these diseases and in prion disease research in general but we know of no attempts to raise MAbs against native human PrP(C). We immunized prion protein gene ablated (PrP(-/-)) mice with native human PrP(C) purified from platelets (pHuPrP) generating a predominantly IgG isotype anti-pHuPrP polyclonal antibody response in all mice. Following fusion of splenocytes from the immunized mice with SP2/0 myeloma cells, we were able to identify single cell clone and cryopreserve 14 stable hybridoma cell lines producing MAbs that reacted with pHuPrP. The properties of these MAbs (such as isotype, binding to native/denatured pHuPrP, and HuPrP epitopes recognized) are described. Furthermore, several of these MAbs showed a selectivity in their ability to immunoprecipitate disease associated PrP(Sc) and its corresponding protease resistant core (PrP(res)).

  20. Generation of “LYmph Node Derived Antibody Libraries” (LYNDAL) for selecting fully human antibody fragments with therapeutic potential

    PubMed Central

    Diebolder, Philipp; Keller, Armin; Haase, Stephanie; Schlegelmilch, Anne; Kiefer, Jonathan D; Karimi, Tamana; Weber, Tobias; Moldenhauer, Gerhard; Kehm, Roland; Eis-Hübinger, Anna M; Jäger, Dirk; Federspil, Philippe A; Herold-Mende, Christel; Dyckhoff, Gerhard; Kontermann, Roland E; Arndt, Michaela AE; Krauss, Jürgen

    2014-01-01

    The development of efficient strategies for generating fully human monoclonal antibodies with unique functional properties that are exploitable for tailored therapeutic interventions remains a major challenge in the antibody technology field. Here, we present a methodology for recovering such antibodies from antigen-encountered human B cell repertoires. As the source for variable antibody genes, we cloned immunoglobulin G (IgG)-derived B cell repertoires from lymph nodes of 20 individuals undergoing surgery for head and neck cancer. Sequence analysis of unselected “LYmph Node Derived Antibody Libraries” (LYNDAL) revealed a naturally occurring distribution pattern of rearranged antibody sequences, representing all known variable gene families and most functional germline sequences. To demonstrate the feasibility for selecting antibodies with therapeutic potential from these repertoires, seven LYNDAL from donors with high serum titers against herpes simplex virus (HSV) were panned on recombinant glycoprotein B of HSV-1. Screening for specific binders delivered 34 single-chain variable fragments (scFvs) with unique sequences. Sequence analysis revealed extensive somatic hypermutation of enriched clones as a result of affinity maturation. Binding of scFvs to common glycoprotein B variants from HSV-1 and HSV-2 strains was highly specific, and the majority of analyzed antibody fragments bound to the target antigen with nanomolar affinity. From eight scFvs with HSV-neutralizing capacity in vitro, the most potent antibody neutralized 50% HSV-2 at 4.5 nM as a dimeric (scFv)2. We anticipate our approach to be useful for recovering fully human antibodies with therapeutic potential. PMID:24256717

  1. DNA shuffling: induced molecular breeding to produce new generation long-lasting vaccines.

    PubMed

    Marshall, Sergio H

    2002-11-01

    The paradigm for classic vaccines has been to mimic natural infection, and their success relies mostly on the induction of neutralizing antibodies followed by long-lasting immunity. The outcome of aggressive chronic infections such as HIV and HCV, the reappearance of fastidious diseases such as tuberculosis and the progression of cancer growth suggest that natural immune responses are definitely insufficient in many cases. A new paradigm is needed to design and develop a new high-efficiency generation of vaccines ideally able to surpass the capabilities of natural immune responses. In vitro evolution is a new, important laboratory method to evolve molecules with desired properties, which appears as an appealing alternative to achieve this goal. In its battle against disease, the vertebrate immune system triggers a series of well-known molecular events in order to produce protective neutralizing antibodies. This natural in vivo response shares remarkable similarities with the in vitro technique known as molecular breeding or "DNA shuffling." This method exploits the recombination between genes to dramatically accelerate the rate at which genes can be evolved under selection pressure in the laboratory, producing optimized high-efficiency mutant proteins. Since new generation vaccines are aimed to overcome natural selection and environmental pressures to fully inactivate rapidly developing pathogen variants, they could be engineered, developed and selected through the application of directed DNA shuffling procedures. This review highlights the potential of the procedure in the complex context of natural immune responses and the equilibrium and interaction existing in nature between hosts and pathogens.

  2. NMDA receptor antibodies

    PubMed Central

    Ramberger, Melanie; Bsteh, Gabriel; Schanda, Kathrin; Höftberger, Romana; Rostásy, Kevin; Baumann, Matthias; Aboulenein-Djamshidian, Fahmy; Lutterotti, Andreas; Deisenhammer, Florian; Berger, Thomas

    2015-01-01

    Objectives: To analyze the frequency of NMDA receptor (NMDAR) antibodies in patients with various inflammatory demyelinating diseases of the CNS and to determine their clinical correlates. Methods: Retrospective case-control study from 2005 to 2014 with the detection of serum IgG antibodies to NMDAR, aquaporin-4, and myelin oligodendrocyte glycoprotein by recombinant live cell-based immunofluorescence assays. Fifty-one patients with acute disseminated encephalomyelitis, 41 with neuromyelitis optica spectrum disorders, 34 with clinically isolated syndrome, and 89 with multiple sclerosis (MS) were included. Due to a known association of NMDAR antibodies with seizures and behavioral symptoms, patients with those clinical manifestations were preferentially included and are therefore overrepresented in our cohort. Nine patients with NMDAR encephalitis, 94 patients with other neurologic diseases, and 48 healthy individuals were used as controls. Results: NMDAR antibodies were found in all 9 patients with NMDAR encephalitis but in only 1 of 215 (0.5%) patients with inflammatory demyelination and in none of the controls. This patient had relapsing-remitting MS with NMDAR antibodies present at disease onset, with an increase in NMDAR antibody titer with the onset of psychiatric symptoms and cognitive deficits. Conclusion: In demyelinating disorders, NMDAR antibodies are uncommon, even in those with symptoms seen in NMDAR encephalitis. PMID:26309901

  3. Therapeutic antibody technology 97.

    PubMed

    Larrick, J W; Gavilondo, J

    1998-01-01

    Almost 200 antibody aficionados attended the Therapeutic Antibody Technology 97 meeting, held September 21-24, 1997 at the Holiday Inn, Union Square in the heart of San Francisco, CA. The meeting was sponsored by the Palo Alto Institute of Molecular Medicine and organized by James W. Larrick (PAIMM) and Dennis R. Burton (Scripps Research Institute). The meeting featured excellent discussions on many interesting talks and a number of poster presentations. It is likely that another meeting will be organized in 2 years, however in the meantime, an effort is underway to organize a 'Virtual Antibody Society' to be set up on the web server at Scripps Research Institute in La Jolla, CA (Questions and comments on this project can be sent to: Jwlarrick@aol.com or Burton@scripps.edu). Richard Lerner (Scripps) gave the keynote address on 'Catalytic Antibodies', describing recent work with Carlos Barbas on so-called reactive immunization to generate a high activity aldolase catalytic antibody. This antibody, soon to be described in an article in Science, is the first commercially available catalytic antibody.

  4. Cytological aspects of melanotic variant of medullary thyroid carcinoma.

    PubMed

    de Lima, M A; Dias Medeiros, J; Rodrigues Da Cunha, L; de Cássia Caldas Pessôa, R; Silveira Tavares, F; de Fátima Borges, M; Marinho, E O

    2001-03-01

    We had the opportunity to examine a case of fine-needle aspiration (FNA) of a melanotic variant of medullary thyroid carcinoma (MTC) in a 20-yr-old man. The patient presented a single node, hardened and mobile upon deglutition, in the right lobe of the thyroid, for 9 mo, without symptoms of glandular dysfunction. Calcitonin (138 pg/ml), urinary calcium (177 mg/dl), and the carcinoembryonic antigen (341 ng/ml) were increased. The nodular aspirate, drawn by FNA, was represented by pleomorphic cells, with frequent intranuclear cytoplasmic inclusions, sometimes bi- or multinucleated, with abundant, finely granular cytoplasm, sometimes containing a brown pigment resembling melanin. An immunohistochemical study using monoclonal antibodies (Dako Corp., Carpinteria, CA) showed that the neoplastic cells were intensely and diffusely positive for calcitonin and chromogranin, and focally positive for HMB45. In view of these findings, the case was characterized as a melanotic variant of medullary carcinoma, a rare type of neoplasia, but having a prognosis similar to the classical variant of MTC.

  5. Monoclonal antibodies to leukotoxin of Actinobacillus actinomycetemcomitans.

    PubMed Central

    DiRienzo, J M; Tsai, C C; Shenker, B J; Taichman, N S; Lally, E T

    1985-01-01

    Hybridoma cell lines which produce monoclonal antibodies to a leukotoxin from Actinobacillus actinomycetemcomitans were prepared. The monoclonal antibodies were selected for their ability to neutralize the cytotoxic activity of the leukotoxin and recognize the toxin on nitrocellulose blots. The antibodies belonged to either the immunoglobulin G1 (IgG1) or IgG2 subclass and differed in their ability to bind to the leukotoxin on nitrocellulose blots. However, only slight differences in neutralization titers were observed. Use of the monoclonal antibodies revealed that polymyxin B-extracted or osmotic shock-released leukotoxin could be separated into several high-molecular-weight polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunoblot analysis with the monoclonal antibodies also demonstrated that the leukotoxin was present in eight oral strains of A. actinomycetemcomitans that had been previously classified by a biological assay as leukotoxic. The availability of these monoclonal antibodies should facilitate and expand studies concerning the role of the leukotoxin in the pathogenicity of A. actinomycetemcomitans. Images PMID:3965404

  6. Monoclonal antibody "gold rush".

    PubMed

    Maggon, Krishan

    2007-01-01

    The market, sales and regulatory approval of new human medicines, during the past few years, indicates increasing number and share of new biologics and emergence of new multibillion dollar molecules. The global sale of monoclonal antibodies in 2006 were $20.6 billion. Remicade had annual sales gain of $1 billion during the past 3 years and five brands had similar increase in 2006. Rituxan with 2006 sales of $4.7 billion was the best selling monoclonal antibody and biological product and the 6th among the top selling medicinal brand. It may be the first biologic and monoclonal antibody to reach $10 billion annual sales in the near future. The strong demand from cancer and arthritis patients has surpassed almost all commercial market research reports and sales forecast. Seven monoclonal antibody brands in 2006 had sales exceeding $1 billion. Humanized or fully human monoclonal antibodies with low immunogenicity, enhanced antigen binding and reduced cellular toxicity provide better clinical efficacy. The higher technical and clinical success rate, overcoming of technical hurdles in large scale manufacturing, low cost of market entry and IND filing, use of fully human and humanized monoclonal antibodies has attracted funds and resources towards R&D. Review of industry research pipeline and sales data during the past 3 years indicate a real paradigm shift in industrial R&D from pharmaceutical to biologics and monoclonal antibodies. The antibody bandwagon has been joined by 200 companies with hundreds of new projects and targets and has attracted billions of dollars in R&D investment, acquisitions and licensing deals leading to the current Monoclonal Antibody Gold Rush.

  7. Oxidation in the complementarity-determining regions differentially influences the properties of therapeutic antibodies

    PubMed Central

    Dashivets, Tetyana; Stracke, Jan; Dengl, Stefan; Knaupp, Alexander; Pollmann, Jan; Buchner, Johannes; Schlothauer, Tilman

    2016-01-01

    ABSTRACT Therapeutic antibodies can undergo a variety of chemical modification reactions in vitro. Depending on the site of modification, either anti