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Sample records for conjugado anti igg

  1. A RECOMBINANT IgG Fc THAT RECAPITULATES THE ANTI-INFLAMMATORY ACTIVITY OF IVIG

    PubMed Central

    Anthony, Robert M.; Nimmerjahn, Falk; Ashline, David J.; Reinhold, Vernon N.; Paulson, James C.; Ravetch, Jeffrey V.

    2008-01-01

    High doses of monomeric IgG purified from pooled human plasma confer anti-inflammatory activity for a wide variety of autoimmune diseases. The heterogeneity of IVIG, derived from its Fab specificity, IgG subclass distribution and variable glycosylation have confounded efforts to develop a recombinant substitute for this blood-derived product. Recent studies have demonstrated that this paradoxical anti-inflammatory activity of IgG is completely dependent on sialylation of the N-linked glycan of the IgG Fc fragment. Determining the precise glycan requirements for this anti-inflammatory activity allowed appropriate glycan engineering of an IgG1 Fc fragment, leading to the generation of a fully recombinant, sialylated IgG1 Fc with greatly enhanced potency. PMID:18420934

  2. Optimization of the cutoff value for a commercial anti-dengue virus IgG immunoassay.

    PubMed

    Marrero-Santos, Karla M; Beltrán, Manuela; Carrión-Lebrón, Jessica; Sanchez-Vegas, Carolina; Hamer, Davidson H; Barnett, Elizabeth D; Santiago, Luis M; Hunsperger, Elizabeth A

    2013-03-01

    A commercial anti-dengue virus (anti-DENV) indirect IgG enzyme-linked immunosorbent assay (ELISA) for serological diagnosis was evaluated for its utility in determining previous DENV exposure in U.S. travelers. The Boston Area Travel Medicine Network clinics used Focus Diagnostics anti-DENV IgG ELISA to measure anti-DENV IgG antibodies in 591 pretravel specimens from U.S. residents who had traveled to countries where dengue is endemic. When using the manufacturer's index cutoff value for this ELISA, false-positive results were observed that overestimated the perceived past DENV exposure in U.S. travelers. Validation of 121 of these anti-DENV IgG results by plaque reduction neutralization test (PRNT) was used for receiver operating characteristic (ROC) curve optimization of the index cutoff value from 1 to 3.0, improving the specificity of the anti-DENV IgG ELISA from 24% to 95.7%. Additionally, previous vaccination with yellow fever virus contributed to 52.8% of the false-positive rate in the anti-DENV IgG ELISA results. Optimization of the cutoff value of the anti-DENV IgG ELISA provided better interpretation and confidence in the results and eliminated the need for confirmation by PRNT. The travel history of U.S. travelers was also useful for categorizing these travelers into groups for analysis of previous DENV exposure. PMID:23302742

  3. Estimation of anti-D IgG in red blood cell eluates using the specific radioactivity of 125I-labeled IgG: effect of unlabeled, cytophilic IgG

    SciTech Connect

    Masouredis, S.P.; Mahan, L.C.; Sudora, E.J.; Langley, J.W.; Victoria, E.J.

    1981-01-01

    The specific radioactivity of conventionally prepared 125I IgG anti-D eluates is significantly less (from 1/5 to 1/20) than that of the 125I IgG fraction used to prepare the eluate. This discrepancy is due to the release of unlabeled, cytophilic IgG from normal red blood cells during eluate preparation and does not represent an underestimation of the eluate anti-D IgG content. Cytophilic IgG content of eluates plays an important role in reducing the nonimmunologic binding of labeled antibody IgG. The results justify the assumption used in numerous studies that the specific radioactivity of 125I IgG fractions can be used to provide a valid estimate of the anti-D IgG content of eluates.

  4. Pathogenicity and Epitope Characteristics Do Not Differ in IgG Subclass-Switched Anti-Desmoglein 3 IgG1 and IgG4 Autoantibodies in Pemphigus Vulgaris

    PubMed Central

    Ellebrecht, Christoph T.; Yu, Xiaocong; Posner, Marshall R.; Payne, Aimee S.

    2016-01-01

    Pemphigus vulgaris (PV) is characterized by IgG1 and IgG4 autoantibodies to desmoglein (Dsg) 3, causing suprabasal blistering of skin and mucous membranes. IgG4 is the dominant autoantibody subclass in PV and correlates with disease activity, whereas IgG1 can be associated with remittent disease. It is unknown if switching the same variable region between IgG4 and IgG1 directly impacts pathogenicity. Here, we tested whether three pathogenic PV monoclonal antibodies (mAbs) from three different patients demonstrate differences in antigen affinity, epitope specificity, or pathogenicity when expressed as IgG1 or IgG4. F706 anti-Dsg3 IgG4 and F779 anti-Dsg3 IgG1, previously isolated as heterohybridomas, and Px43, a monovalent anti-Dsg3/Dsg1 IgG antibody isolated by phage display, were subcloned to obtain paired sets of IgG1 and IgG4 mAbs. Using ELISA and cell surface staining assays, F706 and F779 demonstrated similar antigen binding affinities of IgG1 and IgG4, whereas Px43 showed 3- to 8-fold higher affinity of IgG4 versus IgG1 by ELISA, but identical binding affinities to human skin, perhaps due to targeting of a quaternary epitope best displayed in tissues. All 3 mAb pairs targeted the same extracellular cadherin (EC) domain on Dsg3, caused Dsg3 internalization in primary human keratinocytes, and caused suprabasal blisters in human skin at comparable doses. We conclude that switching IgG1 and IgG4 subclasses of pathogenic PV mAbs does not directly affect their antigen binding or pathogenic properties. PMID:27304671

  5. Effect of Anti-Epileptic Drugs on Serum Level of IgG Subclasses

    PubMed Central

    Ashrafi, Mahmoud-Reza; Hosseini, Seyed-Ahmad; Biglari, Mohammad; Abolmaali, Sarah; Azizi Malamiri, Reza; Mombeini, Hoda; Pourpak, Zahra; Saladjegheh, Narges; Rezaei, Nima; Samadian, Azam; Aghamohammadi, Asghar

    2010-01-01

    Objective There are some controversial studies on effects of anti-epileptic drugs (AEDs) on serum IgG subclasses; however, the role of these medications is still unclear. The aim of this study was evaluation the effects of anti-epileptic drugs on serum concentration of IgG and its subclasses Methods Serum IgG and IgG subclasses of 61 newly diagnosed epileptic patients were measured at the beginning of monotherapy with carbamazepine, sodium valproate, and phenobarbital, and 6 months later. Measurement of IgG and its subclasses was performed using nephlometry and ELISA techniques, respectively. Findings Reduction of at least one IgG subclass was found in 6 patients 6 months after treatment with AEDs. Among 27 patients receiving carbamazepine, decrease in at least one serum IgG subclass level was found in 5 patients. Among 20 patients using sodium valproate, only one patient showed decrease in IgG2 subclass. None of the 14 patients using phenobarbital revealed significant decrease in IgG subclasses. No infection was seen in the patients with reduction of subclasses. Conclusion Although in our study, children with selective IgG subclass deficiency were asymptomatic, assessment of serum immunoglobulin levels could be recommended at starting the administration of AEDs and in serial intervals afterward in epileptic patients. PMID:23056716

  6. Dose-dependent platelet stimulation and inhibition induced by anti-PIA1 IgG

    SciTech Connect

    Ryu, T.; Davis, J.M.; Schwartz, K.A. )

    1990-07-01

    The PIA1 antibody produces several clinically distinct and severe thrombocytopenias. Investigations have demonstrated divergent effects on platelet function; prior reports demonstrated inhibition, while a conflicting publication showed platelet activation. We have resolved this conflict using anti-PIA1 IgG produced by a patient with posttransfusion purpura. Relatively low concentrations stimulated platelet aggregation and release of adenosine triphosphate (ATP) whereas high concentrations inhibited platelet function, producing a thrombasthenia-like state. The number of molecules of platelet-associated IgG necessary to initiate aggregation and ATP release (2,086 +/- 556) or produce maximum aggregation (23,420 +/- 3,706) or complete inhibition (63,582 +/- 2654) were measured with a quantitative radiometric assay for bound anti-PIA1. Preincubation of platelets with high concentrations of PIA1 antibody inhibited platelet aggregation with 10 mumol/L adenosine diphosphate and blocked 125I-labeled fibrinogen platelet binding. Platelet activation with nonfibrinogen dependent agonist, 1 U/ml thrombin, was not inhibited by this high concentration of PIA1 IgG. In conclusion, anti-PIAI IgG produces (1) stimulation of platelet aggregation and ATP release that is initiated with 2000 molecules IgG per platelet and is associated with an increase of 125I-fibrinogen binding; (2) conversely, inhibition of platelet aggregation is observed with maximum antibody binding, 63,000 molecules IgG per platelet, and is mediated via a blockade of fibrinogen binding.

  7. Anti-amyloidogenic Activity of IgGs Contained in Normal Plasma

    PubMed Central

    Williams, Angela D.; McWilliams-Koeppen, Helen P.; Acero, Luis; Weber, Alfred; Ehrlich, Hartmut; Schwarz, Hans P.; Solomon, Alan

    2010-01-01

    Introduction We have previously shown that a subpopulation of naturally occurring human IgGs has therapeutic potential for the amyloid-associated disorders. These molecules cross-react with conformational epitopes on amyloidogenic assemblies, including amyloid beta (Aβ) protein fibrils that are a pathological hallmark of Alzheimer’s disease. Materials and Methods Using our europium-linked immunosorbant assay, we established that ∼95% of 260 screened donor plasma samples had amyloid fibril-reactive IgGs and Aβ conformer-reactive IgGs with minimal binding to Aβ monomers. Anti-amyloidogenic reactivity was diverse and attributed to Aβ targeting multiple fibril-related binding sites and/or variations in multidentate binding. Results and Discussion There was no correlation between anti-fibril and anti-oligomer reactivity and donor age (19 to 60 years old) or gender. These findings demonstrate the inherent but diverse anti-amyloidogenic activity of natural IgGs contained in normal plasma. Conclusion Our studies provide support for investigating the clinical significance and physiological function of this novel class of antibodies. PMID:20405179

  8. Enhancement of anti-OVA IgG2c production in vivo by enalapril

    PubMed Central

    Almeida, L.C.; Muraro, L.S.; Albuquerque, D.A.

    2016-01-01

    Angiotensin-converting enzyme (ACE) inhibitors have non-hemodynamic, pleiotropic effects on the immune response. The effects of ACE inhibitors on the production of cytokines and T-cell functions are well established. However, little is known on the effects of these medicines on humoral response to foreign antigens. In this study, we investigated the effect of enalapril treatment on ovalbumin (OVA)-specific IgG1 and IgG2c production in mice determined by ELISA. Two groups of 8-week-old C57BL/6 females mice (3–4/group) were subcutaneously immunized with OVA (10 μg/animal) in presence of Alhydrogel (1 mg/mouse) and boosted at day 21. The mice were treated with enalapril (5 mg/kg daily, po) or were left without treatment for one month. The animals were bled from the orbital plexus on days 0, 7, 14, 21, and 28 after the first immunization and the sera were stored at –20°C until usage. OVA-specific serum IgG1 and IgG2c were determined by ELISA using serum from each individual animal. The results showed that enalapril significantly increased anti-OVA serum IgG2c in the secondary response without affecting IgG1 synthesis. These data expand our understanding on the properties of enalapril on the immune response, including antibody production. PMID:27409332

  9. Enhancement of anti-OVA IgG2c production in vivo by enalapril.

    PubMed

    Almeida, L C; Muraro, L S; Albuquerque, D A

    2016-07-11

    Angiotensin-converting enzyme (ACE) inhibitors have non-hemodynamic, pleiotropic effects on the immune response. The effects of ACE inhibitors on the production of cytokines and T-cell functions are well established. However, little is known on the effects of these medicines on humoral response to foreign antigens. In this study, we investigated the effect of enalapril treatment on ovalbumin (OVA)-specific IgG1 and IgG2c production in mice determined by ELISA. Two groups of 8-week-old C57BL/6 females mice (3-4/group) were subcutaneously immunized with OVA (10 μg/animal) in presence of Alhydrogel (1 mg/mouse) and boosted at day 21. The mice were treated with enalapril (5 mg/kg daily, po) or were left without treatment for one month. The animals were bled from the orbital plexus on days 0, 7, 14, 21, and 28 after the first immunization and the sera were stored at -20°C until usage. OVA-specific serum IgG1 and IgG2c were determined by ELISA using serum from each individual animal. The results showed that enalapril significantly increased anti-OVA serum IgG2c in the secondary response without affecting IgG1 synthesis. These data expand our understanding on the properties of enalapril on the immune response, including antibody production. PMID:27409332

  10. Significantly Lower Anti-Leishmania IgG Responses in Sudanese versus Indian Visceral Leishmaniasis

    PubMed Central

    El-Safi, Sayda; Sundar, Shyam; Falconar, Andrew K.; Singh, Om Prakash; Kumar, Rajiv; Ahmed, Osman; Boelaert, Marleen; Miles, Michael A.

    2014-01-01

    Background Visceral leishmaniasis (VL), a widely distributed systemic disease caused by infection with the Leishmania donovani complex (L. donovani and L. infantum), is almost always fatal if symptomatic and untreated. A rapid point-of-care diagnostic test for anti-Leishmania antibodies, the rK39-immunochromatographic test (rK39-ICT), has high sensitivity and specificity in South Asia but is less sensitive in East Africa. One of the underlying reasons may be continent-specific molecular diversity in the rK39 antigen within the L. donovani complex. However, a second reason may be differences in specific IgG anti-Leishmania levels in patients from different geographical regions, either due to variable antigenicity or immunological response. Methodology/Principal Findings We determined IgG titres of Indian and Sudanese VL patients against whole cell lysates of Indian and Sudanese L. donovani strains. Indian VL patients had significantly higher IgG titres against both L. donovani strains compared to Sudanese VL patients (p<0.0001). Mean reciprocal log10 50% end-point titres (1/log10t50) were i) 3.80 and 3.88 for Indian plasma and ii) 2.13 and 2.09 for Sudanese plasma against Indian and Sudanese antigen respectively (p<0.0001). Overall, the Indian VL patients therefore showed a 46.8–61.7 -fold higher mean ELISA titre than the Sudanese VL patients. The higher IgG titres occurred in children (<16 years old) and adults of either sex from India (mean 1/log10t50: 3.60–4.15) versus Sudan (mean 1/log10t50: 1.88–2.54). The greatest difference in IgG responses was between male Indian and Sudanese VL patients of ≥ 16 years old (mean 1/log10t50: 4.15 versus 1.99 = 144-fold (p<0.0001). Conclusions/Significance Anti-Leishmania IgG responses among VL patients in Sudan were significantly lower than in India; this may be due to chronic malnutrition with Zn2+ deficiency, or variable antigenicity and capacity to generate IgG responses to Leishmania antigens. Such differential

  11. Characterization of IgG4 anti-neurofascin 155 antibody-positive polyneuropathy

    PubMed Central

    Ogata, Hidenori; Yamasaki, Ryo; Hiwatashi, Akio; Oka, Nobuyuki; Kawamura, Nobutoshi; Matsuse, Dai; Kuwahara, Motoi; Suzuki, Hidekazu; Kusunoki, Susumu; Fujimoto, Yuichi; Ikezoe, Koji; Kishida, Hitaru; Tanaka, Fumiaki; Matsushita, Takuya; Murai, Hiroyuki; Kira, Jun-ichi

    2015-01-01

    Objective To investigate anti-neurofascin 155 (NF155) antibody-positive chronic inflammatory demyelinating polyneuropathy (CIDP). Methods Sera from 50 consecutive CIDP patients diagnosed in our clinic, 32 patients with multiple sclerosis, 40 patients with other neuropathies including 26 with Guillain–Barré syndrome (GBS)/Fisher syndrome, and 30 healthy controls were measured for anti-NF antibodies by flow cytometry using HEK293 cell lines stably expressing human NF155 or NF186. Four additional CIDP patients with anti-NF155 antibodies referred from other clinics were enrolled for clinical characterization. Results The positivity rate for anti-NF155 antibodies in CIDP patients was 18% (9/50), who all showed a predominance of IgG4 subclass. No other subjects were positive, except one GBS patient harboring IgG1 anti-NF155 antibodies. No anti-NF155 antibody carriers had anti-NF186 antibodies. Anti-NF155 antibody-positive CIDP patients had a significantly younger onset age, higher frequency of drop foot, gait disturbance, tremor and distal acquired demyelinating symmetric phenotype, greater cervical root diameter on magnetic resonance imaging neurography, higher cerebrospinal fluid protein levels, and longer distal and F-wave latencies than anti-NF155 antibody-negative patients. Marked symmetric hypertrophy of cervical and lumbosacral roots/plexuses was present in all anti-NF155 antibody-positive CIDP patients examined by neurography. Biopsied sural nerves from two patients with anti-NF155 antibodies demonstrated subperineurial edema and occasional paranodal demyelination, but no vasculitis, inflammatory cell infiltrates, or onion bulbs. Among anti-NF155 antibody-positive patients, treatment responders more frequently had daily oral corticosteroids and/or immunosuppressants in addition to intravenous immunoglobulins than nonresponders did. Interpretation Anti-NF155 antibodies occur in a subset of CIDP patients with distal-dominant involvement and symmetric nerve

  12. Anti-Apolipoprotein A-1 IgG Levels Predict Coronary Artery Calcification in Obese but Otherwise Healthy Individuals

    PubMed Central

    Quercioli, Alessandra; Montecucco, Fabrizio; Galan, Katia; Ratib, Osman; Roux-Lombard, Pascale; Pagano, Sabrina; Mach, François; Schindler, Thomas H.; Vuilleumier, Nicolas

    2012-01-01

    We aimed at determining whether anti-apolipoprotein (apo) A-1 IgG levels are independent predictors of coronary artery calcification (CAC) and coronary endothelial dysfunction in obese and nonobese subjects without cardiovascular disease. 48 nonobese and 43 obese subjects were included. CAC score was measured by thorax scanner and defined by an Agatston score > 0. Coronary endothelial dysfunction was determined by measuring myocardial blood flow responses to cold pressor test (CPT) on PET/CT. Serum anti-apoA-1 IgG levels were measured by ELISA. Prevalence of coronary calcification was similar between the two study groups, but the prevalence of coronary endothelial dysfunction was higher in obese subjects. Anti-apoA-1 IgG levels and positivity rate were higher in obese than in nonobese individuals. CAC score was higher in anti-apoA-1 IgG positive subjects. ROC analyses indicated that anti-apoA-1 IgG levels were significant predictors of CAC > 0, but not of coronary endothelial dysfunction with a negative predictive value of 94%. Anti-apoA-1 IgG positivity was associated with a 17-fold independent increased risk of CAC > 0. In conclusion, those preliminary results indicate that anti-apoA-1 IgG autoantibodies are raised in obese subjects and independently predict the presence of coronary calcification in this population but not the presence of coronary endothelial dysfunction. PMID:23258951

  13. Anti-neosporal IgG and IgE antibodies in canine neosporosis.

    PubMed

    Jesus, E E V; Almeida, M A O; Atta, A M

    2007-01-01

    Neospora caninum infection provokes neurological disorders, recurrent abortion and death in dogs and cattle. Dogs are both intermediate and definitive host of N. caninum. Thus, the development of sensitive and specific immunoassays to diagnose canine neosporosis is essential to control this disease. This work investigated serum anti-neosporal IgG and IgE antibodies in 140 dogs represented by 30 healthy animals (group I), 11 dogs showing acute N. caninum infection (group II), 50 urban dogs with serological evidence of canine neosporosis in indirect fluorescent antibody test (IFAT) (group III) and 49 urban dogs without clinical and laboratory evidences of neosporosis (group IV). Enzyme-linked immunosorbent assay (ELISA) and western immunoblotting, both using a soluble N. caninum tachyzoite antigen (SNA), investigated these two isotypes of antibodies, while a Urea-ELISA measured the avidity of the IgG antibodies. Anti-Toxoplasma gondii IgG antibodies were also investigated in the animals. Anti-neosporal IgG was found in all animals from groups II and III, whereas 32.7% (16/49) of dogs from group IV were reactive. IgG antibodies of low avidity were demonstrated in dogs from group II (median 35.3%), while animals from groups III and IV had IgG antibodies of high avidity (medians of 61.5% and 61.7% respectively). IgE antibodies were found in four (13.3%) and five (16.6%) dogs from groups III and IV respectively. Dogs presenting acute infection (group II) or chronic infection (group III) had IgG antibodies to several neosporal antigens, mainly of 29-30 and 35 kDa, while 13 of 16 dogs from group IV recognized antigens from 14 to 170 kDa. Antibodies to T. gondii were detected in 36 of 50 (72%) sera from group III and 25 of 49 (51%) sera from group IV. We concluded that IgG-ELISA and Urea-ELISA with SNA may substitute for IFAT in both laboratory routine and epidemiological studies of canine neosporosis. PMID:18035978

  14. Anti-Leishmania infantum IgG Antibody Avidity in Visceral Leishmaniasis

    PubMed Central

    Tiburcio, Monique Gomes Salles; Anversa, Laís; Kanunfre, Kelly Aparecida; Ferreira, Antonio Walter; Rodrigues Júnior, Virmondes

    2013-01-01

    IgG avidity tests are used to discriminate acute from chronic infections. There are few reports on the IgG avidity profile of patients with visceral leishmaniasis (VL). This study investigated the anti-Leishmania IgG avidity in patients with classic VL (n = 10), patients showing clinical cure after treatment (n = 18), and asymptomatic subjects with at least one positive Leishmania test (n = 20). All subjects were from areas in Brazil where VL is endemic. Serum samples were collected from each subject on two different occasions. IgG avidity was evaluated by Western blotting. The proportion of high-avidity antibodies was higher in all samples from patients with classic VL. In contrast, low-avidity antibodies predominated in subjects with a history of VL, including 13 cases (72.2%) in the first assessment and 14 (77.8%) in the second. Fifteen (75%) of the asymptomatic subjects presented a predominance of low-avidity antibodies in the first assessment, and the frequency of high-avidity antibodies increased over time in seven subjects (35%) of this group. Antibodies against the 14- and/or 16-kDa antigen fraction were detected in the first assessment in all patients with classic VL, in 10 (55.5%) treated patients, and in 10 (50%) asymptomatic subjects. These were high-avidity antibodies in most cases. In the asymptomatic group, an increase in IgG avidity against the 14- and/or 16-kDa antigen fraction was observed in three cases (15%). The results indicate distinct responses in infected and asymptomatic subjects, probably associated with the length of time after infection. In this respect, IgG avidity tests represent a new approach to better characterize asymptomatic VL. PMID:24006136

  15. Does the antibody production ability affect the serum anti-Helicobacter pylori IgG titer?

    PubMed Central

    Chung, Hyun Ah; Lee, Sun-Young; Moon, Hee Won; Kim, Jeong Hwan; Sung, In-Kyung; Park, Hyung Seok; Shim, Chan Sup; Han, Hye Seung

    2016-01-01

    AIM To investigate the relationship between serum titers of anti-Helicobacter pylori (H. pylori) immunoglobulin G (IgG) and hepatitis B virus surface antibody (HBsAb). METHODS Korean adults were included whose samples had positive Giemsa staining on endoscopic biopsy and were studied in the hepatitis B virus surface antigen (HBsAg)/HBsAb serologic assay, pepsinogen (PG) assay, and H. pylori serologic test on the same day. Subjects were excluded if they were positive for HBsAg, had a recent history of medication, or had other medical condition(s). We analyzed the effects of the following factors on serum titers of HBsAb and the anti-H. pylori IgG: Age, density of H. pylori infiltration in biopsy samples, serum concentrations of PG I and PG II, PG I/II ratio, and white blood cell count. RESULTS Of 111 included subjects, 74 (66.7%) exhibited a positive HBsAb finding. The serum anti-H. pylori IgG titer did not correlate with the serum HBsAb titer (P = 0.185); however, it correlated with the degree of H. pylori infiltration on gastric biopsy (P < 0.001) and serum PG II concentration (P = 0.042). According to the density of H. pylori infiltration on gastric biopsy, subjects could be subdivided into those with a marked (median: 3.95, range 0.82-4.00) (P = 0.458), moderate (median: 3.37, range 1.86-4.00), and mild H. pylori infiltrations (median: 2.39, range 0.36-4.00) (P < 0.001). Subjects with a marked H. pylori infiltration on gastric biopsy had the highest serological titer, whereas in subjects with moderate and mild H. pylori infiltrations titers were correspondingly lower (P < 0.001). After the successful eradication, significant decreases of the degree of H. pylori infiltration (P < 0.001), serum anti-H. pylori IgG titer (P < 0.001), and serum concentrations of PG I (P = 0.028) and PG II (P = 0.028) were observed. CONCLUSION The anti-H. pylori IgG assay can be used to estimate the burden of bacteria in immunocompetent hosts with H. pylori infection, regardless

  16. APPRAISAL OF PRENATAL ANTI-TOXOPLASMA GONDII (IGG+IGM)- IHA/IGM-ELISA SCREENING IN SINGLE SAMPLES VIA IGG AVIDITY TEST.

    PubMed

    El-Bali, Mohammed; Zaglool, Dina A M; Khodari, Yousif A W; Al-Harthi, Saeed A

    2016-04-01

    Congenital toxoplasmosis is associated with important morbidity and mortality. Since vertical transmission of Toxoplasma gondii can occur in acute cases, antenatal screening for recent infections is vital. Accurate determination of acute toxoplasmosis requires a combination of immunoassays, usually not routinely applied for screening purposes. This study evaluated the anti-T. gondii (IgG+IgM)/IgM prenatal screening procedure by IgG avidity assay. The routine prenatal screening for (IgG+IgM) anti-T. gondii by indirect hemagglutination (IHA) in serum samples was done of 2247 pregnant women who attended two hospitals between 2011 and 2013 revealed 487 (21.7%) positive samples. Examination of IHA-positive sera by IgM and IgG/IgG-avidity concurrent ELISA tests revealed 7 positive and 3 border-line IgM-ELISA titers during the initial check-up of 10 women, who were then followed up at 3-4 week-intervals. Among these, 4 (40%) showed simultaneous high avidity IgG antibodies, indicating distant infection by the parasite, and no anti-T. gondii specific IgG could be detected in follow-up sera of two cases (20%), indicating false IgM initial positive results. Only 4 (40%) women showed simultaneous IgM and low avidity IgG antibodies indicating active infections. Avoidance of an over-diagnosis of acute toxoplasmosis Anti-T. gondii (IgG+IgM)/IgM prenatal screening must be supplemented by a discriminative test like IgG avidity ELISA. PMID:27363056

  17. Competition between Serum IgG, IgM, and IgA Anti-Glycan Antibodies

    PubMed Central

    Muthana, Saddam M.; Xia, Li; Campbell, Christopher T.; Zhang, Yalong; Gildersleeve, Jeffrey C.

    2015-01-01

    Anti-glycan antibodies are an abundant subpopulation of serum antibodies with critical functions in many immune processes. Changes in the levels of these antibodies can occur with the onset of disease, exposure to pathogens, or vaccination. As a result, there has been significant interest in exploiting anti-glycan antibodies as biomarkers for many diseases. Serum contains a mixture of anti-glycan antibodies that can recognize the same antigen, and competition for binding can potentially influence the detection of antibody subpopulations that are more relevant to disease processes. The most abundant antibody isotypes in serum are IgG, IgM, and IgA, but little is known regarding how these different isotypes compete for the same glycan antigen. In this study, we developed a multiplexed glycan microarray assay and applied it to evaluate how different isotypes of anti-glycan antibodies (IgA, IgG, and IgM) compete for printed glycan antigens. While IgG and IgA antibodies typically outcompete IgM for peptide or protein antigens, we found that IgM outcompete IgG and IgA for many glycan antigens. To illustrate the importance of this effect, we provide evidence that IgM competition can account for the unexpected observation that IgG of certain antigen specificities appear to be preferentially transported from mothers to fetuses. We demonstrate that IgM in maternal sera compete with IgG resulting in lower than expected IgG signals. Since cord blood contains very low levels of IgM, competition only affects maternal IgG signals, making it appear as though certain IgG antibodies are higher in cord blood than matched maternal blood. Taken together, the results highlight the importance of competition for studies involving anti-glycan antibodies. PMID:25807519

  18. Prevalence of anti-rubella, anti-measles and anti-mumps IgG antibodies in neonates and pregnant women in Catalonia (Spain) in 2013: susceptibility to measles increased from 2003 to 2013.

    PubMed

    Plans, P; de Ory, F; Campins, M; Álvarez, E; Payà, T; Guisasola, E; Compte, C; Vellbé, K; Sánchez, C; Lozano, M J; Aran, I; Bonmatí, A; Carreras, R; Jané, M; Cabero, L

    2015-06-01

    Non-immune neonates and non-immune pregnant women are at risk of developing rubella, measles and mumps infections, including congenital rubella syndrome. We describe the seroepidemiology of measles, mumps and rubella (MMR) in neonates and pregnant women in Catalonia (Spain). Anti-rubella, anti-measles and anti-mumps serum IgG titres were assessed using enzyme-linked immunosorbent assay (ELISA) tests in 353 cord blood samples from neonates of a representative sample of pregnant women obtained in 2013. The prevalence of protective antibody titres in neonates was 96 % for rubella IgG (≥8 IU/ml), 90 % for measles IgG (>300 IU/ml) and 84 % for mumps IgG (>460 EU/ml). Slightly lower prevalences of protective IgG titres, as estimated from the cord blood titres, were found in pregnant women: 95 % for rubella IgG, 89 % for measles IgG and 81 % for mumps IgG. The anti-measles and anti-mumps IgG titres and the prevalences of protective IgG titres against measles and mumps increased significantly (p < 0.001) with maternal age. The prevalence of protective anti-measles IgG titres decreased by 7 % [odds ratio (OR) = 0.15, p < 0.001), the prevalence of protective anti-rubella IgG titres increased by 3 % (OR = 1.80, p < 0.05) and the MMR vaccination coverage (during childhood) in pregnant women increased by 54 % (OR = 2.09, p < 0.001) from 2003 to 2013. We recommend to develop an MMR prevention programme in women of childbearing age based on mass MMR vaccination or MMR screening and vaccination of susceptible women to increase immunity levels against MMR. PMID:25666082

  19. Identification of Anti-Long Chain Saturated Fatty Acid IgG Antibodies in Serum of Patients with Type 2 Diabetes

    PubMed Central

    Nicholas, Dequina A.; Salto, Lorena M.; Boston, Ava M.; Kim, Nan Sun; Larios, Marco; Beeson, W. Lawrence; Firek, Anthony F.; Casiano, Carlos A.; Langridge, William H. R.; Cordero-MacIntyre, Zaida; De Leon, Marino

    2015-01-01

    High levels of serum long chain saturated fatty acids (LCSFAs) have been associated with inflammation in type 2 diabetes. Dietary SFAs can promote inflammation, the secretion of IgG antibodies, and secretion of the proinflammatory cytokine IL-1β. This study characterizes anti-LCSFA IgG antibodies from patients with type 2 diabetes. Serum samples from several cohorts with type 2 diabetes were analyzed for the presence of anti-LCSFA IgG, the cytokine IL-1β, and nonesterified fatty acids. Anti-LCSFA IgG was isolated from patient samples and used for in vitro characterization of avidity and specificity. A cohort participating in En Balance, a diabetes health education program that improved diabetes management, tested positive for anti-LCSFA IgG. Following the 3-month program, the cohort showed a significant reduction in anti-LCSFA IgG levels. Anti-LCSFA antibodies isolated from these patients demonstrated high avidity, were specific for long chain SFAs, and correlated with serum fatty acids in patients with managed type 2 diabetes. Interestingly, anti-LCSFA IgG neutralized PA-induced IL-1β secretion by dendritic cells. Our data shows that nonesterified SFAs are recognized by IgG antibodies present in human blood. The identification of anti-LCSFA IgG antibodies in human sera establishes a basis for further exploration of lipid induced immune responses in diabetic patients. PMID:26633920

  20. Gastrointestinal stability of therapeutic anti-TNF α IgG1 monoclonal antibodies.

    PubMed

    Yadav, Vipul; Varum, Felipe; Bravo, Roberto; Furrer, Esther; Basit, Abdul W

    2016-04-11

    Monoclonal antibodies (mAbs) are highly effective therapeutic agents, administered exclusively by the parenteral route owing to their previously-documented instability in the gastrointestinal (GI) tract when delivered orally. To investigate the extent of the validity of this assumption, the stability of the tumor necrosis factor alpha (TNF-α) neutralizing IgG1 mAbs, infliximab and adalimumab, was studied in human GI conditions. In gastric fluid, infliximab and adalimumab degraded rapidly, with complete degradation occurring within 1min. In small intestinal fluid, the molecules were shown to be more stable, but nonetheless degraded within a short time frame of 30min. Investigations into the mechanisms responsible for infliximab and adalimumab instability in the small intestine revealed that the proteolytic enzyme elastase, and to a lesser extent the enzymes trypsin and chymotrypsin, was responsible for their degradation. By contrast, in the human colon, 75% and 50% of the dose of infliximab and adalimumab, respectively, were intact after 60min, with conversion of mAbs into F(ab')2 Fab and Fc fragments detected in colonic conditions. These data indicate that therapeutic IgG1 antibodies are more stable in the colon than in the upper GI tract, therefore highlighting the potential for oral delivery of anti-TNF-α mAbs targeted to the colon. PMID:26892815

  1. Detecting fish parvalbumin with commercial mouse monoclonal anti-frog parvalbumin IgG.

    PubMed

    Chen, Lingyun; Hefle, Sue L; Taylor, Steve L; Swoboda, Ines; Goodman, Richard E

    2006-07-26

    Parvalbumin is a calcium-binding muscle protein that is highly conserved across fish species and amphibians. It is the major cross-reactive allergen associated with both fish and frog allergy. We used two-dimensional electrophoretic and immunoblotting techniques to investigate the utility of a commercial monoclonal anti-frog parvalbumin IgG for detecting parvalbumin present in some commonly consumed fish species. The 2D electrophoresis and immunoblots revealed species-specific differences in proteins that appear to represent various numbers of isoforms of parvalbumin in carp (5), catfish (3), cod (1) and tilapia (2). No parvalbumin was detected in yellowfin tuna. Based on minor differences in relative intensities of protein staining and immunodetection, parvalbumin isoforms may have slight differences in the epitope region recognized by the anti-frog parvalbumin antibody. These results suggest that the frog anti-parvalbumin antibody can be used as a valuable tool to detect parvalbumins from the fish tested in this study, except yellowfin tuna. PMID:16848548

  2. Allogeneic IgG combined with dendritic cell stimuli induces anti-tumor T cell immunity

    PubMed Central

    Carmi, Yaron; Spitzer, Matthew H.; Linde, Ian L.; Burt, Bryan M; Prestwood, Tyler R.; Perlman, Nikola; Davidson, Matthew G.; Kenkel, Justin A.; Segal, Ehud; Pusapati, Ganesh V.; Bhattacharya, Nupur; Engleman, Edgar G.

    2015-01-01

    While cancers grow in their hosts and evade host immunity through immunoediting and immunosuppression1–5, tumors are rarely transmissible between individuals. Much like transplanted allogeneic organs, allogeneic tumors are reliably rejected by host T cells, even when the tumor and host share the same major histocompatibility complex (MHC) alleles, the most potent determinants of transplant rejection6–10. How such tumor-eradicating immunity is initiated remains unknown, though elucidating this process could provide a roadmap for inducing similar responses against naturally arising tumors. We found that allogeneic tumor rejection is initiated by naturally occurring tumor-binding IgG antibodies, which enable dendritic cells (DC) to internalize tumor antigens and subsequently activate tumor-reactive T cells. We exploited this mechanism to successfully treat autologous and autochthonous tumors. Either systemic administration of DC loaded with allogeneic IgG (alloIgG)-coated tumor cells or intratumoral injection of alloIgG in combination with DC stimuli induced potent T cell mediated anti-tumor immune responses, resulting in tumor eradication in mouse models of melanoma, pancreas, lung and breast cancer. Moreover, this strategy led to eradication of distant tumors and metastases, as well as the injected primary tumors. To assess the clinical relevance of these findings, we studied antibodies and cells from patients with lung cancer. T cells from these patients responded vigorously to autologous tumor antigens after culture with alloIgG-loaded DC, recapitulating our findings in mice. These results reveal that tumor-binding alloIgG can induce powerful anti-tumor immunity that can be exploited for cancer immunotherapy. PMID:25924063

  3. FcRn-mediated intestinal absorption of IgG anti-IgE/IgE immune complexes in mice

    PubMed Central

    Paveglio, Sara; Puddington, Lynn; Rafti, Ektor; Matson, Adam P.

    2012-01-01

    Background The mechanism(s) responsible for the acquisition of maternal antibody isotypes other than IgG are not fully understood. Objective To define the ability of the neonatal Fc receptor for IgG uptake (FcRn) to mediate intestinal absorption of IgG1 anti-IgE/IgE immune complexes. Methods C57BL/6 allergic ovalbumin (OVA)-immune foster mothers were generated to nurse naïve FcRn+/− or FcRn−/− progeny. At the time of weaning, serum levels of OVA-specific antibodies and IgG1 anti-IgE/IgE immune complexes were determined in allergic foster mothers and FcRn+/+, FcRn+/−, or FcRn−/− breastfed offspring. In separate experiments, FcRn+/− or FcRn−/− neonatal mice were gavage fed TNP-specific IgE as IgG1 anti-IgE/IgE immune complexes, IgG1 isotype control and IgE, or IgE alone. Mice were sacrificed 2 hours after feeding to determine serum levels and biologic activity of absorbed TNP-specific IgE. Results As expected, the absorption of maternal OVA-specific IgG1 in FcRn−/− offspring was at levels 103–104 less than observed in FcRn+/+ or FcRn+/− offspring. Surprisingly, FcRn expression also influenced the absorption of maternal IgE. OVA-specific IgE was detected in FcRn+/+ and FcRn+/− offspring, but not in FcRn−/− offspring. IgG1 anti-IgE/IgE immune complexes were detected in allergic foster mothers and correlated strongly with levels in FcRn+/+ and FcRn+/− offspring (rho=0.88, P <0.0001). Furthermore, FcRn expression was required for neonatal mice to absorb TNP-specific IgE when fed as IgG1 anti-IgE/IgE immune complexes. When immune complexes were generated with IgG1 anti-IgE directed against the Cε4 domain, the absorbed IgE was able to function in antigen-dependent basophil degranulation. Conclusions and Clinical Relevance These data demonstrate a novel mechanism by which FcRn may facilitate absorption of maternal antibodies other than IgG. These findings are clinically relevant because FcRn mediates the transplacental passage of maternal

  4. Label-free and real-time detections of the interactions of swine IgG with goat anti-swine IgG by oblique-incidence reflectivity difference technique

    NASA Astrophysics Data System (ADS)

    Wang, J. Y.; Dai, J.; He, L. P.; Sun, Y.; Lu, H. B.; Jin, K. J.; Yang, G. Z.

    2012-09-01

    With the oblique-incidence reflectivity difference (OIRD) technique, we successfully label-free detected the interaction of swine IgG with different concentrations of 0.125, 0.25, 0.5, 1 mg/ml, and 5 μg/ml goat anti-swine IgG, and real-time detected the reaction dynamic processes of 0.5 mg/ml swine IgG and goat anti-swine IgG with different concentration of 5, 10, and 20 μg/ml, respectively. The interaction times are about 2043, 1828, and 1347 s for the reactions of 0.5 mg/ml swine IgG and goat anti-swine IgG of 5, 10, and 20 μg/ml, respectively. By fitting the reaction dynamic curves, we obtained that the association constant of swine IgG and goat anti-swine IgG is 1620.77 M-1.S-1 at temperature about 22 °C. The experimental results demonstrate that the OIRD is a promising and competing method for label-free and real time detecting the biomolecular interactions and achieving the quantitative information of reaction kinetics.

  5. Specificity of human anti-carbohydrate IgG antibodies as probed with polyacrylamide-based glycoconjugates.

    PubMed

    Smorodin, E P; Kurtenkov, O A; Sergeyev, B L; Pazynina, G V; Bovin, N V

    2004-01-01

    The TF, Tn, and SiaTn glycotopes are frequently expressed in cancer-associated mucins. Antibodies to these glycotopes were found in human serum. A set of polyacrylamide (PAA)--based glycoconjugates was applied to the direct and competitive enzyme-linked immunosorbent assays (ELISA) to characterize the specificity of serum IgG antibodies. The anti-TF, -Tn and -SiaTn IgG were affinity purified from serum of cancer patients and characterized using PAA-conjugates and free saccharides. The anti-TF and -Tn antibodies were shown to be specific. The anti-TF IgG bound both Galbeta1-3GalNAcalpha- and Galbeta1-3GalNAcbeta-PAA, the latter was three-four times more effective inhibitor of antibody binding. The anti-Tn IgG reacted only with GalNAcalpha-PAA. The anti-SiaTn IgG cross-reacted with Tn-PAA but SiaTn-PAA was five-six times more effective inhibitor in a competitive assay. The IC50 values for PAA-conjugates with the corresponding antibodies typically ranged from 2 to 5 x 10(-8) M. The antibodies display a low specificity to mucin-type glycoconjugates in comparison with PAA-conjugates as was shown for mucins isolated from human malignant tumor tissues, ovine submaxillary mucin (OSM) and asialo-OSM. The unusual IgG-antibody specificity to GalNAcbeta and GalNAcbeta1-3GalNAcbeta ligands was found in human serum. PMID:15001840

  6. Structure of full-length human anti-PD1 therapeutic IgG4 antibody pembrolizumab.

    PubMed

    Scapin, Giovanna; Yang, Xiaoyu; Prosise, Winifred W; McCoy, Mark; Reichert, Paul; Johnston, Jennifer M; Kashi, Ramesh S; Strickland, Corey

    2015-12-01

    Immunoglobulin G4 antibodies exhibit unusual properties with important biological consequences. We report the structure of the human full-length IgG4 S228P anti-PD1 antibody pembrolizumab, solved to 2.3-Å resolution. Pembrolizumab is a compact molecule, consistent with the presence of a short hinge region. The Fc domain is glycosylated at the CH2 domain on both chains, but one CH2 domain is rotated 120° with respect to the conformation observed in all reported structures to date, and its glycan chain faces the solvent. We speculate that this new conformation is driven by the shorter hinge. The structure suggests a role for the S228P mutation in preventing the IgG4 arm exchange. In addition, this unusual Fc conformation suggests possible structural diversity between IgG subclasses and shows that use of isolated antibody fragments could mask potentially important interactions, owing to molecular flexibility. PMID:26595420

  7. Preparation and characterization of novel IgG affinity resin coupling anti-Fc camelid single-domain antibodies.

    PubMed

    Tu, Zhui; Xu, Yang; Fu, Jinheng; Huang, Zhibing; Wang, Yao; Liu, Bin; Tao, Yong

    2015-03-01

    This work aimed to evaluate novel affinity resin used to purify immunoglobulin G (IgG) with a variable domain of the heavy chain of the heavy-chain antibody (VHH) as an affinity ligand. The VHH, isolated from a naïve camelid single-domain phage display library, exhibits not only affinity to the fragment crystallizable (Fc) region of IgG but also high thermal stability. This anti-Fc VHH (AFV) was expressed as a soluble protein in Escherichia coli and purified using a simple heat treatment procedure. The effects of pH and NaCl concentrations on the capacity of AFV resin were also investigated. Results showed a robust property of the AFV resin. It could bind IgGs at various pH conditions (from 6.0 to 9.0) and NaCl concentrations. The static binding capacities of AFV resin ranged from 3.40±0.53mg/ml to 15.04±0.37mg/ml measured using rabbit, mouse, and human IgGs. The bound IgGs can be efficiently eluted at pH 5.0, which is conducive to acid-sensitive IgGs and prevents the aggregation of IgGs. After 10 purification cycles or a 7-day period of storage at 37°C, recovery did not decrease. These findings suggested that VHHs from non-immunized library could also be robust and functional reagent as an affinity purification ligand. PMID:25614967

  8. Enzyme immunoassay for anti-treponemal IgG: screening or confirmatory test?

    PubMed Central

    Young, H; Moyes, A; McMillan, A; Patterson, J

    1992-01-01

    AIMS: To review the performance of the Venereal Diseases Research Laboratory (VDRL) test and the Treponema pallidum haemagglutination assay (TPHA) as a combined screen for syphilis to provide a baseline for assessing screening by anti-treponemal IGG EIA. METHODS: Between 1980 and 1987 all serum samples were screened by both VDRL and TPHA tests. The FTA-ABS test was also used in suspected early primary syphilis, or when one of the other tests was positive. A positive result in a screening test was confirmed by quantitative testing. From 1988 all specimens were screened with an enzyme immunoassay (Captia Syph G) as a single screening test. RESULTS: Of the 44 primary, 47 secondary, and 38 early latent cases of syphilis, the VDRL and TPHA detected 32 (73%) and 31 (71%) of the primary cases; the combination detected 37 (84%). All 85 cases of cases of secondary and early latent infection were reactive in the TPHA test, whereas the VDRL was reactive in only 68 (80%). EIA had a reported sensitivity of 82% for primary infection. CONCLUSIONS: EIA can be used as a single screening test for detecting early syphilis because its results are comparable with those of the combined VDRL and TPHA tests. The conventional VDRL test should not be used as a single screening test. PMID:1740512

  9. Anti-rhesus D prophylaxis in pregnant women is based on sialylated IgG antibodies

    PubMed Central

    Ehlers, Marc

    2013-01-01

    Red blood cells (RBCs) from a rhesus D (RhD)-positive fetus that reach the bloodstream of an RhD-negative pregnant woman during birth can induce a pathogenic antibody (Ab) response against the RhD-positive RBCs, leading to fetal hemolytic disease in subsequent pregnancies. To prevent a pathogenic immune reaction, the RhD-negative mother receives serum immunoglobulin G (IgG) containing polyclonal RhD-specific IgG Abs that is purified from healthy RhD-negative men immunized with RhD-positive RBCs. However, the protective mechanism of these polyclonal RhD-specific IgG Abs is unclear. It has become increasingly clear that the effector function of IgG Abs is regulated by the glycan pattern linked to the Fc region of IgG Abs. Non-fucosylated (afucosylated) IgG Abs have a higher affinity for activating Fc gamma receptors, and thus induce a stronger Ab-dependent cellular cytotoxicity (ADCC) reaction than do fucosylated IgG Abs. Agalactosylated and asialylated, autoantigen-specific serum IgG Abs correlate with pro-inflammatory immune responses and disease activity in patients with rheumatoid arthritis. In contrast, galactosylated and sialylated IgG Abs are immunosuppressive and inhibit in form of immune complexes (ICs) dendritic cell (DC) maturation and pro-inflammatory T and B cell immune responses in an antigen-specific manner. However, the galactosylation and sialylation levels of the protective polyclonal RhD-specific IgG Abs are unknown. Here, we purified RhD-specific IgG Abs from the approved commercial product Rhophylac® (CSL Behring) and found that these RhD-specific IgG Abs were even more galactosylated and sialylated than the total Rhophylac® IgG Abs. This result suggests that these galactosylated and sialylated polyclonal RhD-specific IgG Abs are immunosuppressive and induce tolerance against RhD, which would be in strong contrast to a low fucosylated, low galactosylated and low sialylated monoclonal RhD-specific IgG Ab developed to prevent fetal hemolytic

  10. Low positive predictive value of anti-Brugia malayi IgG and IgG4 serology for the diagnosis of Wuchereria bancrofti.

    PubMed

    Chanteau, S; Glaziou, P; Moulia-Pelat, J P; Plichart, C; Luquiaud, P; Cartel, J L

    1994-01-01

    Enzyme-linked immunosorbent assays (ELISAs) for anti-Brugia malayi immunoglobulin (Ig) G and IgG4 were evaluated on sera from 1561 subjects in French Polynesia for the serodiagnosis of Wuchereria bancrofti filariasis, compared with the test for Onchocerca gibsoni circulating antigen (Og4C3) as a 'gold standard'. The sensitivity of the ELISA-IgG and ELISA-IgG4 assays was 90.8% and 94.5%, and the specificity was 45.9% and 50.7%. The positive predictive values were 41% and 45% respectively for an antigen prevalence rate of 30%. Thus antibody prevalences exceeded by two-fold the antigen prevalence, which itself exceeded by two-fold the prevalence of microfilaraemia. PMID:7886763

  11. Anti-aquaporin-4 IgG in Patients Presenting with Unilateral Optic Neuritis: A Cohort Study

    PubMed Central

    Etemadifar, Masoud; Abtahi, Mohammad-Ali; Razmjoo, Hassan; Abtahi, Seyed-Hossein; Dehghani, Ali-Reza; Abtahi, Zahra-Alsadat; Akbari, Mojtaba; Mazaheri, Shahir; Maghzi, Amir-Hadi

    2012-01-01

    Background: Optic neuritis (ON) can be the first presentation of multiple sclerosis (MS) or neuromyelitis optica (NMO). Anti-aquaporin-4 IgG (AQP4 IgG) is a highly specific and moderately sensitive biomarker for NMO. This study was designed to assess the rate of seropositivity for AQP4 IgG, and the short-term outcome of patients presenting with single isolated ON (SION). Methods: A cohort of 41 consecutive patients experiencing severe (< 20 / 200) SION (not fulfilling the diagnostic criteria for MS or NMO), was prospectively recruited. Blood sampling was carried out immediately after the diagnosis of ON, and AQP4 IgG was tested qualitatively, using an indirect immunofluorescence kit. After clinical and paraclinical investigations, all the patients were followed up for a short-term period of at least 18 months. Results: The seroprevalence among the initial ON patients was 9.7% (4 / 41). The short-term conversion rate to MS and NMO was estimated to be about 7.3 and 4.9%, respectively. The conversion rate to NMO in initially seropositive patients was greater than that for the whole cohort [2 / 4 (50%) vs. 2 / 41 (4.9%); P = 0.035; Odds ratio: 19.5, 95% confidence interval: 1.73 to 219.50]. Conclusion: AQP4 IgG seropositive SION patients were more likely to develop NMO in comparison to the total SION population. Further studies, with a longer follow-up period and larger sample sizes are warranted to assess the clinical and prognostic value of assessing AQP4 IgG in SION. PMID:23024849

  12. Anti-CTLA-4 antibodies of IgG2a isotype enhance antitumor activity through reduction of intratumoral regulatory T cells.

    PubMed

    Selby, Mark J; Engelhardt, John J; Quigley, Michael; Henning, Karla A; Chen, Timothy; Srinivasan, Mohan; Korman, Alan J

    2013-07-01

    Antitumor activity of CTLA-4 antibody blockade is thought to be mediated by interfering with the negative regulation of T-effector cell (Teff) function resulting from CTLA-4 engagement by B7-ligands. In addition, a role for CTLA-4 on regulatory T cells (Treg), wherein CTLA-4 loss or inhibition results in reduced Treg function, may also contribute to antitumor responses by anti-CTLA-4 treatment. We have examined the role of the immunoglobulin constant region on the antitumor activity of anti-CTLA-4 to analyze in greater detail the mechanism of action of anti-CTLA-4 antibodies. Anti-CTLA-4 antibody containing the murine immunoglobulin G (IgG)2a constant region exhibits enhanced antitumor activity in subcutaneous established MC38 and CT26 colon adenocarcinoma tumor models compared with anti-CTLA-4 containing the IgG2b constant region. Interestingly, anti-CTLA-4 antibodies containing mouse IgG1 or a mutated mouse IgG1-D265A, which eliminates binding to all Fcγ receptors (FcγR), do not show antitumor activity in these models. Assessment of Teff and Treg populations at the tumor and in the periphery showed that anti-CTLA-4-IgG2a mediated a rapid and dramatic reduction of Tregs at the tumor site, whereas treatment with each of the isotypes expanded Tregs in the periphery. Expansion of CD8(+) Teffs is observed with both the IgG2a and IgG2b anti-CTLA-4 isotypes, resulting in a superior Teff to Treg ratio for the IgG2a isotype. These data suggest that anti-CTLA-4 promotes antitumor activity by a selective reduction of intratumoral Tregs along with concomitant activation of Teffs. PMID:24777248

  13. Glycosylation pattern of anti-platelet IgG is stable during pregnancy and predicts clinical outcome in alloimmune thrombocytopenia.

    PubMed

    Sonneveld, Myrthe E; Natunen, Suvi; Sainio, Susanna; Koeleman, Carolien A M; Holst, Stephanie; Dekkers, Gillian; Koelewijn, Joke; Partanen, Jukka; van der Schoot, C Ellen; Wuhrer, Manfred; Vidarsson, Gestur

    2016-07-01

    Fetal or neonatal alloimmune thrombocytopenia (FNAIT) is a potentially life-threatening disease where fetal platelets are destroyed by maternal anti-platelet IgG alloantibodies. The clinical outcome varies from asymptomatic, to petechiae or intracranial haemorrhage, but no marker has shown reliable correlation with severity, making screening for FNAIT impractical and highly inefficient. We recently found IgG Fc-glycosylation towards platelet and red blood cell antigens to be skewed towards decreased fucosylation, increased galactosylation and sialylation. The lowered core-fucosylation increases the affinity of the pathogenic antibodies to FcγRIIIa and FcγRIIIb, and hence platelet destruction. Here we analysed the N-linked glycans of human platelet antigen (HPA)-1a specific IgG1 with mass spectrometry in large series of FNAIT cases (n = 166) including longitudinal samples (n = 26). Besides a significant decrease in Fc-fucosylation after the first pregnancy (P = 0·0124), Fc-glycosylation levels remained stable during and after pregnancy and in subsequent pregnancies. Multiple logistic regression analysis identified anti-HPA-1a -fucosylation (P = 0·006) combined with galactosylation (P = 0·021) and antibody level (P = 0·038) correlated with bleeding severity, making these parameters a feasible marker in screening for severe cases of FNAIT. PMID:27017954

  14. [The development and certification of the Hepabest anti-HBc IgG test system for detecting antibodies to the core antigen of the hepatitis B virus].

    PubMed

    Iaroslavtseva, O A; Netesova, I G; Karpenko, L I; Mel'nikova, O V; Zaĭtsev, S A; Il'ichev, A A

    1998-01-01

    The comparison of the newly developed "HepaBest anti-HBc IgG" assay system for the detection of hepatitis B virus (HBV) core antigen with the reference system "ImmunoComb HBc IgG" (Orgenics, France-Israel) and its approbation on 91 serum samples from patients in the Infectious Clinical Hospital were carried out. The coincidence rate of the results obtained with the use of the two assay systems was 87.9%. The system "HepaBest anti-HBc IgG" permitted the detection of patients whose sera contained no other HBV markers, except anti-HBc IgG. This assay system may be recommended for use in clinical and epidemiological investigations for ascertaining the diagnosis. PMID:9783401

  15. Comparative Analysis for the Presence of IgG Anti-Aquaporin-1 in Patients with NMO-Spectrum Disorders.

    PubMed

    Sánchez Gomar, Ismael; Díaz Sánchez, María; Uclés Sánchez, Antonio José; Casado Chocán, José Luis; Suárez-Luna, Nela; Ramírez-Lorca, Reposo; Villadiego, Javier; Toledo-Aral, Juan José; Echevarría, Miriam

    2016-01-01

    Detection of IgG anti-Aquaporin-4 (AQP4) in serum of patients with Neuromyelitis optica syndrome disorders (NMOSD) has improved diagnosis of these processes and differentiation from Multiple sclerosis (MS). Recent findings also claim that a subgroup of patients with NMOSD, serum negative for IgG-anti-AQP4, present antibodies anti-AQP1 instead. Explore the presence of IgG-anti-AQP1 using a previously developed cell-based assay (CBA) highly sensitive to IgG-anti-AQP4. Serum of 205 patients diagnosed as NMOSD (8), multiple sclerosis (94), optic neuritis (39), idiopathic myelitis (29), other idiopathic demyelinating disorders of the central nervous system (9), other neurological diseases (18) and healthy controls (8), were used in a CBA over fixed HEK cells transfected with hAQP1-EGFP or hM23-AQP4-EGFP, treated with Triton X-100 and untreated. ELISA was also performed. Analysis of serum with our CBA indicated absence of anti-AQP1 antibodies, whereas in cells pretreated with detergent, noisy signal made reliable detection impossible. ELISA showed positive results in few serums. The low number of NMOSD serums included in our study reduces its power to conclude the specificity of AQP1 antibodies as new biomarkers of NMOSD. Our study does not sustain detection of anti-AQP1 in serum of NMOSD patients but further experiments are expected. PMID:27455255

  16. Comparative Analysis for the Presence of IgG Anti-Aquaporin-1 in Patients with NMO-Spectrum Disorders

    PubMed Central

    Sánchez Gomar, Ismael; Díaz Sánchez, María; Uclés Sánchez, Antonio José; Casado Chocán, José Luis; Suárez-Luna, Nela; Ramírez-Lorca, Reposo; Villadiego, Javier; Toledo-Aral, Juan José; Echevarría, Miriam

    2016-01-01

    Detection of IgG anti-Aquaporin-4 (AQP4) in serum of patients with Neuromyelitis optica syndrome disorders (NMOSD) has improved diagnosis of these processes and differentiation from Multiple sclerosis (MS). Recent findings also claim that a subgroup of patients with NMOSD, serum negative for IgG-anti-AQP4, present antibodies anti-AQP1 instead. Explore the presence of IgG-anti-AQP1 using a previously developed cell-based assay (CBA) highly sensitive to IgG-anti-AQP4. Serum of 205 patients diagnosed as NMOSD (8), multiple sclerosis (94), optic neuritis (39), idiopathic myelitis (29), other idiopathic demyelinating disorders of the central nervous system (9), other neurological diseases (18) and healthy controls (8), were used in a CBA over fixed HEK cells transfected with hAQP1-EGFP or hM23-AQP4-EGFP, treated with Triton X-100 and untreated. ELISA was also performed. Analysis of serum with our CBA indicated absence of anti-AQP1 antibodies, whereas in cells pretreated with detergent, noisy signal made reliable detection impossible. ELISA showed positive results in few serums. The low number of NMOSD serums included in our study reduces its power to conclude the specificity of AQP1 antibodies as new biomarkers of NMOSD. Our study does not sustain detection of anti-AQP1 in serum of NMOSD patients but further experiments are expected. PMID:27455255

  17. Goat anti-rabbit IgG conjugated fluorescent dye-doped silica nanoparticles for human breast carcinoma cell recognition.

    PubMed

    Chen, Min-Yan; Chen, Ze-Zhong; Wu, Ling-Ling; Tang, Hong-Wu; Pang, Dai-Wen

    2013-11-12

    We report an indirect method for cancer cell recognition using photostable fluorescent silica nanoprobes as biological labels. The dye-doped fluorescent silica nanoparticles were synthesized using the water-in-oil (W/O) reverse microemulsion method. The silica matrix was produced by the controlled hydrolysis of tetraethylorthosilicate (TEOS) in water nanodroplets with the initiation of ammonia (NH3·H2O). Fluorescein isothiocyanate (FITC) or rhodamine B isothiocyanate conjugated with dextran (RBITC-Dextran) was doped in silica nanoparticles (NPs) with a size of 60 ± 5 nm as a fluorescent signal element by covalent bonding and steric hindrance, respectively. The secondary antibody, goat anti-rabbit IgG, was conjugated on the surface of the PEG-terminated modified FITC-doped or RBITC-Dextran-doped silica nanoparticles (PFSiNPs or PBSiNPs) by covalent binding to the PEG linkers using the cyanogen bromide method. The concentrations of goat anti-rabbit IgG covering the nanoprobes were quantified via the Bradford method. In the proof-of-concept experiment, an epithelial cell adhesion molecule (EpCAM) on the human breast cancer SK-Br-3 cell surface was used as the tumor marker, and the nanoparticle functionalized with rabbit anti-EpCAM antibody was employed as the nanoprobe for cancer cell recognition. Compared with fluorescent dye labeled IgG (FITC-IgG and RBITC-IgG), the designed nanoprobes display dramatically increased stability of fluorescence as well as photostability under continuous irradiation. PMID:24179992

  18. A Unique Report: Development of Super Anti-Human IgG Monoclone with Optical Density Over Than 3

    PubMed Central

    Aghebati Maleki, Leili; Baradaran, Behzad; Abdolalizadeh, Jalal; Ezzatifar, Fatemeh; Majidi, Jafar

    2013-01-01

    Purpose: Monoclonal antibodies and related conjugates are key reagents used in biomedical researches as well as, in treatment, purification and diagnosis of infectious and non- infectious diseases. Methods: Balb/c mice were immunized with purified human IgG. Spleen cells of the most immune mouse were fused with SP2/0 in the presence of Poly Ethylene Glycol (PEG). Supernatant of hybridoma cells was screened for detection of antibody by ELISA. Then, the sample was assessed for cross-reactivity with IgM & IgA by ELISA and confirmed by immunoblotting. The subclasses of the selected mAbs were determined. The best clone was injected intraperitoneally to some pristane-injected mice. Anti-IgG mAb was purified from the animals' ascitic fluid by Ion exchange chromatography and then, mAb was conjugated with HRP. Results: In the present study, over than 50 clones were obtained that 1 clone had optical density over than 3. We named this clone as supermonoclone which was selected for limiting dilution. The result of the immunoblotting, showed sharp band in IgG position and did not show any band in IgM&IgA position. Conclusion: Based on the findings of this study, the conjugated monoclonal antibody could have application in diagnosis of infectious diseases like Toxoplasmosis, Rubella and IgG class of other infectious and non- infectious diseases. PMID:24312857

  19. Anti-rubella, Mumps and Measles IgG Antibodies in Medical Students of Tehran University.

    PubMed

    Keshavarz, Maryam; Nicknam, Mohammad Hossein; Tebyanian, Majid; Shahkarami, Mohammad Kazem; Izad, Maryam

    2016-06-01

    Measles, mumps and rubella are viral infectious diseases that may result in serious complications. Since the production of vaccines, the number of cases of these diseases has been dropped. Nevertheless, these infectious diseases are still one of the major health problems in developing countries. In this study, in order to evaluate the protective responses against measles, mumps and rubella, the level and avidity of virus-specific IgG antibodies were measured in 53 medical students of Tehran University, aged between 20-30 years. Except for mumps vaccine, all the students had been vaccinated against measles and rubella according to Iran's nationwide mass vaccination protocol for all persons aged 5-25 in 2003. Our results showed that 96.2% of the volunteers had a protective level (>15 IU/ml) of IgG against rubella, 79.2% had a protective level (>11 IU/ml) of IgG against measles and 64.16% had a protective level (>11 IU/ml) of IgG against mumps. Over ten years after nationwide measles-rubella vaccination campaign, most young adults aged 20-30 had protective levels of humoral immunity against measles and rubella. However, Iranian young population is still unvaccinated against mumps, and therefore relatively large number of young adults had no protective level of IgG against it. This finding may be due to reduction in circulating of wild strain. We recommend screening of medical students for immunity against infectious agents such as measles, mumps, rubella, because they are at a high risk of these infectious agents. PMID:27424140

  20. Production of anti-horse antibodies induced by IgG, F(ab')2 and Fab applied repeatedly to rabbits. Effect on antivenom pharmacokinetics.

    PubMed

    Vázquez, Hilda; Olvera, Felipe; Alagón, Alejandro; Sevcik, Carlos

    2013-12-15

    We separated whole IgG, Fab and F(ab')2 fragments from horse plasma. We previously studied the pharmacokinetics of these immunoglobulins and fragments in rabbits and shown that Fab and F(ab')2 pharmacokinetics were well described by a three-exponential kinetics, while IgG and IgG(T) pharmacokinetics, however, deviated from the three-exponential kinetics 120 h after injecting a bolus of the immunotherapeutics; this departure was shown to be due to a surge of anti-horse antibodies occurring after 120 h, peaking at ≈260 h and decaying slowly afterward (Vázquez et al., 2010). We now describe antivenom pharmacokinetics and anti-horse IgG production in rabbits receiving three boluses (300 μg/kg, I.V.) of Fab, F(ab')2 or IgG separated by 21 days. PMID:24047962

  1. Conjugation of an anti transferrin receptor IgG3-avidin fusion protein with biotinylated saporin results in significant enhancement of its cytotoxicity against malignant hematopoietic cells.

    PubMed

    Daniels, Tracy R; Ng, Patrick P; Delgado, Tracie; Lynch, Maureen R; Schiller, Gary; Helguera, Gustavo; Penichet, Manuel L

    2007-11-01

    We have previously developed an antibody fusion protein composed of a mouse/human chimeric IgG3 specific for the human transferrin receptor genetically fused to avidin (anti-hTfR IgG3-Av) as a universal delivery system for cancer therapy. This fusion protein efficiently delivers biotinylated FITC into cancer cells via TfR-mediated endocytosis. In addition, anti-hTfR IgG3-Av alone exhibits intrinsic cytotoxic activity and interferes with hTfR recycling, leading to the rapid degradation of the TfR and lethal iron deprivation in certain malignant B-cell lines. We now report on the cytotoxic effects of a conjugate composed of anti-hTfR IgG3-Av and biotinylated saporin 6 (b-SO6), a toxin derived from the plant Saponaria officinalis that inhibits protein synthesis. Conjugation of anti-hTfR IgG3-Av with b-SO6 enhances the cytotoxic effect of the fusion protein in sensitive cells and also overcomes the resistance of malignant cells that show low sensitivity to the fusion protein alone. Our results show for the first time that loading anti-hTfR IgG3-Av with a biotinylated toxin enhances the cytotoxicity of the fusion protein alone. These results suggest that anti-hTfR IgG3-Av has great potential as a therapeutic agent for a wide range of applications due to its intrinsic cytotoxic activity plus its ability to deliver biotinylated molecules into cancer cells. PMID:18025284

  2. Anti-Aβ Oligomer IgG and Surface Sialic Acid in Intravenous Immunoglobulin: Measurement and Correlation with Clinical Outcomes in Alzheimer’s Disease Treatment

    PubMed Central

    Kwon, Hyewon; Finke, John M.

    2015-01-01

    The fraction of IgG antibodies with anti-oligomeric Aβ affinity and surface sialic acid was compared between Octagam and Gammagard intravenous immunoglobulin (IVIG) using two complementary surface plasmon resonance methods. These comparisons were performed to identify if an elevated fraction existed in Gammagard, which reported small putative benefits in a recent Phase III clinical trial for Alzheimer’s Disease. The fraction of anti-oligomeric Aβ IgG was found to be higher in Octagam, for which no cognitive benefits were reported. The fraction and location of surface-accessible sialic acid in the Fab domain was found to be similar between Gammagard and Octagam. These findings indicate that anti-oligomeric Aβ IgG and total surface sialic acid alone cannot account for reported clinical differences in the two IVIG products. A combined analysis of sialic acid in anti-oligomeric Aβ IgG did reveal a notable finding that this subgroup exhibited a high degree of surface sialic acid lacking the conventional α2,6 linkage. These results demonstrate that the IVIG antibodies used to engage oligomeric Aβ in both Gammagard and Octagam clinical trials did not possess α2,6-linked surface sialic acid at the time of administration. Anti-oligomeric Aβ IgG with α2,6 linkages remains untested as an AD treatment. PMID:25826319

  3. Diagnostic Value of the Serum Anti-Toxocara IgG Titer for Ocular Toxocariasis in Patients with Uveitis at a Tertiary Hospital in Korea

    PubMed Central

    Bae, Ki Woong; Ahn, Seong Joon; Park, Kyu Hyung

    2016-01-01

    Purpose This study evaluated the prevalence of ocular toxocariasis (OT) in patients with uveitis of unknown etiology who visited a tertiary hospital in South Korea and assessed the success of serum anti-Toxocara immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) as a diagnostic test for OT. Methods The records of consecutive patients with intraocular inflammation of unknown etiology were reviewed. All participants underwent clinical and laboratory investigations, including ELISA for serum anti-Toxocara IgG. OT was diagnosed based on typical clinical findings. Clinical characteristics, seropositivity, and IgG titers were compared between patients diagnosed with OT and non-OT uveitis. The seropositivity and the diagnostic value of anti-Toxocara IgG was investigated among patients with different types of uveitis. Results Of 238 patients with uveitis of unknown etiology, 71 (29.8%) were diagnosed with OT, and 80 (33.6%) had positive ELISA results for serum anti-Toxocara IgG. The sensitivity and specificity of the ELISA test were 91.5% (65 / 71) and 91.0% (152 / 167), respectively. The positive predictive value of the serum anti-Toxocara IgG assay was 81.3%. Among patients with anterior, intermediate, posterior, and panuveitis, the prevalence rates of OT were 8.3%, 47.1%, 44.8%, and 7.1%, respectively; the seropositivity percentages were 18.1%, 47.1%, 43.7%, and 17.9%; and the positive predictive values were 38.5%, 95.8%, 92.1%, and 40.0%. The serum anti-Toxocara IgG titer also significantly decreased following albendazole treatment. Conclusions OT is a common cause of intraocular inflammation in the tertiary hospital setting. Considering that OT is more prevalent in intermediate and posterior uveitis, and that the positive predictive value of the anti-Toxocara IgG assay is high, a routine test for anti-Toxocara IgG might be necessary for Korean patients with intermediate and posterior uveitis. PMID:27478352

  4. CD14 as a Mediator of the Mineralocorticoid Receptor-Dependent Anti-apolipoprotein A-1 IgG Chronotropic Effect on Cardiomyocytes.

    PubMed

    Mannic, Tiphaine; Satta, Nathalie; Pagano, Sabrina; Python, Magaly; Virzi, Julien; Montecucco, Fabrizio; Frias, Miguel A; James, Richard W; Maturana, Andres D; Rossier, Michel F; Vuilleumier, Nicolas

    2015-12-01

    In vitro and animal studies point to autoantibodies against apolipoprotein A-1 (anti-apoA-1 IgG) as possible mediators of cardiovascular (CV) disease involving several mechanisms such as basal heart rate interference mediated by a mineralocorticoid receptor-dependent L-type calcium channel activation, and a direct pro-inflammatory effect through the engagement of the toll-like receptor (TLR) 2/CD14 complex. Nevertheless, the possible implication of these receptors in the pro-arrhythmogenic effect of anti-apoA-1 antibodies remains elusive. We aimed at determining whether CD14 and TLRs could mediate the anti-apoA-1 IgG chronotropic response in neonatal rat ventricular cardiomyocytes (NRVC). Blocking CD14 suppressed anti-apoA-1 IgG binding to NRVC and the related positive chronotropic response. Anti-apoA-1 IgG alone induced the formation of a TLR2/TLR4/CD14 complex, followed by the phosphorylation of Src, whereas aldosterone alone promoted the phosphorylation of Akt by phosphatidylinositol 3-kinase (PI3K), without affecting the chronotropic response. In the presence of both aldosterone and anti-apoA-1 IgG, the localization of TLR2/TLR4/CD14 was increased in membrane lipid rafts, followed by PI3K and Src activation, leading to an L-type calcium channel-dependent positive chronotropic response. Pharmacological inhibition of the Src pathway led to the decrease of L-type calcium channel activity and abrogated the NRVC chronotropic response. Activation of CD14 seems to be a key regulator of the mineralocorticoid receptor-dependent anti-apoA-1 IgG positive chronotropic effect on NRVCs, involving relocation of the CD14/TLR2/TLR4 complex into lipid rafts followed by PI3K and Src-dependent L-type calcium channel activation. PMID:26393305

  5. Og4C3 circulating antigen, anti-Brugia malayi IgG and IgG4 titers in Wuchereria bancrofti infected patients, according to their parasitological status.

    PubMed

    Chanteau, S; Glaziou, P; Luquiaud, P; Plichart, C; Moulia-Pelat, J P; Cartel, J L

    1994-09-01

    This study involved 221 microfilaremic (Mf+), 302 amicrofilaremic (Mf-) antigen positive (AG+) and 1454 Mf-antigen negative (AG-) individuals living in endemic villages. Whatever the group considered, antigen and antibody titers were widely distributed. Og4C3 antigen, detected both in Mf- and Mf+ patients, was significantly higher in Mf+ patients. The Mf parasitological status did not significantly influence the antifilarial antibodies levels in the infected AG+ individuals, although IgG4 was more discriminant. In the supposedly uninfected individuals (Mf-AG-), anti-filarial IgG and IgG4 could be detected in a large proportion of the group. Og4C3 circulating antigen test was confirmed to be a good marker of active Wuchereria bancrofti infection. PMID:7899800

  6. Epitope specificity of rabbit immunoglobulin G (IgG) elicited by pneumococcal type 23F synthetic oligosaccharide- and native polysaccharide-protein conjugate vaccines: comparison with human anti-polysaccharide 23F IgG.

    PubMed Central

    Alonso de Velasco, E; Verheul, A F; van Steijn, A M; Dekker, H A; Feldman, R G; Fernández, I M; Kamerling, J P; Vliegenthart, J F; Verhoef, J; Snippe, H

    1994-01-01

    Streptococcus pneumoniae type 23F capsular polysaccharide (PS23F) consitss of a repeating glycerol-phosphorylated branched tetrasaccharide. The immunogenicities of the following related antigens were investigated: (i) a synthetic trisaccharide comprising the backbone of one repeating unit, (ii) a synthetic tetrasaccharide comprising the complete repeating unit, and (iii) native PS23F (all three conjugated to keyhole limpet hemocyanin [KLH]) and (iv) formalin-killed S. pneumoniae 23F. All antigens except the trisaccharide-KLH conjugate induced relatively high anti-PS23F antibody levels in rabbits. The epitope specificity of such antibodies was then studied by means of an inhibition immunoassay. The alpha(1-->2)-linked L-rhamnose branch was shown to be immunodominant for immunoglobulin G (IgG) induced by tetrasaccharide-KLH, PS23F-KLH, and killed S. pneumoniae 23F: in most sera L-rhamnose totally inhibited the binding of IgG to PS23F. Thus, there appears to be no major difference in epitope specificity between IgG induced by tetrasaccharide-KLH and that induced by antigens containing the polymeric form of PS23F. Human anti-PS23F IgG (either vaccine induced or naturally acquired) had a different epitope specificity: none of the inhibitors used, including L-rhamnose and tetrasaccharide-KLH, exhibited substantial inhibition. These observations suggest that the epitope recognized by human IgG on PS23F is larger than the epitope recognized by rabbit IgG. Both human and rabbit antisera efficiently opsonized type 23F pneumococci, as measured in a phagocytosis assay using human polymorphonuclear leukocytes. PMID:7509318

  7. Where to Now for Standardization of Anti-Rubella Virus IgG Testing.

    PubMed

    Dimech, Wayne

    2016-07-01

    The lack of standardization of rubella IgG testing continues to be a problem 20 years since the standard was introduced. The situation is complex and poorly understood. As demonstrated by an article in this issue (E. Bouthry, M. Furione, D. Huzly, A. Ogee-Nwankwo, L. Hao, A. Adebayo, J. Icenogle, A. Sarasini, M. Grazia Revello, L. Grangeot-Keros, and C. Vauloup-Fellous, J Clin Microbiol 54:1720-1725, 2016, http://dx.doi.org/10.1128/JCM.00383-16), the problem remains. The situation is far from being resolved, but at least the process for change has started. PMID:27170018

  8. Increased levels of anti-non-Gal IgG following pig-to-baboon bone marrow transplantation correlate with failure of engraftment

    PubMed Central

    Liang, Fan; Wamala, Isaac; Scalea, Joseph; Tena, Aseda; Cormack, Taylor; Pratts, Shannon; Struuck, Raimon Duran; Elias, Nahel; Hertl, Martin; Huang, Christene A.; Sachs, David H.

    2013-01-01

    Background The development of genetically modified pigs which lack the expression of alpha 1–3 galactosyl transferase, (GalT-KO pigs) has facilitated the xenogeneic transplantation of porcine organs and tissues into primates by avoiding hyperacute rejection due to pre-existing antibodies against the Gal epitope. However, antibodies against other antigens (anti-non-Gal antibodies), are found at varying levels in the pre-transplant sera of most primates. We have previously found that baboons with high levels of pre-transplant anti-non-Gal IgG, conditioned with a non-myeloablative conditioning regimen, failed to engraft following pig-to-baboon bone marrow transplantation [8]. Two baboons with low levels of pre-transplant anti-non-Gal IgG, conditioned with the same regimen, showed porcine bone marrow progenitors at 28 days following transplantation, suggesting engraftment. These baboons also showed evidence of donor-specific hypo-responsiveness. This observation led us to investigate the hypothesis that selecting for baboon recipients with low pre-transplant anti-non-Gal IgG levels might improve engraftment levels following GalT-KO pig-to-baboon bone marrow transplantation. Methods Five baboons, with low pre-transplant anti-non-Gal IgG levels, received transplantation of bone marrow cells (1–5 × 10^9/kg of recipient weight) from GalT-KO pigs. They received a non-myeloablative conditioning regimen consisting of low-dose total body irradiation (150cGy), thymic irradiation (700cGy), anti-thymocyte globulin (ATG) and tacrolimus. In addition, two baboons received Rituximab and Bortezomib (Velcade) treatment as well as extra-corporeal immunoadsorption using GalT-KO pig livers. Bone marrow engraftment was assessed by porcine-specific PCR on colony forming units (CFU) of day 28 bone marrow aspirates. Anti-non-Gal antibody levels were assessed by serum binding towards GalT-KO PBMC using flow cytometry (FACS). Peripheral macro-chimerism was measured by FACS using pig and

  9. Anti-GaL IgG antibodies in sera of newborn humans and baboons and its significance in pig xenotransplantation.

    PubMed

    Minanov, O P; Itescu, S; Neethling, F A; Morgenthau, A S; Kwiatkowski, P; Cooper, D K; Michler, R E

    1997-01-27

    We have previously demonstrated that hyperacute rejection does not occur in a pig-to-newborn baboon heart transplant model, presumably because of low levels of cytotoxic antipig antibodies present in the serum of newborn baboons. Cytotoxic antipig antibodies are primarily directed to alpha-1,3-galactosyl (alpha Gal) residues on endothelial cell surface structures Twenty-one full-term humans and 5 full-term baboons were tested for complement mediated lysis (CML) of pig kidney (PK-15) cells and anti-alpha Gal activity with an ELISA using BSA-conjugated alpha Gal residues as target. To evaluate the significance of the anti-alpha Gal titers in vivo 5 newborn baboons underwent heterotopic pig cardiac xenotransplantation. Six of 21 human samples and 1 of 5 baboon samples demonstrated significant cytotoxicity to PK-15 cells. Twelve of 21 newborn humans had anti-alpha Gal IgG antibodies at titers of 1:80 or greater. None of the samples had anti-alpha Gal IgM. In newborn baboons, 1 of 5 sera had anti-alpha Gal IgG antibodies at titers greater than 1:80 and none of these samples had anti-alpha Gal IgM. Xenografts survived for an average of 3.6 days, even in the baboon with high anti-alpha Gal IgG titers. Analysis of the explanted grafts showed minimal evidence of complement-mediated hyperacute rejection (HAR), but prominent mononuclear cell infiltrates. In serum tested posttransplant there was an induced anti-alpha Gal response with cytotoxicity against PK-15 cells. These results show that anti-alpha Gal IgM is absent in newborn human and baboon sera, allowing pig grafts to avoid HAR. However, the presence of anti-alpha Gal IgG may be associated with mononuclear cell infiltration of the xenograft and its subsequent rejection. PMID:9020315

  10. [Anti-GD1b IgG antibody-related Guillain-Barré syndrome initially mimicking brainstem infarction].

    PubMed

    Ikuta, N; Koga, M; Ogasawara, J; Morimatsu, M; Yuki, N

    2001-01-01

    We described a 58-year-old woman with Guillain-Barré syndrome, who initially showed rapid progression of brainstem infarction-like signs. She developed superficial sensory disturbance on the left side, dysarthria, and left-predominant limb weakness within a few hours. She showed bilateral extensor plantar responses and head CT scan detected no abnormality. It was difficult to be distinguished from brainstem infarction until symmetrical limb weakness and generalized areflexia appeared. Serum anti-GD1b IgG antibody with cross-reactivity with GM1b was detected. Cerebrospinal fluid examination revealed albuminocytologic dissociation on day 5. After 5 sessions of immunoadsorption therapy, her symptoms gradually lessened. Anti-GD1b antibody has been detected in patients with sensory ataxic neuropathy. Our patient, however, was characterized with early involvement of brainstem with ataxia of cerebellar type. Our case suggests that anti-GD1b antibody-associated neuropathy has a broad spectrum of clinical features, which are related to cross-reactivity of this antibody. PMID:11481856

  11. Prevalence estimation of tick-borne encephalitis virus (TBEV) antibodies in dogs from Finland using novel dog anti-TBEV IgG MAb-capture and IgG immunofluorescence assays based on recombinant TBEV subviral particles.

    PubMed

    Levanov, Lev; Vera, Cristina Pérez; Vapalahti, Olli

    2016-07-01

    Tick-borne encephalitis (TBE) is one of the most dangerous human neurological infections occurring in Europe and Northern parts of Asia with thousands of cases and millions vaccinated against it. The risk of TBE might be assessed through analyses of the samples taken from wildlife or from animals which are in close contact with humans. Dogs have been shown to be a good sentinel species for these studies. Serological assays for diagnosis of TBE in dogs are mainly based on purified and inactivated TBEV antigens. Here we describe novel dog anti-TBEV IgG monoclonal antibody (MAb)-capture assay which is based on TBEV prME subviral particles expressed in mammalian cells from Semliki Forest virus (SFV) replicon as well as IgG immunofluorescence assay (IFA) which is based on Vero E6 cells transfected with the same SFV replicon. We further demonstrate their use in a small-scale TBEV seroprevalence study of dogs representing different regions of Finland. Altogether, 148 dog serum samples were tested by novel assays and results were compared to those obtained with a commercial IgG enzyme immunoassay (EIA), hemagglutination inhibition test and IgG IFA with TBEV infected cells. Compared to reference tests, the sensitivities of the developed assays were 90-100% and the specificities of the two assays were 100%. Analysis of the dog serum samples showed a seroprevalence of 40% on Åland Islands and 6% on Southwestern archipelago of Finland. In conclusion, a specific and sensitive EIA and IFA for the detection of IgG antibodies in canine sera were developed. Based on these assays the seroprevalence of IgG antibodies in dogs from different regions of Finland was assessed and was shown to parallel the known human disease burden as the Southwestern archipelago and Åland Islands in particular had considerable dog TBEV antibody prevalence and represent areas with high risk of TBE for humans. PMID:27189583

  12. Passive transfer of IgG anti-GM1 antibodies impairs peripheral nerve repair

    PubMed Central

    Lopez, Pablo H.; Zhang, Gang; Zhang, Jiangyang; Lehmann, Helmar C.; Griffin, John W.; Schnaar, Ronald L.; Sheikh, Kazim A.

    2010-01-01

    Anti-GM1 antibodies are present in some patients with autoimmune neurological disorders. These antibodies are most frequently associated with acute immune neuropathy called Guillain-Barré syndrome (GBS). Some clinical studies associate the presence of these antibodies with poor recovery in GBS. The patients with incomplete recovery have failure of nerve repair, particularly axon regeneration. Our previous work indicates that monoclonal antibodies can inhibit axon regeneration by engaging cell surface gangliosides (Lehmann et al., 2007). We asked whether passive transfer of human anti-GM1 antibodies from patients with GBS modulate axon regeneration in an animal model. Human anti-GM1 antibodies were compared with other GM1 ligands, cholera toxin B subunit and a monoclonal anti-GM1 antibody. Our results show that patient derived anti-GM1 antibodies and cholera toxin β subunit impair axon regeneration/repair after PNS injury in mice. Comparative studies indicated that the antibody/ligand-mediated inhibition of axon regeneration is dependent on antibody/ligand characteristics such as affinity-avidity and fine specificity. These data indicate that circulating immune effectors such as human autoantibodies, which are exogenous to the nervous system, can modulate axon regeneration/nerve repair in autoimmune neurological disorders such as GBS. PMID:20631181

  13. ENZYMATIC DEGLYCOSYLATION CONVERTS PATHOGENIC NEUROMYELITIS OPTICA ANTI-AQUAPORIN-4 IgG INTO THERAPEUTIC ANTIBODY

    PubMed Central

    Tradtrantip, Lukmanee; Ratelade, Julien; Zhang, Hua; Verkman, A.S.

    2013-01-01

    Objective Neuromyelitis optica (NMO) is caused by binding of pathogenic autoantibodies (NMO-IgG) to aquaporin-4 (AQP4) on astrocytes, which initiates complement-dependent cytotoxicity (CDC) and inflammation. We recently introduced mutated antibody (aquaporumab) and small-molecule blocker strategies for therapy of NMO, based on prevention of NMO-IgG binding to AQP4. Here, we investigated an alternative strategy involving neutralization of NMO-IgG effector function by selective IgG heavy-chain deglycosylation with bacteria-derived endoglycosidase S (EndoS). Methods Cytotoxicity and NMO pathology were measured in cell and spinal cord slice cultures, and in mice exposed to control or EndoS-treated NMO-IgG. Results EndoS treatment of NMO patient serum reduced by >95 % CDC and antibody-dependent cell-mediated cytotoxicity (ADCC), without impairment of NMO-IgG binding to AQP4. Cytotoxicity was also prevented by addition of EndoS after NMO-IgG binding to AQP4. The EndoS-treated, non-pathogenic NMO-IgG competitively displaced pathogenic NMO-IgG bound to AQP4, and prevented NMO pathology in spinal cord slice culture and mouse models of NMO. Interpretation EndoS deglycosylation converts pathogenic NMO-IgG autoantibodies into therapeutic blocking antibodies. EndoS treatment of blood may be beneficial in NMO, which may be accomplished, for example, by therapeutic apheresis using surface-immobilized EndoS. PMID:23055279

  14. Correlation between the Amount of Anti-D Antibodies and IgG Subclasses with Severity of Haemolytic Disease of Foetus and Newborn

    PubMed Central

    Velkova, Emilija

    2015-01-01

    AIM: The aim of this study was to investigate the influence of subclasses to IgG anti-D on the intensity of hemolytic disease of fetus and newborn (HDFN) at 45 fetuses/newborns with symptoms of mild and severe HDFN in Republic of Macedonia. MATERIAL AND METHODS: In retrospective and prospective studies, in a period of 10 years, from 2004 to 2014, there have been immunohemathology tests performed on 22 009 samples on serums of pregnant women. RESULTS: At 37.78% of the total number of tested patients, IgG1 and IgG3 was the reason for severe HDFN. At 17.77% of the total number of tested patients, which had only IgG1detected, was the reason for serious intensity of HDFN. The correlation of the titer to anti-D antibodies in the mother’s serum and the intensity of HDFN were researched in 48 newborns. The titers between 1:8 and 1:32 resulted in 3 cases of HDFN with symptoms of severe disease and in 4 cases there were no signs of HDFN. At 12 women that had a titre between 1:32 and 1:512, five of the newborns developed severe HDFN, and seven had symptoms of mild and weak intensity form. In 3 cases the titer was higher than 512, and out of them one newborn had weak symptoms of HDFN, one developed severe HDFN and one ended with foetal death. Only in one case the titer reached a value higher than 1000, and it ended with a fetal death. CONCLUSIONS: The titers of the pregnant women serum those are lower than 32 and those higher than 1000 can well predict HDFN. The titers of anti-D antibodies between 64 and 512 have no exact predictive value. IgG1 and IgG3 subclasses of anti-D have no predictive value by themselves, and cannot foresee the outcome of HDFN. The research study results suggest that IgG1 and IgG3 should be included in a multi – parameter protocol for evaluation of the HDFN intensity. They can give a real assessment of the expected HDFN intensity in combination with the titer hight and the significance of the antibodies.

  15. Determination of anti-canine IgG using a continuous filtration/dissolution system based on the formation of a high-molecular size immunocomplex.

    PubMed

    Reyes, F D; Arce, C; Moreno, A; Fernández Romero, J M; Luque de Castro, M D

    2001-10-31

    A method for the determination of monoclonal antibody anti-canine-IgG based on a continuous filtration/dissolution system is presented as prototype for further developments. The basis of the system is the continuous formation of a high-molecular immunocomplex, which is temporally retained on a microfilter located prior to the detector. The immunochemical method consists of the development of a sandwich type heterogeneous non-competitive reaction to yield a high molecular immunocomplex, as a result of the affinity interaction between streptavidin and biotincanine IgG and the immunoreaction between canine IgG and mAb anti-canine IgG, which occurs in solution. Goat anti-mouse IgG labelled with peroxidase is used as tracer. The extension of the immunoreaction is monitored fluorimetrically via the condensation product between 4-hydroxyphenylacetic acid and hydrogen peroxide in the presence of the peroxidase retained on the filter. The method provides a dynamic range from 10(-4) to 500 mug l(-1) with an IC(50) of 0.554 mug 1(-1) (for a biotin-IgG dilution of 1:250, chi(2)=0.6085, r(2)=0.9991, n=14) and a precision, expressed as R.S.D.%, lower than 4.7%. After modifications, the method here proposed can be extended for monitoring analytes of interest in the agrochemical, food and environmental areas, as far as permitted by the availability to produce the corresponding monoclonal antibody. PMID:18968430

  16. Immunoreactivity and avidity of IgG anti-β2-glycoprotein I antibodies from patients with autoimmune diseases to different peptide clusters of β2-glycoprotein I.

    PubMed

    Artenjak, A; Locatelli, I; Brelih, H; Simonič, D M; Ulcova-Gallova, Z; Swadzba, J; Musial, J; Iwaniec, T; Stojanovich, L; Conti, F; Valesini, G; Avčin, T; Cohen Tervaert, J W; Shoenfeld, Y; Blank, M; Ambrožič, A; Sodin-Semrl, S; Božič, B; Čučnik, S

    2015-02-01

    The pathogenicity of antibodies against β2-glycoprotein I (anti-β2GPI) depends on multiple factors such as subclass type, epitope binding and avidity. Due to their large heterogeneity, their impact on antiphospholipid syndrome (APS) onset is still not fully clarified. We studied the binding characteristics of IgG anti-β2GPI with known avidity from sera of 201 autoimmune patients (87 with APS, 67 with APS associated with systemic lupus erythematosus (SLE), 47 with only SLE) to six β2GPI peptides corresponding to amino acid clusters on domains I-II, II, III and III-IV by indirect ELISA and evaluated their association with clinical features of APS. Peptides A (LKTPRV; domain I-II), B (KDKATF; domain IV) and C (TLRVYK; domain III) were derived from a hexapeptide phage display library previously shown to react with pathogenic monoclonal anti-β2GPI. Peptides D (NGPANSK; domain III), E (YNPLWFV; domain II) and F (KMDGNHP; domain III-IV) represent surface amino acid clusters on β2GPI. The percentage of patients positive for peptides were observed as follows: 30.3% for peptide D, 28.90% for B, 25.9% for C, 24.9% for E, 24.4% for F and 10.0% for A. The anti-peptide antibodies in studied serum samples were predominantly of heterogeneous avidity, followed by law avidity anti-peptide antibodies, whereas only a few were of high avidity. Positive and negative correlations were found between several anti-peptide antibodies and the rate of thrombosis. Our results indicated diverse reactivity of IgG anti-β2GPI to different epitopes on β2GPI. Classification of IgG anti-β2GPI into subgroups regarding epitope specificity and avidity could represent an additional tool in understanding their pathogenicity in APS. PMID:25395339

  17. Cetuximab in combination with anti-human IgG antibodies efficiently down-regulates the EGF receptor by macropinocytosis

    SciTech Connect

    Berger, Christian; Madshus, Inger Helene; Stang, Espen

    2012-12-10

    The monoclonal antibody C225 (Cetuximab) blocks binding of ligand to the epidermal growth factor receptor (EGFR). In addition, it is known that incubation with C225 induces endocytosis of the EGFR. This endocytosis has previously been shown to be increased when C225 is combined with an additional monoclonal anti-EGFR antibody. However, the effects of antibody combinations on EGFR activation, endocytosis, trafficking and degradation have been unclear. By binding a secondary antibody to the C225-EGFR complex, we here demonstrate that a combination of antibodies can efficiently internalize and degrade the EGFR. Although the combination of antibodies activated the EGFR kinase and induced ubiquitination of the EGFR, the kinase activity was not required for internalization of the EGFR. In contrast to EGF-induced EGFR down-regulation, the antibody combination efficiently degraded the EGFR without initiating downstream proliferative signaling. The antibody-induced internalization of EGFR was found not to depend on clathrin and/or dynamin, but depended on actin polymerization, suggesting induction of macropinocytosis. Macropinocytosis may cause internalization of large membrane areas, and this could explain the highly efficient internalization of the EGFR induced by combination of antibodies. -- Highlight: Black-Right-Pointing-Pointer Cetuximab induced endocytosis of EGFR increases upon combination with anti-human IgG. Black-Right-Pointing-Pointer Antibody combination causes internalization of EGFR by macropinocytosis. Black-Right-Pointing-Pointer Antibody-induced internalization of EGFR is independent of EGFR kinase activity. Black-Right-Pointing-Pointer Antibody combination may have a zipper effect and cross-link EGFRs on neighboring cells.

  18. Antitumor Efficacy of Anti-GD2 IgG1 Is Enhanced by Fc Glyco-Engineering.

    PubMed

    Xu, Hong; Guo, Hongfen; Cheung, Irene Y; Cheung, Nai-Kong V

    2016-07-01

    The affinity of therapeutic antibodies for Fcγ receptors (FcγRs) strongly influences their antitumor potency. To generate antibodies with optimal binding and immunologic efficacy, we compared the affinities of different versions of an IgG1 Fc region that had an altered peptide backbone, altered glycans, or both. To produce IgG1 with glycans that lacked α1,6-fucose, we used CHO cells that were deficient in the enzyme UDP-N-acetylglucosamine: α-3-d-mannoside-β-1,2-N-acetylglucosaminyltransferase I (GnT1), encoded by the MGAT1 gene. Mature N-linked glycans require this enzyme, and without it, CHO cells synthesize antibodies carrying only Man5-GlcNAc2, which were more effective in antibody-dependent cell-mediated cytotoxicity (ADCC). Our engineered IgG1, hu3F8-IgG1, is specific for GD2, a neuroendocrine tumor ganglioside. Its peptide mutant is IgG1-DEL (S239D/I332E/A330L), both produced in wild-type CHO cells. When produced in GnT1-deficient CHO cells, we refer to them as IgG1n and IgG1n-DEL, respectively. Affinities for human FcγRs were measured using Biacore T-100 (on CD16 and CD32 polymorphic alleles), their immunologic properties compared for ADCC and complement-mediated cytotoxicity (CMC) in vitro, and pharmacokinetics and antitumor effects were compared in vivo in humanized mice. IgG1n and IgG1n-DEL contained only mannose and acetylglucosamine and had preferential affinity for activating CD16s, over inhibitory CD32B, receptors. In vivo, the antitumor effects of IgG1, IgG1-DEL, and IgG1n-DEL were similar but modest, whereas IgG1n was significantly more effective (P < 0.05). Thus, IgG1n antibodies produced in GnT1-deficient CHO cells may have potential as improved anticancer therapeutics. Cancer Immunol Res; 4(7); 631-8. ©2016 AACR. PMID:27197064

  19. Functional anti-polysaccharide IgG titres induced by unadjuvanted pneumococcal-conjugate vaccine when delivered by microprojection-based skin patch.

    PubMed

    Pearson, Frances E; Muller, David A; Roalfe, Lucy; Zancolli, Marta; Goldblatt, David; Kendall, Mark A F

    2015-11-27

    Adequate access to effective and affordable vaccines is essential for the prevention of mortality due to infectious disease. Pneumonia--a consequence of Streptococcus pneumoniae infection--is the world's leading cause of death in children aged under 5 years. The development of a needle-free, thermostable pneumococcal-conjugate vaccine (PCV) could revolutionise the field by reducing cold-chain and delivery constraints. Skin patches have been used to deliver a range of vaccines, with some inducing significantly higher vaccine-specific immunogenicity than needle-injected controls in pre-clinical models, though they have yet to be used to deliver a PCV. We dry-coated a licensed PCV onto a microprojection-based patch (the Nanopatch) and delivered it to mouse skin. We analysed resulting anti-polysaccharide IgG responses. With and without adjuvant, anti-polysaccharide IgG titres induced by Nanopatch immunisation were significantly higher than dose-matched intramuscular controls. These improved responses were primarily obtained against pneumococcal serotypes 4 and 14. Importantly, capsule-specific IgG correlated with functionality in an opsonophagocytic killing assay. We demonstrate enhanced anti-PCV immunogenicity when delivered by Nanopatch over intramuscular injection. As the first study of a PCV delivered by a skin vaccination technology, this report indicates the potential for reduced costs and greater global distribution of such a vaccine. PMID:26518398

  20. Identification of anti-HPA-1a allo-antibodies using IgG platelet antibody detection and crossmatch system assay with Galileo Echo.

    PubMed

    Di Cristofaro, Julie; Frassati, Coralie; Montagnie, Rolande; Basire, Agnes; Merieux, Yves; Picard, Christophe

    2015-01-01

    Fetal/neonatal allo-immune thrombocytopenia is the most frequent and the most dangerous clinical condition involving anti-human platelet antigens (HPA)-1a allo-antibodies. Anti-HPA-1a allo-immunization requires rapid and accurate diagnosis to determine appropriate treatment. The Capture-P Ready-Screen assay (C-PRS) is a new qualitative immunoassay to detect IgG anti-human leukocyte antigen (HLA) and anti-HPA allo-antibodies. The aim of this study is to assess the identification of anti-HPA-1a allo-antibodies using the C-PRS assay, associated with HLA class I stripping reagents, on the automated benchtop analyzer Galileo Echo. Forty-nine sera were analyzed: without anti-HLA class I or anti-HPA allo-antibodies, with anti-HLA class I allo-antibodies, with anti-HPA-1a allo-antibodies, among which with anti-HLA class I allo-antibodies. None of the samples without allo-antibodies were reactive. Only anti-HLA antibodies, detected by cytotoxicity-dependent complement and not by Luminex, remained positive before and after stripping reagents. Of the 13 samples, anti-HPA-1a allo-antibodies that were correctly identified before and after incubation with HLA assassin reagent were 70% and 85%, respectively. Anti-glycoprotein auto-antibodies and anti-HLA allo-antibodies do not interfere with the detection of anti-HPA-1a antibodies. This preliminary study indicates that further improvement of the test will be helpful in developing a clinically useful assay in the future. PMID:25101933

  1. Evidence that FcRn mediates the transplacental passage of maternal IgE in the form of IgG anti-IgE/IgE immune complexes

    PubMed Central

    Bundhoo, Arvin; Paveglio, Sara; Rafti, Ektor; Dhongade, Ashish; Blumberg, Richard S.; Matson, Adam P.

    2015-01-01

    Background The mechanism(s) responsible for acquisition of maternal antibody isotypes other than IgG are not fully understood. This uncertainty is a major reason underlying the continued controversy regarding whether cord blood (CB) IgE originates in the mother or fetus. Objective To investigate the capacity of maternal IgE to be transported across the placenta in the form of IgG anti-IgE/IgE immune complexes (ICs) and to determine the role of the neonatal Fc receptor (FcRn) in mediating this process. Methods Maternal and CB serum concentrations of IgE, IgG anti-IgE, and IgG anti-IgE/IgE ICs were determined in a cohort of allergic and non-allergic mother/infant dyads. Madin-Darby Canine Kidney (MDCK) cells stably transfected with human FcRn were used to study the binding and transcytosis of IgE in the form of IgG anti-IgE/IgE ICs. Results Maternal and CB serum concentrations of IgG anti-IgE/IgE ICs were highly correlated, regardless of maternal allergic status. IgG anti-IgE/IgE ICs generated in vitro bound strongly to FcRn-expressing MDCK cells and were transcytosed in an FcRn-dependent manner. Conversely, monomeric IgE did not bind to FcRn and was not transcytosed. IgE was detected in solutions of transcytosed IgG anti-IgE/IgE ICs, even though essentially all the IgE remained in complex form. Similarly, the majority of IgE in CB sera was found to be complexed to IgG. Conclusions and Clinical Relevance These data indicate that human FcRn facilitates the transepithelial transport of IgE in the form of IgG anti-IgE/IgE ICs. They also strongly suggest that the majority of IgE in CB sera is the result of FcRn-mediated transcytosis of maternal-derived IgG anti-IgE/IgE ICs. These findings challenge the widespread perception that maternal IgE does not cross the placenta. Measuring maternal or CB levels of IgG anti-IgE/IgE ICs may be a more accurate predictor of allergic risk. PMID:25652137

  2. A rare case of Addison's disease, hepatitis, thyreoiditis, positive IgG anti-tissue transglutaminase antibodies and partial IgA deficiency

    PubMed Central

    Mihaylova, Snejina; Yankova, Petja; Atanasova, Iliana; Nikolova-Vlahova, Milena; Naumova, Elissaveta

    2016-01-01

    Introduction Selective IgA deficiency (IgAD) is the most prevalent type of primary immune deficiencies, but partial IgA deficiency is even more common. Addison's disease is a rare condition associated with primary adrenal insufficiency due to infection or autoimmune destruction of the adrenals. The association between IgA deficiency and Addison's disease is very rare. Case and laboratory data We observed a 22-year-old male patient with marked darkening of the skin, especially on the palms and areolae, jaundice on the skin and sclera, astheno-adynamia, hypotension (80/50 mm Hg), and pain in the right hypochondrium. The laboratory investigations revealed increased serum levels of total and indirect bilirubin, AST, ALT, GGT and LDH, negative HBsAg, anti-HBc IgM, anti-HCV and anti-HAV IgM, very low serum IgA levels (0.16 g/l) with normal IgG and IgM, negative ANA, ANCA, AMA, LKM-1, anti-GAD-60, anti-IA-2, anti-thyroglobulin antibodies, a mild increase in anti-TPO antibodies titer, a marked increase in IgG anti-tissue transglutaminase antibodies, with no typical changes in cellular immunity, negative T-SPOT-TB test, HLA – A*01; B*08; DRB1*03; DQB1*02, karyotype – 46, XY. Conclusions We present a rare case of partial IgA deficiency with Addison's disease, hepatitis, thyroiditis and positive anti-tissue transglutaminase antibodies. IgAD and some autoimmune disorders share several predisposing HLA genes, thus explaining the increased prevalence of IgAD in certain patient groups. PMID:27536208

  3. Younger patients with primary Sjögren's syndrome are more likely to have salivary IgG anti-muscarinic acetylcholine receptor type 3 antibodies.

    PubMed

    Jayakanthan, K; Ramya, J; Mandal, Santosh Kumar; Sandhya, P; Gowri, M; Danda, Debashish

    2016-03-01

    Acetylcholine type 3 receptor (M3R) is recognized as an autoantigen in primary Sjögren's syndrome (pSS). Assay of anti-M3R antibody levels in serum is fraught with low sensitivity for diagnosis of pSS. Salivary assay is more likely to improve the diagnostic accuracy. Patients with pSS classified either by the American European Consensus Group (AECG) or American college of Rheumatology (ACR) criteria, attending rheumatology clinic between October 2014 and July 2015 were included. Hospital staff and lupus patients constituted healthy and disease controls, respectively. Evaluation of pSS included clinical evaluation, laboratory tests, ESSDAI and ESSPRI scoring. Unstimulated saliva was collected by the spitting method. Salivary IgG antibody against M3R (anti-M3R) was quantified by indirect ELISA. In this study, 43 patients with pSS, 34 with lupus and 42 healthy controls were recruited. The frequency of anti-M3R antibody levels was 55.81, 17.64 and 7 % for pSS, lupus and healthy controls, respectively. Area under the Receiver Operator Characteristic was 0.7791 (95 % CI,, 0.67-0.87). Sensitivity and specificity of the assay for diagnosis of pSS were 44.19 and 88.16 %, respectively. Salivary anti-M3R IgG antibody positivity was associated with lower age, shorter disease duration and higher globulin levels in our cohort. Salivary anti-M3R IgG antibody assay has high specificity in pSS; younger patients and those with hyperglobulinemia more frequently tested positive for this antibody. PMID:26809799

  4. Postoperative change of anti-Thomsen-Friedenreich and Tn IgG level: The follow-up study of gastrointestinal cancer patients

    PubMed Central

    Smorodin, Eugeniy P; Kurtenkov, Oleg A; Sergeyev, Boris L; Kodar, Kristel E; Chuzmarov, Valentin I; Afanasyev, Vladimir P

    2008-01-01

    AIM: To study the influence of tumor removal on the serum level of IgG antibodies to tumor-associated Thomsen-Friedenreich (TF), Tn carbohydrate epitopes and xenogeneic αGal, and to elucidate on the change of the level during the follow-up as well as its association with the stage and morphology of the tumor and the values of blood parameters in gastrointestinal cancer. METHODS: Sixty patients with gastric cancer and 34 patients with colorectal cancer in stages I-IV without distant metastases were subjected to follow-up. The level of antibodies in serum was determined by the enzyme-linked immunosorbent assay (ELISA) using synthetic polyacrylamide (PAA) glycoconjugates. Biochemical and haematological analyses were performed using automated equipment. RESULTS: In gastrointestinal cancer, the TF antibody level was found to have elevated significantly after the removal of G3 tumors as compared with the preoperative level (u = 278.5, P < 0.05). After surgery, the TF and Tn antibody level was elevated in the majority of gastric cancer patients (sign test, 20 vs 8, P < 0.05, and 21 vs 8, P < 0.05, respectively). In gastrointestinal cancer, the elevated postoperative level of TF, Tn and αGal antibodies was noted in most patients with G3 tumors (sign test, 22 vs 5, P < 0.01; 19 vs 6, P < 0.05; 24 vs 8, P < 0.01, respectively), but the elevation was not significant in patients with G1 + G2 resected tumors. The postoperative follow-up showed that the percentage of patients with G3 resected tumors of the digestive tract, who had a mean level of anti-TF IgG above the cut-off value (1.53), was significantly higher than that of patients with G1 + G2 resected tumors (χ2 = 3.89, all patients; χ2 = 5.34, patients without regional lymph node metastases; P < 0.05). The percentage of patients with a tumor in stage I, whose mean anti-TF IgG level remained above the cut-off value (1.26), was significantly higher than that of patients with the cancer in stages III-IV (χ2 = 4

  5. Destruction of IgG anti-A sensitized erythrocytes by mononuclear leucocytes from normal and ABO haemolytic disease affected infants.

    PubMed Central

    Romano, E L; Rossi Devivo, M L; Soyano, A; Linares, J

    1984-01-01

    Studies were undertaken to investigate the antibody-dependent cell-mediated cytotoxicity (ADCC) activity of mononuclear leucocytes (MNL) from cord and healthy adult blood and that from infants with ABO haemolytic disease. The ADCC levels of MNL from both types of newborn blood were found to be higher than that of MNL from adult blood. The extent of ADCC was positively related to the degree of antibody sensitization of the red cells and to the effector cell target cell ratio. The ADCC activity was effected mainly by the adherent cell fraction and could be inhibited by cytochalasin B, hydrocortisone and also by high concentrations (more than 0.5 mg/ml) of non-specific free human IgG. Phagocytosis was also demonstrated to be an important mechanism in the destruction of IgG anti-A coated red cells by the MNL. PMID:6538121

  6. A noncytolytic antibody-like extendin-4-IgG4 fusion protein as a long-acting potential anti-diabetic agent

    PubMed Central

    Li, Xiaoxia; Hu, Pinliang; Yang, Rungong; Bai, Jie; Wang, Xingheng; Fu, Shuhong; Yang, Siyi; Ma, Jinwei; Gong, Meiliang; Chen, Hong; Zhou, Feng; Chen, Yanbing; Zhou, Qian

    2015-01-01

    Background: GLP-1 and its analogs have a variety of anti-diabetic effects. However, short half-life and rapid degraded by DPP-IV limits the therapeutic potential of the native GLP-1. So, many DPP-IV-resistant and long-acting GLP-1 analogs were developed. In this study, an antibody-like extendin-4-IgG4 fusion protein was developed. Methods: The γ4 constant region contains two amino acid substitutions relative to native γ4 (S228P and L235E) lead to affinity for FcγRI to be low and stability of the IgG4 molecular. The fusion protein was expressed in CHO cells and assembled into an immunoglobulin-like structure with molecular weight of approximately 130 kDa. Results: The Exendin-4-IgG4 fusion protein was found to affinity bind GLP-1R in vitro. In vivo when compared the potency and duration of glucose-lowering effects in diabetic (db/db) mice at the same dose, exendin-4 resulted in a glucose-lowering effect that persisted only for 6 hours, but the extendin-4-IgG4 fusion protein for more than 168 hours. Injecting subcutaneously with a high dose of the fusion protein led normal BALB/c mice to the lower blood glucose level but did not cause serious hypoglycemia. Especially, the half-life time of the fusion protein in cynomolgus monkeys was about 180 hours, almost the longest half-life time among the developed GPL-1 analogues, which suggested a longer half-life time in human. Conclusions: The intact antibody-like fusion protein has more advantages than the Fc fusion protein including the intent of prolonging the half-life. These results also suggested the fusion protein was a safe and long-acting potential anti-diabetic agent. PMID:26064256

  7. Anti-endomysial antibody of IgG1 isotype detection strongly increases the prevalence of coeliac disease in patients affected by type I diabetes mellitus

    PubMed Central

    Picarelli, A; Sabbatella, L; Di Tola, M; Vetrano, S; Casale, C; Anania, MC; Porowska, B; Vergari, M; Schiaffini, R; Gargiulo, P

    2005-01-01

    A strong association between type 1 insulin-dependent diabetes mellitus (IDDM1) and coeliac disease (CD) is well documented, but it is known that prevalence values are underestimated. Serum anti-endomysial antibodies (EMA), considered diagnostic for CD because of their high sensitivity and specificity, belong to the IgA class, but the existence of EMA of IgG1 isotype in the presence or absence of IgA deficiency was reported. In order to re-evaluate the occurrence of CD in IDDM1 patients we performed a screening in IDDM1 patients using EMA of both isotypes. Ninety-four adults affected by IDDM1 (unaffected by CD before enrolling) were enrolled and 83 blood donors as controls. All subjects were on a gluten-containing diet. Histology and biopsy culture were performed. EMA IgA and IgG1 in sera and culture supernatants were detected. Serum EMA were positive in 13 of 94 IDDM1 patients (13·8%). Six of 13 presented IgA-EMA, seven of 13 presented IgG1-EMA. No EMA were found in the control population. Total intestinal atrophy was found in all six patients with serum IgA-EMA and in five of seven with serum IgG1-EMA. Diagnosis of CD was confirmed by histology and organ culture in all 13 patients with serum EMA. The prevalence of CD in the patients affected by IDDM1 was 6·4% for IgA-EMA-positive and 7·4% for IgG1-EMA-positive patients. We confirmed the prevalence of CD in the IDDM1 population obtained with IgA-EMA screening only (6·4%). This prevalence value increases dramatically to 13·8% when IgG1-EMA are also used in the screening. We conclude that IgG1-EMA should also be sought whenever an IDDM1 patient undergoes screening for CD. PMID:16178863

  8. Identification of gangliosides recognized by IgG anti-GalNAc-GD1a antibodies in bovine spinal motor neurons and motor nerves.

    PubMed

    Yoshino, Hiide; Ariga, Toshio; Suzuki, Akemi; Yu, Robert K; Miyatake, Tadashi

    2008-08-28

    The presence of immunoglobulin G (IgG)-type antibodies to the ganglioside, N-acetylgalactosaminyl GD1a (GalNAc-GD1a), is closely associated with the pure motor type of Guillain-Barré syndrome (GBS). In the present study, we isolated disialogangliosides from the motor neurons and motor nerves of bovine spinal cords by DEAE-Sephadex column chromatography. The disialoganglioside fraction contained GD1a, GD2, GD1b, and three gangliosides, designated X1, X2 and X3. Serum from a patient with axonal GBS with IgG anti-GalNAc-GD1a antibody yielded positive immunostaining with X1, X2, and X3. When isolated by preparative thin-layer chromatography (TLC), X1 migrated at the same position as GalNAc-GD1a from Tay-Sachs brain, suggesting that X1 is GalNAc-GD1a containing N-acetylneuraminic acid (NeuAc). TLC of isolated X2 revealed that it migrated between GD1a and GD2. On the other hand, X3 had a migratory rate on TLC between and GD1b and GT1b. Since both X2 and X3 were recognized by IgG anti-GalNAc-GD1a antibody, the results suggest that X2 is a GalNAc-GD1a species containing a mixture containing a NeuAc-and an N-glycolylneuraminic acid (NeuGc) species, and X3 is a GalNAc-GD1a species with two NeuGc. This evidence indicating the specific localization of GalNAc-GD1a and its isomers in spinal motor neurons should be useful in elucidating the pathogenic role of IgG anti-GalNAc-GD1a antibody in pure motor-type GBS. PMID:18598683

  9. The 5XFAD Mouse Model of Alzheimer's Disease Exhibits an Age-Dependent Increase in Anti-Ceramide IgG and Exogenous Administration of Ceramide Further Increases Anti-Ceramide Titers and Amyloid Plaque Burden

    PubMed Central

    Dinkins, Michael B.; Dasgupta, Somsankar; Wang, Guanghu; Zhu, Gu; He, Qian; Kong, Ji Na; Bieberich, Erhard

    2015-01-01

    We present evidence that 5XFAD Alzheimer's disease model mice develop an age-dependent increase in antibodies against ceramide, suggesting involvement of autoimmunity against ceramide in Alzheimer's disease pathology. To test this, we increased serum anti-ceramide IgG (2-fold) by ceramide administration and analyzed amyloid plaque formation in 5XFAD mice. There were no differences in soluble or total amyloid-β levels. However, females receiving ceramide had increased plaque burden (number, area, and size) compared to controls. Ceramide-treated mice showed an increase of serum exosomes (up to 3-fold using Alix as marker), suggesting that systemic anti-ceramide IgG and exosome levels are correlated with enhanced plaque formation. PMID:25720409

  10. Adjuvanticity of a Recombinant Calreticulin Fragment in Assisting Anti-β-Glucan IgG Responses in T Cell-Deficient Mice

    PubMed Central

    Li, Wei-Ji; Long, Kai; Dong, Hong-Liang

    2013-01-01

    Polysaccharide-encapsulated fungi are the chief source of diseases in immunocompromised hosts such as those infected with human immunodeficiency virus or neutropenia patients. Currently available polysaccharide-protein conjugate vaccines are mainly T cell dependent and are usually ineffective in weakened immune systems. In this study, laminarin, a well-characterized β-1,3-glucan, was conjugated with a prokaryotically expressed recombinant fragment (amino acids [aa] 39 to 272) of calreticulin (rCRT/39–272), which exhibits extraordinarily potent immunogenicity and adjuvanticity in experimental animals. The resultant conjugate reserves the immunostimulatory effect of rCRT/39–272 on naïve murine B cells and is capable of eliciting anti-β-glucan IgG (mostly IgG1) responses in not only BALB/c mice but also athymic nude mice. Laminarin-CRT-induced mouse antibodies (Abs) are able to bind with Candida albicans and inhibit its growth in vitro. In addition, vaccination with laminarin-CRT partially protects mice from lethal C. albicans challenge. These results imply that rCRT/39–272 could be used as an ideal carrier or adjuvant for carbohydrate vaccines aimed at inducing or boosting IgG responses to fungal infections in immunodeficient hosts. PMID:23408527

  11. Chimeric Anti-CD14 IGG2/4 Hybrid Antibodies for Therapeutic Intervention in Pig and Human Models of Inflammation

    PubMed Central

    Lau, Corinna; Gunnarsen, Kristin S.; Høydahl, Lene S.; Andersen, Jan Terje; Berntzen, Gøril; Pharo, Anne; Lindstad, Julie K.; Ludviksen, Judith K.; Brekke, Ole-Lars; Barratt-Due, Andreas; Nielsen, Erik Waage; Stokes, Christopher R.; Espevik, Terje; Sandlie, Inger

    2013-01-01

    CD14 is a key recognition molecule of innate immune responses, interacting with several TLRs. TLR signaling cross-talks extensively with the complement system, and combined CD14 and complement inhibition has been proved effective in attenuating inflammatory responses. Pig models of human diseases have emerged as valuable tools to study therapeutic intervention, but suitable neutralizing Abs are rare. Undesired Fc-mediated functions, such as platelet activation and IL-8 release induced by the porcine CD14-specific clone Mil2, limit further studies. Therefore, an inert human IgG2/IgG4 hybrid C region was chosen for an rMil2. As revealed in ex vivo and in vivo pig experiments, rMil2 inhibited the CD14-mediated proinflammatory cytokine response similar to the original clone, but lacked the undesired Fc-effects, and inflammation was attenuated further by simultaneous complement inhibition. Moreover, rMil2 bound porcine FcRn, a regulator of t1/2 and biodistribution. Thus, rMil2, particularly combined with complement inhibitors, should be well suited for in vivo studies using porcine models of diseases, such as sepsis and ischemia-reperfusion injury. Similarly, the recombinant anti-human CD14 IgG2/4 Ab, r18D11, was generated with greatly reduced Fc-mediated effects and preserved inhibitory function ex vivo. Such Abs might be drug candidates for the treatment of innate immunity-mediated human diseases. PMID:24062486

  12. The use of anti-IgG monoclonal antibodies in mapping the monocyte receptor site on IgG.

    PubMed

    Partridge, L J; Woof, J M; Jefferis, R; Burton, D R

    1986-12-01

    Monoclonal antibodies (MAbs) directed against epitopes on the C gamma 1, C gamma 2, C gamma 3 and C gamma 2-C gamma 3 interface regions of human IgG were used to attempt to localize the monocyte Fc receptor (FcR) binding site. The MAbs have been assayed for their capacity to inhibit the interaction between 125I-labelled IgG (125I-IgG) and human monocytes or human histiocytic lymphoma U937 cells. Two MAbs specific for epitopes on the N-terminal region of the C gamma 2 domain, and one MAb recognizing an epitope in the C gamma 2-C gamma 3 inter-domain region inhibited binding of 125I-IgG to monocyte FcRs. The remaining MAbs, against a C-terminal C gamma 3 domain epitope, another C gamma 2/C gamma 3 region epitope and the G1m(f) allotope on the C gamma 1 domain did not inhibit the interaction. The capacity of the MAbs to bind to their respective epitopes on cell surface FcR-bound IgG was also studied, using indirect radiobinding and immunofluorescence assays. All of the MAbs, except those with C gamma 2 domain specificities, were able to detect FcR-bound IgG under these conditions. The results confirm the role of the C gamma 2 domain in the interaction of IgG with monocytes and demonstrate that epitopes in the C gamma 3 and C gamma 2-C gamma 3 regions are not involved in the binding site. PMID:2434846

  13. Inducible T-cell co-stimulator ligand (ICOSL) blockade leads to selective inhibition of anti-KLH IgG responses in subjects with systemic lupus erythematosus

    PubMed Central

    Sullivan, B A; Tsuji, W; Kivitz, A; Peng, J; Arnold, G E; Boedigheimer, M J; Chiu, K; Green, C L; Kaliyaperumal, A; Wang, C; Ferbas, J; Chung, J B

    2016-01-01

    Objectives To evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of single-dose and multiple-dose administration of AMG 557, a human anti-inducible T cell co-stimulator ligand (ICOSL) monoclonal antibody, in subjects with systemic lupus erythematosus (SLE). Methods Patients with mild, stable SLE (n=112) were enrolled in two clinical trials to evaluate the effects of single (1.8–210 mg subcutaneous or 18 mg intravenous) and multiple (6 –210 mg subcutaneous every other week (Q2W)×7) doses of AMG 557. Subjects received two 1 mg intradermal injections 28 days apart of keyhole limpet haemocyanin (KLH), a neoantigen, to assess PD effects of AMG 557. Safety, PK, target occupancy, anti-KLH antibody responses, lymphocyte subset analyses and SLE-associated biomarkers and clinical outcomes were assessed. Results AMG 557 demonstrated an acceptable safety profile. The PK properties were consistent with an antibody directed against a cell surface target, with non-linear PK observed at lower concentrations and linear PK at higher concentrations. Target occupancy by AMG 557 was dose dependent and reversible, and maximal occupancy was achieved in the setting of this trial. Anti-AMG 557 antibodies were observed, but none were neutralising and without impact on drug levels. A significant reduction in the anti-KLH IgG response was observed with AMG 557 administration without discernible changes in the anti-KLH IgM response or on the overall IgG levels. No discernible changes were seen in lymphocyte subsets or in SLE-related biomarkers and clinical measures. Conclusions The selective reduction in anti-KLH IgG demonstrates a PD effect of AMG 557 in subjects with SLE consistent with the biology of the ICOS pathway and supports further studies of AMG 557 as a potential therapeutic for autoimmune diseases. Trial registration numbers NCT02391259 and NCT00774943. PMID:27099766

  14. A Human Monoclonal IgG That Binds Aβ Assemblies and Diverse Amyloids Exhibits Anti-Amyloid Activities In Vitro and In Vivo

    PubMed Central

    O'Nuallain, Brian; Puligedda, Rama Devudu; Ondrejcak, Tomas; Adekar, Sharad P.; Chen, Cindy; Cruz, Pedro E.; Rosario, Awilda M.; Macy, Sallie; Mably, Alexandra J.; Walsh, Dominic M.; Vidal, Ruben; Solomon, Alan; Brown, Daniel; Rowan, Michael J.; Golde, Todd E.

    2015-01-01

    Alzheimer's disease (AD) and familial Danish dementia (FDD) are degenerative neurological diseases characterized by amyloid pathology. Normal human sera contain IgG antibodies that specifically bind diverse preamyloid and amyloid proteins and have shown therapeutic potential in vitro and in vivo. We cloned one of these antibodies, 3H3, from memory B cells of a healthy individual using a hybridoma method. 3H3 is an affinity-matured IgG that binds a pan-amyloid epitope, recognizing both Aβ and λ Ig light chain (LC) amyloids, which are associated with AD and primary amyloidosis, respectively. The pan-amyloid-binding properties of 3H3 were demonstrated using ELISA, immunohistochemical studies, and competition binding assays. Functional studies showed that 3H3 inhibits both Aβ and LC amyloid formation in vitro and abrogates disruption of hippocampal synaptic plasticity by AD-patient-derived soluble Aβ in vivo. A 3H3 single-chain variable fragment (scFv) retained the binding specificity of the 3H3 IgG and, when expressed in the brains of transgenic mice using an adeno-associated virus (AAV) vector, decreased parenchymal Aβ amyloid deposition in TgCRND8 mice and ADan (Danish Amyloid) cerebral amyloid angiopathy in the mouse model of FDD. These data indicate that naturally occurring human IgGs can recognize a conformational, amyloid-specific epitope and have potent anti-amyloid activities, providing a rationale to test their potential as antibody therapeutics for diverse neurological and other amyloid diseases. PMID:25904780

  15. Monitoring of Anti-Hepatitis E Virus Antibody Seroconversion in Asymptomatically Infected Blood Donors: Systematic Comparison of Nine Commercial Anti-HEV IgM and IgG Assays

    PubMed Central

    Vollmer, Tanja; Diekmann, Juergen; Eberhardt, Matthias; Knabbe, Cornelius; Dreier, Jens

    2016-01-01

    Diagnosis of hepatitis E virus (HEV) is usually determined serologically by detection of the presence of immunoglobulin (Ig)M antibodies or rising anti-HEV IgG titers. However, serological assays have demonstrated a significant variation in their sensitivities and specificities. In this study, we present the systematic comparison of different immunological anti-HEV assays using complete seroconversion panels of 10 virologically confirmed HEV genotype 3 infected individuals. Assay sensitivities were further evaluated by testing serially diluted World Health Organization (WHO) reference reagent for hepatitis E virus antibody and one patient sample infected with HEV genotype 3. Anti-HEV IgM and IgG antibody presence was determined using the immunological assays Wantai HEV IgM/IgG enzyme-linked immunosorbent assay (ELISA) (Sanbio, Uden, The Netherlands), recomWell HEV IgM/IgG (Mikrogen, Neuried, Germany), HEV IgM ELISA 3.0, HEV ELISA, HEV ELISA 4.0, Assure HEV IgM Rapid Test (all MP Biomedicals Europe, Illkirch Cedex, France) and Anti-HEV ELISA (IgM/IgG, Euroimmun, Lübeck, Germany). The assays showed differences regarding their analytical and diagnostic sensitivities, with anti-HEV IgM assays (n = 5) being more divergent compared to anti-HEV IgG (n = 4) assays in this study. Considerable variations were observed particularly for the detection period of IgM antibodies. This is the first study systematically characterizing serologic assays on the basis of seroconversion panels, providing sample conformity for a conclusive comparison. Future studies should include the assay comparison covering the four different genotypes. PMID:27556482

  16. Monitoring of Anti-Hepatitis E Virus Antibody Seroconversion in Asymptomatically Infected Blood Donors: Systematic Comparison of Nine Commercial Anti-HEV IgM and IgG Assays.

    PubMed

    Vollmer, Tanja; Diekmann, Juergen; Eberhardt, Matthias; Knabbe, Cornelius; Dreier, Jens

    2016-01-01

    Diagnosis of hepatitis E virus (HEV) is usually determined serologically by detection of the presence of immunoglobulin (Ig)M antibodies or rising anti-HEV IgG titers. However, serological assays have demonstrated a significant variation in their sensitivities and specificities. In this study, we present the systematic comparison of different immunological anti-HEV assays using complete seroconversion panels of 10 virologically confirmed HEV genotype 3 infected individuals. Assay sensitivities were further evaluated by testing serially diluted World Health Organization (WHO) reference reagent for hepatitis E virus antibody and one patient sample infected with HEV genotype 3. Anti-HEV IgM and IgG antibody presence was determined using the immunological assays Wantai HEV IgM/IgG enzyme-linked immunosorbent assay (ELISA) (Sanbio, Uden, The Netherlands), recomWell HEV IgM/IgG (Mikrogen, Neuried, Germany), HEV IgM ELISA 3.0, HEV ELISA, HEV ELISA 4.0, Assure HEV IgM Rapid Test (all MP Biomedicals Europe, Illkirch Cedex, France) and Anti-HEV ELISA (IgM/IgG, Euroimmun, Lübeck, Germany). The assays showed differences regarding their analytical and diagnostic sensitivities, with anti-HEV IgM assays (n = 5) being more divergent compared to anti-HEV IgG (n = 4) assays in this study. Considerable variations were observed particularly for the detection period of IgM antibodies. This is the first study systematically characterizing serologic assays on the basis of seroconversion panels, providing sample conformity for a conclusive comparison. Future studies should include the assay comparison covering the four different genotypes. PMID:27556482

  17. Characterization of warm-reactive IgG anti-lymphocyte antibodies in systemic lupus erythematosus. Relative specificity for mitogen-activated T cells and their soluble products.

    PubMed

    Litvin, D A; Cohen, P L; Winfield, J B

    1983-01-01

    In addition to previously described cold-reactive IgM anti-lymphocyte antibodies maximally cytotoxic for resting cells at 15 degrees C, sera from patients with systemic lupus erythematosus (SLE) were found to contain a new type of antibody preferentially reactive at physiologic temperatures with mitogen-activated lymphocytes. This antibody lacked specificity for unstimulated lymphocytes, and was shown to be of the IgG class both by indirect immunofluorescence and in immunochemical experiments. Certain SLE sera also contained IgG antibodies with the capacity to develop plaques with mitogen-activated T lymphocyte preparations used in a reverse hemolytic plaque assay, indicating reactivity with products released by activated cells. The elimination of the ability of SLE sera to develop plaques after absorption with viable mitogen-stimulated lymphocytes, but not with resting cells, suggested that these antibodies were directed toward activation "neoantigen(s)" shed from the cell surface membrane. Surface membrane phenotype analyses performed by using a variety of monoclonal antibody reagents indicated that the plaque-forming cells (PFC) detected with SLE sera were activated T lymphocytes not restricted to single OKT4+, OKT8+, or Ia antigen+ subpopulations. Essentially all PFC expressed transferrin receptors. The present data raise the possibility that certain of the interesting effects of anti-lymphocyte antibodies on immunologic function in SLE may be mediated by interactions of these new type(s) of antibodies with activated lymphocytes or their products, rather than through blocking or depletion effects on resting precursor cells. PMID:6600174

  18. Mechanism-Based Competitive Binding Model to Investigate the Effect of Neonatal Fc Receptor Binding Affinity on the Pharmacokinetic of Humanized Anti-VEGF Monoclonal IgG1 Antibody in Cynomolgus Monkey.

    PubMed

    Ng, Chee M; Fielder, Paul J; Jin, Jin; Deng, Rong

    2016-07-01

    The quantitative relationship between neonatal Fc receptor (FcRn) binding affinity at both acidic and physiological pH and the pharmacokinetics of protein engineered FcRn IgG1 variants has not yet been reported. Our objective was to develop a quantitatively mechanism-based competitive binding model to describe the effects of FcRn binding affinity at acidic and physiological pH on the pharmacokinetics of anti-VEGF IgG1 antibodies when both endogenous and exogenous antibodies are competing for the same FcRn. Pharmacokinetic (PK) and FcRn binding data from five Fc variants of humanized anti-VEGF IgG1 monoclonal antibodies with wide range of FcRn binding affinity were used for the analysis. Sixty-seven anti-VEGF IgG1 antibody-treated animals and 25 control animals with simulated endogenous IgG levels were used to develop the final model. A hybrid iterative two stages and Monte Carlo parametric expectation-maximization method was used to obtain the final model parameters estimates. The final model well described the observed PK data. Quantitative FcRn binding affinity-pharmacokinetics relationships was constructed to provide important biological insights in better understanding of the FcRn binding effect on pharmacokinetics of anti-VEGF IgG1 antibodies in cynomolgus monkeys and served as an important model-based drug discovery platform to guide the design and development of the future generation of anti-VEGF or other therapeutic IgG1 antibodies. PMID:27075465

  19. Cloning of Human IgG Fc cDNA and Expression of Whole Human Anti-HBsAg Antibody in CHO Cells.

    PubMed

    Tong, Yi-Gang; Xu, Jing; Liu, Guo-Qi; Zhang, Yong-Guo; Cheng, Wan-Rong; Liu, Shu-Ling; Wang, Hai-Tao

    2000-01-01

    Messenger RNA was extracted from human peripheral lymphocytes and first strand cDNA was prepared by reverse-transciption. The cDNA of Fc fragment of human IgG1 was then obtained by PCR and was cloned into the pGEM T-vector. The DNA sequences encoding signal peptides of both light and heavy chains were synthesized and cloned respectively. For construction of the light chain expression plasmid, the light chain signal sequence was linked with the light chain variable and constant regions (VL-CL) which had been cloned previously by screening of phage display libraries with HBsAg. The resulting full-lenth light chain sequence was then inserted into pcDNA3.1, a mammalian expression vector. For construction of the heavy chain expression plasmid, the heavy chain signal sequence, the variable region, the first constant region (VH-CH1, cloned previously by screening of phage display libraries with HBsAg) and Fc fragment sequence were ligated to form a full-length heavy chain ORF, which was then cloned into another mammalian expression vector, pCI-DHFR1. CHO(dhfr(-)) cells were cotransfected with the above light and heavy chain expression plasmids, and cell clones expressing human anti-HBsAg antibodies were selected by G418 and methotrexate (MTX). The recombinant human antibodies were purified with protein L affinity chromatography from the cell culture medium. As human serum IgG, the recombinant IgG exhibited only one band with a molecular weight of more than 100 kD in non-reducing SDS-PAGE in reducing SDS-PAGE, however, it turned out to be two bands of approximately 50 kD and 25 kD respectively. Western-blot analysis demonstrated that the whole IgG in the non-reducing SDS-PAGE, and the heavy chain in the reducing SDS-PAGE both reacted with goat anti-human Fc antiserum. PMID:12075430

  20. The Relation of the Level of Serum Anti-TF, -Tn and -Alpha-Gal IgG to Survival in Gastrointestinal Cancer Patients

    PubMed Central

    Smorodin, Eugeniy; Sergeyev, Boris; Klaamas, Kersti; Chuzmarov, Valentin; Kurtenkov, Oleg

    2013-01-01

    Objective: To evaluate the relation of the level of serum anti-TF, -Tn and -αGal carbohydrate antibodies to survival in gastrointestinal cancer patients. Methods: The level of anti-TF (Thomsen-Friedenreich antigen), -Tn and -αGal IgG was analysed in the serum of patients with gastric (n = 83) and colorectal (n = 51) cancers in the long-term follow-up, using ELISA with polyacrylamide glycoconjugates. To evaluate overall survival and the risk of death, the Kaplan-Meier method and the Cox proportional hazards model were used in the univariate analysis of patients groups. Results: A significantly better survival was observed: (1) in patients with an increased level of anti-TF antibodies (all, stage III, T2-4, N1-2 and G3; P = 0.004-0.038, HR = 0.16-0.46); and (2) in patients with an increased level of anti-Tn antibodies (G1-2 tumors; P = 0.034-0.042, HR = 0.34-0.47). A significantly worse survival was observed in gastrointestinal, gastric and colorectal groups with an increased level of serum anti-αGal antibodies. This association depended on the patho-morphology of tumors (all, stages I-II, III, T2-4, N0, N1-2 and G1-2; P = 0.006-0.048, HR = 1.99-2.33). In the combined assessment of the anti-TF and -αGal antibodies level of the whole gastrointestinal group (n = 53), P = 0.002, HR = 0.25, 95% CI 0.094-0.655. In the follow-up, the survival time was shorter in patients whose level of anti-αGal antibodies rose (P = 0.009-0.040, HR = 2.18-4.27). The level of anti-TF antibodies inversely correlated with neutrophil/lymphocyte ratio (NLR, r = - 0.401, P = 0.004, n = 49). Patients with a higher level of anti-αGal antibodies and NLR values demonstrated a significantly worse survival (P = 0.009, HR = 2.98, n = 48). Conclusions: The preoperative levels of anti-TF, -Tn and -αGal antibodies and their dynamics are of prognostic significance. The method for the determination of circulating anti-carbohydrate antibodies may be a useful supplement in clinical outcome assessment

  1. Model IgG Monoclonal Autoantibody–Anti-Idiotype Pair for Dissecting the Humoral Immune Response to Oxidized Low Density Lipoprotein

    PubMed Central

    Chang, Shang-Hung; Johns, Michael; Boyle, Joseph J.; McConnell, Ellen; Kirkham, Paul A.; Bicknell, Colin; Zahoor-ul-Hassan Dogar, M.; Edwards, Robert J.; Gale-Grant, Oliver; Khamis, Ramzi; Ramkhelawon, Kurrun V.V.

    2012-01-01

    Increasing evidence implicates IgG autoantibodies against oxidized forms of low density lipoprotein (oxLDL) in the pathophysiology of atherosclerotic arterial disease. However, insufficient knowledge of their structure and function is a key gap. Using an elderly LDL receptor-deficient atherosclerotic mouse, we isolated a novel IgG3k against oxLDL (designated MAb LO1). LO1 reacts with copper-oxidized LDL, but minimally with native LDL. Further analysis showed that MAb LO1 also reacts in vitro with malondialdehyde-conjugated LDL (MDA-LDL), a known key epitope in copper-oxidized LDL preparations. By screening a phage library expressing single chain variable region antibodies (scFv), we selected an anti-idiotype scFv (designated H3) that neutralizes MAb LO1 binding to MDA-LDL. Amino acid substitutions between H3 and an irrelevant control scFv C12 showed that residues in the H3 CDRH2, CDRH3, and CDRL2 are all critical for MAb LO1 binding, consistent with a conformational epitope on H3 involving both heavy and light chains. Comparison of amino acids in H3 CDRH2 and CDRL2 with apoB, the major LDL protein, showed homologous sequences, suggesting H3 has structural similarities to the MAb LO1 binding site on MDA-LDL. Immunocytochemical staining showed that MAb LO1 binds epitopes in mouse and human atherosclerotic lesions. The MAb LO1-H3 combination therefore provides a very promising model for analyzing the structure and function of an individual IgG autoantibody in relation to atherosclerosis. PMID:22509912

  2. Detection of Hantaan virus RNA from anti-Hantaan virus IgG seronegative rodents in an area of high endemicity in Republic of Korea.

    PubMed

    No, Jin Sun; Kim, Won-Keun; Kim, Jeong-Ah; Lee, Seung-Ho; Lee, Sook-Young; Kim, Ji Hye; Kho, Jeong Hoon; Lee, Daesang; Song, Dong Hyun; Gu, Se Hun; Jeong, Seong Tae; Kim, Heung-Chul; Klein, Terry A; Song, Jin-Won

    2016-04-01

    Hantaan virus (HTNV), of the family Bunyaviridae, causes hemorrhagic fever with renal syndrome (HFRS) in humans. Although the majority of epidemiologic studies have found that rodents are seropositive for hantavirus-specific immunoglobulin, the discovery of hantavirus RNA in seronegative hosts has led to an investigation of the presence of HTNV RNA in rodents captured in HFRS endemic areas. HTNV RNA was detected in seven (3.8%) of 186 anti-HTNV IgG seronegative rodents in Republic of Korea (ROK) during 2013-2014. RT-qPCR for HTNV RNA revealed dynamic virus-host interactions of HTNV in areas of high endemicity, providing important insights into the epidemiology of hantaviruses. PMID:26917012

  3. EndoS Reduces the Pathogenicity of Anti-mCOL7 IgG through Reduced Binding of Immune Complexes to Neutrophils

    PubMed Central

    Yu, Xinhua; Zheng, Junfeng; Collin, Mattias; Schmidt, Enno; Zillikens, Detlef; Petersen, Frank

    2014-01-01

    Endo-β-N-acetylglucosaminidase (EndoS) has been shown to act as a potent pathogen-derived immunomodulatory molecule in autoimmune diseases. Here we investigated how EndoS treatment reduces the pathogenicity of rabbit anti-mCOL7 IgG using different experimental models of epidermolysis bullosa acquisita (EBA). Our results show that the EndoS treatment does not interfere with the binding of the antibody to the antigen but reduces immune complex (IC)-mediated neutrophil activation by impairing the binding of the IC to FcγR on neutrophils. On the basis of this newly identified EndoS-mediated mechanism we hope to develop new strategies in the treatment of the disease. PMID:24504190

  4. Anti-EBOV GP IgGs Lacking α1-3-Galactose and Neu5Gc Prolong Survival and Decrease Blood Viral Load in EBOV-Infected Guinea Pigs

    PubMed Central

    Reynard, Olivier; Jacquot, Frédéric; Evanno, Gwénaëlle; Mai, Hoa Le; Martinet, Bernard; Duvaux, Odile; Bach, Jean-Marie; Conchon, Sophie; Judor, Jean-Paul; Perota, Andrea; Lagutina, Irina; Duchi, Roberto; Lazzari, Giovanna; Le Berre, Ludmilla; Perreault, Hélène; Lheriteau, Elsa; Raoul, Hervé; Volchkov, Viktor; Galli, Cesare; Soulillou, Jean-Paul

    2016-01-01

    Polyclonal xenogenic IgGs, although having been used in the prevention and cure of severe infectious diseases, are highly immunogenic, which may restrict their usage in new applications such as Ebola hemorrhagic fever. IgG glycans display powerful xenogeneic antigens in humans, for example α1–3 Galactose and the glycolyl form of neuraminic acid Neu5Gc, and IgGs deprived of these key sugar epitopes may represent an advantage for passive immunotherapy. In this paper, we explored whether low immunogenicity IgGs had a protective effect on a guinea pig model of Ebola virus (EBOV) infection. For this purpose, a double knock-out pig lacking α1–3 Galactose and Neu5Gc was immunized against virus-like particles displaying surface EBOV glycoprotein GP. Following purification from serum, hyper-immune polyclonal IgGs were obtained, exhibiting an anti-EBOV GP titer of 1:100,000 and a virus neutralizing titer of 1:100. Guinea pigs were injected intramuscularly with purified IgGs on day 0 and day 3 post-EBOV infection. Compared to control animals treated with IgGs from non-immunized double KO pigs, the anti-EBOV IgGs-treated animals exhibited a significantly prolonged survival and a decreased virus load in blood on day 3. The data obtained indicated that IgGs lacking α1–3 Galactose and Neu5Gc, two highly immunogenic epitopes in humans, have a protective effect upon EBOV infection. PMID:27280712

  5. The effects of selected drugs, including chlorpromazine and non-steroidal anti-inflammatory agents, on polyclonal IgG synthesis and interleukin 1 production by human peripheral blood mononuclear cells in vitro.

    PubMed

    Martinez, F; Coleman, J W

    1989-05-01

    We tested a range of drugs for their effects on in vitro polyclonal IgG synthesis by human peripheral blood mononuclear cells (PBMC) stimulated with the lectin pokeweed mitogen (PWM). The test drugs were selected on the basis of reported disruptive effects on immune function in vivo. IgG production between day 4 and days 7 or 8 of culture was measured by biotin-streptavidin sandwich ELISA. The anti-psychotic agent chlorpromazine (0.55-1.7 microM) enhanced IgG synthesis to approximately double control levels. In contrast, the non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin, piroxicam, ibuprofen and aspirin inhibited IgG synthesis by up to 50%, with a rank order of potency that reflects their activity as inhibitors of cyclo-oxygenase. Phenytoin, procainamide, propylthiouracil, methimazole, D-penicillamine and D-penicillamine-L-cysteine all failed to modulate IgG synthesis at non-toxic concentrations. The potentiation and inhibition of IgG synthesis by chlorpromazine and indomethacin, respectively, was observed only when the drug was present during the first 24 h of culture. Neither chlorpromazine nor indomethacin, at non-toxic concentrations, affected PHA- and PWM-stimulated proliferation of PBMC. In addition, chlorpromazine, indomethacin and piroxicam, at concentrations which produced maximal modulation of IgG synthesis, and D-penicillamine and D-penicillamine-L-cysteine at 10 microM failed to influence production of interleukin-1-like activity. We conclude that chlorpromazine and NSAIDs, although they exert opposite effects on IgG synthesis, act at an early stage of B cell differentiation that appears to be independent of interleukin 1 synthesis and early proliferative events. PMID:2788047

  6. Anti-EBOV GP IgGs Lacking α1-3-Galactose and Neu5Gc Prolong Survival and Decrease Blood Viral Load in EBOV-Infected Guinea Pigs.

    PubMed

    Reynard, Olivier; Jacquot, Frédéric; Evanno, Gwénaëlle; Mai, Hoa Le; Salama, Apolline; Martinet, Bernard; Duvaux, Odile; Bach, Jean-Marie; Conchon, Sophie; Judor, Jean-Paul; Perota, Andrea; Lagutina, Irina; Duchi, Roberto; Lazzari, Giovanna; Le Berre, Ludmilla; Perreault, Hélène; Lheriteau, Elsa; Raoul, Hervé; Volchkov, Viktor; Galli, Cesare; Soulillou, Jean-Paul

    2016-01-01

    Polyclonal xenogenic IgGs, although having been used in the prevention and cure of severe infectious diseases, are highly immunogenic, which may restrict their usage in new applications such as Ebola hemorrhagic fever. IgG glycans display powerful xenogeneic antigens in humans, for example α1-3 Galactose and the glycolyl form of neuraminic acid Neu5Gc, and IgGs deprived of these key sugar epitopes may represent an advantage for passive immunotherapy. In this paper, we explored whether low immunogenicity IgGs had a protective effect on a guinea pig model of Ebola virus (EBOV) infection. For this purpose, a double knock-out pig lacking α1-3 Galactose and Neu5Gc was immunized against virus-like particles displaying surface EBOV glycoprotein GP. Following purification from serum, hyper-immune polyclonal IgGs were obtained, exhibiting an anti-EBOV GP titer of 1:100,000 and a virus neutralizing titer of 1:100. Guinea pigs were injected intramuscularly with purified IgGs on day 0 and day 3 post-EBOV infection. Compared to control animals treated with IgGs from non-immunized double KO pigs, the anti-EBOV IgGs-treated animals exhibited a significantly prolonged survival and a decreased virus load in blood on day 3. The data obtained indicated that IgGs lacking α1-3 Galactose and Neu5Gc, two highly immunogenic epitopes in humans, have a protective effect upon EBOV infection. PMID:27280712

  7. Individual Restriction Of Fine Specificity Variability In Anti-GM1 IgG Antibodies Associated With Guillain-Barré Syndrome

    PubMed Central

    Lardone, Ricardo D.; Yuki, Nobuhiro; Irazoqui, Fernando J.; Nores, Gustavo A.

    2016-01-01

    Elevated titers of serum antibodies against GM1 ganglioside are associated with a variety of autoimmune neuropathies. Much evidence indicates these autoantibodies play a primary role in the disease processes, but the mechanism for their appearance is unclear. We studied the fine specificity of anti-GM1 antibodies of the IgG isotype present in sera from patients with Guillain-Barré syndrome (GBS), using thin-layer chromatogram-immunostaining of GM1, asialo-GM1 (GA1), GD1b and GM1-derivatives with small modifications on the oligosaccharide moiety. We were able to distinguish populations of antibodies with different fine specificity. Remarkably, individual patients presented only one or two of them, and different patients had different populations. This restriction in the variability of antibody populations suggests that the appearance of the anti-GM1 antibodies is a random process involving restricted populations of lymphocytes. With the origin of disease-associated anti-GM1 antibodies as a context, this finding could provide explanation for the “host susceptibility factor” observed in GBS following enteritis with GM1 oligosaccharide-carrying strains of Campylobacter jejuni. PMID:26818965

  8. Human anti-Aβ IgGs target conformational epitopes on synthetic dimer assemblies and the AD brain-derived peptide.

    PubMed

    Welzel, Alfred T; Williams, Angela D; McWilliams-Koeppen, Helen P; Acero, Luis; Weber, Alfred; Blinder, Veronika; Mably, Alex; Bunk, Sebastian; Hermann, Corinna; Farrell, Michael A; Ehrlich, Hartmut J; Schwarz, Hans P; Walsh, Dominic M; Solomon, Alan; O'Nuallain, Brian

    2012-01-01

    Soluble non-fibrillar assemblies of amyloid-beta (Aβ) and aggregated tau protein are the proximate synaptotoxic species associated with Alzheimer's disease (AD). Anti-Aβ immunotherapy is a promising and advanced therapeutic strategy, but the precise Aβ species to target is not yet known. Previously, we and others have shown that natural human IgGs (NAbs) target diverse Aβ conformers and have therapeutic potential. We now demonstrate that these antibodies bound with nM avidity to conformational epitopes on plate-immobilized synthetic Aβ dimer assemblies, including synaptotoxic protofibrils, and targeted these conformers in solution. Importantly, NAbs also recognized Aβ extracted from the water-soluble phase of human AD brain, including species that migrated on denaturing PAGE as SDS-stable dimers. The critical reliance on Aβ's conformational state for NAb binding, and not a linear sequence epitope, was confirmed by the antibody's nM reactivity with plate-immobilized protofibrills, and weak uM binding to synthetic Aβ monomers and peptide fragments. The antibody's lack of reactivity against a linear sequence epitope was confirmed by our ability to isolate anti-Aβ NAbs from intravenous immunoglobulin using affinity matrices, immunoglobulin light chain fibrils and Cibacron blue, which had no sequence similarity with the peptide. These findings suggest that further investigations on the molecular basis and the therapeutic/diagnostic potential of anti-Aβ NAbs are warranted. PMID:23209707

  9. Human Anti-Aβ IgGs Target Conformational Epitopes on Synthetic Dimer Assemblies and the AD Brain-Derived Peptide

    PubMed Central

    Welzel, Alfred T.; Williams, Angela D.; McWilliams-Koeppen, Helen P.; Acero, Luis; Weber, Alfred; Blinder, Veronika; Mably, Alex; Bunk, Sebastian; Hermann, Corinna; Farrell, Michael A.; Ehrlich, Hartmut J.; Schwarz, Hans P.; Walsh, Dominic M.; Solomon, Alan; O’Nuallain, Brian

    2012-01-01

    Soluble non-fibrillar assemblies of amyloid-beta (Aβ) and aggregated tau protein are the proximate synaptotoxic species associated with Alzheimer’s disease (AD). Anti-Aβ immunotherapy is a promising and advanced therapeutic strategy, but the precise Aβ species to target is not yet known. Previously, we and others have shown that natural human IgGs (NAbs) target diverse Aβ conformers and have therapeutic potential. We now demonstrate that these antibodies bound with nM avidity to conformational epitopes on plate-immobilized synthetic Aβ dimer assemblies, including synaptotoxic protofibrils, and targeted these conformers in solution. Importantly, NAbs also recognized Aβ extracted from the water-soluble phase of human AD brain, including species that migrated on denaturing PAGE as SDS-stable dimers. The critical reliance on Aβ’s conformational state for NAb binding, and not a linear sequence epitope, was confirmed by the antibody’s nM reactivity with plate-immobilized protofibrills, and weak uM binding to synthetic Aβ monomers and peptide fragments. The antibody’s lack of reactivity against a linear sequence epitope was confirmed by our ability to isolate anti-Aβ NAbs from intravenous immunoglobulin using affinity matrices, immunoglobulin light chain fibrils and Cibacron blue, which had no sequence similarity with the peptide. These findings suggest that further investigations on the molecular basis and the therapeutic/diagnostic potential of anti-Aβ NAbs are warranted. PMID:23209707

  10. The TUBEX typhoid test based on particle-inhibition immunoassay detects IgM but not IgG anti-O9 antibodies.

    PubMed

    Tam, Frankie Chi Hang; Lim, Pak Leong

    2003-11-01

    A serological test kit (TUBEX, IDL Biotech, Sweden) developed recently for the diagnosis of typhoid fever detects antibodies to the Salmonella enterica serovar Typhi lipopolysaccharide (LPS) O9 antigen. The antibodies are detected by their ability to inhibit the interaction between two types of reagent particles: (a). indicator latex microspheres sensitized with an anti-O9 monoclonal antibody, and (b). magnetic microspheres sensitized with S. typhi LPS. Following rapid mixing of the serum with these reagents and sedimentation of the magnetic particles by magnetic force, the concentration of indicator particles left in suspension provides a measure of the inhibition. Whereas it was previously assumed that both IgM and IgG antibodies could inhibit in the system, the present study reveals, surprisingly, that only the IgM antibodies do. It is not clear why IgG anti-O9 antibodies, both of mouse and human origin, do not inhibit, although these can bind to the LPS-sensitized magnetic particles as efficiently as the IgM antibodies. In addition, they can also inhibit very well in another detection system (ELISA) which uses a similar assay format and the same antibody and antigen reagents. Increasing the size of the LPS-sensitized microspheres made no difference; microscopic analysis of the TUBEX reaction mixture revealed that while the indicator particles bound abundantly to the IgG-aggregated LPS-sensitized particles, forming large clumps, these only formed a very light decoration on the IgM-aggregated particles. Thus, the TUBEX system is ideally suited for use in the diagnosis of infections as it allows IgM antibodies to be detected easily and rapidly from whole sera. PMID:14604543

  11. In vitro induction of IgG anti-DNA antibody from high density B cells of systemic lupus erythematosus patients by an HLA DR-restricted T cell clone.

    PubMed Central

    Murakami, M; Kumagai, S; Sugita, M; Iwai, K; Imura, H

    1992-01-01

    An HLA-DR restricted T cell clone (26G11) which recognized a lymphoid cell-derived autoantigen associated with DR4 molecule was shown to induce not only autologous but also allogenic DR4+ B cells to produce large amounts of antibodies of the IgG and IgM classes. Using the helper activity of this clone, we investigated the mechanism of anti-DNA antibody production in DR-matched patients with systemic lupus erythematosus (SLE). When cultured with 26G11 cells, B cells from DR-matched normal control subjects produced large amounts of IgM anti-DNA antibody, but did not produce IgG anti-DNA antibody which is thought to have a pathological role in SLE. In contrast, B cells from DR-matched patients with active SLE spontaneously produced a fairly large amount of IgG anti-DNA antibody, and the production was augmented by the T cell clone. Little IgG anti-DNA antibody was produced by the B cells of patients with inactive SLE in either the presence or absence of T cell clone. We next fractionated B cells into low density B (LD-B) and high density B (HD-B) cells by centrifugation on discontinuous Percoll density gradients. IgG anti-DNA antibody was spontaneously produced by LD-B cells of active SLE patients but not by those either of inactive SLE patients or normal controls. On the other hand, although IgG anti-DNA antibody was not spontaneously produced by the HD-B cells of both active and inactive SLE patients, it could easily be induced by their culture with the T cell clone. Our results clearly show the existence of IgG anti-DNA antibody-producing B cells in the peripheral blood of SLE patients irrespective of their disease activity and suggest that autoreactive T cells may play a pathogenic role in SLE through the induction of autoantibody production. PMID:1424281

  12. Detection of IgG Anti-Leishmania Antigen by Flow Cytometry as a Diagnostic Test for Cutaneous Leishmaniasis.

    PubMed

    Pedral-Sampaio, Geraldo; Alves, Jessé S; Schriefer, Albert; Magalhães, Andréa; Meyer, Roberto; Glesby, Marshall J; Carvalho, Edgar M; Carvalho, Lucas P

    2016-01-01

    Diagnosis of cutaneous leishmaniasis (CL) relies on clinical presentation, parasite isolation, histopathologic evaluation and positive Montenegro skin test. However, the low amounts of parasites in the lesion of these individuals make parasite isolation and histopatologic diagnosis unreliable, often leading to false-negative results. Also, 15% of people living in endemic areas have sub-clinical infection characterized by positive Montenegro skin test, which may contribute to misdiagnosis. Although the main Leishmania killing mechanism is through cell-mediated immune response, antibodies against Leishmania antigens are found in infected individuals. Here our goal was to develop a new serological technique using polystyrene microspheres sensitized with soluble Leishmania antigens as a tool for the detection of IgG in serum from CL patients by flow cytometry. To validate the assay we carried out a comparative test (ELISA) commonly used as a diagnostic test for parasitic diseases. To determine cross-reactivity we used serum from patients with Chagas disease, caused by a trypanosome that has several proteins with high homology to those of the Leishmania genus. We observed that the flow cytometry technique was more sensitive than the ELISA, but, less specific. Our results show that the flow cytometry serologic test can be used to confirm CL cases in L. braziliensis transmission areas, however, presence of Chagas disease has to be ruled out in these individuals. PMID:27622535

  13. A quantitative ELISA for antigen-specific IgG subclasses using equivalence dilutions of anti-kappa and anti-subclass specific secondary reagents. Application to the study of the murine immune response against the capsular polysaccharide of Neisseria meningitidis serogroup B.

    PubMed

    Colino, J; Diez, M; Outschoorn, I

    1996-04-19

    We have developed an enzyme-linked immunosorbent assay (ELISA) to measure murine antigen-specific IgG antibodies of defined subclass using precalibrated equivalence dilutions of anti-kappa (in the standard) and each anti-IgG subclass-specific polyclonal secondary antibody (in the test sample). The calibration of secondary reagents could be carried out easily with a set of monoclonal antibodies (MoAbs) specific for all IgG subclasses. These MoAbs do not require purification or standardization. In addition the MoAbs can be of different antigenic specificity. Once the equivalence dilutions have been determined, they can be applied in a quantitative ELISA using the same antigen in the standard and sample, and using only one IgG subclass standard for the determination of all the IgG subclasses. The method is easy to standardize for many antigenic systems. It is particularly useful when the only standard available is one standardized MoAb of the appropriate specificity, and it could be adapted to use with standard polyclonal antibodies having a known content of total antigen-specific IgG bearing kappa chains but unknown IgG subclass composition. The use of this method to quantitate IgG specific for the capsular polysaccharide of Neisseria meningitidis serogroup B (CpsB) gave highly reproducible measures with an interbatch CV of 5-6% similar for all IgG subclasses and low detection limits ranging from 0.3 ng/well for IgG3 to 0.8 ng/well for IgG2a. The IgG subclass response observed after immunization with live meningococci was mainly IgG2a (74%) and IgG2b (18%). Hyperimmunization modified this IgG distribution to one of mainly IgG3 (62%) and IgG1 (28%) which was maintained in the response to a single immunization 4 weeks later, possibly indicating the generation of resting B cells during continuous stimulation. PMID:8621957

  14. Blockade of immunoregulatory Fc-signalling by HIV peptides: oligopeptides from HIV gp120 and gp41 bind the Fc portion of IgG and increase the in vitro anti-ssDNA response.

    PubMed Central

    Rahimpour, R; Anderson, C C; Sinclair, N R

    1993-01-01

    Concomitant ligation of antigen receptors with Fc-receptors negatively signals B cells. Antibodies to the Fc portion of IgG prevent this negative Fc-signalling, provided that these antibodies do not emit Fc signals. Prevention of Fc signals leads to augmented antibody responses to self and foreign antigens, and reduces the requirement for T cells by 10- to 100-fold in T cell-dependent antibody responses. In ELISA assays, peptides from conserved portions of the glycoproteins, HIV-1 gp120 or gp41 from HIV-1 and HIV-2 bind to the Fc portion of IgG, but do not bind the F(ab')2 portion of IgG. HIV-derived peptides, which bind to the Fc portion of IgG, augment the antibody-forming cell response to single-stranded (ss)DNA. The spontaneous response to ssDNA using spleen cells from young mice, and the response in the presence of exogenous DNA using spleen cells from old mice, are augmented to the greatest extent. These results demonstrate that HIV peptides bind to the Fc portion of IgG and augment immune responses to DNA; they suggest the possibility that blockade of the Fc portion of IgG antibodies is associated with a reduction in Fc-mediated regulation of anti-self responses. Blockade of regulatory Fc-signalling may account for increased circulating immunoglobulins and autoantibodies in clinical AIDS. PMID:8403512

  15. Effective therapy of human lymphoma xenografts with a novel recombinant ribonuclease/anti-CD74 humanized IgG4 antibody immunotoxin.

    PubMed

    Chang, Chien-Hsing; Sapra, Puja; Vanama, Sailaja S; Hansen, Hans J; Horak, Ivan D; Goldenberg, David M

    2005-12-15

    Ranpirnase (Rap) is a cytotoxic ribonuclease (RNase) isolated from frog oocytes. Here we describe high antitumor activity of a novel immunotoxin, 2L-Rap-hLL1-gamma4P, composed of 2 Rap molecules, each fused to the N terminus of the light chain of hLL1, an internalizing anti-CD74 humanized antibody. To reduce unwanted side effects, the constant region of hLL1 was changed from gamma1 to gamma4 and further to gamma4P by replacing serine228 to proline to prevent the formation of a half immunoglobulin G (IgG) common for IgG4. In vitro, 2L-Rap-hLL1-gamma4P retained RNase activity, specific binding to CD74, and was significantly more potent against CD74+ cell lines (Daudi, Raji, and MC/CAR) than naked hLL1. In vivo, the pharmacokinetic profile of 2L-Rap-hLL1-gamma4P was similar to that of naked hLL1. The maximum tolerated dose of 2L-Rap-hLL1-gamma4P in severe combined immunodeficient mice (SCID) or BALB/c mice was 50 microg per mouse. In Raji and Daudi Burkitt lymphoma xenograft models, treatment with a single 5 to 50 microg dose of 2L-Rap-hLL1-gamma4P, given as early or delayed treatment, resulted in cures of most animals. Treatment with 2L-Rap-hLL1-gamma4P was significantly better than all controls, including saline, naked hLL1, and nonspecific immunotoxin. In conclusion, 2L-Rap-hLL1-gamma4P demonstrated excellent in vitro and in vivo efficacy and thus merits further consideration as a therapeutic for CD74+ tumors. PMID:16109781

  16. Anaphylaxis to IGIV in immunoglobulin-naïve common variable immunodeficiency patient in the absence of IgG anti-IgA antibodies: successful administration of low IgA-containing immunoglobulin.

    PubMed

    Gharib, Asal; Caperton, Caroline; Gupta, Sudhir

    2016-01-01

    Although severe reactions to immunoglobulin preparations have been frequently reported, IgE antibodies against IgA are usually not investigated; and occur predominantly in previously sensitized patients. The purpose is to report anaphylaxis to IGIV during initial infusion in a patient with common variable immunodeficiency with absent IgA without prior sensitization and in the absence of detectable IgG anti-IgA antibodies, and positive skin tests for immediate hypersensitivity to four different preparations of IGIV, one subcutaneous immunoglobulin preparation, and to purified IgA. Patient was treated without side effects with IGIV preparation depleted of IgA to which immediate hypersensitivity skin test was negative. This case demonstrates that patients with CVID with no IgA and without prior exposure to immunoglobulin or plasma may develop anaphylaxis following initial infusion of IGIV, which appears to be due to IgE anti-IgA, and independent of IgG anti-IgA antibodies. Since there is no good correlation between anaphylaxis/anaphylactic reactions and IgG anti-IgA antibodies, and IgE anti-IgA antibody test is commercially unavailable, we suggest that the patients with CVID with absence of IgA might be skin tested for immediate hypersensitivity prior to initiation of immunoglobulin administration. However, such recommendation may require studies on a large number of patients with CVID with no detectable IgA. PMID:27190527

  17. Clostridium difficile PSI polysaccharide: synthesis of pentasaccharide repeating block, conjugation to exotoxin B subunit, and detection of natural anti-PSI IgG antibodies in horse serum.

    PubMed

    Jiao, Yuening; Ma, Zuchao; Hodgins, Doug; Pequegnat, Brittany; Bertolo, Lisa; Arroyo, Luis; Monteiro, Mario A

    2013-08-30

    Clostridium difficile is the most common cause of antimicrobial-associated diarrhea in humans and may cause death. Previously, we discovered that C. difficile expresses three polysaccharides, named PSI, PSII, and PSIII. It has now been established that PSII is a conserved antigen abundantly present on the cell-surface and biofilm of C. difficile. In contrast, the expression of PSI and PSIII appears to be stochastic processes. In this work, the total chemical synthesis of the PSI pentasaccharide repeating unit carrying a linker at the reducing end, α-l-Rhap-(1→3)-β-d-Glcp-(1→4)-[α-l-Rhap-(1→3)]-α-d-Glcp-(1→2)-α-d-Glcp-(1→O(CH2)5NH2, was achieved by a linear synthesis strategy from four monosaccharide building blocks. The synthesized PSI pentasaccharide was conjugated to a subunit of C. difficile exotoxin B yielding a potential dual C. difficile vaccine. More significantly, sera from healthy horses were shown to contain natural anti-PSI IgG antibodies that detected both the synthetic non-phosphorylated PSI repeat and the native PSI polysaccharide, with a slightly higher recognition of the native PSI polysaccharide. PMID:23597587

  18. Identification of rabies virus mimotopes screened from a phage display peptide library with purified dog anti-rabies virus serum IgG.

    PubMed

    Yang, Limin; Cen, Junyu; Xue, Qinghua; Li, Jing; Bi, Yuhai; Sun, Lei; Liu, Wenjun

    2013-06-01

    The rabies virus glycoprotein (G) is a key protein for both virus infectivity and eliciting protective immunity as an antigen. What is more, the nucleoprotein (N) is also a significant rabies virus antigen. In this study, purified anti-rabies virus IgG from dogs immunized with the standard CVS-11 strain was used to screen the Ph.D.-12™ Phage Display Peptide Library for peptides that correspond to or mimic native G and N epitopes. In contrast to previous reports that use monoclonal antibodies or human anti-rabies virus serum, this study describes the first use of dog serum to screen for epitopes. After three rounds of biopanning, selected phage clones were identified by plaque screening, western blotting (WB), and ELISA. Positive phage clones were sequenced, and their amino acid sequences were deduced. Alignment of the peptide sequences to G and N indicated that the epitope peptides matched well with G amino acids at positions 34-42, 198-200, 226-264, 296-371, and 330-343, as well as to N amino acids at positions 22-168 (N-terminal) and 262-450 (C-terminal), confirming that the sequences were indeed mimicking epitopes. Thirty percent of the selected clones matched reported antigenic regions located at sites II and III of the glycoprotein. Two sequences, LEPKGRYDDPWT and ATRYDDIWASTA, that have no homology to the known antigenic sites of either the G or N exhibited a common RYDD-W-T motif that is highly homologous to the amino acid residues at positions 126-141 of the G. This finding indicates that this motif may be a new potential RABV G B cell epitope. Amino acids 126-141 containing the RYDD-W-T motif may become a novel key epitope region and allow the development of a rabies vaccine or diagnostic reagents for the treatment of rabies. PMID:23499997

  19. IgG4 anti-phospholipase A2 receptor might activate lectin and alternative complement pathway meanwhile in idiopathic membranous nephropathy: an inspiration from a cross-sectional study.

    PubMed

    Yang, Yang; Wang, Chao; Jin, Liping; He, Fagui; Li, Changchun; Gao, Qingman; Chen, Guanglei; He, Zhijun; Song, Minghui; Zhou, Zhuliang; Shan, Fujun; Qi, Ka; Ma, Lu

    2016-08-01

    The deposition of IgG4 of antibodies against phospholipase A2 receptor (anti-PLA2R) is predominating in the kidneys of patients with idiopathic membranous nephropathy, while its predictive value has not been determined. It was a retrospective study, and 438 patients were included. Serum samples of two time points [before intervention (baseline) and after 1.5-year treatment (endpoint)] were detected for total and IgG4 anti-PLA2R. IgG4 <0.26 RU/mL or total <20 RU/mL was considered as seronegativity. Bi-positivity/bi-negativity was defined when patients'antibodies were found positive or negative both at the baseline and endpoint. Completed remission (CR) was a major clinical outcome. A series of complement ingredients (MASP-1/2, MBL, C3a, C5a, Factor B, Ba, Bb and C5b-9) were measured in the patients of bi-positivity and bi-negativity: (1) meta-analysis based on six papers conducted seropositivity of anti-PLA2R was a useful predictor for achieving CR, but there was a high heterogeneity; (2) there was significant correlation between the baseline and decrease in IgG4 subclass and the achievement of CR; (3) bi-negativity of IgG4 has a high accuracy of predicting CR compared with total antibodies; (4) in patients of bi-positivity, those achieving CR showed lower MASP-1/2, MBL, C3a, C5a, FB, Ba and Bb than patients failing to achieve CR; (5) the titers of endpoint and decrease in Ba and Bb were associated with improvement of 24 h-UP in those of bi-positivity; and (6) the decrease in Ba was a significant factor for achieving CR in those of bi-positivity. Continuous IgG4 negativity was a useful tool to predict the achievement of CR; however, in patients of continuous IgG4 positivity, those with lower activation of lectin and alternative pathways would still more probably achieve CR. PMID:26837241

  20. Suppression of allo-human leucocyte antigen (HLA) antibodies secreted by B memory cells in vitro: intravenous immunoglobulin (IVIg) versus a monoclonal anti-HLA-E IgG that mimics HLA-I reactivities of IVIg

    PubMed Central

    Zhu, D; Ravindranath, M H; Terasaki, P I; Miyazaki, T; Pham, T; Jucaud, V

    2014-01-01

    B memory cells remain in circulation and secrete alloantibodies without antigen exposure > 20 years after alloimmunization postpartum or by transplantation. These long-lived B cells are resistant to cytostatic drugs. Therapeutically, intravenous immunoglobulin (IVIg) is administered to reduce allo-human leucocyte antigen (HLA) antibodies pre- and post-transplantation, but the mechanism of reduction remains unclear. Recently, we reported that IVIg reacts with several HLA-I alleles and the HLA reactivity of IVIg is lost after its HLA-E reactivity is adsorbed out. Therefore, we have generated an anti-HLA-E monoclonal antibody that mimics the HLA-reactivity of IVIg to investigate whether this antibody suppresses IgG secretion, as does IVIg. B cells were purified from the blood of a woman in whose blood the B memory cells remained without antigen exposure > 20 years after postpartum alloimmunization. The B cells were stimulated with cytokines using a well-defined culture system. The anti-HLA-E monoclonal antibody (mAb) significantly suppressed the allo-HLA class-II IgG produced by the B cells, and that this suppression was far superior to that by IVIg. These findings were confirmed with HLA-I antibody secreted by the immortalized B cell line, developed from the blood of another alloimmunized woman. The binding affinity of the anti-HLA-E mAb for peptide sequences shared (i.e. shared epitopes) between HLA-E and other β2-microglobulin-free HLA heavy chains (open conformers) on the cell surface of B cells may act as a ligand and signal suppression of IgG production of activated B memory cells. We propose that anti-HLA-E monoclonal antibody may also be useful to suppress allo-HLA IgG production in vivo. PMID:24611451

  1. A fully human IgG1 anti-PD-L1 MAb in an in vitro assay enhances antigen-specific T-cell responses

    PubMed Central

    Grenga, Italia; Donahue, Renee N; Lepone, Lauren M; Richards, Jacob; Schlom, Jeffrey

    2016-01-01

    Monoclonal antibodies (MAbs) that interfere with checkpoint molecules are being investigated for the treatment of infectious diseases and cancer, with the aim of enhancing the function of an impaired immune system. Avelumab (MSB0010718C) is a fully human IgG1 MAb targeting programmed death-ligand 1 (PD-L1), which differs from other checkpoint-blocking antibodies in its ability to mediate antibody-dependent cell-mediated cytotoxicity. These studies were conducted to define whether avelumab could enhance the detection of antigen-specific immune response in in vitro assays. Peripheral blood mononuclear cells from 17 healthy donors were stimulated in vitro, with and without avelumab, with peptide pools encoding for cytomegalovirus, Epstein–Barr virus, influenza and tetanus toxin or the negative peptide control encoding for human leukocyte antigen. These studies show for the first time that the addition of avelumab to an antigen-specific IVS assay (a) increased the frequency of activated antigen-specific CD8+ T lymphocytes, and did so to a greater extent than that seen with commercially available PD-L1-blocking antibodies, (b) reduced CD4+ T-cell proliferation and (c) induced a switch in the production of Th2 to Th1 cytokines. Moreover, there was an inverse correlation between the enhancement of CD8+ T-cell activation and reduction in CD4+ T-cell proliferation induced by avelumab. These findings provide the rationale for the use of avelumab anti-PD-L1 in in vitro assays to monitor patient immune responses to immunotherapies. PMID:27350882

  2. Defense-in-depth by mucosally administered anti-HIV dimeric IgA2 and systemic IgG1 mAbs: complete protection of rhesus monkeys from mucosal SHIV challenge.

    PubMed

    Sholukh, Anton M; Watkins, Jennifer D; Vyas, Hemant K; Gupta, Sandeep; Lakhashe, Samir K; Thorat, Swati; Zhou, Mingkui; Hemashettar, Girish; Bachler, Barbara C; Forthal, Donald N; Villinger, Francois; Sattentau, Quentin J; Weiss, Robin A; Agatic, Gloria; Corti, Davide; Lanzavecchia, Antonio; Heeney, Jonathan L; Ruprecht, Ruth M

    2015-04-21

    Although IgA is the most abundantly produced immunoglobulin in humans, its role in preventing HIV-1 acquisition, which occurs mostly via mucosal routes, remains unclear. In our passive mucosal immunizations of rhesus macaques (RMs), the anti-HIV-1 neutralizing monoclonal antibody (nmAb) HGN194, given either as dimeric IgA1 (dIgA1) or dIgA2 intrarectally (i.r.), protected 83% or 17% of the RMs against i.r. simian-human immunodeficiency virus (SHIV) challenge, respectively. Data from the RV144 trial implied that vaccine-induced plasma IgA counteracted the protective effector mechanisms of IgG1 with the same epitope specificity. We thus hypothesized that mucosal dIgA2 might diminish the protection provided by IgG1 mAbs targeting the same epitope. To test our hypothesis, we administered HGN194 IgG1 intravenously (i.v.) either alone or combined with i.r. HGN194 dIgA2. We enrolled SHIV-exposed, persistently aviremic RMs protected by previously administered nmAbs; RM anti-human IgG responses were undetectable. However, low-level SIV Gag-specific proliferative T-cell responses were found. These animals resemble HIV-exposed, uninfected humans, in which local and systemic cellular immune responses have been observed. HGN194 IgG1 and dIgA2 used alone and the combination of the two neutralized the challenge virus equally well in vitro. All RMs given only i.v. HGN194 IgG1 became infected. In contrast, all RMs given HGN194 IgG1+dIgA2 were completely protected against high-dose i.r. SHIV-1157ipEL-p challenge. These data imply that combining suboptimal defenses at the mucosal and systemic levels can completely prevent virus acquisition. Consequently, active vaccination should focus on defense-in-depth, a strategy that seeks to build up defensive fall-back positions well behind the fortified frontline. PMID:25769884

  3. Defense-in-depth by mucosally administered anti-HIV dimeric IgA2 and systemic IgG1 mAbs: Complete protection of rhesus monkeys from mucosal SHIV challenge

    PubMed Central

    Sholukh, Anton M.; Watkins, Jennifer D.; Vyas, Hemant K.; Gupta, Sandeep; Lakhashe, Samir K.; Thorat, Swati; Zhou, Mingkui; Hemashettar, Girish; Bachler, Barbara C.; Forthal, Donald N.; Villinger, Francois; Sattentau, Quentin J.; Weiss, Robin A.; Agatic, Gloria; Corti, Davide; Lanzavecchia, Antonio; Heeney, Jonathan L.; Ruprecht, Ruth M.

    2015-01-01

    Although IgA is the most abundantly produced immunoglobulin in humans, its role in preventing HIV-1 acquisition, which occurs mostly via mucosal routes, remains unclear. In our passive mucosal immunizations of rhesus macaques (RMs), the anti-HIV-1 neutralizing monoclonal antibody (nmAb) HGN194, given either as dimeric IgA1 (dIgA1) or dIgA2 intrarectally (i.r.), protected 83% or 17% of the RMs against i.r. simian-human immunodeficiency virus (SHIV) challenge, respectively. Data from the RV144 trial implied that vaccine-induced plasma IgA counteracted the protective effector mechanisms of IgG1 with the same epitope specificity. We thus hypothesized that mucosal dIgA2 might diminish the protection provided by IgG1 mAbs targeting the same epitope. To test our hypothesis, we administered HGN194 IgG1 intravenously (i.v.) either alone or combined with i.r. HGN194 dIgA2. We enrolled SHIV-exposed, persistently aviremic RMs protected by previously administered nmAbs; RM anti-human IgG responses were undetectable. However, low-level SIV Gag-specific proliferative T-cell responses were found. These animals resemble HIV-exposed, uninfected humans, in which local and systemic cellular immune responses have been observed. HGN194 IgG1 and dIgA2 used alone and the combination of the two neutralized the challenge virus equally well in vitro. All RMs given only i.v. HGN194 IgG1 became infected. In contrast, all RMs given HGN194 IgG1 + dIgA2 were completely protected against high-dose i.r. SHIV-1157ipEL-p challenge. These data imply that combining suboptimal defenses at the mucosal and systemic levels can completely prevent virus acquisition. Consequently, active vaccination should focus on defense-in-depth, a strategy that seeks to build up defensive fall-back positions well behind the fortified frontline. PMID:25769884

  4. A single recombinant anti-RhD IgG prevents RhD immunization: association of RhD-positive red blood cell clearance rate with polymorphisms in the FcgammaRIIA and FcgammaIIIA genes.

    PubMed

    Miescher, Sylvia; Spycher, Martin O; Amstutz, Hanspeter; De Haas, Masja; Kleijer, Marion; Kalus, Ulrich J; Radtke, Hartmut; Hubsch, Alphonse; Andresen, Irmgard; Martin, Roland M; Bichler, Johann

    2004-06-01

    A single recombinant immunoglobulin G1 (IgG1) anti-RhD antibody (MonoRho) was compared with a currently used polyclonal anti-RhD product (Rhophylac) in a phase 1 study for safety, efficacy of Rhesus D (RhD)-positive red blood cell (RBC) clearance, and prevention of RhD immunization in RhD-negative men challenged with 15 mL RhD-positive RBCs. Both the polyclonal product and recombinant anti-RhD effectively cleared RhD-positive RBCs after intravenous and intramuscular injection. The recombinant anti-RhD demonstrated a slower clearance rate compared with the polyclonal anti-RhD. There was no dose response, and there was considerable variation among subjects who received the same dose of recombinant anti-RhD. Interestingly, RhD-positive RBC clearance rates were strongly associated with Fcgamma receptor IIA (FcgammaRIIA) and FcgammaIIIA but not with FcgammaIIIB polymorphisms. Subjects homozygous for FcgammaRIIA-131H or FcgammaRIIIA-158V allotypes showed a faster clearance rate compared with both the heterozygote and the corresponding alternative homozygote allotypes. A similar but less marked trend was seen for the polyclonal anti-RhD. Despite the variation in clearance rates there was no evidence of anti-RhD alloantibodies in any of the subjects at +6 months after the RBC challenge. PMID:14976055

  5. Dimeric FcγR Ectodomains as Probes of the Fc Receptor Function of Anti-Influenza Virus IgG.

    PubMed

    Wines, Bruce D; Vanderven, Hillary A; Esparon, Sandra E; Kristensen, Anne B; Kent, Stephen J; Hogarth, P Mark

    2016-08-15

    Ab-dependent cellular cytotoxicity, phagocytosis, and Ag presentation are key mechanisms of action of Abs arising in vaccine or naturally acquired immunity, as well of therapeutic mAbs. Cells expressing the low-affinity FcγRs (FcγRII or CD32 and FcγRIII or CD16) are activated for these functions when receptors are aggregated following the binding of IgG-opsonized targets. Despite the diversity of the Fc receptor proteins, IgG ligands, and potential responding cell types, the induction of all FcγR-mediated responses by opsonized targets requires the presentation of multiple Fc regions in close proximity to each other. We demonstrated that such "near-neighbor" Fc regions can be detected using defined recombinant soluble (rs) dimeric low-affinity ectodomains (rsFcγR) that have an absolute binding requirement for the simultaneous engagement of two IgG Fc regions. Like cell surface-expressed FcγRs, the binding of dimeric rsFcγR ectodomains to Ab immune complexes was affected by Ab subclass, presentation, opsonization density, Fc fucosylation, or mutation. The activation of an NK cell line and primary NK cells by human IgG-opsonized influenza A hemagglutinin correlated with dimeric rsFcγRIIIa binding activity but not with Ab titer. Furthermore, the dimeric rsFcγR binding assay sensitively detected greater Fc receptor activity to pandemic H1N1 hemagglutinin after the swine influenza pandemic of 2009 in pooled human polyclonal IgG. Thus these dimeric rsFcγR ectodomains are validated, defined probes that should prove valuable in measuring the immune-activating capacity of IgG Abs elicited by infection or vaccination or experimentally derived IgG and its variants. PMID:27385782

  6. FcR blocking activity in serum of actively enhanced rat renal allograft recipients due to IgG anti-class II MHC alloantibody.

    PubMed Central

    Marshall, H E; Bolton, E M; Gracie, J A; Cocker, J E; Sandilands, G P; Bradley, J A

    1990-01-01

    In some rat strain combinations, pre-operative donor-specific blood transfusion produces long-term renal allograft survival, although the underlying mechanisms are unclear. This study has examined whether Fc receptor (FcR)-blocking activity could be detected in the serum of unmodified PVG strain recipients bearing a rejecting renal allograft and in recipients bearing an actively enhanced graft following pre-operative blood transfusion. Serum harvested on Day 5 from actively enhanced PVG recipients of DA rat renal allografts was shown to specifically inhibit erythrocyte-antibody (EA) rosette formation with donor strain, but not third-party, splenocytes, while the levels of EA rosette inhibition (EAI) in Day 5 serum from rejecting rats remained markedly lower. This FcR-blocking activity was present in enhanced serum fractions, prepared by discontinuous density gradient centrifugation, which corresponded to the 7 S peak. Purified IgG prepared from enhanced serum was also found to inhibit EA rosette formation with donor splenocytes, and absorption of the IgG preparations with donor strain erythrocytes failed to abrogate EA rosette inhibition. Further experiments, in which absorbed IgG from enhanced animals was tested for FcR blocking activity against splenocytes of defined major histocompatability complex (MHC) subregion specificities, established that FcR-blocking activity was mediated by IgG alloantibodies directed against donor MHC class II antigens. Whether the presence of such antibodies early after transplantation contributes to the beneficial effect of blood transfusion on graft survival remains to be determined. PMID:2312162

  7. Multiplexed Anti-Toxoplasma IgG, IgM, and IgA Assay on Plasmonic Gold Chips: towards Making Mass Screening Possible with Dye Test Precision.

    PubMed

    Li, Xiaoyang; Pomares, Christelle; Gonfrier, Géraldine; Koh, Byumseok; Zhu, Shoujun; Gong, Ming; Montoya, Jose G; Dai, Hongjie

    2016-07-01

    Toxoplasmosis is an infection caused by the protozoan parasite Toxoplasma gondii that can lead to severe sequelae in the fetus during pregnancy. Definitive serologic diagnosis of the infection during gestation is made mostly by detecting T. gondii-specific antibodies, including IgG and IgM, individually in a single serum sample by using commercially available kits. The IgA test is used by some laboratories as an additional marker of acute infection. Most of the commercial tests have failed to reach 100% correlation with the reference method, the Sabin-Feldman dye test for the detection of Toxoplasma IgG antibodies. For Toxoplasma IgM and IgA antibodies, there is no reference method and their evaluation is done by comparing the results of one assay to those of another. There is a need for multiplexed assay platforms, as the serological diagnosis of T. gondii infection does not rely on the detection of a single Ig subtype. Here we describe the development of a plasmonic gold chip with vast fluorescence enhancement in the near-infrared region for simultaneous detection of IgG, IgM, and IgA antibodies against T. gondii in an ∼1-μl serum or whole-blood sample. When 168 samples were tested on this platform, IgG antibody detection sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were all 100%. IgM antibody detection achieved 97.6% sensitivity and 96.9% specificity with a 90.9% PPV and a 99.2% NPV. Thus, the nanoscience-based plasmonic gold platform enables a high-performance, low-cost, multiplexed assay requiring ultrasmall blood volumes, paving the way for the implementation of universal screening for toxoplasmosis infection during gestation. PMID:27008879

  8. Foal IgG and opsonizing anti-Rhodococcus equi antibodies after immunization of pregnant mares with a protective VapA candidate vaccine.

    PubMed

    Cauchard, Julien; Sevin, Corinne; Ballet, Jean-Jacques; Taouji, Saïd

    2004-11-30

    The aim of this study was to evaluate serum IgG antibody levels and opsonizing activity in foals from pregnant mares immunized with either proteins from an R. equi strain containing virulence-associated protein A (VapA), an immunodominant surface-expressed lipoprotein encoded by a virulence plasmid crucial for virulence in foals, or a whole killed virulent R. equi preparation. Forty-eight pregnant mares were distributed into three groups, i.e. 24 immunized with R. equi VapA protein antigen associated with a water-based nanoparticle adjuvant (Montanide IMS 3012), 8 immunized with whole killed R. equi, and 16 non-immunized as control. Serum IgG and opsonizing capacity were evaluated during pregnancy in mares, and up to day 45 post-delivery in foals in which R. equi infections were recorded in the first 6 months of life. Pregnant mares immunized with virulent R. equi proteins developed higher serum IgG and opsonic activity which were transferred to the foals than either in the whole R. equi immunized or the control group. Four foals developed pneumonia in the control group while none in immunized groups. Results support further evaluation of VapA protein antigen associated with a water-based nanoparticle adjuvant as a candidate vaccine for immunization of pregnant mares resulting in passive antibody-mediated protection of foals. PMID:15530741

  9. Somatic mutations in the variable regions of a human IgG anti-double-stranded DNA autoantibody suggest a role for antigen in the induction of systemic lupus erythematosus.

    PubMed

    van Es, J H; Gmelig Meyling, F H; van de Akker, W R; Aanstoot, H; Derksen, R H; Logtenberg, T

    1991-02-01

    The processes that govern the generation of pathogenic anti-DNA autoantibodies in human systemic lupus erythematosus (SLE) are largely unknown. Autoantibodies may arise as a consequence of polyclonal B cell activation and/or antigen-driven B cell activation and selection. The role of these processes in humoral autoimmunity may be studied by molecular genetic analysis of immunoglobulin (Ig) variable (V) regions of antibodies that are characteristic of SLE. We have analyzed the gene elements that encode a high affinity, IgG anti-double-stranded DNA autoantibody secreted by a monoclonal Epstein-Barr virus (EBV)-transformed cell line derived from a patient with active SLE. In addition, we have identified, cloned, and sequenced the germline counterparts of the VH and VL genes expressed in this autoantibody. The comparison of both sets of gene elements shows that the autoantibody VH and VL regions harbor numerous somatic mutations characteristic of an antigen-driven immune response. The light chain expressed in this autoantibody is a somatically mutated variant of the kv325 germline gene that is frequently associated with paraproteins having autoantibody activity and with Ig molecules produced by malignant B cells that express the CD5 antigen. Furthermore, the utilized DH segment has been repeatedly found in multireactive, low affinity IgM anti-DNA autoantibodies from SLE patients and healthy individuals. These results suggest that pathogenic IgG anti-DNA autoantibodies in human SLE may arise through antigen-driven selection of somatic mutations in the gene elements that frequently encode multireactive IgM autoantibodies. PMID:1899104

  10. Effect of Antenatal Parasitic Infections on Anti-vaccine IgG Levels in Children: A Prospective Birth Cohort Study in Kenya

    PubMed Central

    Malhotra, Indu; McKibben, Maxim; Mungai, Peter; McKibben, Elisabeth; Wang, Xuelei; Sutherland, Laura J.; Muchiri, Eric M.; King, Charles H.; King, Christopher L.; LaBeaud, A. Desiree

    2015-01-01

    Background Parasitic infections are prevalent among pregnant women in sub-Saharan Africa. We investigated whether prenatal exposure to malaria and/or helminths affects the pattern of infant immune responses to standard vaccinations against Haemophilus influenzae (Hib), diphtheria (DT), hepatitis B (Hep B) and tetanus toxoid (TT). Methods and Findings 450 Kenyan women were tested for malaria, schistosomiasis, lymphatic filariasis (LF), and intestinal helminths during pregnancy. After three standard vaccinations at 6, 10 and 14 weeks, their newborns were followed biannually to age 36 months and tested for absolute levels of IgG against Hib, DT, Hep B, and TT at each time point. Newborns’ cord blood (CB) lymphocyte responses to malaria blood-stage antigens, soluble Schistosoma haematobium worm antigen (SWAP), and filaria antigen (BMA) were also assessed. Three immunophenotype categories were compared: i) tolerant (those having Plasmodium-, Schistosoma-, or Wuchereria-infected mothers but lacking respective Th1/Th2-type recall responses at birth to malaria antigens, SWAP, or BMA); ii) sensitized (those with infected/uninfected mothers and detectable Th1/Th2-type CB recall response to respective parasite antigen); or iii) unexposed (no evidence of maternal infection or CB recall response). Overall, 78.9% of mothers were infected with LF (44.7%), schistosomiasis (32.4%), malaria (27.6%) or hookworm (33.8%). Antenatal maternal malaria, LF, and hookworm were independently associated with significantly lower Hib-specific IgG. Presence of multiple maternal infections was associated with lower infant IgG levels against Hib and DT antigens post-vaccination. Post-vaccination IgG levels were also significantly associated with immunophenotype: malaria-tolerized infants had reduced response to DT, whereas filaria-tolerized infants showed reduced response to Hib. Conclusions There is an impaired ability to develop IgG antibody responses to key protective antigens of Hib and

  11. Evaluation of a novel human IgG1 anti-claudin3 antibody that specifically recognizes its aberrantly localized antigen in ovarian cancer cells and that is suitable for selective drug delivery

    PubMed Central

    Romani, Chiara; Cocco, Emiliano; Bignotti, Eliana; Moratto, Daniele; Bugatti, Antonella; Todeschini, Paola; Bandiera, Elisabetta; Tassi, Renata; Zanotti, Laura; Pecorelli, Sergio; Sartori, Enrico; Odicino, Franco E.; de Marco, Ario; Davide Santin, Alessandro; Ravaggi, Antonella; Mitola, Stefania

    2015-01-01

    Membrane protein claudin3 has been recently suggested as a marker for biologically aggressive tumors and a possible target for the therapeutic delivery of active anti-cancer compounds. Claudin3-binding molecules such as the Clostridium perfringens enterotoxin (CPE), CPE-related molecules, and murine and chimeric antibodies have shown promising antitumor efficacy in preclinical oncological settings. We first engineered a fully human anti-claudin3 IgG1 antibody (IgGH6) by fusing the human IgG1 Fc-domain to the anti-claudin3 scFvH6 previously isolated from a pre-immune phage display library. The construct was expressed in mammalian cells and specifically targeted claudin3 endogenously expressed on the surface of different human ovarian cancer cell lines. No detectable cross-reactivity with other homologous claudins was observed. The epitope recognized by IgGH6 is located within the minor extracellular domain of claudin3 and becomes accessible only in tumor cells characterized by incomplete junction formation. Confocal microscopy experiments demonstrated that IgGH6 was actively internalized in tumor cells after binding to native claudin3 and co-localized, likely within intracellular vesicles, with the C-CPE peptide. Preliminary results indicate that IgGH6 accumulated in vivo in free claudin3 ovarian carcinoma xenografts. For its selective uptake in tumor cells and its human nature, IgGH6 represents a valuable candidate for antibody-drug conjugate therapeutic applications in ovarian cancer patients. PMID:26416446

  12. Antibody Conjugation Approach Enhances Breadth and Potency of Neutralization of Anti-HIV-1 Antibodies and CD4-IgG

    PubMed Central

    Gavrilyuk, Julia; Ban, Hitoshi; Uehara, Hisatoshi; Sirk, Shannon J.; Saye-Francisco, Karen; Cuevas, Angelica; Zablowsky, Elise; Oza, Avinash; Seaman, Michael S.; Burton, Dennis R.

    2013-01-01

    Broadly neutralizing antibodies PG9 and PG16 effectively neutralize 70 to 80% of circulating HIV-1 isolates. In this study, the neutralization abilities of PG9 and PG16 were further enhanced by bioconjugation with aplaviroc, a small-molecule inhibitor of virus entry into host cells. A novel air-stable diazonium hexafluorophosphate reagent that allows for rapid, tyrosine-selective functionalization of proteins and antibodies under mild conditions was used to prepare a series of aplaviroc-conjugated antibodies, including b12, 2G12, PG9, PG16, and CD4-IgG. The conjugated antibodies blocked HIV-1 entry through two mechanisms: by binding to the virus itself and by blocking the CCR5 receptor on host cells. Chemical modification did not significantly alter the potency of the parent antibodies against nonresistant HIV-1 strains. Conjugation did not alter the pharmacokinetics of a model IgG in blood. The PG9-aplaviroc conjugate was tested against a panel of 117 HIV-1 strains and was found to neutralize 100% of the viruses. PG9-aplaviroc conjugate IC50s were lower than those of PG9 in neutralization studies of 36 of the 117 HIV-1 strains. These results support this new approach to bispecific antibodies and offer a potential new strategy for combining HIV-1 therapies. PMID:23427154

  13. Antibody conjugation approach enhances breadth and potency of neutralization of anti-HIV-1 antibodies and CD4-IgG.

    PubMed

    Gavrilyuk, Julia; Ban, Hitoshi; Uehara, Hisatoshi; Sirk, Shannon J; Saye-Francisco, Karen; Cuevas, Angelica; Zablowsky, Elise; Oza, Avinash; Seaman, Michael S; Burton, Dennis R; Barbas, Carlos F

    2013-05-01

    Broadly neutralizing antibodies PG9 and PG16 effectively neutralize 70 to 80% of circulating HIV-1 isolates. In this study, the neutralization abilities of PG9 and PG16 were further enhanced by bioconjugation with aplaviroc, a small-molecule inhibitor of virus entry into host cells. A novel air-stable diazonium hexafluorophosphate reagent that allows for rapid, tyrosine-selective functionalization of proteins and antibodies under mild conditions was used to prepare a series of aplaviroc-conjugated antibodies, including b12, 2G12, PG9, PG16, and CD4-IgG. The conjugated antibodies blocked HIV-1 entry through two mechanisms: by binding to the virus itself and by blocking the CCR5 receptor on host cells. Chemical modification did not significantly alter the potency of the parent antibodies against nonresistant HIV-1 strains. Conjugation did not alter the pharmacokinetics of a model IgG in blood. The PG9-aplaviroc conjugate was tested against a panel of 117 HIV-1 strains and was found to neutralize 100% of the viruses. PG9-aplaviroc conjugate IC50s were lower than those of PG9 in neutralization studies of 36 of the 117 HIV-1 strains. These results support this new approach to bispecific antibodies and offer a potential new strategy for combining HIV-1 therapies. PMID:23427154

  14. Adverse effects of IgG therapy.

    PubMed

    Berger, Melvin

    2013-01-01

    IgG is widely used for patients with immune deficiencies and in a broad range of autoimmune and inflammatory disorders. Up to 40% of intravenous infusions of IgG may be associated with adverse effects (AEs), which are mostly uncomfortable or unpleasant but often are not serious. The most common infusion-related AE is headache. More serious reactions, including true anaphylaxis and anaphylactoid reactions, occur less frequently. Most reactions are related to the rate of infusion and can be prevented or treated just by slowing the infusion rate. Medications such as nonsteroidal anti-inflammatory drugs, antihistamines, or corticosteroids also may be helpful in preventing or treating these common AEs. IgA deficiency with the potential of IgG or IgE antibodies against IgA increases the risk of some AEs but should not be viewed as a contraindication if IgG therapy is needed. Potentially serious AEs include renal dysfunction and/or failure, thromboembolic events, and acute hemolysis. These events usually are multifactorial, related to combinations of constituents in the IgG product as well as risk factors for the recipient. Awareness of these factors should allow minimization of the risks and consequences of these AEs. Subcutaneous IgG is absorbed more slowly into the circulation and has a lower incidence of AEs, but awareness and diligence are necessary whenever IgG is administered. PMID:24565701

  15. Detection of anti-U3-RNP/fibrillarin IgG antibodies by line immunoblot assay has comparable clinical significance to immunoprecipitation testing in systemic sclerosis.

    PubMed

    Peterson, Lisa K; Jaskowski, Troy D; Mayes, Maureen D; Tebo, Anne E

    2016-04-01

    The aim of this study was to evaluate the performance and clinical relevance of a commercially available line immunoblot assay (LIA) for detecting anti-U3-RNP/fibrillarin (anti-U3-RNP), against immunoprecipitation (gold standard). This study involved a multi-ethnic cohort of 1000 American systemic sclerosis (SSc) patients and 50 healthy controls. Antinuclear antibodies and centromere antibodies were detected by indirect immunofluorescent antibody test, anti-topo I by immunodiffusion and anti-RNAP III by ELISA. The presence of anti-U3-RNP in select serum samples was detected by immunoprecipitation (IP) and LIA. By IP, U3-RNP antibody was detected in 75 (7.5 %) patients with SSc. Overall agreement between LIA and IP was very good (κ = 0.966). Analytic sensitivity and specificity of the U3-RNP LIA was 100 and 94.7 %, respectively. Clinical features associated with positivity for the anti-U3-RNP antibody include diffuse cutaneous SSc and increased prevalence of renal crisis, consistent with previous studies that used IP. Testing for U3-RNP antibodies is only performed by a small number of laboratories due to the complexity of both performance and interpretation of the IP. LIA is faster and less complex than IP. Excellent agreement between IP and LIA demonstrates that LIA is an acceptable and attractive alternative to IP for anti-U3-RNP detection. PMID:26467972

  16. Identification of immunodominant VP1 linear epitope of enterovirus 71 (EV71) using synthetic peptides for detecting human anti-EV71 IgG antibodies in Western blots.

    PubMed

    Foo, D G W; Ang, R X; Alonso, S; Chow, V T K; Quak, S H; Poh, C L

    2008-03-01

    A major IgG-specific immunodominant VP1 linear epitope of enterovirus 71 (EV71) strain 41 (5865/SIN/00009), defined by the core sequence LEGTTNPNG, was identified by Pepscan analysis. Oligonucleotides corresponding to the amino-acid sequence of synthetic peptide SP32 were cloned and over-expressed in Escherichia coli as a recombinant glutathione-S-transferase (GST)-SP32 fusion protein. In ELISAs, this protein did not react with human anti-EV71 IgG antibodies, but there was significant immunoreactivity according to western blot analysis. The amino-acid sequence of SP32 was highly specific for detecting EV71 strains in western blot analysis, and showed no immunoreactivity with monoclonal antibodies raised against other enteroviruses, e.g., CA9 and Echo 6. PMID:18076666

  17. Alum and Squalene-Oil-in-Water Emulsion Enhance the Titer and Avidity of Anti-Aβ Antibodies Induced by Multimeric Protein Antigen (1–11)E2, Preserving the Igg1-Skewed Isotype Distribution

    PubMed Central

    Mantile, Francesca; Trovato, Maria; Santoni, Andrea; Barba, Pasquale; Ottonello, Simone; De Berardinis, Piergiuseppe; Prisco, Antonella

    2014-01-01

    The development of active immunotherapy for Alzheimer's disease (AD) requires the identification of immunogens that can ensure a high titer antibody response toward Aβ, while minimizing the risks of adverse reactions. Multimeric protein (1–11)E2 induces a robust and persistent antibody response to Aβ in mice, when formulated in Freund's adjuvant. The goal of this translational study was to evaluate the immunogenicity of (1–11)E2 formulated in alum (Alhydrogel 2%), or in a squalene oil-in-water emulsion (AddaVax), or without adjuvant. A IgG1-skewed isotype distribution was observed for the anti-Aβ antibodies generated in mice immunized with either the non-adjuvanted or the adjuvanted vaccine, indicating that (1–11)E2 induces a Th2-like response in all tested conditions. Both Alhydrogel 2% and AddaVax enhanced the titer and avidity of the anti-Aβ response elicited by (1–11)E2. We conclude that (1–11)E2 is a promising candidate for anti-Aβ immunization protocols that include alum or squalene-oil-in-water emulsion, or no adjuvant. PMID:24983378

  18. Characterization of the biological anti-staphylococcal functionality of hUK-66 IgG1, a humanized monoclonal antibody as substantial component for an immunotherapeutic approach

    PubMed Central

    Oesterreich, Babett; Lorenz, Birgit; Schmitter, Tim; Kontermann, Roland; Zenn, Michael; Zimmermann, Bastian; Haake, Markus; Lorenz, Udo; Ohlsen, Knut

    2014-01-01

    Multi-antigen immunotherapy approaches against Staphylococcus aureus are expected to have the best chance of clinical success when used in combinatorial therapy, potentially incorporating opsonic killing of bacteria and toxin neutralization. We recently reported the development of a murine monoclonal antibody specific for the immunodominant staphylococcal antigen A (IsaA), which showed highly efficient staphylococcal killing in experimental infection models of S. aureus. If IsaA-specific antibodies are to be used as a component of combination therapy in humans, the binding specificity and biological activity of the humanized variant must be preserved. Here, we describe the functional characterization of a humanized monoclonal IgG1 variant designated, hUK-66. The humanized antibody showed comparable binding kinetics to those of its murine parent, and recognized the target antigen IsaA on the surface of clinically relevant S. aureus lineages. Furthermore, hUK-66 enhances the killing of S. aureus in whole blood (a physiological environment) samples from healthy subjects and patients prone to staphylococcal infections such as diabetes and dialysis patients, and patients with generalized artery occlusive disease indicating no interference with already present natural antibodies. Taken together, these data indicate that hUK-66 mediates bacterial killing even in high risk patients and thus, could play a role for immunotherapy strategies to combat severe S. aureus infections. PMID:24495867

  19. Human IgG4: a structural perspective

    PubMed Central

    Davies, Anna M; Sutton, Brian J

    2015-01-01

    IgG4, the least represented human IgG subclass in serum, is an intriguing antibody with unique biological properties, such as the ability to undergo Fab-arm exchange and limit immune complex formation. The lack of effector functions, such as antibody-dependent cell-mediated cytotoxicity and complement-dependent cytotoxicity, is desirable for therapeutic purposes. IgG4 plays a protective role in allergy by acting as a blocking antibody, and inhibiting mast cell degranulation, but a deleterious role in malignant melanoma, by impeding IgG1-mediated anti-tumor immunity. These findings highlight the importance of understanding the interaction between IgG4 and Fcγ receptors. Despite a wealth of structural information for the IgG1 subclass, including complexes with Fcγ receptors, and structures for intact antibodies, high-resolution crystal structures were not reported for IgG4-Fc until recently. Here, we highlight some of the biological properties of human IgG4, and review the recent crystal structures of IgG4-Fc. We discuss the unexpected conformations adopted by functionally important Cγ2 domain loops, and speculate about potential implications for the interaction between IgG4 and FcγRs. PMID:26497518

  20. Evaluation of a novel hexavalent humanized anti-IGF-1R antibody and its bivalent parental IgG in diverse cancer cell lines.

    PubMed

    Chang, Chien-Hsing; Wang, Yang; Trisal, Preeti; Li, Rongxiu; Rossi, Diane L; Nair, Anju; Gupta, Pankaj; Losman, Michele; Cardillo, Thomas M; Rossi, Edmund A; Goldenberg, David M

    2012-01-01

    A major mechanism of monoclonal antibodies that selectively target the insulin-like growth factor type 1 receptor (IGF-1R) to inhibit tumor growth is by downregulating the receptor, regardless whether they are capable (antagonistic) or incapable (agonistic) of blocking the binding of cognate ligands. We have developed and characterized a novel agonistic anti-IGF-1R humanized antibody, hR1, and used the Dock-and-Lock (DNL) method to construct Hex-hR1, the first multivalent antibody comprising 6 functional Fabs of hR1, with the aim of enhancing potency of hR1. Based on cross-blocking experiments, hR1 recognizes a region of cysteine-rich domain on the α-subunit, different from the epitopes mapped for existing anti-IGF-1R antibodies, yet hR1 is similar to other anti-IGF-1R antibodies in downregulating IGF-1R and inhibiting proliferation, colony formation, or invasion of selected cancer cell lines in vitro, as well as suppressing growth of the RH-30 rhabdomyosarcoma xenograft in nude mice when combined with the mTOR inhibitor, rapamycin. Hex-hR1 and hR1 are generally comparable in their bioactivities under the in-intro and in-vivo conditions investigated. Nevertheless, in selective experiments involving a direct comparison of potency, Hex-hR1 demonstrated a stronger effect on inhibiting cell proliferation stimulated by IGF-1 and could effectively downregulate IGF-1R at a concentration as low as 20 pM. PMID:22952934

  1. Evaluation of a Novel Hexavalent Humanized Anti-IGF-1R Antibody and Its Bivalent Parental IgG in Diverse Cancer Cell Lines

    PubMed Central

    Chang, Chien-Hsing; Wang, Yang; Trisal, Preeti; Li, Rongxiu; Rossi, Diane L.; Nair, Anju; Gupta, Pankaj; Losman, Michele; Cardillo, Thomas M.; Rossi, Edmund A.; Goldenberg, David M.

    2012-01-01

    A major mechanism of monoclonal antibodies that selectively target the insulin-like growth factor type 1 receptor (IGF-1R) to inhibit tumor growth is by downregulating the receptor, regardless whether they are capable (antagonistic) or incapable (agonistic) of blocking the binding of cognate ligands. We have developed and characterized a novel agonistic anti-IGF-1R humanized antibody, hR1, and used the Dock-and-Lock (DNL) method to construct Hex-hR1, the first multivalent antibody comprising 6 functional Fabs of hR1, with the aim of enhancing potency of hR1. Based on cross-blocking experiments, hR1 recognizes a region of cysteine-rich domain on the α-subunit, different from the epitopes mapped for existing anti-IGF-1R antibodies, yet hR1 is similar to other anti-IGF-1R antibodies in downregulating IGF-1R and inhibiting proliferation, colony formation, or invasion of selected cancer cell lines in vitro, as well as suppressing growth of the RH-30 rhabdomyosarcoma xenograft in nude mice when combined with the mTOR inhibitor, rapamycin. Hex-hR1 and hR1 are generally comparable in their bioactivities under the in-intro and in-vivo conditions investigated. Nevertheless, in selective experiments involving a direct comparison of potency, Hex-hR1 demonstrated a stronger effect on inhibiting cell proliferation stimulated by IGF-1 and could effectively downregulate IGF-1R at a concentration as low as 20 pM. PMID:22952934

  2. Inhibition of nitrate transport by anti-nitrate reductase IgG fragments and the identification of plasma membrane associated nitrate reductase in roots of barley seedlings

    NASA Technical Reports Server (NTRS)

    Ward, M. R.; Tischner, R.; Huffaker, R. C.

    1988-01-01

    Membrane associated nitrate reductase (NR) was detected in plasma membrane (PM) fractions isolated by aqueous two-phase partitioning from barley (Hordeum vulgare L. var CM 72) roots. The PM associated NR was not removed by washing vesicles with 500 millimolar NaCl and 1 millimolar EDTA and represented up to 4% of the total root NR activity. PM associated NR was stimulated up to 20-fold by Triton X-100 whereas soluble NR was only increased 1.7-fold. The latency was a function of the solubilization of NR from the membrane. NR, solubilized from the PM fraction by Triton X-100 was inactivated by antiserum to Chlorella sorokiniana NR. Anti-NR immunoglobulin G fragments purified from the anti-NR serum inhibited NO3- uptake by more than 90% but had no effect on NO2- uptake. The inhibitory effect was only partially reversible; uptake recovered to 50% of the control after thorough rinsing of roots. Preimmune serum immunoglobulin G fragments inhibited NO3- uptake 36% but the effect was completely reversible by rinsing. Intact NR antiserum had no effect on NO3- uptake. The results present the possibility that NO3- uptake and NO3- reduction in the PM of barley roots may be related.

  3. Reactivity of human anti-alpha-galactosyl IgG antibody with alpha(1-->3)-linked galactosyl epitopes exposed on basement membranes and on glomerular epithelial cells: an in vitro and in vivo study in the mouse.

    PubMed Central

    Vecchi, M L; Davin, J C; Castronovo, V; Foidart, J M; Malaise, M; Foidart, J B; Dechene, C; Sangiorgi, G B; Mahieu, P

    1989-01-01

    Anti-alpha-galactosyl antibody (a-Gal Ab) is a human natural antibody belonging to the IgG class, found in high titres in all normal sera regardless of blood group, and specifically recognizing alpha (1-->3)-linked galactosyl residues. We have observed by radioimmunoassay, ELISA, passive haemagglutination and immunofluorescence blocking studies that affinity-purified a-Gal Ab reacted with mouse laminin, but not with the other mouse basement membrane proteins tested; it was able to fix complement in vitro. When injected intravenously into mice, the a-Gal Ab was found to mainly accumulate in kidneys, liver, spleen and lungs. No acute respiratory distress syndrome was observed shortly after the i.v. injection of 100 or 200 microg of antibodies. These doses of a-Gal Ab were also unable to induce acute glomerular injury. However, in primary cultures, the a-Gal Ab (100 or 200 microg per ml of medium) was shown to impair the attachment of mouse glomerular epithelial cells to mouse laminin and to elicit complement-dependent cell damage. The data indicate that the a-Gal Ab can interact in vitro and/or in vivo with alpha (1-->3)-linked galactosyl residues exposed on murine laminin or on murine cultured glomerular epithelial cells. Although this antibody fails to be pathogenic when administered at low doses in the intact animal, similar doses can alter some metabolic properties of these cells in vitro. PMID:12412761

  4. Blood clearance of radiolabeled antibody: enhancement by lactosamination and treatment with biotin-avidin or anti-mouse IgG antibodies

    SciTech Connect

    Klibanov, A.L.; Martynov, A.V.; Slinkin, M.A.; Sakharov, I.Yu.; Smirnov, M.D.; Muzykantov, V.R.; Danilov, S.M.; Torchilin, V.P.

    1988-12-01

    Methods of rapid blood clearance of In-labeled mouse monoclonal antibody 9B9 against angiotensin-converting enzyme were studied. Indium-111-9B9 is specifically accumulated in rat lung, but its blood clearance is relatively slow and target-to-blood radioactivity ratio/g tissue (localization ratio) increases from 11 to 30 only 48 hr postinjection. Injection of second (anti-mouse immunoglobulin) antibodies results in slight (1.8-fold) increase of 9B9 localization ratio. Chemical modification of 9B9 aminogroups with lactose results in enhanced liver uptake and rapid blood clearance of antibody. Blood radioactivity level decreases tenfold, and as a result localization ratio increases threefold (up to 38 in 30 min). Injection of avidin following the injection of biotinylated 9B9 results in rapid clearance of blood radioactivity with increased uptake in liver and spleen. Lung uptake is not changed. Localization ratio increases fivefold over the avidin-untreated animal value. Implications of these approaches for various applications in immunoimaging are discussed.

  5. A new multi-host species indirect ELISA using protein A/G conjugate for detection of anti-Toxoplasma gondii IgG antibodies with comparison to ELISA-IgG, agglutination assay and Western blot.

    PubMed

    Al-Adhami, Batol H; Gajadhar, Alvin A

    2014-02-24

    Toxoplasma gondii is a zoonotic protozoan parasite which can cause significant disease and losses in livestock and wild animals. It is increasingly recognized as an important foodborne pathogen in a broad range of food animals and products. Effective control strategies require rapid, reliable and cost-effective detection methods for large scale surveys and diagnostic applications in a broad range of warm-blooded animals. To overcome one or more of these shortcomings in the currently available detection methods for T. gondii infection a non-species-specific protein A/G conjugate was used in the development of an indirect ELISA (ELISA-A/G) for the detection of IgG antibodies in serum samples obtained from experimentally infected pigs. The performance of the assay was evaluated using serum samples from pigs, cats, mice and seals with known positive or negative status for T. gondii infection. Results of the ELISA-A/G obtained with pig serum samples were compared with those generated by traditional ELISA using host specific IgG conjugate (ELISA-IgG), modified agglutination test (MAT) and Western blot analysis (WB). Using protein A/G conjugate, comparative analysis of results from 77 samples obtained from T. gondii infected pigs showed excellent agreement between the ELISA-A/G and in-house ELISA-IgG (0.917 κ). Similar agreements were also observed when these samples were tested by a commercial ELISA kit (0.816 κ), MAT (0.816 κ) and WB (0.79 κ). A total of 86 serum samples obtained from cats, mice and seals experimentally infected with T. gondii and tested by the ELISA-A/G as well as MAT for the presence of anti-Toxoplasma IgG antibodies yielded Kappa value of 1.0 for cats and mice and 0.79 for seals. These results show that the ELISA-A/G is a suitable method for serological detection of T. gondii infection in multiple host species and has the potential for testing samples from a broad range of domestic, wild, and aquatic mammalian host species. Simultaneous testing

  6. IgG1 deficiency exacerbates experimental autoimmune myasthenia gravis in BALB/c mice

    PubMed Central

    Huda, Ruksana; Strait, Richard T.; Tüzün, Erdem; Finkelman, Fred D.; Christadoss, Premkumar

    2015-01-01

    Myasthenia gravis is an autoimmune disease characterized by muscle weakness due to neuromuscular junction (NMJ) damage by anti-acetylcholine receptor (AChR) auto-antibodies and complement. In experimental autoimmune myasthenia gravis (EAMG), which is induced by immunization with Torpedo AChR in CFA, anti-AChR IgG2b and IgG1 are the predominant isotypes in the circulation. Complement activation by isotypes such as IgG2b plays a crucial role in EAMG pathogenesis; this suggested the possibility that IgG1, which does not activate complement through the classical pathway, may suppress EAMG. In this study, we show that AChR-immunized BALB/c mice genetically deficient for IgG1 produce higher levels of complement-activating isotypes of anti-AChR, especially IgG3 and IgG2a, and develop increased IgG3/IgG2a deposits at the NMJ, as compared to wild type (WT) BALB/c mice. Consistent with this, AChR-immunized IgG1−/− BALB/c mice lose muscle strength and muscle AChR to a greater extent than AChR-immunized WT mice. These observations demonstrate that IgG1 deficiency leads to increased severity of EAMG associated with an increase in complement activating IgG isotypes. Further studies are needed to dissect the specific role or mechanism of IgG1 in limiting EAMG and that of EAMG exacerbating role of complement activating IgG3 and IgG2a in IgG1 deficiency. PMID:25867470

  7. Potential Mechanisms for IgG4 Inhibition of Immediate Hypersensitivity Reactions.

    PubMed

    James, Louisa K; Till, Stephen J

    2016-03-01

    IgG4 is the least abundant IgG subclass in human serum, representing less than 5 % of all IgG. Increases in IgG4 occur following chronic exposure to antigen and are generally associated with states of immune tolerance. In line with this, IgG4 is regarded as an anti-inflammatory antibody with a limited ability to elicit effective immune responses. Furthermore, IgG4 attenuates allergic responses by inhibiting the activity of IgE. The mechanism by which IgG4 inhibits IgE-mediated hypersensitivity has been investigated using a variety of model systems leading to two proposed mechanisms. First by sequestering antigen, IgG4 can function as a blocking antibody, preventing cross-linking of receptor bound IgE. Second IgG4 has been proposed to co-stimulate the inhibitory IgG receptor FcγRIIb, which can negatively regulate FcεRI signaling and in turn inhibit effector cell activation. Recent advances in our understanding of the structural features of human IgG4 have shed light on the unique functional and immunologic properties of IgG4. The aim of this review is to evaluate our current understanding of IgG4 biology and reassess the mechanisms by which IgG4 functions to inhibit IgE-mediated allergic responses. PMID:26892721

  8. Performance Evaluation of the VIDAS® Measles IgG Assay and Its Diagnostic Value for Measuring IgG Antibody Avidity in Measles Virus Infection

    PubMed Central

    Dina, Julia; Creveuil, Christian; Gouarin, Stephanie; Viron, Florent; Hebert, Amelie; Freymuth, Francois; Vabret, Astrid

    2016-01-01

    The objective of this study is primarily to compare the performance of the VIDAS® Measles immunoglobulin (Ig)G assay to that of two other serological assays using an immunoassay technique, Enzygnost® Anti-measles Virus/IgG (Siemens) and Measles IgG CAPTURE EIA® (Microimmune). The sensitivity and the agreement of the VIDAS® Measles IgG assay compared to the Enzygnost® Anti-measles Virus/IgG assay and the Measles IgG CAPTURE EIA® assay are 100%, 97.2% and 99.0%, 98.4%, respectively. The very low number of negative sera for IgG antibodies does not allow calculation of specificity. As a secondary objective, we have evaluated the ability of the VIDAS® Measles IgG assay to measure anti-measles virus IgG antibody avidity with the help of the VIDAS® CMV IgG Avidity reagent, using 76 sera from subjects with measles and 238 other sera. Different groups of populations were analyzed. In the primary infection measles group, the mean IgG avidity index was 0.16 (range of 0.07 to 0.93) compared to 0.79 (range of 0.25 to 1) in the serum group positive for IgG antibodies and negative for IgM. These data allow to define a weak anti-measles virus IgG antibody avidity as an avidity index (AI) < 0.3 and a strong avidity as an AI > 0.6. The VIDAS® Measles IgG assay has a performance equivalent to that of other available products. Its use, individual and quick, is well adapted to testing for anti-measles immunity in exposed subjects. PMID:27556477

  9. Performance Evaluation of the VIDAS(®) Measles IgG Assay and Its Diagnostic Value for Measuring IgG Antibody Avidity in Measles Virus Infection.

    PubMed

    Dina, Julia; Creveuil, Christian; Gouarin, Stephanie; Viron, Florent; Hebert, Amelie; Freymuth, Francois; Vabret, Astrid

    2016-01-01

    The objective of this study is primarily to compare the performance of the VIDAS(®) Measles immunoglobulin (Ig)G assay to that of two other serological assays using an immunoassay technique, Enzygnost(®) Anti-measles Virus/IgG (Siemens) and Measles IgG CAPTURE EIA(®) (Microimmune). The sensitivity and the agreement of the VIDAS(®) Measles IgG assay compared to the Enzygnost(®) Anti-measles Virus/IgG assay and the Measles IgG CAPTURE EIA(®) assay are 100%, 97.2% and 99.0%, 98.4%, respectively. The very low number of negative sera for IgG antibodies does not allow calculation of specificity. As a secondary objective, we have evaluated the ability of the VIDAS(®) Measles IgG assay to measure anti-measles virus IgG antibody avidity with the help of the VIDAS(®) CMV IgG Avidity reagent, using 76 sera from subjects with measles and 238 other sera. Different groups of populations were analyzed. In the primary infection measles group, the mean IgG avidity index was 0.16 (range of 0.07 to 0.93) compared to 0.79 (range of 0.25 to 1) in the serum group positive for IgG antibodies and negative for IgM. These data allow to define a weak anti-measles virus IgG antibody avidity as an avidity index (AI) < 0.3 and a strong avidity as an AI > 0.6. The VIDAS(®) Measles IgG assay has a performance equivalent to that of other available products. Its use, individual and quick, is well adapted to testing for anti-measles immunity in exposed subjects. PMID:27556477

  10. An autoanalyzer test for the quantitation of platelet-associated IgG

    NASA Technical Reports Server (NTRS)

    Levitan, Nathan; Teno, Richard A.; Szymanski, Irma O.

    1986-01-01

    A new quantitative antiglobulin consumption (QAC) test for the measurement of platelet-associated IgG is described. In this test washed platelets are incubated with anti-IgG at a final dilution of 1:2 million. The unneutralized fraction of anti-IgG remaining in solution is then measured with an Autoanalyzer and soluble IgG is used for calibration. The dose-response curves depicting the percent neutralization of anti-IgG by platelets and by soluble IgG were compared in detail and found to be nearly identical, indicating that platelet-associated IgG can be accurately quantitated by this method. The mean IgG values were 2287 molecules/platelet for normal adults and 38,112 molecules/platelet for ITP patients. The Autoanalyzer QAC test is a sensitive and reproducible assay for the quantitation of platelet-associated IgG.

  11. Protective role of mouse IgG1 in cryoglobulinaemia; insights from an animal model and relevance to human pathology.

    PubMed

    Chemouny, Jonathan Maurice; Hurtado-Nedelec, Margarita; Flament, Héloïse; Ben Mkaddem, Sanae; Daugas, Eric; Vrtovsnik, François; Berthelot, Laureline; Monteiro, Renato C

    2016-08-01

    Strait et al. described a novel mouse model of cryoglobulinaemia by challenging mice deficient in the immunoglobulin (Ig)G1 subclass (γ1(-) mice) with goat anti-mouse IgD [5]. The phenotype of wild-type mice was not remarkable, whereas γ1(-) mice developed IgG3 anti-goat IgG cryoglobulins as well as severe and lethal glomerulonephritis. Renal phenotype could not be rescued in γ1(-) mice by the deletion of C3, fragment crystalline γ receptor (FcγR) or J chain. On the other hand, early injection of IgG1, IgG2a or IgG2b inhibited the pathogenic effects of IgG3 in an antigen-dependent manner even in the absence of the FcγRIIb, an anti-inflammatory receptor. The authors concluded that the pathogenic role of IgG3 and the protective characteristic of IgG1 in this model were not explained by their abilities to bind to FcRs or effector molecules but are rather due to structural discrepancies enhancing the precipitation properties/solubility of IgG3/IgG1-containing immune complexes. The present article aims to discuss the current knowledge on IgG biology and the properties of IgGs explaining their differential propensity to acquire cryoglobulin activity. PMID:26410885

  12. Enrichment of total serum IgG4 in patients with pemphigus

    PubMed Central

    Funakoshi, T.; Lunardon, L.; Ellebrecht, C.T.; Nagler, A.R.; O’Leary, C.E.; Payne, A.S.

    2013-01-01

    Summary Background Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are potentially fatal blistering diseases caused by autoantibodies targeting desmoglein (Dsg) adhesion proteins. Previous studies have shown an IgG4 > IgG1 predominance of anti-Dsg antibodies in pemphigus; however, no studies have examined total serum IgG4 levels in pemphigus. IgG4 is induced by chronic antigen stimulation, which could occur with persistent skin blistering and potentially elevate the total serum IgG4 relative to other IgG subclasses in patients with pemphigus. Objectives The primary aim of the study was to quantitate total and Dsg-specific IgG subclasses in patients with pemphigus. Methods IgG subclasses and Dsg-specific IgG1 and IgG4 were quantitated in patients with PV and PF, and in sera from age-matched controls using a subclass enzyme-linked immunosorbent assay. The effectiveness of IgG4 depletion in blocking IgG pathogenicity in PV was determined using a keratinocyte dissociation assay. Results Dsg-specific antibodies comprised a median of 7·1% and 4·2% of total IgG4 in patients with PV and PF, respectively, with eightfold and fourfold enrichment in IgG4 vs. IgG1. Total serum IgG4, but not other IgG subclasses, was enriched in patients with PV and PF compared with age-matched controls (P = 0·004 and P = 0·005, respectively). IgG4 depletion of PV sera reduced pathogenicity in a keratinocyte dissociation assay and showed that affinity-purified IgG4 is more pathogenic than other serum IgG fractions. Conclusions Dsg-specific autoantibodies are significantly enriched in IgG4, which may explain the enrichment of total serum IgG4 in some patients with pemphigus. By preferentially targeting autoimmune rather than beneficial immune antibodies, IgG4-targeted therapies may offer safer treatment options for pemphigus. PMID:22803659

  13. Aberrant IgG isotype generation in mice with abnormal behaviors.

    PubMed

    Kim, So-Nam; Jo, Gwang-Ho; Kim, Hyoung-Ah; Heo, Yong

    2016-01-01

    BTBR T+tf/J (BTBR) mice were recently cited as a suitable animal model for the study of autism because of their behavioral characteristics and immunological changes similar to those reported from autistic subjects. The BTBR mouse was reported to have significantly higher levels of serum IgG, brain IgG deposits and anti-brain IgG than highly social C57BL/6 mice, suggesting involvement of aberrant immune responses in the occurrence of autism. Up-regulation of IgG production was investigated here, with a focus on the pattern of IgG isotype distribution compared with that in FVB/NJ (FVB) mice, another highly social control strain. The results indicated that levels of serum IgG1, IgG2b and IgG3 in post-natal day 21 BTBR mice was significantly higher than FVB mice, regardless of sex, resulting in higher IgG1:IgG2a ratios in BTBR mice than in FVB mice (statistical significance in males). A similar outcome regarding the IgG1:IgG2a ratio was observed in culture supernatants of bone marrow cells from these hosts. A presence of brain-reactive IgG in the sera of BTBR was higher than in FVB mice; levels of brain-reactive IgG against whole brain homogenates were higher in BTBR than in FVB mice, with significant differences seen in the striatum and substantia nigra regions. Levels of IgG1 deposited in the cerebellum, cortex, hippocampus or striatum of both BTBR male and female mice were significantly higher than in FVB counterparts. Overall, these results suggest that alterations in IgG isotype production or deposition in the brain could be implicated in the aberrant immune reactivities of BTBR mice. PMID:25691089

  14. A homologue of the rabbit kappa-chain allotype b9 ON IgG from a cottontail rabbit.

    PubMed

    Tosi, S L; Mage, R G; Tosi, R M

    1976-08-01

    Eight out of 12 anti-b9 antisera tested strongly bound 125IgG of only one of four individual cottontail rabbits (Sylvilagus floridanus). In addition to this apparent polymorphism of a b9 homologue in cottontail rabbits, a polymorphism defined by some anti-b5 antisera was found. Three of 15 anti-b5 antisera reacted with IgG from only two of the four cottontail rabbits. Reactions with anti-b4 and anti-b6 were similar to those with hare IgG. Most anti-b4 and anti-b6 antisera bound the IgG from each animal. The cottontails we tested also resembled the hare with respect to their weak reactivity with some anti-a2 antisera (Vh allotype) and strong reactivity with anti-15 (an allotype localized in the Fc portion of rabbit gamma-chains). PMID:820806

  15. Mitochondrial-dependent Autoimmunity in Membranous Nephropathy of IgG4-related Disease

    PubMed Central

    Buelli, Simona; Perico, Luca; Galbusera, Miriam; Abbate, Mauro; Morigi, Marina; Novelli, Rubina; Gagliardini, Elena; Tentori, Chiara; Rottoli, Daniela; Sabadini, Ettore; Saito, Takao; Kawano, Mitsuhiro; Saeki, Takako; Zoja, Carlamaria; Remuzzi, Giuseppe; Benigni, Ariela

    2015-01-01

    The pathophysiology of glomerular lesions of membranous nephropathy (MN), including seldom-reported IgG4-related disease, is still elusive. Unlike in idiopathic MN where IgG4 prevails, in this patient IgG3 was predominant in glomerular deposits in the absence of circulating anti-phospholipase A2 receptor antibodies, suggesting a distinct pathologic process. Here we documented that IgG4 retrieved from the serum of our propositus reacted against carbonic anhydrase II (CAII) at the podocyte surface. In patient's biopsy, glomerular CAII staining increased and co-localized with subepithelial IgG4 deposits along the capillary walls. Patient's IgG4 caused a drop in cell pH followed by mitochondrial dysfunction, excessive ROS production and cytoskeletal reorganization in cultured podocytes. These events promoted mitochondrial superoxide-dismutase-2 (SOD2) externalization on the plasma membrane, becoming recognizable by complement-binding IgG3 anti-SOD2. Among patients with IgG4-related disease only sera of those with IgG4 anti-CAII antibodies caused low intracellular pH and mitochondrial alterations underlying SOD2 externalization. Circulating IgG4 anti-CAII can cause podocyte injury through processes of intracellular acidification, mitochondrial oxidative stress and neoantigen induction in patients with IgG4 related disease. The onset of MN in a subset of patients could be due to IgG4 antibodies recognizing CAII with consequent exposure of mitochondrial neoantigen in the context of multifactorial pathogenesis of disease. PMID:26137589

  16. Bovine IgG2a antibodies to Haemophilus somnus and allotype expression.

    PubMed Central

    Corbeil, L B; Gogolewski, R P; Kacskovics, I; Nielsen, K H; Corbeil, R R; Morrill, J L; Greenwood, R; Butler, J E

    1997-01-01

    Bovine IgG2a has been implicated in protection against pyogenic infections, including those caused by Haemophilus somnus. To further investigate the role of IgG2a in defense against H. somnus, IgG1 and IgG2a antibodies were purified from antiserum against an immunodominant 40 kDa outer membrane protein (p40) of H. somnus, which was previously shown to passively protect calves against H. somnus pneumonia. The passive protective capacity of anti-p40 IgG1 or IgG2a was evaluated in vivo in calves. Purified anti-p40 IgG1 or IgG2a was incubated with H. somnus for 15 min before intrabronchial inoculation of calves. Bacteria incubated with anti-p40 IgG1 or IgG2a were inoculated into one caudal lung lobe and bacteria incubated with IgG1 or IgG2a from the respective preimmunization serum were inoculated into the contralateral lobe. The volumes of pneumonia in the right and left lungs were determined 24 h later. The difference in volume of pneumonia with H. somnus preincubated in IgG1 pre- and postimmunization anti p40 was less (16 cm3, P = 0.298) than the difference in volume of pneumonia with H. somnus preincubated in IgG2a pre- and postimmunization anti p40 (30 cm3, P = 0.146). Although the differences in lesion size between pre- and postimmunization serum were not statistically significant, the trend suggests IgG2a may be more protective than IgG1. To examine this further, the peptide specificity of these IgG1 and IgG2a antibodies to p40 was examined. After limited proteolysis of p40, IgG2a antibodies reacted with 2 peptides not recognized by IgG1 antibodies. Other peptides were recognized by both isotypes. Since these studies suggested that IgG2a may be important in protection against infection, we then investigated some aspects of the role of the 2 IgG2a allotypes, A1 and A2. In retrospective studies of age differences in expression of IgG2a allotypes, no heterozygotes were detected in calves of 60 d old or less, and fewer heterozygotes were detected in calves 61-120 d

  17. Cross-species analysis of Fc engineered anti-Lewis-Y human IgG1 variants in human neonatal receptor transgenic mice reveal importance of S254 and Y436 in binding human neonatal Fc receptor.

    PubMed

    Burvenich, Ingrid J G; Farrugia, William; Lee, Fook T; Catimel, Bruno; Liu, Zhanqi; Makris, Dahna; Cao, Diana; O'Keefe, Graeme J; Brechbiel, Martin W; King, Dylan; Spirkoska, Violeta; Allan, Laura C; Ramsland, Paul A; Scott, Andrew M

    2016-01-01

    IgG has a long half-life through engagement of its Fc region with the neonatal Fc receptor (FcRn). The FcRn binding site on IgG1 has been shown to contain I253 and H310 in the CH2 domain and H435 in the CH3 domain. Altering the half-life of IgG has been pursued with the aim to prolong or reduce the half-life of therapeutic IgGs. More recent studies have shown that IgGs bind differently to mouse and human FcRn. In this study we characterize a set of hu3S193 IgG1 variants with mutations in the FcRn binding site. A double mutation in the binding site is necessary to abrogate binding to murine FcRn, whereas a single mutation in the FcRn binding site is sufficient to no longer detect binding to human FcRn and create hu3S193 IgG1 variants with a half-life similar to previously studied hu3S193 F(ab')2 (t1/2β, I253A, 12.23 h; H310A, 12.94; H435A, 12.57; F(ab')2, 12.6 h). Alanine substitutions in S254 in the CH2 domain and Y436 in the CH3 domain showed reduced binding in vitro to human FcRn and reduced elimination half-lives in huFcRn transgenic mice (t1/2β, S254A, 37.43 h; Y436A, 39.53 h; wild-type, 83.15 h). These variants had minimal effect on half-life in BALB/c nu/nu mice (t1/2β, S254A, 119.9 h; Y436A, 162.1 h; wild-type, 163.1 h). These results provide insight into the interaction of human Fc by human FcRn, and are important for antibody-based therapeutics with optimal pharmacokinetics for payload strategies used in the clinic. PMID:27030023

  18. The Thomsen-Friedenreich antigen and alphaGal-specific human IgG glycoforms: concanavalin A reactivity and relation to survival of cancer patients.

    PubMed

    Kodar, Kristel; Kurtenkov, Oleg; Klaamas, Kersti

    2009-01-01

    Glycan structures of IgG strongly influence the affinity for Fcgamma receptors and antibody effector functions. However, no particular attention has been paid yet to the glycosylation of tumor antigen-specific IgG. The objectives of this study were (i) to investigate the concanavalin A lectin (ConA) reactivity of human anti-Thomsen-Friedenreich (TF) and anti-alphaGal specific IgG in gastric cancer patients and healthy controls and (ii) to evaluate whether the ConA-reactivity of anti-TF and anti-alphaGal specific IgG is associated with the survival rate of patients with cancer. Total IgG was purified from the sera of patients with gastric cancer and healthy blood donors. The anti-TF and anti-alphaGal glycotope specific IgG were detected with ELISA using synthetic saccharide-polyacrylamide conjugates as antigen. In parallel plate, the ConA reactivity of the anti-TF or anti-alphaGal IgG was determined and the ConA index was calculated. Results show that serum anti-TF specific IgG antibodies of patients with cancer contain significantly higher content of ConA positive IgG glycoform compared to IgG of controls. No correlation between the ConA reactivity of anti-TF IgG and anti-alphaGal IgG was observed. High level of anti-TF IgG ConA reactivity was associated with a significantly lower survival rate of patients with gastric cancer. PMID:19860583

  19. B-cell-independent sialylation of IgG.

    PubMed

    Jones, Mark B; Oswald, Douglas M; Joshi, Smita; Whiteheart, Sidney W; Orlando, Ron; Cobb, Brian A

    2016-06-28

    IgG carrying terminal α2,6-linked sialic acids added to conserved N-glycans within the Fc domain by the sialyltransferase ST6Gal1 accounts for the anti-inflammatory effects of large-dose i.v. Ig (IVIg) in autoimmunity. Here, B-cell-specific ablation of ST6Gal1 in mice revealed that IgG sialylation can occur in the extracellular environment of the bloodstream independently of the B-cell secretory pathway. We also discovered that secreted ST6Gal1 is produced by cells lining central veins in the liver and that IgG sialylation is powered by serum-localized nucleotide sugar donor CMP-sialic acid that is at least partially derived from degranulating platelets. Thus, antibody-secreting cells do not exclusively control the sialylation-dependent anti-inflammatory function of IgG. Rather, IgG sialylation can be regulated by the liver and platelets through the corresponding release of enzyme and sugar donor into the cardiovascular circulation. PMID:27303031

  20. Nontuberculous mycobacterial infection with concurrent IgG4-related lymphadenopathy.

    PubMed

    Liu, Ting-Ting; Weng, Shao-Wen; Wang, Ming-Chung; Huang, Wan-Ting

    2016-03-01

    Disseminated nontuberculous mycobacteria (NTM) infection with concurrent IgG4-related lymphadenopathy has not been reported. We described a patient with neutralizing autoantibodies to interferon-gamma (IFN-γ) and elevated levels of serum IgG4 presenting with generalized lymphadenopathy and reactive dermatosis. Histologically, lymph nodes (LNs) showed effaced nodal architecture with polymorphic infiltrates, mimicking angioimmunoblastic T-cell lymphoma. Both the absolute number and the ratio of IgG4+ plasma cells to IgG+ plasma cells were increased. Mycobacterium abscessus was isolated from cultures of LNs, and demonstrated by polymerase chain reaction-restriction fragment length polymorphism. The skin biopsy showed neutrophilic dermatosis, consistent with Sweet syndrome. The patient met the criteria of both adult-onset immunodeficiency syndrome and IgG4-related lymphadenopathy. This case provides evidence of disseminated NTM infection with concurrent type III IgG4-related lymphadenopathy in the patient with anti-IFN-γ autoantibodies. PMID:26660641

  1. Sialylation converts arthritogenic IgG into inhibitors of collagen-induced arthritis.

    PubMed

    Ohmi, Yuhsuke; Ise, Wataru; Harazono, Akira; Takakura, Daisuke; Fukuyama, Hidehiro; Baba, Yoshihiro; Narazaki, Masashi; Shoda, Hirofumi; Takahashi, Nobunori; Ohkawa, Yuki; Ji, Shuting; Sugiyama, Fumihiro; Fujio, Keishi; Kumanogoh, Atsushi; Yamamoto, Kazuhiko; Kawasaki, Nana; Kurosaki, Tomohiro; Takahashi, Yoshimasa; Furukawa, Koichi

    2016-01-01

    Rheumatoid arthritis (RA)-associated IgG antibodies such as anti-citrullinated protein antibodies (ACPAs) have diverse glycosylation variants; however, key sugar chains modulating the arthritogenic activity of IgG remain to be clarified. Here, we show that reduced sialylation is a common feature of RA-associated IgG in humans and in mouse models of arthritis. Genetically blocking sialylation in activated B cells results in exacerbation of joint inflammation in a collagen-induced arthritis (CIA) model. On the other hand, artificial sialylation of anti-type II collagen antibodies, including ACPAs, not only attenuates arthritogenic activity, but also suppresses the development of CIA in the antibody-infused mice, whereas sialylation of other IgG does not prevent CIA. Thus, our data demonstrate that sialylation levels control the arthritogenicity of RA-associated IgG, presenting a potential target for antigen-specific immunotherapy. PMID:27046227

  2. Sialylation converts arthritogenic IgG into inhibitors of collagen-induced arthritis

    PubMed Central

    Ohmi, Yuhsuke; Ise, Wataru; Harazono, Akira; Takakura, Daisuke; Fukuyama, Hidehiro; Baba, Yoshihiro; Narazaki, Masashi; Shoda, Hirofumi; Takahashi, Nobunori; Ohkawa, Yuki; Ji, Shuting; Sugiyama, Fumihiro; Fujio, Keishi; Kumanogoh, Atsushi; Yamamoto, Kazuhiko; Kawasaki, Nana; Kurosaki, Tomohiro; Takahashi, Yoshimasa; Furukawa, Koichi

    2016-01-01

    Rheumatoid arthritis (RA)-associated IgG antibodies such as anti-citrullinated protein antibodies (ACPAs) have diverse glycosylation variants; however, key sugar chains modulating the arthritogenic activity of IgG remain to be clarified. Here, we show that reduced sialylation is a common feature of RA-associated IgG in humans and in mouse models of arthritis. Genetically blocking sialylation in activated B cells results in exacerbation of joint inflammation in a collagen-induced arthritis (CIA) model. On the other hand, artificial sialylation of anti-type II collagen antibodies, including ACPAs, not only attenuates arthritogenic activity, but also suppresses the development of CIA in the antibody-infused mice, whereas sialylation of other IgG does not prevent CIA. Thus, our data demonstrate that sialylation levels control the arthritogenicity of RA-associated IgG, presenting a potential target for antigen-specific immunotherapy. PMID:27046227

  3. A monoclonal antibody against hinge-cleaved IgG restores effector function to proteolytically-inactivated IgGs in vitro and in vivo

    PubMed Central

    Brezski, Randall J; Kinder, Michelle; Grugan, Katharine D; Soring, Keri L; Carton, Jill; Greenplate, Allison R; Petley, Theodore; Capaldi, Dorie; Brosnan, Kerry; Emmell, Eva; Watson, Sharon; Jordan, Robert E

    2014-01-01

    We report a chimeric monoclonal antibody (mAb) directed to a neo-epitope that is exposed in the IgG lower hinge following proteolytic cleavage. The mAb, designated 2095–2, displays specificity for IdeS-generated F(ab’)2 fragments, but not for full-length IgG or for closely-related F(ab’)2 fragments generated with other proteases. A critical component of the specificity is provided by the C-terminal amino acid of the epitope corresponding to gly-236 in the IgG1 (also IgG4) hinge. By its ability to bind to IdeS-cleaved anti-CD20 mAb, mAb 2095–2 fully restored antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against WIL2-S cells to the otherwise inactive anti-CD20 IgG1 F(ab’)2 fragment. Similarly, 2095–2 reinstated ADCC against MDA-MB-231 cells to an anti-CD142 IgG1 F(ab’)2 fragment. mAb 2095–2 was also capable of eliciting both CDC and ADCC to IgG4 F(ab’)2 fragments, an IgG subclass that has weaker ADCC and CDC when intact relative to intact IgG1. The in vitro cell-based efficacy of 2095–2 was extended to the in vivo setting using platelets as a cell clearance surrogate. In a canine model, the co-administration of 2095–2 together with IdeS-generated, platelet-targeting anti-CD41/61 F(ab’)2 fragment not only restored platelet clearance, but did so at a rate and extent of clearance that exceeded that of intact anti-CD41/61 IgG at comparable concentrations. To further explore this unexpected amplification effect, we conducted a rat study in which 2095–2 was administered at a series of doses in combination with a fixed dose of anti-CD41/61 F(ab’)2 fragments. Again, the combination, at ratios as low as 1:10 (w/w) 2095–2 to F(ab’)2, proved more effective than the anti-CD41/61 IgG1 alone. These findings suggest a novel mechanism for enhancing antibody-mediated cell-killing effector functions with potential applications in pathologic settings such as tumors and acute infections where protease

  4. A monoclonal antibody against hinge-cleaved IgG restores effector function to proteolytically-inactivated IgGs in vitro and in vivo.

    PubMed

    Brezski, Randall J; Kinder, Michelle; Grugan, Katharine D; Soring, Keri L; Carton, Jill; Greenplate, Allison R; Petley, Theodore; Capaldi, Dorie; Brosnan, Kerry; Emmell, Eva; Watson, Sharon; Jordan, Robert E

    2014-01-01

    We report a chimeric monoclonal antibody (mAb) directed to a neo-epitope that is exposed in the IgG lower hinge following proteolytic cleavage. The mAb, designated 2095-2, displays specificity for IdeS-generated F(ab')₂ fragments, but not for full-length IgG or for closely-related F(ab')₂ fragments generated with other proteases. A critical component of the specificity is provided by the C-terminal amino acid of the epitope corresponding to gly-236 in the IgG1 (also IgG4) hinge. By its ability to bind to IdeS-cleaved anti-CD20 mAb, mAb 2095-2 fully restored antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) against WIL2-S cells to the otherwise inactive anti-CD20 IgG1 F(ab')₂ fragment. Similarly, 2095-2 reinstated ADCC against MDA-MB-231 cells to an anti-CD142 IgG1 F(ab')₂ fragment. mAb 2095-2 was also capable of eliciting both CDC and ADCC to IgG4 F(ab')₂ fragments, an IgG subclass that has weaker ADCC and CDC when intact relative to intact IgG1. The in vitro cell-based efficacy of 2095-2 was extended to the in vivo setting using platelets as a cell clearance surrogate. In a canine model, the co-administration of 2095-2 together with IdeS-generated, platelet-targeting anti-CD41/61 F(ab')₂ fragment not only restored platelet clearance, but did so at a rate and extent of clearance that exceeded that of intact anti-CD41/61 IgG at comparable concentrations. To further explore this unexpected amplification effect, we conducted a rat study in which 2095-2 was administered at a series of doses in combination with a fixed dose of anti-CD41/61 F(ab')₂ fragments. Again, the combination, at ratios as low as 1:10 (w/w) 2095-2 to F(ab')₂, proved more effective than the anti-CD41/61 IgG1 alone. These findings suggest a novel mechanism for enhancing antibody-mediated cell-killing effector functions with potential applications in pathologic settings such as tumors and acute infections where protease activity is

  5. Contactin-1 IgG4 antibodies cause paranode dismantling and conduction defects.

    PubMed

    Manso, Constance; Querol, Luis; Mekaouche, Mourad; Illa, Isabel; Devaux, Jérôme J

    2016-06-01

    Paranodal axoglial junctions formed by the association of contactin-1, contactin-associated protein 1, and neurofascin-155, play important functions in nerve impulse propagation along myelinated axons. Autoantibodies to contactin-1 and neurofascin-155 define chronic inflammatory demyelinating polyradiculoneuropathy subsets of patients with specific clinical features. These autoantibodies are mostly of the IgG4 isotype, but their pathogenicity has not been proven. Here, we investigated the mechanisms how IgG subclasses to contactin-1 affect conduction. We show that purified anti-contactin-1 IgG1 and IgG4 bind to paranodes. To determine whether these isotypes can pass the paranodal barrier, we incubated isolated sciatic nerves with the purified antibody or performed intraneural injections. We found that IgG4 diffused into the paranodal regions in vitro or after intraneural injections. IgG4 infiltration was slow and progressive. In 24 h, IgG4 accessed the paranode borders near the nodal lumen, and completely fill the paranodal segments by 3 days. By contrast, control IgG, anti-contactin-1 IgG1, or even anti-contactin-associated-protein-2 IgG4 did not pass the paranodal barrier. To determine whether chronic exposure to these antibodies is pathogenic, we passively transferred anti-contactin-1 IgG1 and IgG4 into Lewis rats immunized with P2 peptide. IgG4 to contactin-1, but not IgG1, induced progressive clinical deteriorations combined with gait ataxia. No demyelination, axonal degeneration, or immune infiltration were observed. Instead, these animals presented a selective loss of the paranodal specialization in motor neurons characterized by the disappearance of the contactin-associated protein 1/contactin-1/neurofascin-155 complex at paranodes. Paranode destruction did not affect nodal specialization, but resulted in a moderate node lengthening. The sensory nerves and dorsal root ganglion were not affected in these animals. Electrophysiological examination further

  6. The rearranged V(H) domain of a physiologically selected anti-single-stranded DNA antibody as a precursor for formation of IgM and IgG antibodies to diverse antigens.

    PubMed

    Li, J; Fernandez, L; O'Connor, K C; Imanishi-Kari, T; Stollar, B D

    2001-10-01

    It has been proposed that autoreactivity of modest affinity contributes to positive selection of a preimmunization B cell repertoire, whereas high-affinity autoreactivity leads to negative selection. This hypothesis predicts that a B cell producing a physiologically selected unmutated ssDNA-binding Ab should be a precursor of cells that respond to diverse exogenous Ags. To test this prediction, we prepared transgenic mice bearing the rearranged V(H) domain of an IgM Ab from a nonautoimmune mouse immunized with a DNA-protein complex, poly(dC)-methylated BSA. The Ab, dC1, binds both poly(dC) and ssDNA. It is encoded by V(H) and V(L) gene segments with no mutations, suggesting that the producing cell may have been selected before and activated during immunization. The dC1V(H) transgene was targeted to the IgH locus. In heterozygous mice, on a nonautoimmune C57BL/6 background, the transgene allotype was expressed on B cell surfaces and in serum Ig, but about one-third of B cells expressed the endogenous allele instead. Total serum Ig concentrations were normal and included both transgene- and endogenous gene-coded IgM and IgG. The transgene V(H) D(H)J(H) was expressed in splenic IgM cDNA with few or no mutations, and in IgG cDNA with multiple mutations. The transgene allotype was also expressed in Abs formed on immunization with thyroglobulin, pneumococcal polysaccharide, and ssDNA-methylated BSA. Consistent with the hypothesis, cells with a rearranged autoreactive V(H) domain selected for reactivity with a form of ssDNA did serve as precursors for cells producing IgM and IgG Abs to diverse Ags. PMID:11564791

  7. MuSK induced experimental autoimmune myasthenia gravis does not require IgG1 antibody to MuSK.

    PubMed

    Küçükerden, Melike; Huda, Ruksana; Tüzün, Erdem; Yılmaz, Abdullah; Skriapa, Lamprini; Trakas, Nikos; Strait, Richard T; Finkelman, Fred D; Kabadayı, Sevil; Zisimopoulou, Paraskevi; Tzartos, Socrates; Christadoss, Premkumar

    2016-06-15

    Sera of myasthenia gravis (MG) patients with muscle-specific receptor kinase-antibody (MuSK-Ab) predominantly display the non-complement fixing IgG4 isotype. Similarly, mouse IgG1, which is the analog of human IgG4, is the predominant isotype in mice with experimental autoimmune myasthenia gravis (EAMG) induced by MuSK immunization. The present study was performed to determine whether IgG1 anti-MuSK antibody is required for immunized mice to develop EAMG. Results demonstrated a significant correlation between clinical severity of EAMG and levels of MuSK-binding IgG1+, IgG2+ and IgG3+ peripheral blood B cells in MuSK-immunized wild-type (WT) mice. Moreover, MuSK-immunized IgG1 knockout (KO) and WT mice showed similar EAMG severity, serum MuSK-Ab levels, muscle acetylcholine receptor concentrations, neuromuscular junction immunoglobulin and complement deposit ratios. IgG1 and IgG3 were the predominant anti-MuSK isotypes in WT and IgG1 KO mice, respectively. These observations demonstrate that non-IgG1 isotypes can mediate MuSK-EAMG pathogenesis. PMID:27235354

  8. Proteolytic components of serum IgG preparations

    PubMed Central

    Li, L; Kalaga, R; Paul, S

    2000-01-01

    Chemical catalysis, an effector mechanism utilized by fully assembled antibodies, can also be mediated by the isolated antibody subunits. Because trace amounts of free light chains (L chains) are present in IgG preparations, a detailed study was undertaken to identify the constituents responsible for the polyreactive proteolytic activity of IgG purified from human sera, determined as the extent of cleavage of the model peptide substrate Pro-Phe-Arg-methylcoumarinamide. Two proteolytic species with approximate mass of 50 kD and 150 kD were separated by repetitive gel filtration in a denaturing solvent (6 m guanidine hydrochloride). The activity of the renatured 50-kD fraction (in fluorescence units/μg protein) was more than 45-fold greater than of the 150-kD fraction. Both fractions lost the activity following immunoadsorption on immobilized anti-IgG antibody. Fab fragments prepared from the 150-kD IgG fraction retained the activity. Reducing and non-reducing SDS-electrophoresis suggested the 50-kD fraction isolated from the IgG preparations to be a mixture of heavy chain (H chain) monomers and disulphide bonded L chain dimers. Electrophoretically homogeneous monomers of 50-kD H chains and 25-kD L chains were prepared by gel filtration of reduced and alkylated IgG from seven human subjects. Each of the alkylated L chain preparations displayed the proteolytic activity. The activity in alkylated H chains was undetectable or only marginally greater than the background values. L chain dimers appear to be the major species responsible for the polyreactive proteolytic activity of serum IgG preparations, with a smaller contribution furnished by tetrameric IgG. PMID:10792374

  9. IgG Suppresses Antibody Responses in Mice Lacking C1q, C3, Complement Receptors 1 and 2, or IgG Fc-Receptors

    PubMed Central

    Bergström, Joakim J. E.; Heyman, Birgitta

    2015-01-01

    Antigen-specific IgG antibodies, passively administered to mice or humans together with large particulate antigens like erythrocytes, can completely suppress the antibody response against the antigen. This is used clinically in Rhesus prophylaxis, where administration of IgG anti-RhD prevents RhD-negative women from becoming immunized against RhD-positive fetal erythrocytes aquired transplacentally. The mechanisms by which IgG suppresses antibody responses are poorly understood. We have here addressed whether complement or Fc-receptors for IgG (FcγRs) are required for IgG-mediated suppression. IgG, specific for sheep red blood cells (SRBC), was administered to mice together with SRBC and the antibody responses analyzed. IgG was able to suppress early IgM- as well as longterm IgG-responses in wildtype mice equally well as in mice lacking FcγRIIB (FcγRIIB knockout mice) or FcγRI, III, and IV (FcRγ knockout mice). Moreover, IgG was able to suppress early IgM responses equally well in mice lacking C1q (C1qA knockout mice), C3 (C3 knockout mice), or complement receptors 1 and 2 (Cr2 knockout mice) as in wildtype mice. Owing to the previously described severely impaired IgG responses in the complement deficient mice, it was difficult to assess whether passively administered IgG further decreased their IgG response. In conclusion, Fc-receptor binding or complement-activation by IgG does not seem to be required for its ability to suppress antibody responses to xenogeneic erythrocytes. PMID:26619292

  10. Structure and antigenicity analysis of the IgG gene for Nyctereutes procyonoides

    PubMed Central

    Zhao, Cui; Guo, Shuyuan; Pang, Xiaoru; Song, Daozhen; Fu, Shijun

    2015-01-01

    Objective Nyctereutes procyonoides immunoglobulin G (IgG) gene is partially cloned. Material and methods In order to obtain a certain length (966bp) of Nyctereutes procyonoides immunoglobulin G (IgG), two pairs of primers are designed according to the conserved nucleotide sequence of canine (GenBank:AF354265, AF354265, AF354266, AF354267) and mink (GenBank: L07789). Using Bioinformatics technology and Western-blot to analyze antigenicity of Nyctereutes procyonoides IgG-B gene. Results The homology for nucleotide sequence of IgG between Nyctereutes procyonoides and canine (IgG A, IgG B, IgG C, IgG D), mink, Homo sapiens, Oryctolagus cuniculus, Mus musculus, Anas platyrhynchos and gallus were respectively (88.1%, 93.6%, 85.4%, 87.2%), 83.7%, 74.8%, 71.8%, 69.2%, 51.6%, 48.4%. It can be seen that there was high homology of aminoacid sequence between IgG of Nyctereutes procyonoides and IgG (A, B, C, D) of canine. And the serum antibody of Nyctereutes procyonoides had obviously cross-reaction with HRP conjugated rabbit anti-dog IgG, compared with those of canine, oryctolagus cuniculus, mus musculus, mink, gallus. Conclusions We successfully got Nyctereutes procyonoides immuneglobulin G (IgG) gene (Gen- Bank: KM010191). There is the closest ties of consanguinity of IgG exist between Nyctereutes procyonoides and canine among the mammal through the genetic evolution. The detection and treament of canine distemper can be used on Nyctereutes procyonoides. PMID:26648768

  11. Mosquitocidal properties of IgG targeting the glutamate-gated chloride channel in three mosquito disease vectors (Diptera: Culicidae)

    PubMed Central

    Meyers, Jacob I.; Gray, Meg; Foy, Brian D.

    2015-01-01

    ABSTRACT The glutamate-gated chloride channel (GluCl) is a highly sensitive insecticide target of the avermectin class of insecticides. As an alternative to using chemical insecticides to kill mosquitoes, we tested the effects of purified immunoglobulin G (IgG) targeting the extracellular domain of GluCl from Anopheles gambiae (AgGluCl) on the survivorship of three key mosquito disease vectors: Anopheles gambiae s.s., Aedes aegypti and Culex tarsalis. When administered through a single blood meal, anti-AgGluCl IgG reduced the survivorship of A. gambiae in a dose-dependent manner (LC50: 2.82 mg ml−1, range 2.68–2.96 mg ml−1) but not A. aegypti or C. tarsalis. We previously demonstrated that AgGluCl is only located in tissues of the head and thorax of A. gambiae. To verify that AgGluCl IgG is affecting target antigens found outside the midgut, we injected it directly into the hemocoel via intrathoracic injection. A single, physiologically relevant concentration of anti-AgGluCl IgG injected into the hemocoel equally reduced mosquito survivorship of all three species. To test whether anti-AgGluCl IgG was entering the hemocoel of each of these mosquitoes, we fed mosquitoes a blood meal containing anti-AgGluCl IgG and subsequently extracted their hemolymph. We only detected IgG in the hemolymph of A. gambiae, suggesting that resistance of A. aegypti and C. tarsalis to anti-AgGluCl IgG found in blood meals is due to deficient IgG translocation across the midgut. We predicted that anti-AgGluCl IgG's mode of action is by antagonizing GluCl activity. To test this hypothesis, we fed A. gambiae blood meals containing anti-AgGluCl IgG and the GluCl agonist ivermectin (IVM). Anti-AgGluCl IgG attenuated the mosquitocidal effects of IVM, suggesting that anti-AgGluCl IgG antagonizes IVM-induced activation of GluCl. Lastly, we stained adult, female A. aegypti and C. tarsalis for GluCl expression. Neuronal GluCl expression in these mosquitoes was similar to previously

  12. Contactin 1 IgG4 associates to chronic inflammatory demyelinating polyneuropathy with sensory ataxia

    PubMed Central

    Miura, Yumako; Devaux, Jérôme J.; Fukami, Yuki; Manso, Constance; Belghazi, Maya; Wong, Anna Hiu Yi

    2015-01-01

    A Spanish group recently reported that four patients with chronic inflammatory demyelinating polyneuropathy carrying IgG4 autoantibodies against contactin 1 showed aggressive symptom onset and poor response to intravenous immunoglobulin. We aimed to describe the clinical and serological features of Japanese chronic inflammatory demyelinating polyneuropathy patients displaying the anti-contactin 1 antibodies. Thirteen of 533 (2.4%) patients with chronic inflammatory demyelinating polyneuropathy had anti-contactin 1 IgG4 whereas neither patients from disease or normal control subjects did (P = 0.02). Three of 13 (23%) patients showed subacute symptom onset, but all of the patients presented with sensory ataxia. Six of 10 (60%) anti-contactin 1 antibody-positive patients had poor response to intravenous immunoglobulin, whereas 8 of 11 (73%) antibody-positive patients had good response to corticosteroids. Anti-contactin 1 IgG4 antibodies are a possible biomarker to guide treatment option. PMID:25808373

  13. A simultaneous two-colour detection method of human IgG- and IgE-reactive proteins from lactic acid bacteria.

    PubMed

    Markiewicz, Lidia Hanna; Szymkiewicz, Agata; Szyc, Anna; Wróblewska, Barbara

    2016-07-01

    Whole cell extracts of two Lactobacillus strains were tested with primary antibodies from two pooled sera from allergic patients. Fluorescently labelled anti-human IgG and anti-human IgE secondary antibodies applied in Western blotting, together with an appropriate image acquisition protocol facilitated imagining bacterial proteins that reacted with human IgG and IgE. PMID:27184086

  14. [Serum IgG antibodies to GD1a and GM1 gangliosides in elderly people].

    PubMed

    Kolyovska, V

    2016-01-01

    Nowadays, the percentage of elderly people in society grows. Good nutrition and medical care help older people to have a normal life over 80 to 90 years. In the last ten years it is of critical importance to establish the clinical significance of serum IgG anti-GD1a and anti-GM1 ganglioside antibodies as potential biomarkers for neuronal damage in neurodegenerative diseases and immune-mediated neuropathies and demyelination. In the current study, the diagnostic values of IgG anti-GD1a and anti-GM1 antibodies were determined by the ELISA method in serum samples of 18 elderly patients (71-91 years). Significantly elevated serum IgG anti-GD1a and anti-GM1 antibodies titers were detected only in patients over 80 years. These data suggest that the immune-mediated neuropathies, neurodegeneration and demyelination in healthy elderly occur after 80 years old. Therefore, IgG anti-GD1a and anti-GM1 antibodies can serve as biomarkers, showing the nervous system dysfunction. PMID:26973195

  15. Increased in vivo effector function of human IgG4 isotype antibodies through afucosylation.

    PubMed

    Gong, Qian; Hazen, Meredith; Marshall, Brett; Crowell, Susan R; Ou, Qinglin; Wong, Athena W; Phung, Wilson; Vernes, Jean-Michel; Meng, Y Gloria; Tejada, Max; Andersen, Dana; Kelley, Robert F

    2016-01-01

    For some antibodies intended for use as human therapeutics, reduced effector function is desired to avoid toxicities that might be associated with depletion of target cells. Since effector function(s), including antibody-dependent cell-mediated cytotoxicity (ADCC), require the Fc portion to be glycosylated, reduced ADCC activity antibodies can be obtained through aglycosylation of the human IgG1 isotype. An alternative is to switch to an IgG4 isotype in which the glycosylated antibody is known to have reduced effector function relative to glycosylated IgG1 antibody. ADCC activity of glycosylated IgG1 antibodies is sensitive to the fucosylation status of the Fc glycan, with both in vitro and in vivo ADCC activity increased upon fucose removal ("afucosylation"). The effect of afucosylation on activity of IgG4 antibodies is less well characterized, but it has been shown to increase the in vitro ADCC activity of an anti-CD20 antibody. Here, we show that both in vitro and in vivo activity of anti-CD20 IgG4 isotype antibodies is increased via afucosylation. Using blends of material made in Chinese hamster ovary (CHO) and Fut8KO-CHO cells, we show that ADCC activity of an IgG4 version of an anti-human CD20 antibody is directly proportional to the fucose content. In mice transgenic for human FcγRIIIa, afucosylation of an IgG4 anti-mouse CD20 antibody increases the B cell depletion activity to a level approaching that of the mIgG2a antibody. PMID:27216702

  16. Human IgG1 antibodies suppress angiogenesis in a target-independent manner

    PubMed Central

    Bogdanovich, Sasha; Kim, Younghee; Mizutani, Takeshi; Yasuma, Reo; Tudisco, Laura; Cicatiello, Valeria; Bastos-Carvalho, Ana; Kerur, Nagaraj; Hirano, Yoshio; Baffi, Judit Z; Tarallo, Valeria; Li, Shengjian; Yasuma, Tetsuhiro; Arpitha, Parthasarathy; Fowler, Benjamin J; Wright, Charles B; Apicella, Ivana; Greco, Adelaide; Brunetti, Arturo; Ruvo, Menotti; Sandomenico, Annamaria; Nozaki, Miho; Ijima, Ryo; Kaneko, Hiroki; Ogura, Yuichiro; Terasaki, Hiroko; Ambati, Balamurali K; Leusen, Jeanette HW; Langdon, Wallace Y; Clark, Michael R; Armour, Kathryn L; Bruhns, Pierre; Verbeek, J Sjef; Gelfand, Bradley D; De Falco, Sandro; Ambati, Jayakrishna

    2016-01-01

    Aberrant angiogenesis is implicated in diseases affecting nearly 10% of the world’s population. The most widely used anti-angiogenic drug is bevacizumab, a humanized IgG1 monoclonal antibody that targets human VEGFA. Although bevacizumab does not recognize mouse Vegfa, it inhibits angiogenesis in mice. Here we show bevacizumab suppressed angiogenesis in three mouse models not via Vegfa blockade but rather Fc-mediated signaling through FcγRI (CD64) and c-Cbl, impairing macrophage migration. Other approved humanized or human IgG1 antibodies without mouse targets (adalimumab, alemtuzumab, ofatumumab, omalizumab, palivizumab and tocilizumab), mouse IgG2a, and overexpression of human IgG1-Fc or mouse IgG2a-Fc, also inhibited angiogenesis in wild-type and FcγR humanized mice. This anti-angiogenic effect was abolished by Fcgr1 ablation or knockdown, Fc cleavage, IgG-Fc inhibition, disruption of Fc-FcγR interaction, or elimination of FcRγ-initated signaling. Furthermore, bevacizumab’s Fc region potentiated its anti-angiogenic activity in humanized VEGFA mice. Finally, mice deficient in FcγRI exhibited increased developmental and pathological angiogenesis. These findings reveal an unexpected anti-angiogenic function for FcγRI and a potentially concerning off-target effect of hIgG1 therapies. PMID:26918197

  17. IgG4-related skin disease.

    PubMed

    Tokura, Y; Yagi, H; Yanaguchi, H; Majima, Y; Kasuya, A; Ito, T; Maekawa, M; Hashizume, H

    2014-11-01

    IgG4-related disease (IgG4-RD) is a recently established clinical entity characterized by high levels of circulating IgG4, and tissue infiltration of IgG4(+) plasma cells. IgG4-RD exhibits a distinctive fibroinflammatory change involving multiple organs, such as the pancreas and salivary and lacrimal glands. The skin lesions of IgG4-RD have been poorly characterized and may stem not only from direct infiltration of plasma cells but also from IgG4-mediated inflammation. Based on the documented cases together with ours, we categorized the skin lesions into seven subtypes: (1) cutaneous plasmacytosis (multiple papulonodules or indurations on the trunk and proximal part of the limbs), (2) pseudolymphoma and angiolymphoid hyperplasia with eosinophilia (plaques and papulonodules mainly on the periauricular, cheek and mandible regions), (3) Mikulicz disease (palpebral swelling, sicca syndrome and exophthalmos), (4) psoriasis-like eruption (strikingly mimicking psoriasis vulgaris), (5) unspecified maculopapular or erythematous eruptions, (6) hypergammaglobulinaemic purpura (bilateral asymmetrical palpable purpuric lesions on the lower extremities) and urticarial vasculitis (prolonged urticarial lesions occasionally with purpura) and (7) ischaemic digit (Raynaud phenomenon and digital gangrene). It is considered that subtypes 1-3 are induced by direct infiltration of IgG4(+) plasma cells, while the other types (4-7) are caused by secondary mechanisms. IgG4-related skin disease is defined as IgG4(+) plasma-cell-infiltrating skin lesions that form plaques, nodules or tumours (types 1-3), but may manifest secondary lesions caused by IgG4(+) plasma cells and/or IgG4 (types 4-7). PMID:25065694

  18. Intravenous IgG (IVIG) and subcutaneous IgG (SCIG) preparations have comparable inhibitory effect on T cell activation, which is not dependent on IgG sialylation, monocytes or B cells.

    PubMed

    Issekutz, Andrew C; Rowter, Derek; Miescher, Sylvia; Käsermann, Fabian

    2015-10-01

    IVIG modulates T cell activation in vitro and inflammatory-autoimmune conditions in vivo. Sialylation of IgG, Fc receptor interactions, modulation of monocyte/macrophage/B cell functions have been implicated in IVIG effects. Subcutaneous IgG (SCIG) therapy is increasingly used for IgG replacement but whether these preparations share the effects of IVIG on T cell modulation is not documented. We compared the potency of SCIG-Hizentra™ (20% IgG preparation) with IVIG-Privigen® (10% IgG) for T cell inhibition, and assessed the involvement of IgG sialylation, monocytes and B cells in this process. Human PBMCs or sorted cells were cultured 3-7 days, and T cells were stimulated with immobilized anti-CD3 mAb or Candida antigen. Thymidine incorporation into DNA was quantitated and cytokines assayed by ELISA/Luminex® assay. IVIG and SCIG both dose-dependently (1-20mg/ml) inhibited (up to >80%) T cell proliferation to anti-CD3 mAb. Response to Candida albicans was comparably inhibited by IVIG and SCIG by 50-80% at 10mg/ml with inhibition even at 3mg/ml (P<0.05). These effects were not affected by depletion of sialic acid containing IgG using neuraminidase treatment or lectin affinity chromatography. With anti-CD3 or Candida stimulation, IL-1β, IL-2, IL-5, IL-6, IL-13, GMCSF, TNF-α, interferon-γ (with anti-CD3) and IL-17 (with Candida) levels were suppressed by IVIG or SCIG, with no effect on IL-4, IL-10, IL-12, IL-15 or TGFβ. Monocytes or B cells were not required for IgG-induced suppression of proliferation, in fact depletion of monocytes potentiated the IgG-induced inhibition. Reconstitution with monocytes restored the original inhibitory effect. These data show that IVIG (Privigen®) and SCIG (Hizentra™) have comparable inhibitory effects on T cell activation, which do not require sialylation of IgG. Inhibition is independent of monocytes or B cells. There is a potent suppression of multiple effector cytokines. Like IVIG, SCIG therapy is expected to show

  19. Canakinumab (ACZ885, a fully human IgG1 anti-IL-1β mAb) induces sustained remission in pediatric patients with cryopyrin-associated periodic syndrome (CAPS)

    PubMed Central

    2011-01-01

    Introduction Cryopyrin-associated periodic syndrome (CAPS) represents a spectrum of three auto-inflammatory syndromes, familial cold auto-inflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal-onset multisystem inflammatory disease/chronic infantile neurological cutaneous and articular syndrome (NOMID/CINCA) with etiology linked to mutations in the NLRP3 gene resulting in elevated interleukin-1β (IL-1β) release. CAPS is a rare hereditary auto-inflammatory disease, which may start early in childhood and requires a life-long treatment. Canakinumab, a fully human anti-IL-1β antibody, produces sustained selective inhibition of IL-1β. This study was conducted to assess the efficacy, safety, and pharmacokinetics of canakinumab in the treatment of pediatric CAPS patients. Methods Seven pediatric patients (five children and two adolescents) with CAPS were enrolled in a phase II, open-label study of canakinumab in patients with CAPS. Canakinumab was administered at a dose of 2 mg/kg subcutaneously (s.c.) (for patients with body weight ≤ 40 kg) or 150 mg s.c. (for patients with body weight > 40 kg) with re-dosing upon each relapse. The primary efficacy variable was time to relapse following achievement of a complete response (defined as a global assessment of no or minimal disease activity and no or minimal rash and values for serum C-reactive protein (CRP) and/or serum amyloid A (SAA) within the normal range, < 10 mg/L). Results All patients achieved a complete response within seven days after the first dose of canakinumab and responses were reinduced on retreatment following relapse. Improvements in symptoms were evident within 24 hours after the first dose, according to physician assessments. The estimated median time to relapse was 49 days (95% CI 29 to 68) in children who received a dose of 2 mg/kg. Canakinumab was well tolerated. One serious adverse event, vertigo, was reported, but resolved during treatment. Conclusions Canakinumab, 2 mg/kg or

  20. Neutrophil functions and serum IgG in growing foals.

    PubMed

    Demmers, S; Johannisson, A; Gröndahl, G; Jensen-Waern, M

    2001-11-01

    The aim of this study was to investigate the phagocytic and killing capacities as well as expression of CD18 of neutrophils obtained from healthy foals from birth to age 8 months. Blood was taken from 6 Standardbred foals at 7 time-points between ages 2-56 days and thereafter once a month. For comparison, cells from 16 mature horses were evaluated. Neutrophil phagocytosis of yeast cells was assessed by flow cytometry after opsonisation with mature pooled serum, autologous serum or anti-yeast IgG. The killing capacity of the neutrophils, as indicated by the oxidative burst, was monitored by chemiluminescence. Serum IgG concentration was measured by radial immunodiffusion. In addition to clinical examination, the amount of serum amyloid A and the total leucocyte count were used as markers for infection. The phagocytic ability was impaired until age 3 weeks, when autologous serum was used as opsonin. Killing capacity was also low initially but, from 3 months onwards, chemiluminescence values were equal to or higher than in mature horses. Serum IgG decreased from 10 g/l at 2 days to 5 g/l at 2 months and then increased gradually to 10 g/l at the end of the study. These findings may in part explain the increased susceptibility to bacterial infections in young horses. PMID:11770989

  1. Granulocyte-associated IgG in neutropenic disorders

    SciTech Connect

    Cines, D.B.; Passero, F.; Guerry, D.; Bina, M.; Dusak, B.; Schreiber, A.D.

    1982-01-01

    We applied a radiolabeled antiglobulin test to a study of patients with a variety of neutropenic disorders. After defining the nature of the interaction of radiolabeled anti-IgG with the neutrophil, we studied 16 patients with neutropenia of uncertain etiology and adequate bone marrow granulocyte precursors. Twelve of these 16 patients had increased neutrophil-associated IgG (PMN-IgG). Patients with the highest levels of PMN-IgG had the lowest neutrophil counts. The majority of patients with neutropenia and increased PMN-IgG had an underlying immunologic disorder that included immune thrombocytopenic purpura in 5 patients and autoimmune hemolytic anemia in 1 patient. In some patients, elevated PMN-IgG preceded other evidence for immunologic disease. The direct antiglobulin test helped to distinguish neutropenic patients with increased PMN-IgG both from patients with neutropenia due to a known nonimmune disorder and from nonneutropenic patients with rheumatoid arthritis or systemic lupus erythematosis. Each of four patients with increased neutrophil-associated IgG treated with systemic corticosteroids responded clinically with an associated fall in neutrophil IgG and a rise in the circulating neutrophil count. The radiolabeled antiglobulin test appears useful in defining a subpopulation of patients with neutropenia due to an underlying immunologic disorder.

  2. Granulocyte-associated IgG in neutropenic disorders

    SciTech Connect

    Cines, D.B.; Passero, F.; Guerry, D. IV; Bina, M.; Dusak, B.; Schreiber, A.D

    1982-01-01

    We applied a radiolabeled antiglobulin test to a study of patients with a variety of neutropenic disorders. After defining the nature of the interaction of radiolabeled anti-IgG with the neutrophil, we studied 16 patients with neutropenia of uncertain etiology and adequate bone marrow granulocyte precursors. Twelve of these 16 patients had increased neutrophil-associated IgG (PMN-IgG). Patients with the highest levels of PMN-IgG had the lowest neutrophil counts. The majority of patients with neutropenia and increased PMN-IgG had an underlying immunologic disorder that included immune thrombocytopenic purpura in 5 patients and autoimmune hemolytic anemia in 1 patient. In some patients, elevated PMN-IgG preceded other evidence for immunologic disease. The direct antiglobulin test helped to distinguish neutropenic patients with increased PMN-IgG both from patients with neutropenia due to a known nonimmune disorder and from noneutropenic patients with rheumatoid arthritis or systemic lupus erythematosis. Each of four patients with increased neutrophil-associated IgG treated with systemic corticosteroids responded clinically with an associated fall in neutrophil IgG and a rise in the circulating neutrophil count. The radiolabeled antiglobulin test appears useful in defining a subpopulation of patients with neutropenia due to an underlying immunologic disorder.

  3. IgG4-related spinal pachymeningitis.

    PubMed

    Lu, Zhang; Tongxi, Liu; Jie, Luo; Yujuan, Jiao; Wei, Jiang; Xia, Liu; Yumin, Zheng; Xin, Lu

    2016-06-01

    The aim of this study is to study the clinical, laboratory, imaging pathology, and prognosis features of IgG4-related spinal pachymeningitis. We worked with a 55-year-old man suffering from IgG4-related spinal pachymeningitis who had the most widespread lesion in his dura mater. We also review previous related studies and discuss the clinical characteristics of this rare disease. In total, eight IgG4-related spinal pachymeningitis patients have been reported in the literature since 2009. They were mostly male patients, 51.7 ± 11.9 years old on average. Cervical and thoracic vertebrae were the most common sites for lesions. The most prominent symptom was varying numbness and weakness of the limbs and/or body associated with spinal cord compression. There was one patient (1/5) with elevated serum IgG4 levels and three patients (3/3) with increased cerebrospinal fluid (CSF) IgG4 index. Positive histopathologic findings are the strongest basis for a diagnosis. All the patients with IgG4-related spinal pachymeningitis responded well to glucocorticoid therapy. IgG4-related spinal pachymeningitis is an orphan disease that mainly occurs in cervical and thoracic vertebrae. Older males are the most susceptible group. Serum IgG4 levels were consistently normal in these cases, so analysis of CSF for IgG4 production (IgG4 index) could become a useful tool. Pathological findings remain the gold standard for diagnosis. Most patients responded favorably to glucocorticoid treatment. PMID:26567899

  4. Extracorporeal immunoadsorption of myeloma IgG and autoimmune antibodies: a clinically feasible modality of treatment.

    PubMed Central

    Ray, P K; Besa, E; Idiculla, A; Rhoads, J E; Bassett, J G; Cooper, D R

    1980-01-01

    Using heat-killed, formalin-stabilized Staphylococcus aureus Cowan I suspension, it was possible to remove myeloma IgG and autoimmune anti-red blood cell antibodies from two patients' plasma following an extracorporeal procedure. The arterial anticoagulated blood was processed through a cell separator machine. The separated plasma was pumped through a bacterial filter containing S. aureus suspension. The adsorbed plasma was then reunited with the blood cells and returned to the patient through the vein. S. aureus Cowan I could selectively remove the myeloma IgG and autoimmune anti-red cell antibodies from the patients' plasma prolonging the lives of these two terminal patients. The immunoadsorption procedure appears to be a safe, practical and quick method for the removal of pathological IgG from the patients' plasma. PMID:7008987

  5. Development and Application of an ELISA for the Detection of Porcine Deltacoronavirus IgG Antibodies

    PubMed Central

    Thachil, Anil; Gerber, Priscilla F.; Xiao, Chao-Ting; Huang, Yao-Wei; Opriessnig, Tanja

    2015-01-01

    Porcine deltacoronavirus (PDCoV), also known as porcine coronavirus HKU15, was first detected in North America in early 2014 and associated with enteric disease in pigs, resulting in an urgent need to further investigate the ecology of this virus. While assays detecting nucleic acids were implemented quickly, assays to detect anti-PDCoV antibodies have not been available. In this study, an indirect anti-PDCoV IgG enzyme-linked immunosorbent assay (ELISA) based on the putative S1 portion of the spike protein was developed and utilized to determine the prevalence of anti-PDCoV IgG in U.S. pigs. The diagnostic sensitivity of the PDCoV ELISA was 91% with a diagnostic specificity of 95%. A total of 968 serum samples were tested including samples with confirmed infection with PDCoV, porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus or porcine respiratory coronavirus. There was no cross-reactivity with any of the other coronaviruses. Among 355 arbitrarily selected serum samples collected in 2014 and originating from 51 farms across 18 U.S. states, anti-PDCoV IgG antibodies were detected in 8.7% of the samples and in 25.5% of the farms whereas anti-PEDV IgG was detected in 22.8% of the samples and in 54.9% of the farms. In addition, anti-PDCoV IgG antibodies were detected in archived samples collected in 2010, perhaps indicating an earlier undetected introduction into the U.S. pig population. Overall, the obtained data suggest that PDCoV seroprevalence in U.S. pigs is lower compared to PEDV and PDCoV may have been introduced to the U.S. prior to PEDV. PMID:25881086

  6. Wuchereria bancrofti filariasis in French Polynesia: age-specific patterns of microfilaremia, circulating antigen, and specific IgG and IgG4 responses according to transmission level.

    PubMed

    Chanteau, S; Glaziou, P; Plichart, C; Luquiaud, P; Moulia-Pelat, J P; N'Guyen, L; Cartel, J L

    1995-01-01

    The age-specific patterns of microfilaremia, Og4C3 antigenemia, anti-Brugia malayi IgG and IgG4 were assessed in 3 villages of low, medium and high transmission level for Wuchereria bancrofti filariasis. The prevalence rates for each of the 4 markers were clearly age dependent and their patterns strongly associated with the transmission level. The antigenemia prevalence rate was consistently higher than the microfilaremia prevalence rate, in all age groups. The prevalences of anti-B. malayi IgG and IgG4 responses were very similar and much higher than those of microfilaremia or antigenemia. Antibody responses reached the plateau at an earlier age and at a higher prevalence with increased intensity of transmission. For all the markers, the prevalence rates were significantly higher in males than in females. PMID:7797377

  7. Enhanced sialylation of a human chimeric IgG1 variant produced in human and rodent cell lines.

    PubMed

    Mimura, Yusuke; Kelly, Ronan M; Unwin, Louise; Albrecht, Simone; Jefferis, Roy; Goodall, Margaret; Mizukami, Yoichi; Mimura-Kimura, Yuka; Matsumoto, Tsuneo; Ueoka, Hiroshi; Rudd, Pauline M

    2016-01-01

    Glycosylation of the IgG-Fc is essential for optimal binding and activation of Fcγ receptors and the C1q component of complement. However, it has been reported that the effector functions are down-regulated when the Fc glycans terminate in sialic acid residues and that sialylated IgG mediates anti-inflammatory effects of intravenous immunoglobulin (IVIG). Although recombinant IgG is hypo-sialylated, Fc sialylation is shown to be markedly increased when a mouse/human chimeric IgG3 Phe243Ala (F243A) variant is expressed in Chinese hamster ovary (CHO)-K1 cells. Here we investigate whether sialylation is increased in IgG1 F243A when expressed in CHO-K1, mouse myeloma J558L and human embryonic kidney (HEK) 293. Although the sialylation level was 2-5% for IgG1 wild type (WT), it was increased to 31%, 10% and 33% for the variant from CHO-K1, J558L and HEK293 cells, respectively. Interestingly, an increased addition of bisecting GlcNAc and α(1-3)-galactose residues to the Fc glycan was observed for HEK293-derived and J558L-derived IgG1 F243A, respectively. Fucosylation of HEK293-derived IgG1 F243A was maintained despite increased bisecting GlcNAc content. Although sialic acid and bisecting GlcNAc residues are reported to have an opposing effect on antibody-dependent cellular cytotoxicity (ADCC), IgG1 F243A showed 7 times lower ADCC activities than IgG1 WT, irrespective of bisecting GlcNAc residue. Thus, highly sialylated, human cell-derived IgG1 F243A with lowered ADCC activity may be of interest for the development of therapeutic antibodies with anti-inflammatory properties as an alternative to IVIG. PMID:26627984

  8. IgM and IgG antibodies to hepatitis C virus in patients with mixed cryoglobulinaemia.

    PubMed Central

    L'Abbate, A; Cutrupi, S; Rognetta, M; Fabiano, C; Craxi, A

    1993-01-01

    To assess the relationship between hepatitis C virus (HCV) infection and essential mixed cryoglobulinaemia (EMC), sera from 23 patients with EMC were tested for IgG and IgM antibodies to HCV antigens and for HCV RNA. Quantitative HCV antibody studies were performed on serum and purified cryoglobulin fractions. HCV antibodies of both IgG and IgM class were found in 22 (96%) patients. Ten of these were also HCV-RNA positives. Higher titres of anti-HCV IgM were present in the 11 patients with evidence of liver damage. Anti-HCV IgG antibodies were shown to be concentrated in the IgG fraction of cryoglobulins in all eight patients studied. These results strongly suggest a role for HCV in the pathogenesis of EMC. PMID:7693384

  9. IgG Conformer's Binding to Amyloidogenic Aggregates

    PubMed Central

    Phay, Monichan; Welzel, Alfred T.; Williams, Angela D.; McWilliams-Koeppen, Helen P.; Blinder, Veronika; O'Malley, Tiernan T.; Solomon, Alan; Walsh, Dominic M.; O'Nuallain, Brian

    2015-01-01

    Amyloid-reactive IgGs isolated from pooled blood of normal individuals (pAbs) have demonstrated clinical utility for amyloid diseases by in vivo targeting and clearing amyloidogenic proteins and peptides. We now report the following three novel findings on pAb conformer's binding to amyloidogenic aggregates: 1) pAb aggregates have greater activity than monomers (HMW species > dimers > monomers), 2) pAbs interactions with amyloidogenic aggregates at least partially involves unconventional (non-CDR) interactions of F(ab) regions, and 3) pAb's activity can be easily modulated by trace aggregates generated during sample processing. Specifically, we show that HMW aggregates and dimeric pAbs present in commercial preparations of pAbs, intravenous immunoglobulin (IVIg), had up to ~200- and ~7-fold stronger binding to aggregates of Aβ and transthyretin (TTR) than the monomeric antibody. Notably, HMW aggregates were primarily responsible for the enhanced anti-amyloid activities of Aβ- and Cibacron blue-isolated IVIg IgGs. Human pAb conformer's binding to amyloidogenic aggregates was retained in normal human sera, and mimicked by murine pAbs isolated from normal pooled plasmas. An unconventional (non-CDR) component to pAb's activity was indicated from control human mAbs, generated against non-amyloid targets, binding to aggregated Aβ and TTR. Similar to pAbs, HMW and dimeric mAb conformers bound stronger than their monomeric forms to amyloidogenic aggregates. However, mAbs had lower maximum binding signals, indicating that pAbs were required to saturate a diverse collection of binding sites. Taken together, our findings strongly support further investigations on the physiological function and clinical utility of the inherent anti-amyloid activities of monomeric but not aggregated IgGs. PMID:26367058

  10. Serum IgG antibodies to C1q in hypocomplementemic urticarial vasculitis syndrome.

    PubMed

    Wisnieski, J J; Naff, G B

    1989-09-01

    Urticaria, angioedema, and arthritis are cardinal features of hypocomplementemic urticarial vasculitis syndrome (HUVS). Considered to be an immune complex-mediated disorder, HUVS has been differentiated from systemic lupus erythematosus (SLE), based on its clinical manifestations and the C1q precipitin (C1q-p) reaction, which is manifested as gel precipitation of C1q by a small percentage of HUVS IgG molecules. This phenomenon has been attributed to an Fc region abnormality, and the responsible IgG molecules are said to possess C1q-p activity. We purified IgG from 4 HUVS patients and confirmed that HUVS IgG contains C1q binding activity. F(ab')2 fragments from these patients also bound to C1q, as measured by 2 different C1q binding methods at physiologic ionic strength; HUVS IgG Fc fragments did not bind to C1q. Preincubation of HUVS F(ab')2 fragments with antibody to human F(ab')2 prevented subsequent binding to C1q. We conclude that IgG antibodies to C1q are present in HUVS serum, and it is likely that these antibodies are C1q-p. Because the clinical manifestations of HUVS and the presence of anti-C1q antibodies have been described in patients with SLE, our findings support the concept that HUVS is an autoimmune syndrome related to SLE. PMID:2528353

  11. Comparison of Four Commercially Available Avidity Tests for Toxoplasma gondii-Specific IgG Antibodies

    PubMed Central

    Breit, L.; Cimon, B.; Franck, J.; Fricker-Hidalgo, H.; Godineau, N.; Houze, S.; Paris, L.; Pelloux, H.; Villena, I.

    2013-01-01

    Toxoplasma infection in pregnant women may cause congenital toxoplasmosis. Diagnosis of infection is based on serological tests aimed at detecting IgM and IgG antibodies against Toxoplasma gondii. However, IgM antibodies are not an accurate marker for discriminating between acute and latent infection. Detection of residual or persistent IgM may occur months or even years after primary infection, while the IgG avidity test is a rapid means of identifying latent infections in pregnant women who exhibit both IgG and IgM anti-Toxoplasma antibodies on initial testing during pregnancy. In this study, we assessed and compared the performances of four commercially available Toxoplasma IgG avidity tests in immunocompetent and immunocompromised patients with acute and latent toxoplasmosis. The positive predictive value of high avidity to confirm latent toxoplasmosis was 100% for all the assays, indicating that high avidity is a hallmark of latent infection. However, the negative predictive value of high avidity ranged from 99.2% (bioMérieux) to 95.3% (Abbott), indicating that acute toxoplasmosis could not be reliably diagnosed based on low IgG avidity alone. Thus, the avidity test provides a rapid means for identifying latent Toxoplasma infection in immunocompetent pregnant women presenting both IgG and IgM anti-Toxoplasma antibodies on initial testing. In terms of cost-effectiveness, avidity testing is a powerful tool that optimizes screening and follow-up of pregnant women while minimizing the costs of screening by avoiding subsequent costly maternal and fetal investigation and unnecessary treatment. The cheapest assay, Vidas Toxo IgG Avidity, also had the best performance for the diagnosis of latent toxoplasmosis. PMID:23239801

  12. Comparison of four commercially available avidity tests for Toxoplasma gondii-specific IgG antibodies.

    PubMed

    Villard, O; Breit, L; Cimon, B; Franck, J; Fricker-Hidalgo, H; Godineau, N; Houze, S; Paris, L; Pelloux, H; Villena, I; Candolfi, E

    2013-02-01

    Toxoplasma infection in pregnant women may cause congenital toxoplasmosis. Diagnosis of infection is based on serological tests aimed at detecting IgM and IgG antibodies against Toxoplasma gondii. However, IgM antibodies are not an accurate marker for discriminating between acute and latent infection. Detection of residual or persistent IgM may occur months or even years after primary infection, while the IgG avidity test is a rapid means of identifying latent infections in pregnant women who exhibit both IgG and IgM anti-Toxoplasma antibodies on initial testing during pregnancy. In this study, we assessed and compared the performances of four commercially available Toxoplasma IgG avidity tests in immunocompetent and immunocompromised patients with acute and latent toxoplasmosis. The positive predictive value of high avidity to confirm latent toxoplasmosis was 100% for all the assays, indicating that high avidity is a hallmark of latent infection. However, the negative predictive value of high avidity ranged from 99.2% (bioMérieux) to 95.3% (Abbott), indicating that acute toxoplasmosis could not be reliably diagnosed based on low IgG avidity alone. Thus, the avidity test provides a rapid means for identifying latent Toxoplasma infection in immunocompetent pregnant women presenting both IgG and IgM anti-Toxoplasma antibodies on initial testing. In terms of cost-effectiveness, avidity testing is a powerful tool that optimizes screening and follow-up of pregnant women while minimizing the costs of screening by avoiding subsequent costly maternal and fetal investigation and unnecessary treatment. The cheapest assay, Vidas Toxo IgG Avidity, also had the best performance for the diagnosis of latent toxoplasmosis. PMID:23239801

  13. IgG4-Related Esophageal Disease Presenting as Esophagitis Dissecans Superficialis With Chronic Strictures.

    PubMed

    Dumas-Campagna, Myriam; Bouchard, Simon; Soucy, Genevieve; Bouin, Mickael

    2014-08-01

    IgG4-related disease is a recently recognized autoimmune systemic disorder that has been described in various organs. The disease is characterized histologically by a dense lymphoplasmocytic infiltrate of IgG4-positive cells, storiform fibrosis and can be associated with tumefactive lesions. IgG4-related disease involving the upper gastrointestinal tract is rare and only two previous case reports have reported IgG4-related esophageal disease. We report the case of a 63-year-old female patient with a long-standing history of severe dysphagia and odynophagia with an initial diagnosis of reflux esophagitis. Symptoms persisted despite anti-acid therapy and control esophagogastroduodenoscopy (EGD) revealed endoscopic images consistent with esophagitis dissecans superficialis (sloughing esophagitis). An underlying autoimmune process was suspected and immunosuppressant agents were tried to control her disease. The patient eventually developed disabling dysphagia secondary to multiple chronic esophageal strictures. A diagnosis of IgG4-related disease was eventually made after reviewing esophageal biopsies and performing an immunohistochemical study with an anti-IgG4 antibody. Treatment attempts with corticosteroids and rituximab was not associated with a significant improvement of the symptoms of dysphagia and odynophagia, possibly because of the chronic nature of the disease associated with a high fibrotic component. Our case report describes this unique case of IgG4-related esophageal disease presenting as chronic esophagitis dissecans with strictures. We also briefly review the main histopathological features and treatment options in IgG4-related disease. PMID:24883156

  14. Normal human IgG prevents endothelial cell activation induced by TNFα and oxidized low-density lipoprotein atherogenic stimuli

    PubMed Central

    RONDA, N; BERNINI, F; GIACOSA, R; GATTI, R; BALDINI, N; BUZIO, C; ORLANDINI, G

    2003-01-01

    Normal human immunoglobulin G (IgG) has anti-inflammatory and immuno-regulatory properties, which are exploited in the therapy of selected diseases. A putative mechanisms of action is the direct regulation of endothelial cell function by natural antiendothelial cell antibodies. Endothelium activation is a critical event in atherosclerosis. We have verified the ability of normal human IgG to modulate endothelial responses to the atherogenic stimuli tumour necrosis factor-α (TNFα) and oxidized low-density lipoproteins (oxLDL) in vitro. Confocal microscopy was used to visualize vascular cell adhesion molecule-1 (CD106) expression on endothelial cells, cytoplasmic free calcium ([Ca++]i) modifications and fluorescein-coupled oxLDL internalization. Cytokine secretion was measured by ELISA on cell supernatants. IgG prevented TNFα induced CD106 membrane expression and an increase in [Ca++]i, and inhibited the secretion of interleukin-6 (IL-6) and macrophage-colony-stimulating factor (M-CSF). IgG also inhibited CD106 expression induced by oxLDL and one pathway of their internalization, but were ineffective on oxLDL induced [Ca++]i rise and apoptosis. F(ab)′2 fragments from IgG, but not monoclonal IgG, reproduce IgG effects. These findings point to a regulatory role for specific antibodies included in circulating normal IgG towards proinflammatory responses of endothelial cells in atherogenesis and suggest possible development of new therapeutic strategies. PMID:12869027

  15. Antiradiation Antitoxin IgG : Immunological neutralization of Radiation Toxins at Acute Radiation Syndromes.

    NASA Astrophysics Data System (ADS)

    Popov, Dmitri; Maliev, Slava

    Introduction: High doses of radiation induce apoptotic necrosis of radio-sensitive cells. Mild doses of radiation induce apoptosis or controlled programmed death of radio-sensitive cells with-out development of inflammation and formation of Radiation Toxins. Cell apoptotic necrosis initiates Radiation Toxins (RT)formation. Radiation Toxins play an important role as a trig-ger mechanism for inflammation development and cell lysis. If an immunotherapy approach to treatment of the acute radiation syndromes (ARS) were to be developed, a consideration could be given to neutralization of radiation toxins (Specific Radiation Determinants-SRD) by specific antiradiation antibodies. Therapeutic neutralization effects of the blocking anti-radiation antibodies on the circulated RT had been studied. Radiation Toxins were isolated from the central lymph of irradiated animals with Cerebrovascular(Cv ARS),Cardiovascular (Cr ARS),Gastrointestinal(Gi ARS) and Haemopoietic (Hp ARS) forms of ARS. To accomplish this objective, irradiated animals were injected with a preparation of anti-radiation immunoglobulin G (IgG) obtained from hyperimmune donors. Radiation-induced toxins that we call Specific Radiation Determinants (SRD) possess toxic (neurotoxic, haemotoxic) characteristics as well as specific antigenic properties. Depending on direct physiochemical radiation damage, they can induce development of many of the pathological processes associated with ARS. We have tested several specific hyperimmune IgG preparations against these radiation toxins and ob-served that their toxic properties were neutralized by the specific antiradiation IgGs. Material and Methods: A scheme of experiments was following: 1.Isolation of radiation toxins (RT) from the central lymph of irradiated animals with different form of ARS. 2.Transformation of a toxic form of the RT to a toxoid form of the RT. 3.Immunization of radiation naive animals. Four groups of rabbits were inoculated with a toxoid form of SRD

  16. Pathologies Associated with Serum IgG4 Elevation

    PubMed Central

    Ebbo, Mikael; Grados, Aurélie; Bernit, Emmanuelle; Vély, Frederic; Boucraut, José; Harlé, Jean-Robert; Daniel, Laurent; Schleinitz, Nicolas

    2012-01-01

    Statement of Purpose. IgG4-related disease (IgG4-RD) is usually associated to an increase of serum IgG4 levels. However other conditions have also been associated to high serum IgG4 levels. Methods. All IgG subclasses analyses performed in our hospital over a one-year period were analyzed. When IgG4 level were over 1.35 g/L, the patient's clinical observation was analyzed and both final diagnosis and reason leading to IgG subclasses analysis were recorded. Only polyclonal increases of IgG4 were considered. Summary of the Results. On 646 IgG subclass analysis performed, 59 patients had serum IgG4 over 1.35 g/L. The final diagnosis associated to serum IgG4 increase was very variable. Most patients (25%) presented with repeated infections, 13.5% with autoimmune diseases, and 10% with IgG4-RD. Other patients presented with cancer, primary immune deficiencies, idiopathic interstitial lung disease, cystic fibrosis, histiocytosis, or systemic vasculitis and 13.5% presented with various pathologies or no diagnosis. Mean IgG4 levels and IgG4/IgG ratio were higher in IgG4-RD than in other pathologies associated to elevated IgG4 levels. Conclusions. Our study confirms that elevation of serum IgG4 is not specific to IgG4-RD. Before retaining IgG4-RD diagnosis in cases of serum IgG4 above 1.35 g/L, several other pathological conditions should be excluded. PMID:22966232

  17. MuSK Myasthenia Gravis IgG4 Disrupts the Interaction of LRP4 with MuSK but Both IgG4 and IgG1-3 Can Disperse Preformed Agrin-Independent AChR Clusters

    PubMed Central

    Koneczny, Inga; Cossins, Judith; Waters, Patrick; Beeson, David; Vincent, Angela

    2013-01-01

    A variable proportion of patients with generalized myasthenia gravis (MG) have autoantibodies to muscle specific tyrosine kinase (MuSK). During development agrin, released from the motor nerve, interacts with low density lipoprotein receptor-related protein-4 (LRP4), which then binds to MuSK; MuSK interaction with the intracellular protein Dok7 results in clustering of the acetylcholine receptors (AChRs) on the postsynaptic membrane. In mature muscle, MuSK helps maintain the high density of AChRs at the neuromuscular junction. MuSK antibodies are mainly IgG4 subclass, which does not activate complement and can be monovalent, thus it is not clear how the antibodies cause disruption of AChR numbers or function to cause MG. We hypothesised that MuSK antibodies either reduce surface MuSK expression and/or inhibit the interaction with LRP4. We prepared MuSK IgG, monovalent Fab fragments, IgG1-3 and IgG4 fractions from MuSK-MG plasmas. We asked whether the antibodies caused endocytosis of MuSK in MuSK-transfected cells or if they inhibited binding of LRP4 to MuSK in co-immunoprecipitation experiments. In parallel, we investigated their ability to reduce AChR clusters in C2C12 myotubes induced by a) agrin, reflecting neuromuscular development, and b) by Dok7- overexpression, producing AChR clusters that more closely resemble the adult neuromuscular synapse. Total IgG, IgG4 or IgG1-3 MuSK antibodies were not endocytosed unless cross-linked by divalent anti-human IgG. MuSK IgG, Fab fragments and IgG4 inhibited the binding of LRP4 to MuSK and reduced agrin-induced AChR clustering in C2C12 cells. By contrast, IgG1-3 antibodies did not inhibit LRP4-MuSK binding but, surprisingly, did inhibit agrin-induced clustering. Moreover, both IgG4 and IgG1-3 preparations dispersed agrin-independent AChR clusters in Dok7-overexpressing C2C12 cells. Thus interference by IgG4 antibodies of the LRP4-MuSK interaction will be one pathogenic mechanism of MuSK antibodies, but IgG1-3 Mu

  18. Association of IgG immunoglobulin and subclasses level with the severity of chromoblastomycosis due to Fonsecaea pedrosoi and therapeutic response to itraconazole.

    PubMed

    Azevedo, C D M P e Silva de; Bruña-Romero, O; Marques, S G; Nascimento, F R F do; Pinto, M C; Silva, L A; Bouillet, L E M; Azevedo, F S de; Stoianoff, M A de Resende

    2014-10-01

    Chromoblastomycosis (CBM) is a chronic, suppurative, granulomatous mycosis of the skin and subcutaneous tissues. The aim of this study was to evaluate the association between IgG antibody levels and the severity of CBM and therapeutic response of patients to itraconazole. A longitudinal study was conducted in patients with CBM due to Fonsecaea pedrosoi and in healthy subjects with chromomycin skin test (CST)+. The dosage of anti-F. pedrosoi IgG antibody performed in 47 healthy individuals with CST+ showed positivity in 97.5 %, with an average titer of 2,109 [standard deviation (SD) + 3,676)] and a mean optical density (OD) of 1.174 (SD + 0.456), showing positive correlation with the induration area of the CST (mm(2)). The level of antibodies in 55 patients with CBM expressed in OD and titration showed that, before treatment, patients with severe disease had higher levels of IgG, IgG1, IgG2, and IgG3 when compared with moderate or mild disease (p < 0.05). According to the time of treatment, the mean antibody titers of IgG, IgG1, and IgG2 were reduced after treatment (p < 0.05). In the assessment of therapeutic response, there was reduction of IgG3 and IgG titers in patients with rapid response (p < 0.05) and IgG2 on rapid and intermediate response (p < 0.05). There was clear evidence of what are the risk factors for exposure to F. pedrosoi in the daily lives of these subjects, with prospects of preventive measures for the target population. The immunological analysis shows that the antibody anti-F. pedrosoi did not exhibit a protective role against infection caused by this agent. PMID:24832023

  19. Human IgG detection in serum on polymer based Mach-Zehnder interferometric biosensors.

    PubMed

    Melnik, Eva; Bruck, Roman; Müellner, Paul; Schlederer, Thomas; Hainberger, Rainer; Lämmerhofer, Michael

    2016-03-01

    We report a new method for detecting human IgG (hIgG) in serum on integrated-optical Mach-Zehnder interferometer biosensors realized in a high index contrast polymer material system. In the linear range of the sensor (5-200 nM) we observed excellent signal recoveries (95-110%) in buffer and serum samples, which indicate the absence of matrix effects. Signal enhancement was reached by using secondary anti-human IgG antibodies, which bind to immobilized target IgGs and allow detecting concentrations down to 100 pM. This polymer based optical sensor is fully compatible with cost-efficient mass production technologies, which makes it an attractive alternative to inorganic optical sensors. Graphical abstract of the hIgG measured on polymer based photonic sensors using a direct binding assay and a signal enhancement strategy with secondary antibodies. PMID:26663736

  20. IgG4-Related Kidney Disease and IgG4-Related Retroperitoneal Fibrosis.

    PubMed

    Kawano, Mitsuhiro; Yamada, Kazunori

    2016-08-01

    Immunoglobulin G4-related kidney disease (IgG4-RKD) is the collective name encompassing renal parenchymal and renal pelvic lesions. The hallmark of renal parenchymal lesions of IgG4-related disease is plasma cell-rich tubulointerstitial nephritis with numerous IgG4-positive plasma cells and characteristic fibrosis. In addition, glomerular lesions are sometimes present, with membranous glomerulonephritis being the most common. Although IgG4-RKD shows good responsiveness to corticosteroid therapy, follow-up imaging studies have revealed that partial cortical scars persist when the start of therapy is delayed. In this review, the authors provide an overview of the latest knowledge of IgG4-RKD, focusing in particular on its pathological and imaging characteristic features. PMID:27466797

  1. High Serum IgG4 Concentrations in Patients with Hashimoto's Thyroiditis.

    PubMed

    Popławska-Kita, Anna; Kościuszko-Zdrodowska, Maria; Siewko, Katarzyna; Telejko, Beata; Hryniewicka, Justyna; Milewski, Robert; Abdelrazek, Saeid Soleman; Szelachowska, Małgorzata; Górska, Maria

    2015-01-01

    Purpose. Since recent reports suggest that Hashimoto thyroiditis (HT) may be associated with IgG4-related disease, we aimed to find out whether the measurement of serum IgG4 allows for the identification of distinct types of HT, with different clinical, sonographic, and serologic characteristics. Methods. The group studied consisted of 53 patients with HT and 28 healthy individuals who underwent thyroid ultrasonography and body composition analysis. Serum concentrations of IgG4, TSH, anti-peroxidase antibodies (TPOAb), anti-TSH receptor antibodies, TNF-α, TGF-β1, Fas Ligand, TRAIL, and chemokines (CXCL9, CXCL11, and CXCL10) were measured by ELISA or radioimmunoassay. Results. The group with IgG4 level >135 IU/ml accounted for 32.5% of the patients. The signs of fibrosis were present in 27.0% of the high-IgG4 patients and in 9.1% of the normal-IgG4 group. The patients with elevated IgG4 required higher doses of L-thyroxine and had significantly lower level of TPOAb (P=0.02) than the non-IgG4-HT individuals and higher TNF-α level in comparison with the controls (P=0.01). Conclusions. Our results suggest that the measurement of serum IgG4 allows for an identification of patients with more rapid progression of HT, requiring higher doses of L-thyroxine. Low TPOAb level and the absence of coexisting autoimmune diseases may suggest distinct pathomechanism of this type of thyroiditis. PMID:25784936

  2. Histopathology of IgG4-Related Autoimmune Hepatitis and IgG4-Related Hepatopathy in IgG4-Related Disease.

    PubMed

    Nakanuma, Yasuni; Ishizu, Yoji; Zen, Yoh; Harada, Kenichi; Umemura, Takeji

    2016-08-01

    Immunoglobulin G4-related disease (IgG4-RD) is a systemic disease involving many organs; it includes IgG4-related sclerosing cholangitis and inflammatory pseudotumor in the hepatobiliary system. Two types of hepatic parenchymal involvement have been reported in IgG4-RD: IgG4-related autoimmune hepatitis (AIH) and IgG4-hepatopathy. Moreover, only three cases of IgG4-related AIH have been reported. Immunoglobulin G4-related AIH is clinicopathologically similar to AIH, except for an elevated serum IgG4 level and heavy infiltration of IgG4-positive plasma cells in the liver tissue. Interestingly, IgG4-related AIH can be complicated by well-known IgG4-RD(s). Immunoglobulin G4-hepatopathy, which includes various histopathological lesions encountered in the liver of patients with type I autoimmune pancreatitis, is classified into five histological categories: portal inflammation, large bile duct damage, portal sclerosis, lobular hepatitis, and cholestasis. Immunoglobulin G4-hepatopathy is currently a collective term covering hepatic lesions primarily or secondarily related to IgG4-related sclerosing cholangitis and type 1 autoimmune pancreatitis. In conclusion, the liver is not immune to IgG4-RD, and at least two types of hepatic involvement in IgG4-RD have been reported: IgG4-related AIH and IgG4-hepatopathy. Additional studies are required to clarify their precise clinical significance with respect to IgG4-RD and inherent liver diseases. PMID:27466793

  3. IgG Subclass Staining in Routine Renal Biopsy Material.

    PubMed

    Hemminger, Jessica; Nadasdy, Gyongyi; Satoskar, Anjali; Brodsky, Sergey V; Nadasdy, Tibor

    2016-05-01

    Immunofluorescence staining plays a vital role in nephropathology, but the panel of antibodies used has not changed for decades. Further classification of immunoglobulin (Ig)G-containing immune-type deposits with IgG subclass staining (IgG1, IgG2, IgG3, and IgG4) has been shown to be of diagnostic utility in glomerular diseases, but their value in the evaluation of renal biopsies has not been addressed systematically in large renal biopsy material. Between January 2007 and June 2014, using direct immunofluorescence, we stained every renal biopsy for the IgG subclasses if there was moderate to prominent glomerular IgG staining and/or IgG-predominant or IgG-codominant glomerular staining. The total number of biopsies stained was 1084, which included 367 cases of membranous glomerulonephritis, 307 cases of lupus nephritis, 74 cases of fibrillary glomerulonephritis, 53 cases of proliferative glomerulonephritis with monoclonal IgG deposits, and 25 cases of antiglomerular basement membrane disease, among others. We found that monoclonality of IgG deposits cannot always be reliably determined on the basis of kappa and lambda light chain staining alone, particularly if concomitant (frequently nonspecific) IgM staining is present. In IgG heavy and heavy and light chain deposition disease (3 cases), subclass staining is very helpful, and in proliferative glomerulonephritis with monoclonal IgG deposits subclass staining is necessary. IgG subclass staining is useful in differentiating primary from secondary membranous glomerulonephritis. In proliferative glomerulonephritis with polyclonal IgG deposition, IgG1 dominance/codominance with concomitant IgG3 and IgG2 but weak or absent IgG4 staining favors an underlying autoimmune disease. IgG subclass staining is a very useful diagnostic method in a selected cohort of renal biopsies, particularly in biopsies with glomerulonephritis with monoclonal IgG deposits. PMID:26848798

  4. Evidence for T Cell Help in the IgG Response against Tandemly Repetitive Trypanosoma cruzi B13 Protein in Chronic Chagas Disease Patients

    PubMed Central

    Duranti, Marcia; Camargo, Ludmila; Victora, Gabriel; Ianni, Barbara; Buck, Paula; Mady, Charles; Kalil, Jorge; Zingales, Bianca; Cunha-Neto, Edecio

    2012-01-01

    The tandemly repetitive Trypanosoma cruzi B13 protein is an immunodominant antigen among Chagas disease patients. Such repetitive domains may behave as T-independent antigens. However, T cells can recognize B13 epitopes in an HLA class II-restricted fashion and could potentially provide cognate T cell help and boost antibody titers. We assessed whether the presence of HLA class II molecules able to present B13 epitopes to T cells could affect anti-B13 IgG levels in a cognate fashion, in both major clinical forms of chronic Chagas disease. We found no difference between anti-B13 IgG antibody levels between patients carrying HLA class II molecules associated to T cell responses or other alleles. The predominant anti-B13 IgG subclass was IgG1, with negligible IgG2, suggesting a T-dependent, noncognate help for antibody production. In addition, the finding of increased anti-B13 IgG levels in sera from CCC patients indicates that clinical presentation is associated with increased anti-B13 antibody levels. PMID:22523642

  5. Infectious Mononucleosis Triggers Generation of IgG Auto-Antibodies against Native Myelin Oligodendrocyte Glycoprotein

    PubMed Central

    Kakalacheva, Kristina; Regenass, Stephan; Wiesmayr, Silke; Azzi, Tarik; Berger, Christoph; Dale, Russell C.; Brilot, Fabienne; Münz, Christian; Rostasy, Kevin; Nadal, David; Lünemann, Jan D.

    2016-01-01

    A history of infectious mononucleosis (IM), symptomatic primary infection with the Epstein Barr virus, is associated with the development of autoimmune diseases and increases the risk to develop multiple sclerosis. Here, we hypothesized that immune activation during IM triggers autoreactive immune responses. Antibody responses towards cellular antigens using a HEp-2 based indirect immunofluorescence assay and native myelin oligodendrocyte glycoprotein (MOG) using a flow cytometry-based assay were determined in 35 patients with IM and in 23 control subjects. We detected frequent immunoglobulin M (IgM) reactivity to vimentin, a major constituent of the intermediate filament family of proteins, in IM patients (27/35; 77%) but rarely in control subjects (2/23; 9%). IgG autoantibodies binding to HEp-2 cells were absent in both groups. In contrast, IgG responses to native MOG, present in up to 40% of children with inflammatory demyelinating diseases of the central nervous system (CNS), were detectable in 7/35 (20%) patients with IM but not in control subjects. Normalization of anti-vimentin IgM levels to increased total IgM concentrations during IM resulted in loss of significant differences for anti-vimentin IgM titers. Anti-MOG specific IgG responses were still detectable in a subset of three out of 35 patients with IM (9%), even after normalization to increased total IgG levels. Vimentin-specific IgM and MOG-specific IgG responses decreased following clinical resolution of acute IM symptoms. We conclude from our data that MOG-specific memory B cells are activated in subset of patients with IM. PMID:26907324

  6. Elevated IgG levels against specific bacterial antigens in obese patients with diabetes and in mice with diet-induced obesity and glucose intolerance.

    PubMed

    Mohammed, Nadeem; Tang, Lihua; Jahangiri, Anisa; de Villiers, Willem; Eckhardt, Erik

    2012-09-01

    High fat diets increase the risk for insulin resistance by promoting inflammation. The cause of inflammation is unclear, but germfree mouse studies have implicated commensal gut bacteria. We tested whether diet-induced obesity, diabetes, and inflammation are associated with anti-bacterial IgG. Blood from lean and obese healthy volunteers or obese patients with diabetes were analyzed by ELISA for IgG against extracts of potentially pathogenic and pro-biotic strains of Escherichia coli (LF-82 and Nissle), Bacteroides thetaiotaomicron, and Lactobacillus acidophilus, and for circulating tumor necrosis factor α (TNFα). C57Bl/6 mice were fed low- or high-fat diets (10% or 60% kcal from fat) for 10 weeks and tested for anti-bacterial IgG, bodyweight, fasting glucose, and inflammation. Obese diabetic patients had significantly more IgG against extracts of E. coli LF-82 compared with lean controls, whereas IgG against extracts of the other bacteria was unchanged. Circulating TNFα was elevated and correlated with IgG against the LF-82 extract. Mice fed high-fat diets had increased fasting glucose levels, elevated TNFα and neutrophils, and significantly more IgG against the LF-82 extracts. Diabetes in obesity is characterized by increased IgG against specific bacterial antigens. Specific commensal bacteria may mediate inflammatory effects of high-fat diets. PMID:22424821

  7. Affinity and catalytic heterogeneity of polyclonal myelin basic protein-hydrolyzing IgGs from sera of patients with multiple sclerosis

    PubMed Central

    Legostaeva, Galina A; Polosukhina, Dar’ya I; Bezuglova, Anna M; Doronin, Boris M; Buneva, Valentina N; Nevinsky, Georgy A

    2010-01-01

    Abstract Human myelin basic protein (hMBP)-hydrolyzing activity was recently shown to be an intrinsic property of antibodies (Abs) from multiple sclerosis (MS) patients. Here, we present the first evidence demonstrating a significant diversity of different fractions of polyclonal IgGs (pIgGs) from MS patients in their affinity for hMBP and in the ability of pIgGs to hydrolyze hBMP at different optimal pHs (3–10.5). IgGs containing λ- and κ-types of light chains demonstrated comparable relative activities in the hydrolysis of hMBP. IgGs of IgG1–IgG4 sub-classes were analyzed for catalytic activity. IgGs of all four sub-classes were catalytically active, with their contribution to the total activity of Abzs in the hydrolysis of hMBP and its 19-mer oligopeptide increasing in the order: IgG1 (1.5–2.1%) < IgG2 (4.9–12.8%) < IgG3 (14.7–25.0%) < IgG4 (71–78%). Our findings suggest that the immune systems of individual MS patients generate a variety of anti-hMBP abzymes with different catalytic properties, which can attack hMBP of myelin-proteolipid shell of axons, playing an important role in MS pathogenesis. PMID:19438809

  8. Assessment of naturally occurring covalent and total dimer levels in human IgG1 and IgG2.

    PubMed

    Yang, Jane; Goetze, Andrew M; Flynn, Gregory C

    2014-03-01

    Antibody dimers, two self-associated monomers, have been detected on both recombinantly expressed and endogenous human IgG proteins. Nearly 10 years ago, Yoo et al. (2003) described low levels of IgG2 covalent dimer, in human serum, but did not quantify the levels. Here we quantify the total and covalent dimer levels of IgG2 and IgG1 in human blood, and study the origin of covalent dimer formation. Low levels (<1%) of total IgG1 and IgG2 dimers were measured in freshly prepared human plasma. Both IgG1 and IgG2 covalent dimers were also found in plasma. Whereas IgG1 covalent dimer levels were significantly reduced by steps intended to eliminate artifacts during sample preparation, IgG2 covalent dimer levels remain stable in such conditions. About 0.4% of IgG2 in plasma was in a covalent dimer form, yet very little (<0.03%) of IgG1 covalent dimer could be considered naturally occurring. IgG2 dimer also formed in vitro under conditions designed to mimic those in blood, suggesting that formation occurs in vivo during circulation. Thus, small amounts of covalent IgG2 dimer do appear to form naturally. PMID:24321397

  9. Glyco-engineering of human IgG1-Fc through combined yeast expression and in vitro chemoenzymatic glycosylation

    PubMed Central

    Wei, Yadong; Li, Cishan; Huang, Wei; Li, Bing; Strome, Scott; Wang, Lai-Xi

    2009-01-01

    The presence and precise structures of the glycans attached at the Fc domain of monoclonal antibodies play an important role in determining antibody's effector functions such as antibody-dependent cell cytotoxicity (ADCC), complement activation, and anti-inflammatory activity. This paper describes a novel approach for glyco-engineering of human IgG1-Fc that combines high-yield expression of human IgG1-Fc in yeast and subsequent in vitro enzymatic glycosylation, using the endoglycosidase-catalyzed transglycosylation as the key reaction. Human IgG1-Fc was first overproduced in Pichia pastoris. Then the heterogeneous yeast glycans were removed by Endo-H treatment to give the GlcNAc-containing IgG1-Fc as a homodimer. Finally, selected homogeneous glycans were attached to the GlcNAc-primer in the IgG1-Fc through an endoglycosidase-catalyzed transglycosylation, using sugar oxazolines as the donor substrates. It was found that the enzymatic transglycosylation was efficient with native GlcNAc-containing IgG1-Fc homodimer without the need to denature the protein, and the reaction could proceed to completion to give homogeneous glycoforms of IgG1-Fc when excess of oligosaccharide oxazolines was used as the donor substrates. The binding of the synthetic IgG1-Fc glycoforms to the FcγIIIa receptor was also investigated. This novel glyco-engineering approach should be useful for providing various homogeneous, natural or synthetic glycoforms of IgG1-Fc for structure-function relationship studies, and for future clinical applications. PMID:18771295

  10. High concentrations of therapeutic IgG1 antibodies are needed to compensate for inhibition of antibody-dependent cellular cytotoxicity by excess endogenous immunoglobulin G.

    PubMed

    Preithner, Susanne; Elm, Stefanie; Lippold, Sandra; Locher, Mathias; Wolf, Andreas; da Silva, Antonio J; Baeuerle, Patrick A; Prang, Nadja S

    2006-03-01

    A common feature of human IgG1 antibodies used for cancer treatment is that their anti-tumour efficacy requires high serum trough levels and continued therapy for several months. Treatment cycles, thereby, consume several grams of IgG1 translating into significant drug needs and costs. The basis for the low in vivo efficacy, which is in contrast to high in vitro antibody-dependent cellular cytotoxicity (ADCC), is not well understood. Here, we have explored factors contributing to this discrepancy using adecatumumab (MT201), a fully human monoclonal IgG1 against epithelial cell adhesion molecule (Ep-CAM) and trastuzumab (Herceptin), a humanized IgG1 with specificity for the human epithelial growth factor receptor type 2 (HER-2) antigen. We found that physiological levels of human sera strongly inhibited ADCC of both IgG1 antibodies. Effects showed some dependence on the density of Ep-CAM and HER-2 targets, the tumour cell line tested and on effector cell and serum donors. Removal of IgG by affinity chromatography abolished the inhibitory effect of a serum pool. Inhibition of ADCC was fully restored by adding back the IgG fraction or by an equal amount of IgG from a commercial source. We further demonstrate that CD56-positive lymphocytes within human PBMC contributed >90% to ADCC and that normal serum levels of IgG effectively competed for in vitro binding of an IgG1 antibody to low-affinity Fcgamma receptor type III (CD16), as is present on natural killer (NK) cells. Competition of serum IgG for binding of therapeutic IgG1 to NK cell may be one important reason why high antibody doses are required in the clinic for treatment of cancer by an ADCC-based mechanism. PMID:16102830

  11. Interleukin-1beta partially alleviates cyclosporin A-induced suppression of IgG1 isotype response to thyroglobulin in BALB/c mice in vivo.

    PubMed Central

    Dalai, S K; Miriyala, B; Kar, S K

    1998-01-01

    Cyclosporin A (CsA) at 120 mg/kg body weight when injected subcutaneously into BALB/c mice along with thyroglobulin emulsified in incomplete Freund's adjuvant (IFA) was found to suppress antigen-specific IgG titre by 86%. Isotyping revealed that both IgG1 and IgG2a titres were suppressed by 87% and 57%, respectively. But under identical conditions when complete Freund's adjuvant (CFA) was used, the suppression of antigen-specific IgG, IgG1 and IgG2a titres was 50%, 51% and 55%, respectively. Injection of anti-IL-1beta-neutralizing hamster monoclonal antibodies along with thyroglobulin and CsA emulsified in CFA increased the suppression of antigen-specific IgG titre. Under such conditions the IgG1 titre was suppressed more than the IgG2a titre. Recombinant human interleukin-1 receptor antagonist (rhuIL-1ra) also enhanced the suppression caused by CsA in the presence of CFA but control hamster immunoglobulin had no such effect. Recombinant human IL-1beta, when administered along with thyroglobulin and CsA emulsified in IFA, alleviated the suppression of antigen-specific IgG titre and the IgG1 titre was alleviated more than the IgG2a titre. Under identical conditions, rhuIL-1ra did not alleviate CsA-induced suppression. Lymphocytes from the lymph nodes of thyroglobulin-sensitized BALB/c mice when stimulated in vitro by thyroglobulin in the presence of CsA, secreted very little interferon-gamma (IFN-gamma) and IL-4, but on addition of an optimal dose of rhuIL-1beta, IFN-gamma and IL-4 secretion was partially restored. PMID:9767461

  12. Specific IgM, IgG and IgG1 directed against Toxoplasma gondii detected by flow cytometry and their potential as serologic tools to support clinical indirect fundoscopic presumed diagnosis of ocular disease.

    PubMed

    Martins, Livia Mattos; Rangel, Alba Lucinia Peixoto; Peixe, Ricardo Guerra; Silva-dos-Santos, Priscila Pinto; Lemos, Elenice Moreira; Martins-Filho, Olindo Assis; Bahia-Oliveira, Lilian Maria Garcia

    2015-02-01

    In the present study we evaluated the anti-Toxoplasma gondii immunoglobulin profiles of a group of 118 individuals living in an endemic area. The aim of the study was to select biomarkers to support the ophthalmological diagnosis of retinal/retinochoroidal scars presumably caused by T. gondii infection. Overall anti-T. gondii reactivity of the IgM, IgG, IgA, IgE and IgG subclasses was investigated by flow cytometry-based anti-fixed tachyzoite antibodies (FC-AFTA) in four groups of subjects, referred to as: i) TOXO(L)--seropositive patients with retinal/retinochoroidal scars presumably caused by T. gondii infection; these patients were further subdivided according to morphological aspects of their ocular scar lesions as A, B or C; ii) TOXO(NL)--seropositive patients without ocular scar lesions; iii) NEG(L)--T. gondii seronegative patients presenting retinal lesions; and iv) NEG(NL)--T. gondii seronegative without retinal lesions (negative controls). Our data demonstrated that anti-T. gondii IgG profiles were able to discriminate the mean reactivity of TOXO(L) from all other clinical groups. Analysis of anti-T. gondii immunoglobulin profiles revealed that IgM and IgG were good biomarkers capable of discriminating between individual reactivity in patients with retinal/retinochoroidal scars presumably caused by T. gondii infection [TOXO(L)] from those caused by other clinical conditions. Furthermore, anti-T. gondii IgG1 reactivity was able to discriminate TOXO(L) from all other clinical groups. In conclusion, the pre-selected IgM, IgG and IgG1 anti-T. gondii antibody subclasses were able to segregate both TOXO(L) and the other subgroups, including the scar lesion group types (A, B, C), from other clinical conditions. These results suggest the applicability of this technique in the clinical laboratory to detect putative biomarker for diagnosis of ocular lesions in T. gondii-infected patients. Studies in other areas implementing the methods described in the present study

  13. A novel clinical entity, IgG4-related disease (IgG4RD): general concept and details.

    PubMed

    Umehara, Hisanori; Okazaki, Kazuichi; Masaki, Yasufumi; Kawano, Mitsuhiro; Yamamoto, Motohisa; Saeki, Takako; Matsui, Shoko; Sumida, Takayuki; Mimori, Tsuneyo; Tanaka, Yoshiya; Tsubota, Kazuo; Yoshino, Tadashi; Kawa, Shigeyuki; Suzuki, Ritsuro; Takegami, Tsutomu; Tomosugi, Naohisa; Kurose, Nozomu; Ishigaki, Yasuhito; Azumi, Atsushi; Kojima, Masaru; Nakamura, Shigeo; Inoue, Dai

    2012-02-01

    IgG4-related disease (IgG4RD) is a novel clinical disease entity characterized by elevated serum IgG4 concentration and tumefaction or tissue infiltration by IgG4-positive plasma cells. IgG4RD may be present in a certain proportion of patients with a wide variety of diseases, including Mikulicz's disease, autoimmune pancreatitis, hypophysitis, Riedel thyroiditis, interstitial pneumonitis, interstitial nephritis, prostatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory aortic aneurysm, and inflammatory pseudotumor. Although IgG4RD forms a distinct, clinically independent disease category and is attracting strong attention as a new clinical entity, many questions and problems still remain to be elucidated, including its pathogenesis, the establishment of diagnostic criteria, and the role of IgG4. Here we describe the concept of IgG4RD and up-to-date information on this emerging disease entity. PMID:21881964

  14. Diagnostic performance of serum IgG4 level for IgG4-related disease: a meta-analysis

    PubMed Central

    Xu, Wen-long; Ling, Ying-chun; Wang, Zhi-kai; Deng, Fang

    2016-01-01

    An elevated serum IgG4 level is one of the most useful factors in the diagnosis of IgG4-related disease (IgG4-RD). In this study, we performed a meta-analysis of the published articles assessing the diagnostic accuracy of serum IgG4 concentrations for IgG4-RD. The databases of MEDLINE/PubMed, EMBASE and Web of Science were systematically searched for relevant studies. Sensitivities and specificities of serum IgG4 in each study were calculated, and the hierarchical summary receiver operating characteristic (HSROC) model with a random effects model were employed to obtain the individual and pooled estimates of sensitivities and specificities. In total, twenty-three studies comprising 6048 patients with IgG4-RD were included in the meta-analysis. The pooled sensitivity was 85% with a 95% confidence interval (CI) of 78–90%; the pooled specificity was 93% with a 95% CI of 90–95%. The HSROC curve for quantitative serum IgG4 lies closer to the upper left corner of the plot, and the area under the curve (AUC) was 0.95 (95% CI 0.93, 0.97), which suggested a high diagnostic accuracy of serum IgG4 for the entity of IgG4-RD. Our study suggests that serum IgG4 has high sensitivity and specificity in the diagnosis of IgG4-RD. PMID:27558881

  15. Diagnostic performance of serum IgG4 level for IgG4-related disease: a meta-analysis.

    PubMed

    Xu, Wen-Long; Ling, Ying-Chun; Wang, Zhi-Kai; Deng, Fang

    2016-01-01

    An elevated serum IgG4 level is one of the most useful factors in the diagnosis of IgG4-related disease (IgG4-RD). In this study, we performed a meta-analysis of the published articles assessing the diagnostic accuracy of serum IgG4 concentrations for IgG4-RD. The databases of MEDLINE/PubMed, EMBASE and Web of Science were systematically searched for relevant studies. Sensitivities and specificities of serum IgG4 in each study were calculated, and the hierarchical summary receiver operating characteristic (HSROC) model with a random effects model were employed to obtain the individual and pooled estimates of sensitivities and specificities. In total, twenty-three studies comprising 6048 patients with IgG4-RD were included in the meta-analysis. The pooled sensitivity was 85% with a 95% confidence interval (CI) of 78-90%; the pooled specificity was 93% with a 95% CI of 90-95%. The HSROC curve for quantitative serum IgG4 lies closer to the upper left corner of the plot, and the area under the curve (AUC) was 0.95 (95% CI 0.93, 0.97), which suggested a high diagnostic accuracy of serum IgG4 for the entity of IgG4-RD. Our study suggests that serum IgG4 has high sensitivity and specificity in the diagnosis of IgG4-RD. PMID:27558881

  16. Effect of IVIG Formulation on IgG Binding to Self- and Exo- Antigens In Vitro and In Vivo

    PubMed Central

    Cattepoel, Susann; Gaida, Annette; Kropf, Alain; Nolte, Marc W.; Bolli, Reinhard; Miescher, Sylvia M.

    2016-01-01

    In relation to the recent trials of Intravenous Immunoglobulin (IVIG) in Alzheimer’s Disease (AD) it was demonstrated that different IgG preparations contain varying amounts of natural anti-amyloid β (Aβ) antibodies as measured by ELISA. We therefore investigated the relevance of ELISA data for measuring low-affinity antibodies, such as anti-Aβ. We analysed the binding of different commercial Immunoglobulin G (IgG) preparations to Aβ, actin and tetanus toxoid in different binding assays to further investigate the possible cause for observed differences in binding to Aβ and actin between different IgG preparations. We show that the differences of commercial IgG preparations in binding to Aβ and actin in ELISA assays are artefactual and only evident in in vitro binding assays. In functional assays and in vivo animal studies the different IVIG preparations exhibited very similar potency. ELISA data alone are not appropriate to analyse and rank the binding capacity of low-affinity antibodies to Aβ or other endogenous self-antigens contained in IgG preparations. Additional analytical methods should be adopted to complement ELISA data. PMID:27561008

  17. A Novel Antibody Engineering Strategy for Making Monovalent Bispecific Heterodimeric IgG Antibodies by Electrostatic Steering Mechanism*

    PubMed Central

    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

    2015-01-01

    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. PMID:25583986

  18. 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. PMID:25583986

  19. Enhancement of antibody-dependent cell-mediated cytotoxicity by endowing IgG with FcαRI (CD89) binding.

    PubMed

    Borrok, M Jack; Luheshi, Nadia M; Beyaz, Nurten; Davies, Gareth C; Legg, James W; Wu, Herren; Dall'Acqua, William F; Tsui, Ping

    2015-01-01

    Fc effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent cell-mediated phagocytosis (ADCP) are crucial to the efficacy of many antibody therapeutics. In addition to IgG, antibodies of the IgA isotype can also promote cell killing through engagement of myeloid lineage cells via interactions between the IgA-Fc and FcαRI (CD89). Herein, we describe a unique, tandem IgG1/IgA2 antibody format in the context of a trastuzumab variable domain that exhibits enhanced ADCC and ADCP capabilities. The IgG1/IgA2 tandem Fc format retains IgG1 FcγR binding as well as FcRn-mediated serum persistence, yet is augmented with myeloid cell-mediated effector functions via FcαRI/IgA Fc interactions. In this work, we demonstrate anti-human epidermal growth factor receptor-2 antibodies with the unique tandem IgG1/IgA2 Fc can better recruit and engage cytotoxic polymorphonuclear (PMN) cells than either the parental IgG1 or IgA2. Pharmacokinetics of IgG1/IgA2 in BALB/c mice are similar to the parental IgG, and far surpass the poor serum persistence of IgA2. The IgG1/IgA2 format is expressed at similar levels and with similar thermal stability to IgG1, and can be purified via standard protein A chromatography. The tandem IgG1/IgA2 format could potentially augment IgG-based immunotherapeutics with enhanced PMN-mediated cytotoxicity while avoiding many of the problems associated with developing IgAs. PMID:25970007

  20. Effector functions of a monoclonal aglycosylated mouse IgG2a: binding and activation of complement component C1 and interaction with human monocyte Fc receptor.

    PubMed

    Leatherbarrow, R J; Rademacher, T W; Dwek, R A; Woof, J M; Clark, A; Burton, D R; Richardson, N; Feinstein, A

    1985-04-01

    Aglycosylated monoclonal anti-DNP mouse IgG2a produced in the presence of tunicamycin was compared with the native monoclonal IgG2a with respect to its ability to interact with the first component of complement, C1, and to compete with human IgG for binding to human monocyte Fc receptors. The aglycosylated IgG2a was found to bind subcomponent C1q with an equivalent capacity to the native IgG2a, but the dissociation constant was found to be increased three-fold. When activation of C1 by the glycosylated and aglycosylated IgG2a was compared, the rate of C1 activation by the aglycosylated IgG2a was reduced approximately three-fold. In contrast aglycosylation was accompanied by a large decrease (greater than or equal to 50-fold) in the apparent binding constant of monomeric IgG2a to human monocytes. The data suggest that the aglycosylated IgG2a has a structure which differs in the CH2 domain from the native IgG2a, and that the heterogeneous N-linked oligosaccharides of this monoclonal IgG2a which occur at a conserved position in the CH2 domain play a role in maintaining the integrity of its monocyte-binding site. This lack of monocyte binding may result either from a localized conformational change occurring in a single CH2 domain or from an alteration in the CH2-CH2 cross-domain architecture which is normally structured by a pair of opposing and interacting oligosaccharides. The minimal changes in C1q binding and C1 activation suggest that the oligosaccharides are, at most, indirectly involved in these events. PMID:4033665

  1. Comprehensive Analysis of the Therapeutic IgG4 Antibody Pembrolizumab: Hinge Modification Blocks Half Molecule Exchange In Vitro and In Vivo.

    PubMed

    Yang, Xiaoyu; Wang, Fengqiang; Zhang, Ying; Wang, Larry; Antonenko, Svetlana; Zhang, Shuli; Zhang, Yi Wei; Tabrizifard, Mohammad; Ermakov, Grigori; Wiswell, Derek; Beaumont, Maribel; Liu, Liming; Richardson, Daisy; Shameem, Mohammed; Ambrogelly, Alexandre

    2015-12-01

    IgG4 antibodies are evolving as an important class of cancer immunotherapies. However, human IgG4 can undergo Fab arm (half molecule) exchange with other IgG4 molecules in vivo. The hinge modification by a point mutation (S228P) prevents half molecule exchange of IgG4. However, the experimental confirmation is still expected by regulatory agencies. Here, we report for the first time the extensive analysis of half molecule exchange for a hinge-modified therapeutic IgG4 molecule, pembrolizumab (Keytruda) targeting programmed death 1 (PD1) receptor that was approved for advanced melanoma. Studies were performed in buffer or human serum using multiple exchange partners including natalizumab (Tysabri) and human IgG4 pool. Formation of bispecific antibodies was monitored by fluorescence resonance energy transfer, exchange with Fc fragments, mixed mode chromatography, immunoassays, and liquid chromatography-mass spectrometry. The half molecule exchange was also examined in vivo in SCID (severe combined immunodeficiency) mice. Both in vitro and in vivo results indicate that the hinge modification in pembrolizumab prevented half molecule exchange, whereas the unmodified counterpart anti-PD1 wt showed active exchange activity with other IgG4 antibodies or self-exchange activity with its own molecules. Our work, as an example expected for meeting regulatory requirements, contributes to establish without ambiguity that hinge-modified IgG4 antibodies are suitable for biotherapeutic applications. PMID:26308749

  2. The effect of Corynebacterium parvum therapy on immunoglobulin class and IgG subclass levels in cancer patients.

    PubMed Central

    James, K.; Clunie, G. J.; Woodruff, M. F.; McBride, W. H.; Stimson, W. H.; Drew, R.; Catty, D.

    1975-01-01

    Detailed serological studies have been undertaken in a small group of cancer patients receiving nonspecific immunotherapy with Corynebacterium parvum (C. parvum). These patients included 4 cases of recurrent malignant melanoma, 2 of stomach cancer and 2 of recurrent breast cancer. They all received an initial i.v. infusion of 20 mg of a formol killed suspension of C. parvum followed by 2 mg (i.m.) at weekly intervals for 10-11 weeks. This protocol consistently resulted in an increase in the circulating IgG levels of all patients but had a variable effect on their IgA, IgM and IgE levels. Increases in the concentration of all 4 IgG subclasses contributed to the overall increase in IgG levels and these changes ranked IgG2 greater than IgG1 greater than IgG3 = IgG4. It also had an inconsistent effect upon the levels of alpha-macroglobulin in pregnancy but the levels of normal serum alpha2-macroglobulin were virtually unchanged. Pre-existing antibodies to C. parvum were noted in all the patients. Titres rose appreciably following C. parvum administration and remained at high, though fluctuating levels, throughout the 100-day period of observation. Absorption studies suggested that the development of antibodies to C. parvum accounted in part for the increased IgG levels noted following this form of therapy. The significance of these changes in relation to the possible anti-tumour effect of C. parvum is discussed. PMID:61040

  3. Binding of normal human IgG to myelin sheaths, glia and neurons.

    PubMed Central

    Aarli, J A; Aparicio, S R; Lumsden, C E; Tönder, O

    1975-01-01

    The binding of normal human serum, purified IgG and IgG fragments to central nervous tissue was studied by the anti-globulin consumption (AGCT) and immunofluorescence (IF) techniques. In the AGCT, F(ab')2 fragments failed to react, whereas IgG and Fc fragments did so. In IF experiments, the binding was localized to myelin sheaths, glia and neurons; Fab monomers at a protein concentration of 1-3 mg/ml dod not react with the tissue, but purified Fc fragments at 0-0625 mg/ml did. The binding is neither tissue- nor species-specific. Lipid and protein extraction procedures indicated that the factor responsible for binding to myelin was basic protein. It was concluded that the binding of normal IgG to central nervous tissue is medicated by the Fc part of the molecule. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 PMID:803915

  4. A prominent lack of IgG1-Fc fucosylation of platelet alloantibodies in pregnancy

    PubMed Central

    Kapur, Rick; Kustiawan, Iwan; Vestrheim, Anne; Koeleman, Carolien A. M.; Visser, Remco; Einarsdottir, Helga K.; Porcelijn, Leendert; Jackson, Dave; Kumpel, Belinda; Deelder, André M.; Blank, Dennis; Skogen, Björn; Killie, Mette Kjaer; Michaelsen, Terje E.; de Haas, Masja; Rispens, Theo; van der Schoot, C. Ellen; Wuhrer, Manfred

    2014-01-01

    Immunoglobulin G (IgG) formed during pregnancy against human platelet antigens (HPAs) of the fetus mediates fetal or neonatal alloimmune thrombocytopenia (FNAIT). Because antibody titer or isotype does not strictly correlate with disease severity, we investigated by mass spectrometry variations in the glycosylation at Asn297 in the IgG Fc because the composition of this glycan can be highly variable, affecting binding to phagocyte IgG-Fc receptors (FcγR). We found markedly decreased levels of core fucosylation of anti-HPA-1a–specific IgG1 from FNAIT patients (n = 48), but not in total serum IgG1. Antibodies with a low amount of fucose displayed higher binding affinity to FcγRIIIa and FcγRIIIb, but not to FcγRIIa, compared with antibodies with a high amount of Fc fucose. Consequently, these antibodies with a low amount of Fc fucose showed enhanced phagocytosis of platelets using FcγRIIIb+ polymorphonuclear cells or FcγRIIIa+ monocytes as effector cells, but not with FcγRIIIa– monocytes. In addition, the degree of anti-HPA-1a fucosylation correlated positively with the neonatal platelet counts in FNAIT, and negatively to the clinical disease severity. In contrast to the FNAIT patients, no changes in core fucosylation were observed for anti-HLA antibodies in refractory thrombocytopenia (post platelet transfusion), indicating that the level of fucosylation may be antigen dependent and/or related to the immune milieu defined by pregnancy. PMID:24243971

  5. A prominent lack of IgG1-Fc fucosylation of platelet alloantibodies in pregnancy.

    PubMed

    Kapur, Rick; Kustiawan, Iwan; Vestrheim, Anne; Koeleman, Carolien A M; Visser, Remco; Einarsdottir, Helga K; Porcelijn, Leendert; Jackson, Dave; Kumpel, Belinda; Deelder, André M; Blank, Dennis; Skogen, Björn; Killie, Mette Kjaer; Michaelsen, Terje E; de Haas, Masja; Rispens, Theo; van der Schoot, C Ellen; Wuhrer, Manfred; Vidarsson, Gestur

    2014-01-23

    Immunoglobulin G (IgG) formed during pregnancy against human platelet antigens (HPAs) of the fetus mediates fetal or neonatal alloimmune thrombocytopenia (FNAIT). Because antibody titer or isotype does not strictly correlate with disease severity, we investigated by mass spectrometry variations in the glycosylation at Asn297 in the IgG Fc because the composition of this glycan can be highly variable, affecting binding to phagocyte IgG-Fc receptors (FcγR). We found markedly decreased levels of core fucosylation of anti-HPA-1a-specific IgG1 from FNAIT patients (n = 48), but not in total serum IgG1. Antibodies with a low amount of fucose displayed higher binding affinity to FcγRIIIa and FcγRIIIb, but not to FcγRIIa, compared with antibodies with a high amount of Fc fucose. Consequently, these antibodies with a low amount of Fc fucose showed enhanced phagocytosis of platelets using FcγRIIIb(+) polymorphonuclear cells or FcγRIIIa(+) monocytes as effector cells, but not with FcγRIIIa(-) monocytes. In addition, the degree of anti-HPA-1a fucosylation correlated positively with the neonatal platelet counts in FNAIT, and negatively to the clinical disease severity. In contrast to the FNAIT patients, no changes in core fucosylation were observed for anti-HLA antibodies in refractory thrombocytopenia (post platelet transfusion), indicating that the level of fucosylation may be antigen dependent and/or related to the immune milieu defined by pregnancy. PMID:24243971

  6. Diagnostic Value of Serum IgG4 for IgG4-Related Disease

    PubMed Central

    Hao, Mingju; Liu, Min; Fan, Gaowei; Yang, Xin; Li, Jinming

    2016-01-01

    Abstract Many studies about serum IgG4 for the diagnosis of IgG4-related disease (IgG4-RD) have been reported. However, these studies had relatively small sample sizes and the diagnostic accuracy values varied much between them. The aim of this study was to perform a meta-analysis to evaluate the diagnostic value of serum IgG4 for IgG4-RD. We conducted a search of relevant articles using MEDLINE, EMBASE, Web of Science, SCOPUS, and Cochrane Library databases published before December 2015. Studies those assessed the diagnostic accuracy of serum IgG4 for IgG4-RD and those provided the cut-off value for serum IgG4 were included. Data were synthesized using the random-effect model. Statistical analysis was performed using STATA with the MIDAS module and Meta-DiSc 1.4 software. A total of 9 case-control studies were analyzed, which included 1235 patients with IgG4-RD and 5696 overall controls. The pooled estimate, for a cut-off value ranged from 135 to 144 mg/dL, produced a sensitivity of 87.2% (95% CI, 85.2–89.0%) and a specificity of 82.6% (95% CI, 81.6–83.6%). The positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 6.48 (95% CI, 3.98–10.57), 0.14 (95% CI, 0.09–0.21), and 45.15 (95% CI, 23.41–87.06), respectively. The area under the curve (AUC) of the summary receiver operating characteristic curve (SROC) was 0.94 (0.92–0.96). When a cut-off value of 2-fold the upper limit of normal was used (ranged from 270 to 280 mg/dL), the pooled sensitivity was 63% (95% CI, 60.0–66.0%), and the specificity was 94.8% (95% CI, 94.1–95.4%). The PLR, NLR, and DOR were 13.3 (95% CI, 7.39–24.0), 0.41 (95% CI, 0.29–0.58) and 33.42 (95% CI, 13.88–80.43), respectively. The AUC of the SROC was 0.92 (0.90–0.94). Only a relatively small number of studies were included, and significant heterogeneity was observed in this meta-analysis. Serum IgG4 is a modestly effective marker to diagnose IgG4-RD. Doubling the cut

  7. Relationship between Antibody Levels, IgG Binding to Plasmodium falciparum-Infected Erythrocytes, and Disease Outcome in Hospitalized Urban Malaria Patients from Dakar, Sénégal

    PubMed Central

    Mbengue, Babacar; Fall, Mouhamadou Mansour; Sylla Niang, Maguette; Niang, Birahim; Varela, Marie Louise; Diatta, Antoine Marie; Mbow, Moustapha; Ndiaye, Kantome; Ndiaye Diallo, Rokhaya; Dieye, Alioune; Perraut, Ronald

    2016-01-01

    Background. Management of clinical malaria requires the development of reliable diagnostic methods and efficient biomarkers for follow-up of patients. Protection is partly based on IgG responses to parasite antigens exposed at the surface of infected erythrocytes (iRBCs). These IgG responses appeared low during clinical infection, particularly in severe disease. Methods. We analyzed the IgG binding capacity to the surface of live erythrocytes infected by knob positive FCR3 strain. Sera from 69 cerebral malaria (CM) and 72 mild malaria (MM) cases were analyzed by ELISA for IgG responses to five antigens from iRBC and by flow cytometry for IgG binding as expressed in labeling index ratio (LIR). The relationship between IgG levels, LIR, parasitemia, age, and the clinical outcomes was evaluated. Results. We found a significant decrease of LIR in adult CM fatal cases compared to surviving patients (p = 0.019). In MM, LIRs were correlated to IgG anti-iRBC and anti-PfEMP3/5 levels. In CM, no correlation was found between LIR, IgG levels, and parasitemia. Conclusion. The IgG binding assay was able to discriminate outcome of cerebral malaria cases and it deserves further development as a potential functional-associated assay for symptomatic malaria analysis. PMID:27563669

  8. Relationship between Antibody Levels, IgG Binding to Plasmodium falciparum-Infected Erythrocytes, and Disease Outcome in Hospitalized Urban Malaria Patients from Dakar, Sénégal.

    PubMed

    Mbengue, Babacar; Fall, Mouhamadou Mansour; Sylla Niang, Maguette; Niang, Birahim; Varela, Marie Louise; Diatta, Antoine Marie; Mbow, Moustapha; Ndiaye, Kantome; Ndiaye Diallo, Rokhaya; Dieye, Alioune; Perraut, Ronald

    2016-01-01

    Background. Management of clinical malaria requires the development of reliable diagnostic methods and efficient biomarkers for follow-up of patients. Protection is partly based on IgG responses to parasite antigens exposed at the surface of infected erythrocytes (iRBCs). These IgG responses appeared low during clinical infection, particularly in severe disease. Methods. We analyzed the IgG binding capacity to the surface of live erythrocytes infected by knob positive FCR3 strain. Sera from 69 cerebral malaria (CM) and 72 mild malaria (MM) cases were analyzed by ELISA for IgG responses to five antigens from iRBC and by flow cytometry for IgG binding as expressed in labeling index ratio (LIR). The relationship between IgG levels, LIR, parasitemia, age, and the clinical outcomes was evaluated. Results. We found a significant decrease of LIR in adult CM fatal cases compared to surviving patients (p = 0.019). In MM, LIRs were correlated to IgG anti-iRBC and anti-PfEMP3/5 levels. In CM, no correlation was found between LIR, IgG levels, and parasitemia. Conclusion. The IgG binding assay was able to discriminate outcome of cerebral malaria cases and it deserves further development as a potential functional-associated assay for symptomatic malaria analysis. PMID:27563669

  9. Phase transitions in human IgG solutions

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Lomakin, Aleksey; Latypov, Ramil F.; Laubach, Jacob P.; Hideshima, Teru; Richardson, Paul G.; Munshi, Nikhil C.; Anderson, Kenneth C.; Benedek, George B.

    2013-09-01

    Protein condensations, such as crystallization, liquid-liquid phase separation, aggregation, and gelation, have been observed in concentrated antibody solutions under various solution conditions. While most IgG antibodies are quite soluble, a few outliers can undergo condensation under physiological conditions. Condensation of IgGs can cause serious consequences in some human diseases and in biopharmaceutical formulations. The phase transitions underlying protein condensations in concentrated IgG solutions is also of fundamental interest for the understanding of the phase behavior of non-spherical protein molecules. Due to the high solubility of generic IgGs, the phase behavior of IgG solutions has not yet been well studied. In this work, we present an experimental approach to study IgG solutions in which the phase transitions are hidden below the freezing point of the solution. Using this method, we have investigated liquid-liquid phase separation of six human myeloma IgGs and two recombinant pharmaceutical human IgGs. We have also studied the relation between crystallization and liquid-liquid phase separation of two human cryoglobulin IgGs. Our experimental results reveal several important features of the generic phase behavior of IgG solutions: (1) the shape of the coexistence curve is similar for all IgGs but quite different from that of quasi-spherical proteins; (2) all IgGs have critical points located at roughly the same protein concentration at ˜100 mg/ml while their critical temperatures vary significantly; and (3) the liquid-liquid phase separation in IgG solutions is metastable with respect to crystallization. These features of phase behavior of IgG solutions reflect the fact that all IgGs have nearly identical molecular geometry but quite diverse net inter-protein interaction energies. This work provides a foundation for further experimental and theoretical studies of the phase behavior of generic IgGs as well as outliers with large propensity to

  10. Phase transitions in human IgG solutions

    PubMed Central

    Wang, Ying; Lomakin, Aleksey; Latypov, Ramil F.; Laubach, Jacob P.; Hideshima, Teru; Richardson, Paul G.; Munshi, Nikhil C.; Anderson, Kenneth C.; Benedek, George B.

    2013-01-01

    Protein condensations, such as crystallization, liquid-liquid phase separation, aggregation, and gelation, have been observed in concentrated antibody solutions under various solution conditions. While most IgG antibodies are quite soluble, a few outliers can undergo condensation under physiological conditions. Condensation of IgGs can cause serious consequences in some human diseases and in biopharmaceutical formulations. The phase transitions underlying protein condensations in concentrated IgG solutions is also of fundamental interest for the understanding of the phase behavior of non-spherical protein molecules. Due to the high solubility of generic IgGs, the phase behavior of IgG solutions has not yet been well studied. In this work, we present an experimental approach to study IgG solutions in which the phase transitions are hidden below the freezing point of the solution. Using this method, we have investigated liquid-liquid phase separation of six human myeloma IgGs and two recombinant pharmaceutical human IgGs. We have also studied the relation between crystallization and liquid-liquid phase separation of two human cryoglobulin IgGs. Our experimental results reveal several important features of the generic phase behavior of IgG solutions: (1) the shape of the coexistence curve is similar for all IgGs but quite different from that of quasi-spherical proteins; (2) all IgGs have critical points located at roughly the same protein concentration at ∼100 mg/ml while their critical temperatures vary significantly; and (3) the liquid-liquid phase separation in IgG solutions is metastable with respect to crystallization. These features of phase behavior of IgG solutions reflect the fact that all IgGs have nearly identical molecular geometry but quite diverse net inter-protein interaction energies. This work provides a foundation for further experimental and theoretical studies of the phase behavior of generic IgGs as well as outliers with large propensity to

  11. Colostrogenesis: IgG1 transcytosis mechanisms.

    PubMed

    Baumrucker, Craig R; Bruckmaier, Rupert M

    2014-03-01

    Biological transport of intact proteins across epithelial cells has been documented for many absorptive and secretory tissues. Immunoglobulins were some of the earliest studied proteins in this category. The transcellular transport (transcytosis) of immunoglobulins in neonatal health and development has been recognized; the process is especially significant with ungulates because they do not transcytose immunoglobulins across the placenta to the neonate. Rather, they depend upon mammary secretion of colostrum and intestinal absorption of immunoglobulins in order to provide intestinal and systemic defense until the young ungulate develops its own humoral defense mechanisms. The neonatal dairy calf's ability to absorb immunoglobulins from colostrum is assisted by a ~24 h "open gut" phenomenon where large proteins pass the intestinal epithelial cells and enter the systemic system. However, a critical problem recognized for newborn dairy calves is that an optimum mass of colostrum Immunoglobulin G (IgG) needs to be absorbed within that 24 h window in order to provide maximal resistance to disease. Many calves do not achieve the optimum because of poor quality colostrum. While many studies have focused on calf absorption, the principal cause of the problem resides with the extreme variation (g to kg) in the mammary gland's capacity to transfer blood IgG1 into colostrum. Colostrum is a unique mammary secretory product that is formed during late pregnancy when mammary cells are proliferating and differentiating in preparation for lactation. In addition to the transcytosis of immunoglobulins, the mammary gland also concentrates a number of circulating hormones into colostrum. Remarkably, the mechanisms in the formation of colostrum in ungulates have been rather modestly studied. The mechanisms and causes of this variation in mammary gland transcytosis of IgG1 are examined, evaluated, and in some cases, explained. PMID:24474529

  12. Viremic HIV controllers exhibit high plasmacytoid dendritic cell\\reactive opsonophagocytic IgG antibody responses against HIV-1 p24 associated with greater antibody isotype diversification

    PubMed Central

    Tjiam, M. Christian; Taylor, James P. A.; Morshidi, Mazmah A.; Sariputra, Lucy; Burrows, Sally; Martin, Jeffrey N.; Deeks, Steven G.; Tan, Dino B.A.; Lee, Silvia; Fernandez, Sonia; French, Martyn A.

    2015-01-01

    Identifying the mechanisms of natural control of HIV-1 infection could lead to novel approaches to prevent or cure HIV infection. Several studies have associated natural control of HIV-1 infection with IgG antibodies against HIV-1 Gag proteins (e.g. p24) and/or production of IgG2 antibodies against HIV-1 proteins. These antibodies likely exert their effect by activating anti-viral effector cell responses rather than virus neutralization. We hypothesized that an opsonophagocytic IgG antibody response against HIV-1 p24 that activates plasmacytoid dendritic cells (pDCs) through FcγRIIa would be associated with control of HIV and that this would be enhanced by antibody isotype diversification. Using the Gen2.2 pDC cell line, we demonstrated that pDC-reactive opsonophagocytic IgG antibody responses against HIV-1 p24 were higher in HIV controllers (HIV RNA <2000 copies/mL) than non-controllers (HIV RNA >10,000 copies/mL) particularly in controllers with low but detectable viremia (HIV RNA 75–2000 copies/mL). Opsonophagocytic antibody responses correlated with plasma levels of IgG1 and IgG2 anti-HIV-1 p24 and notably, correlated inversely with plasma HIV RNA levels in viremic HIV patients. Phagocytosis of these antibodies was mediated via FcγRIIa. Isotype diversification (towards IgG2) was greatest in HIV controllers and depletion of IgG2 from immunoglobulin preparations indicated that IgG2 antibodies to HIV-1 p24 do not enhance phagocytosis, suggesting that they enhance other aspects of antibody function, such as antigen opsonization. Our findings emulate those for pDC-reactive opsonophagocytic antibody responses against coxsackie, picorna and influenza viruses and demonstrate a previously undefined immune correlate of HIV-1 control that may be relevant to HIV vaccine development. PMID:25911748

  13. Improving target cell specificity using a novel monovalent bispecific IgG design

    PubMed Central

    Mazor, Yariv; Oganesyan, Vaheh; Yang, Chunning; Hansen, Anna; Wang, Jihong; Liu, Hongji; Sachsenmeier, Kris; Carlson, Marcia; Gadre, Dhanesh V; Borrok, Martin Jack; Yu, Xiang-Qing; Dall’Acqua, William; Wu, Herren; Chowdhury, Partha Sarathi

    2015-01-01

    Monovalent bispecific IgGs cater to a distinct set of mechanisms of action but are difficult to engineer and manufacture because of complexities associated with correct heavy and light chain pairing. We have created a novel design, “DuetMab,” for efficient production of these molecules. The platform uses knobs-into-holes (KIH) technology for heterodimerization of 2 distinct heavy chains and increases the efficiency of cognate heavy and light chain pairing by replacing the native disulfide bond in one of the CH1-CL interfaces with an engineered disulfide bond. Using two pairs of antibodies, cetuximab (anti-EGFR) and trastuzumab (anti-HER2), and anti-CD40 and anti-CD70 antibodies, we demonstrate that DuetMab antibodies can be produced in a highly purified and active form, and show for the first time that monovalent bispecific IgGs can concurrently bind both antigens on the same cell. This last property compensates for the loss of avidity brought about by monovalency and improves selectivity toward the target cell. PMID:25621507

  14. Transplacental transport of IgG antibodies to preterm infants: a review of the literature.

    PubMed

    van den Berg, J P; Westerbeek, E A M; van der Klis, F R M; Berbers, G A M; van Elburg, R M

    2011-02-01

    Newborn infants, especially preterm infants, have an immature immune system, which is not capable to actively protect against vaccine-preventable infections. Therefore, the newborn is dependent on transplacental transport of Immunoglobulin G (IgG), an active, FcRn receptor mediated process. Fetal IgG rises from approximately 10% of the maternal concentration at 17-22weeks of gestation to 50% at 28-32weeks of gestation. If transplacental acquired IgG is lower in preterm than in term infants, preterm infants are especially at risk for these vaccine-preventable diseases. The aim of this study was to review the transplacental transfer of IgG against vaccine-preventable diseases (measles, rubella, varicella-zoster, mumps, Haemophilus influenza type B, diphtheria, tetanus, pertussis and polio) to (pre)term infants and to identify factors that influence the transplacental transfer of these antigens. After selection, 18 studies on transplacental transport to preterm infants were included. In general, these studies showed for all antibodies that preterm infants have lower antibody concentrations compared with term infants. Maternal and infants antibody concentrations showed a strong correlation in 7 of the included studies. Infant antibody concentration was not associated with parity, maternal age, height or weight. Infants of vaccinated mothers had lower anti-measles antibody titers than infants of natural immunized mothers. IgG titers of preterm infants decrease earlier in life below protective antibody titers than term infants. Combined with their immature immune system, this puts preterm infants at increased risk for vaccine-preventable diseases. PMID:21123010

  15. The impact of lowering the cut-off value on the sensitivity of the Platelia Elisa IgG (Bio-Rad) test for toxoplasmosis diagnosis

    PubMed Central

    Mouri, Oussama; Kendjo, Eric; Touafek, Feriel; Fekkar, Arnaud; Konte, Ousmane; Imbert, Sebastien; Courtin, Régis; Mazier, Dominique; Paris, Luc

    2015-01-01

    Determining specific immune status against Toxoplasma gondii is essential for assessing the risk of reactivation in immunocompromised patients or defining serological monitoring and appropriate prophylactic measures during pregnancy. In France, toxoplasmosis serological screening requires systematic testing for IgM and IgG antibodies. The Platelia Toxo IgG and IgM test (Bio-Rad) is one of the most widely used tests for anti-toxoplasmic antibody detection. We performed a study on 384 sera, including 123 IgG negative (<6 IU/mL) and 261 IgG equivocal (6–9 IU/mL) sera tested with Platelia Toxo IgG and collected during routine screening at Pitié-Salpêtrière Hospital, Paris, France to determine the best-performing IgG titer cut-off value. Out of these 383 sera, 298 were IgM negative by Platelia Toxo IgM and 86 were IgM positive. All sera were also tested against Toxo IgG II LD BIO western blot test as confirmation. Our results indicated that an IgG titer cut-off value of ≥4.4 IU/mL for the Platelia Toxo IgG met the definition of positivity, a value significantly lower than that indicated by the manufacturers. In the presence of IgM antibodies, the IgG titer cut-off decreased significantly to a value ≥0.2 IU/mL. This latter cut-off also allowed adequate diagnosis of proven toxoplasmosis seroconversion in 76.7% of cases (33/43). Our findings may improve toxoplasmosis care by reducing therapeutic intervention time and eliminating the need for further serological monitoring. PMID:26187780

  16. Distinct Patterns of IgG and IgA against Food and Microbial Antigens in Serum and Feces of Patients with Inflammatory Bowel Diseases

    PubMed Central

    Frehn, Lisa; Jansen, Anke; Bennek, Eveline; Mandic, Ana D.; Temizel, Ilknur; Tischendorf, Stefanie; Verdier, Julien; Tacke, Frank; Streetz, Konrad; Trautwein, Christian; Sellge, Gernot

    2014-01-01

    Background Inflammatory bowel disease (IBD) is associated with a defective intestinal barrier and enhanced adaptive immune responses against commensal microbiota. Immune responses against food antigens in IBD patients remain poorly defined. Methods IgG and IgA specific for food and microfloral antigens (wheat and milk extracts; purified ovalbumin; Escherichia coli and Bacteroides fragilis lysates; mannan from Saccharomyces cerevisiae) were analyzed by ELISA in the serum and feces of patients with Crohn's disease (CD; n = 52 for serum and n = 20 for feces), ulcerative colitis (UC; n = 29; n = 17), acute gastroenteritis/colitis (AGE; n = 12; n = 9) as well as non-inflammatory controls (n = 61; n = 39). Results Serum anti-Saccharomyces cerevisiae antibodies (ASCA) and anti-B. fragilis IgG and IgA levels were increased in CD patients whereas antibody (Ab) levels against E. coli and food antigens were not significantly different within the patient groups and controls. Subgroup analysis revealed that CD patients with severe diseases defined by stricturing and penetrating lesions have slightly higher anti-food and anti-microbial IgA levels whereas CD and UC patients with arthropathy have decreased anti-food IgG levels. Treatment with anti-TNF-α Abs in CD patients was associated with significantly decreased ASCA IgG and IgA and anti-E. coli IgG. In the feces specific IgG levels against all antigens were higher in CD and AGE patients while specific IgA levels were higher in non-IBD patients. Anti-food IgG and IgA levels did not correlate with food intolerance. Summary In contrast to anti-microbial Abs, we found only minor changes in serum anti-food Ab levels in specific subgroups of IBD patients. Fecal Ab levels towards microbial and food antigens show distinct patterns in controls, CD and UC patients. PMID:25215528

  17. Anti S enigma in a pregnant patient.

    PubMed

    Kaur, Paramjit; Kaur, Gagandeep; Basu, Sabita; Kaur, Ravneet

    2014-04-01

    Among the antibodies of the MNS blood group system, anti S antibody is generally IgG antibody reacting at 37 °C. It is rarely implicated in hemolytic transfusion reaction; however, it can lead to potentially severe transfusion reactions. Anti S is also capable of causing mild to severe fatal hemolytic disease of newborn. We report a case of anti S antibody in a pregnant patient with complicated falciparum malaria. PMID:24485071

  18. The different effector function capabilities of the seven equine IgG subclasses have implications for vaccine strategies.

    PubMed

    Lewis, Melanie J; Wagner, Bettina; Woof, Jenny M

    2008-02-01

    Recombinant versions of the seven equine IgG subclasses were expressed in CHO cells. All assembled into intact immunoglobulins stabilised by disulphide bridges, although, reminiscent of human IgG4, a small proportion of equine IgG4 and IgG7 were held together by non-covalent bonds alone. All seven IgGs were N-glycosylated. In addition IgG3 appeared to be O-glycosylated and could bind the lectin jacalin. Staphylococcal protein A displayed weak binding for the equine IgGs in the order: IgG1>IgG3>IgG4>IgG7>IgG2=IgG5>IgG6. Streptococcal protein G bound strongly to IgG1, IgG4 and IgG7, moderately to IgG3, weakly to IgG2 and IgG6, and not at all to IgG5. Analysis of antibody effector functions revealed that IgG1, IgG3, IgG4, IgG5 and IgG7, but not IgG2 and IgG6, were able to elicit a strong respiratory burst from equine peripheral blood leukocytes, predicting that the former five IgG subclasses are able to interact with Fc receptors on effector cells. IgG1, IgG3, IgG4 and IgG7, but not IgG2, IgG5 and IgG6, were able to bind complement C1q and activate complement via the classical pathway. The differential effector function capabilities of the subclasses suggest that, for maximum efficacy, equine vaccine strategies should seek to elicit antibody responses of the IgG1, IgG3, IgG4, and IgG7 subclasses. PMID:17669496

  19. Characterization of a Novel Hemolytic Activity of Human IgG Fractions Arising from Diversity in Protein and Oligosaccharide Components

    PubMed Central

    Zhang, Yueling; Ye, Xiangqun; Zhong, Mingqi; Cao, Jinsong; Zou, Haiying; Chen, Jiehui

    2014-01-01

    Human IgG is a well-established multifunctional antigen specific immunoglobulin molecule of the adaptive immune system. However, an antigen nonspecific immunological function of human IgG has never been reported. In this study, human IgG was isolated using ammonium sulfate fractional precipitation and diethylaminoethanol (DEAE) cellulose 52 ion exchange chromatography, from which h-IgG and hs-IgG fractions were purified on the basis of their differential binding to rabbit anti-shrimp hemocyanin antibody (h) and rabbit anti-shrimp hemocyanin's small subunit antibody (hs), respectively. We found that h-IgG had a higher hemolytic activity than hs-IgG against erythrocytes from humans, rabbits, mice and chickens, whereas the control IgG showed negligible activity. h-IgG could interact directly with erythrocyte membranes, and this interaction was suppressed by high molecular weight osmoprotectants, showing that it may follow a colloid-osmotic mechanism. In comparative proteomics and glycomics studies, h-IgG and hs-IgG yielded 20 and 5 significantly altered protein spots, respectively, on a 2-D gel. The mean carbohydrate content of h-IgG and hs-IgG was approximately 3.6- and 2-fold higher than that of IgG, respectively, and the α-d-mannose/α-d-glucose content was in the order of h-IgG>hs-IgG>IgG. In this study, a novel antigen nonspecific immune property of human IgG was investigated, and the diversity in the protein constituents and glycosylation levels may have functional signficance. PMID:24465658

  20. Fully human monoclonal antibody inhibitors of the neonatal fc receptor reduce circulating IgG in non-human primates.

    PubMed

    Nixon, Andrew E; Chen, Jie; Sexton, Daniel J; Muruganandam, Arumugam; Bitonti, Alan J; Dumont, Jennifer; Viswanathan, Malini; Martik, Diana; Wassaf, Dina; Mezo, Adam; Wood, Clive R; Biedenkapp, Joseph C; TenHoor, Chris

    2015-01-01

    The therapeutic management of antibody-mediated autoimmune disease typically involves immunosuppressant and immunomodulatory strategies. However, perturbing the fundamental role of the neonatal Fc receptor (FcRn) in salvaging IgG from lysosomal degradation provides a novel approach - depleting the body of pathogenic immunoglobulin by preventing IgG binding to FcRn and thereby increasing the rate of IgG catabolism. Herein, we describe the discovery and preclinical evaluation of fully human monoclonal IgG antibody inhibitors of FcRn. Using phage display, we identified several potent inhibitors of human-FcRn in which binding to FcRn is pH-independent, with over 1000-fold higher affinity for human-FcRn than human IgG-Fc at pH 7.4. FcRn antagonism in vivo using a human-FcRn knock-in transgenic mouse model caused enhanced catabolism of exogenously administered human IgG. In non-human primates, we observed reductions in endogenous circulating IgG of >60% with no changes in albumin, IgM, or IgA. FcRn antagonism did not disrupt the ability of non-human primates to mount IgM/IgG primary and secondary immune responses. Interestingly, the therapeutic anti-FcRn antibodies had a short serum half-life but caused a prolonged reduction in IgG levels. This may be explained by the high affinity of the antibodies to FcRn at both acidic and neutral pH. These results provide important preclinical proof of concept data in support of FcRn antagonism as a novel approach to the treatment of antibody-mediated autoimmune diseases. PMID:25954273

  1. Antibodies of IgG, IgA and IgM isotypes against cyclic citrullinated peptide precede the development of rheumatoid arthritis

    PubMed Central

    2011-01-01

    Introduction We and others have previously shown that antibodies against cyclic citrullinated proteins (anti-CCP) precede the development of rheumatoid arthritis (RA) and in a more recent study we reported that individuals who subsequently developed RA had increased concentrations of several cytokines and chemokines years before the onset of symptoms of joint disease. Here we aimed to evaluate the prevalence and predictive values of anti-CCP antibodies of IgG, IgM and IgA isotype in individuals who subsequently developed RA and also to relate these to cytokines and chemokines, smoking, genetic factors and radiographic score. Methods A case-control study (1:4 ratio) was nested within the Medical Biobank and the Maternity cohorts of Northern Sweden. Patients with RA were identified from blood donors predating the onset of disease by years. Matched controls were selected randomly from the same registers. IgG, IgA and IgM anti-CCP2 antibodies were determined using EliA anti-CCP assay on ImmunoCAP 250 (Phadia AB, Uppsala, Sweden). Results Of 86 patients with RA identified as blood donors prior to the onset of symptoms, samples were available from 71 for analyses. The median (Q1 to Q3) predating time was 2.5 years (1.1 to 5.9 years). The sensitivity of anti-CCP antibodies in the pre-patient samples was 35.2% for IgG, 23.9% for IgA, and 11.8% for IgM. The presence of IgG and IgA anti-CCP antibodies was highly significant compared with controls. IgG and IgA anti-CCP2 predicted RA significantly in conditional logistic regression models odds ratio (OR) = 94.1, 95% confidence interval (CI) 12.7 to 695.4 and OR = 11.1, 95% CI 4.4 to 28.1, respectively, the IgM anti-CCP showed borderline significance OR = 2.5 95% CI 0.9 to 6.3. Concentrations of all anti-CCP isotypes increased the closer to the onset of symptoms the samples were collected with an earlier and higher increase for IgG and IgA compared with IgM anti-CCP. IgA and IgG anti-CCP positive individuals had different

  2. Sialylation of anti-histone immunoglobulin G autoantibodies determines their capabilities to participate in the clearance of late apoptotic cells.

    PubMed

    Magorivska, I; Muñoz, L E; Janko, C; Dumych, T; Rech, J; Schett, G; Nimmerjahn, F; Bilyy, R; Herrmann, M

    2016-04-01

    The Fc portion of immunoglobulin (Ig)G harbours a single glycosylation site. Glycan sialylation is critical for structure and for certain effector functions of IgG. Anti-histone IgG of patients with systemic lupus erythematosus is reportedly responsible for the recruitment of polymorphonuclear cells (PMN) to the clearance of apoptotic cells. Autoantibodies decorating secondary necrotic cells (SNEC) induce proinflammatory responses after activation of blood-borne phagocytes. Analysing the sialylation status of affinity-purified anti-histone IgG in patients with systemic lupus erythematosus (SLE), we demonstrated that the anti-histone IgG was contained preferentially in the non-sialylated fraction. In functional ex-vivo phagocytosis studies, non-sialylated anti-SNEC IgG directed SNEC preferentially into PMN but did not change their cytokine secretion profiles. In contrast, sialylated IgG reduced the phagocytosis by monocytes of SNEC. Moreover, the sialylated anti-SNEC IgG was not simply anti-inflammatory, but switched the cytokine secretion profiles from interleukin (IL)-6/IL-8 to tumour necrosis factor (TNF)-α/IL-1β. Here we describe how different sialylation statuses of IgG autoantibodies contribute to the complex inflammatory network that regulates chronic inflammation. PMID:26618514

  3. In a SLE mouse model the production of IgG autoantibody requires expression of activation-induced deaminase in early developing B cells

    PubMed Central

    Umiker, Benjamin R.; McDonald, Gabrielle; Larbi, Amma; Medina, Carlos O.; Reth, Michael; Imanishi-Kari, Thereza

    2014-01-01

    Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of pathogenic IgG anti-nuclear antibodies. Pathogenic IgG autoantibody production requires B-cell activation, leading to the production of activation-induced deaminase (AID) and class switching of IgM genes to IgG. To understand how and when B cells are activated to produce these IgG autoantibodies, we studied cells from 564Igi, a mouse model of SLE. 564Igi mice develop a disease profile closely resembling that found in human SLE patients, including the presence of IgG anti-nucleic acid antibodies. We have generated 564Igi mice that conditionally express an activation-induced cytidine deaminase transgene (Aicdatg), either in all B cells or only in mature B cells. Here we show that class-switched pathogenic IgG autoantibodies were produced only in 564Igi mice in which AID was functional in early developing B cells, resulting in loss of tolerance. Furthermore, we show that the absence of AID in early developing B cells also results in increased production of self-reactive IgM, indicating that AID, through somatic hypermutation (SHM), contributes to tolerance. Our results suggest that the pathophysiology of clinical SLE might also be dependent on AID expression in early developing B cells. PMID:25044405

  4. IgG subclass composition of antibodies to HBsAg in circulating immune complexes from patients with hepatitis B virus infections.

    PubMed Central

    Rath, S; Devey, M E

    1988-01-01

    The IgG subclass of antibody associated with hepatitis B surface antigen (HBsAg) in circulating immune complexes (CIC) from patients with either acute or chronic hepatitis B virus (HBV) infections was measured using an isotype and antigen-specific ELISA. All patients were HBsAg positive but were negative for free anti-HBs antibody. The subclass of antibody associated with HBsAg in CIC in both groups was predominantly IgG1 and IgG4. This is in contrast to free anti-HBs in convalescent sera from patients recovering from HBV infection, which are highly restricted to IgG1 and IgG3. The finding of high levels of IgG4 antibodies in CIC suggest that CIC containing this subclass may be cleared less efficiently than CIC containing antibodies of other subclasses. Formation of these CIC may be an important factor in the progression of infection to chronicity and may also be involved in the antigen-specific immunosuppression seen in early acute and chronic HBV infections. PMID:3396217

  5. Selective binding of IgG4 and other negatively charged plasma proteins in normal and diabetic human kidneys.

    PubMed Central

    Melvin, T.; Kim, Y.; Michael, A. F.

    1984-01-01

    Renal tissue from 9 patients with diabetes mellitus (4 with mild and 5 with end-stage disease) and 3 with antiglomerular basement membrane (GBM) nephritis, as well as 5 normal human kidneys, were examined by immunofluorescence microscopy for the presence of plasma proteins of varying isoelectric point (pI). In normal and diabetic kidneys, IgG deposition in basement membranes was restricted to IgG4 (pI 5.5-6.0), the subclass present in lowest concentration in human plasma. IgG1, IgG2, and IgG3 (pI 7.0-9.5) were not detected. In contrast, in anti-GBM nephritis, all four subclasses were present in a linear pattern in GBM. Other plasma proteins of low isoelectric point were detected in basement membranes: albumin (pI 4.9), alpha-1-acid glycoprotein (pI 2.7), amyloid P (pI 3.9-4.8), and alpha-1-antitrypsin (pI 4.5). These studies are consistent with the hypothesis that circulating anionic plasma proteins are electrostatically bound in vivo to positively charged moieties in normal and especially diabetic basement membranes. Images Figure 1 PMID:6375393

  6. An increased level of the Concanavalin A-positive IgG in the serum of patients with gastric cancer as evaluated by a lectin enzyme-linked immunosorbent assay (LELISA).

    PubMed

    Klaamas, K; Kodar, K; Kurtenkov, O

    2008-01-01

    All human immunoglobulins are glycosylated. The changes in IgG glycosylation are associated with autoimmune disorders and pregnancy. Little is known about IgG glycosylation in patients with cancer. A lectin enzyme-linked immunosorbent assay (LELISA) based method was developed for measuring the Concanavalin A - positive IgG in the serum. Its rationale is as follows: PtA was used as a capture agent for binding IgG via the Fc fragment. Then IgG and the ConA-positive glycans on the IgG were detected using an anti-human IgG-F(ab)2 alkaline phosphatase conjugate or biotinylated ConA, respectively. The index ConA binding/total IgG was calculated. Serum samples from patients with gastric carcinoma (n=53) and healthy blood transfusion donors (n=24) were analysed. The protein A-agarose and ConA-sepharose affinity chromatography was applied to the purification of IgG, ConA-positive IgG, and Fab fragments. The LELISA, SDS-PAGE and Western blot methods were used to analyse the purified IgG and Fab fragments. A significantly higher ConA binding to IgG was found in patients with cancer compared to that of blood donors (ConA index = 1.07+/-0.08 (95% CI) and 0.81+/-0.08, respectively; P=0.0002). In donors, a significant correlation between the level of IgG bound to PtA and the ConA binding (r=0.85; p<0.001) was observed. Patients with gastric cancer showed a less pronounced, though significant correlation (r=0.33; P=0.02). Only the Fd fragment of the Fabs derived from both total serum IgG and ConA-positive fraction of IgG contained the ConA-positive glycans. The comparison of the purified IgG and Fab fragments derived from healthy blood donors and patient with gastric cancer showed no difference in either SDS-PAGE, immunoblotting or LELISA pattern. The LELISA is simple, reproducible and suitable for the evaluation of IgG glycosylation changes. The level of ConA positive serum IgG was found to be increased in patients with cancer. No convincing evidence of the presence of

  7. Analysis of specific IgG titers against tick-borne encephalitis in patients with primary antibody deficiency under immunoglobulin substitution therapy: impact of plasma donor origin.

    PubMed

    Goldacker, Sigune; Witte, Torsten; Huzly, Daniela; Schlesier, Michael; Peter, Hans-Hartmut; Warnatz, Klaus

    2014-01-01

    Immunoglobulin (Ig) replacement therapy is effective in reducing infections in patients with primary antibody deficiency (PAD). Diversity of specific antibodies is achieved by pooling plasma from over 1000 donors usually of a given geographic region. However, there is no agreement with regard to an optimal vaccination schedule for plasma donors. Especially for tick-borne encephalitis (TBE), regional vaccination rates differ widely among populations due to the epidemiology of the disease. We analyzed specific antibody titers against TBE in comparison to total IgG levels in 162 serum samples collected from 110 PAD patients substituted with polyvalent intravenous IgG or subcutaneous IgG. Some patients received different IgG products over time leading to a total number of 122 different patient-IgG product combinations. Positive TBE-specific IgG levels were detected in 35 cases when measured by standard ELISA and could be confirmed by demonstration of neutralizing antibodies in 31 cases. The detection of specific antibody levels correlated with the geographic origin of the IgG preparations. No titers were detectable in patients substituted with IgG products from North-American donors, whereas variable degrees of anti-TBE titers were observed in patients receiving products from different European countries. We suggest considering the patients' personal risk for TBE when selecting an appropriate Ig preparation. These data support regional plasma donation in order to address the diverse local infection profile. PMID:25601868

  8. Albumin quotient, IgG concentration, and IgG index determinations in cerebrospinal fluid of neonatal foals.

    PubMed

    Andrews, F M; Geiser, D R; Sommardahl, C S; Green, E M; Provenza, M

    1994-06-01

    Total protein (TP), albumin, and IgG concentrations were measured in CSF from the atlanto-occipital (AO) and lumbosacral (LS) sites and in serum of 15 clinically normal neonatal foals < or = 10 days old (mean, 7.0 days). The albumin quotient (AQ; CSF albumin/serum albumin x 100) and IgG index ([CSF IgG/serum IgG] x [serum albumin/CSF albumin]), indicators of blood-brain barrier permeability and intrathecal IgG production, respectively, were then calculated. Mean +/- SD values obtained from the foals of this study were: serum albumin, 2,900 +/- 240 mg/dl; serum IgG, 1,325 +/- 686 mg/dl; AO CSF total protein (TP), 82.8 +/- 19.2 mg/dl; LS CSF TP, 83.6 +/- 16.1 mg/dl; AO CSF albumin, 52.0 +/- 8.6 mg/dl; LS CSF albumin, 53.8 +/- 15.7 mg/dl; AO CSF IgG, 10.2 +/- 5.5 mg/dl; LS CSF IgG, 9.9 +/- 5.7 mg/dl; AO AQ, 1.86 +/- 0.29; LS AQ, 1.85 +/- 0.51, AO IgG index, 0.52 +/- 0.28; and LS IgG index, 0.48 +/- 0.27. Significant difference between values for the AO and LS sites was not found. A CSF albumin concentration > 85.2 mg/dl or AQ > 2.4, as determined by mean +/- 2 SD, may indicate increased blood-brain barrier permeability. An IgG index value > 1.0 may indicate intrathecal IgG production. Values obtained for foals of this study should serve as baseline for comparison in the evaluation of blood-brain barrier permeability and intrathecal IgG production in neonatal foals with neurologic disease. PMID:7944008

  9. Chemoenzymatic Glycoengineering of Intact IgG Antibodies for Gain of Functions

    PubMed Central

    Huang, Wei; Giddens, John; Fan, Shu-Quan; Toonstra, Christian; Wang, Lai-Xi

    2012-01-01

    The fine structures of Fc N-glycans can modulate the effector functions of IgG antibodies. It has been demonstrated that lack of the core fucose on the Fc N-glycans leads to drastic enhancement of antibody-dependent cellular cytotoxicity (ADCC), while terminal α2,6-sialylation of Fc glycan plays a critical role for the anti-inflammatory activity of human intravenous immunoglobulin (IVIG). We describe in this paper a highly efficient chemoenzymatic method for site-selective Fc glycoengineering of intact monoclonal antibody and IVIG. Two new glycosynthase mutants (EndoS-D233A and D233Q) were generated by site-directed mutagenesis of EndoS (an endoglycosidase from Streptococcus pyogenes), and were found to be capable of effficiently transferring pre-defined N-glycans from corresponding glycan oxazolines to the Fc-deglycosylated intact IgGs without product hydrolysis. As a model study, rituximab (a therapeutic monoclonal antibody) was successfully transformed from mixtures of G0F, G1F and G2F glycoforms to well-defined homogeneous glycoforms, including fully sialylated (S2G2F) glycoform that may gain anti-inflammatory activity, a non-fucosylated G2 glycoform that showed significantly enhanced FcγIIIa receptor binding activity, and an azido-tagged glycoform that can be further transformed into other glycoforms. We also found that EndoS could selectively remove the Fc N-glycans in the presence of FAB glycosylation. This finding, coupled with the remarkable transglycosylation activity of the EndoS glycosynthase mutants, permitted a highly selective glycoengineering of the IVIG’s Fc glycans into a fully sialylated Fc glycoform, which may possess significantly enhanced anti-inflammatory activity. The glycoengineering approach described here provides a general platform to modulate the effector functions of IgG antibodies, enabling the optimization of therapeutic efficacy and gain of new functions of monoclonal antibodies and IVIG. PMID:22747414

  10. Intranasal antigen targeting to MHC class II molecules primes local IgA and serum IgG antibody responses in mice.

    PubMed

    Snider, D P; Underdown, B J; McDermott, M R

    1997-03-01

    Covalent conjugates of hen egg lysozyme (HEL) and anti-major histocompatibility complex (MHC) class II monoclonal antibodies (mAb) were used to immunize mice intranasally. Three weeks after intranasal (IN) priming, mice responded rapidly to IN challenge with a mixture of HEL and cholera toxin (CT), by producing large titres of anti-HEL IgA and IgG1 antibody in serum, and IgA antibody in nasal secretions. No secondary response to HEL plus CT occurred in mice that received no priming or mice primed with HEL alone. The secondary serum IgG antibody response was dominated by the IgG1 subclass. HEL combined with CT adjuvant worked much better than HEL alone in producing the secondary response. Control conjugates, containing an IgG isotype-matched mAb without specificity for mouse tissues, provided poor priming. Mice expressing MHC class II molecules, to which the anti-MHC II mAb could not bind, produced a weak antibody response compared with those that expressed the appropriate. MHC class II molecule. Our results demonstrate that immunotargeting to MHC class II molecules via the IN route allows priming of the local IgA and circulating IgG antibody, and indicate that this technique is a feasible approach for delivery of subunit vaccines in the upper respiratory tract. PMID:9155636

  11. IgG red blood cell autoantibodies in autoimmune hemolytic anemia bind to epitopes on red blood cell membrane band 3 glycoprotein

    SciTech Connect

    Victoria, E.J.; Pierce, S.W.; Branks, M.J.; Masouredis, S.P. )

    1990-01-01

    Red blood cell (RBC) autoantibodies from patients with IgG warm-type autoimmune hemolytic anemia were labeled with iodine 125 and their RBC binding behavior characterized. Epitope-bearing RBC membrane polypeptides were identified after autoantibody immunoprecipitation of labeled membranes and immunoblotting. Immunoaffinity isolation of labeled membrane proteins with 12 different IgG hemolytic autoantibodies with protein A-agarose revealed a major polypeptide at Mr 95 to 110 kd, which coelectrophoresed on sodium dodecylsulfate-polyacrylamide gel electrophoresis with a membrane component isolated with sheep IgG anti-band 3. Immunoprecipitation studies with chymotrypsinized RBCs resulted in the recovery of two labeled membrane polypeptides with molecular weights characteristically resulting from the chymotryptic fragmentation of band 3. Immunoblotting with sheep IgG anti-band 3 of the immunoprecipitated polypeptides confirmed that hemolytic autoantibody binding led to recovery of band 3 or its fragments. Two 125I-labeled IgG hemolytic autoantibodies showed binding behavior consistent with epitope localization on band 3. The labeled RBC autoantibodies bound immunospecifically to all types of human RBC tested, including those of rare Rh type (Rh-null, D--) at a site density of approximately 10(6) per RBC. The 125I-IgG in two labeled autoantibodies was 84% and 92% adsorbable by human and higher nonhuman primate RBCs. Antigen-negative animal RBC bound less than 10%, consistent with immunospecific RBC binding. IgG-1 was the major subclass in five autoantibodies tested; one of six fixed complement; and autoantibody IgG appeared polyclonal by isoelectric focusing. We conclude that IgG eluted from RBCs of patients with autoimmune hemolytic anemia consists predominantly of a single totally RBC-adsorbable antibody population that binds to antigenic determinants on band 3.

  12. IgG4 disease: The great masquerader.

    PubMed

    Yadav, Divya; Liu, Xiuli; Chahal, Prabhleen

    2016-06-01

    Systemic IgG4 disease can have a wide spectrum of clinical presentation, which can mimic several other disease entities. In this report, we describe a series of two patients with IgG4-related disease who were referred to us initially with the diagnosis of acute cholecystitis and the second patient with metastatic pancreatic adenocarcinoma with peritoneal metastasis respectively. PMID:26164258

  13. IgG4-Related Disease: A Multispecialty Condition

    PubMed Central

    da Fonseca, Emanuela Pimenta; Santiago, Mittermayer Barreto

    2014-01-01

    IgG4-related disease (IgG4-RD) is a recently recognized group of conditions, characterized by tumor-like swelling of involved organs, lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells, variable degrees of fibrosis, and elevated serum IgG4 concentrations. Currently IgG4-RD is recognized as a systemic condition that can affect several organs and tissues. Herein we report the case of a 34-year-old male patient who was admitted to our hospital with diffuse abdominal pain, weight loss, and painful stiffness in his neck. He had a history of tumoral mass of the left maxillary region, right palpebral ptosis with protrusion of the eyeball, and chronic dry cough for about 6 years. Laboratory tests revealed polyclonal hypergammaglobulinemia and increased serum IgG4 levels. Immunohistochemical staining of the maxillary biopsy was compatible with IgG4-RD. He had an excellent response to corticosteroid therapy. This case highlights that IgG4-RD should be included in the differential diagnosis with multisystem diseases. PMID:25506457

  14. Interaction of human IgG chimeric antibodies with the human FcRI and FcRII receptors: requirements for antibody-mediated host cell-target cell interaction.

    PubMed

    Walker, M R; Woof, J M; Brüggemann, M; Jefferis, R; Burton, D R

    1989-04-01

    Chimeric monoclonal antibodies (McAb), specific for the hapten 5-iodo-4-hydroxy-3-nitrophenacetyl (NIP), expressing human IgG1, IgG2, IgG3 and IgG4 subclass constant domains, have been examined for their ability to interact with the human FcRII receptor. Human red blood cells (RBC) sensitized by each of these McAbs have been assayed for their ability to form rosettes with the human histiocytic lymphoma U937 cell line, human B cell line Daudi and erythroblastoid K562 cell line. IgG1 and IgG3 sensitized RBC formed significant rosettes with the FcR- and FcRII+ Daudi and K562 cell lines, the percentage of cells forming rosettes being directly proportional to the degree of sensitization of the RBC. Bromelin treating Daudi cells did not alter this pattern of reactivity, whereas bromelin treated FcRI+ and FcRII+ U937 cells formed significant resettes with IgG1, IgG3 and IgG4 sensitized RBC, demonstrating a difference in the IgG subclass specificity between human FcRI and FcRII. Murine IgG2b anti-NIP sensitized RBC did not form rosettes with any cell line tested; however, RBC sensitized by some members of a panel of murine IgG1 McAb, specific for the glycophorin A molecule, were able to form rosettes with Daudi, U937 and K562 cells. This interaction was enhanced by bromelin treating the Daudi or U937 cells and can be correlated to the disposition of the epitopes recognized, relative to the target cell membrane, those McAbs recognizing epitopes furthest from the RBC surface being most effective in interacting with FcRII. The data are interpreted in terms of a simple model for antibody-mediated cell--cell interaction. PMID:2716734

  15. Mucosal IgG Levels Correlate Better with Respiratory Syncytial Virus Load and Inflammation than Plasma IgG Levels

    PubMed Central

    Vissers, Marloes; Ahout, Inge M. L.; de Jonge, Marien I.

    2015-01-01

    Maternal vaccination is currently considered a strategy against respiratory syncytial virus (RSV) infections. In RSV-infected infants, high mucosal IgG levels correlated better with reduced RSV load and lower mucosal CXCL10 levels than plasma IgG levels. For future vaccination strategies against RSV, more focus should be on the mucosal humoral immune response. PMID:26656116

  16. Diagnostic Performance of Serum IgG4 Levels in Patients With IgG4-Related Disease

    PubMed Central

    Yu, Kuang-Hui; Chan, Tien-Ming; Tsai, Ping-Han; Chen, Ching-Hui; Chang, Pi-Yueh

    2015-01-01

    Abstract The aim of this study is to study the clinical features and diagnostic performance of IgG4 in Chinese populations with IgG4-related diseases (IgG4-RDs). The medical records of 2901 adult subjects who underwent serum IgG4 level tests conducted between December 2007 and May 2014 were reviewed. Serum concentrations of IgG4 were measured in 2901 cases, including 161 (5.6%) patients with IgG4-RD and 2740 (94.4%) patients without IgG4-RD (non-IgG4-RD group). The mean age of the IgG4-RD patients was 58.4 ± 16.1 years (range: 21–87), and 48 (29.8%) were women. The mean serum IgG4 level was significantly much higher in IgG4-RD patients than in non-IgG4-RD (1062.6 vs 104.3 mg/dL, P < 0.001) participants. For IgG4 >135 mg/dL, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR)+, and LR− were 86%, 77%, 18%, 99%, 3.70, and 0.19, respectively. When the upper limit of normal was doubled for an IgG4 >270 mg/dL, the corresponding data were 75%, 94%, 43%, 98%, 12.79, and 0.26, respectively. For IgG4 >405 mg/dL (tripling the upper limit of normal), the corresponding data were 62%, 98%, 68%, 98%, 37.00, and 0.39, respectively. When calculated according to the manufacturer's package insert cutoff (>201 mg/dL) for the diagnosis of IgG4-RD, the corresponding sensitivity, specificity, PPV, NPV, LR+, and LR− were 80%, 89%, 29%, 99%, 7.00, and 0.23, respectively. For IgG4 >402 mg/dL (>2× the upper limit of the normal range), the corresponding data were 62%, 98%, 68%, 98%, 36.21, and 0.39, respectively. For IgG4 >603 mg/dL (>3× the upper limit of the normal range), the corresponding data were 50%, 99%, 84%, 97%, 90.77 and 0.51, respectively. The optimal cutoff value of serum IgG4 (measured by nephelometry using a Siemens BN ProSpec instrument and Siemens reagent) for the diagnosis of IgG4-RD was 248 mg/dL, the sensitivity and specificity were 77.6% and 92.8%, respectively. The present

  17. IgG transport across mucosal barriers by neonatal Fc receptor for IgG and mucosal immunity.

    PubMed

    Yoshida, Masaru; Masuda, Atsuhiro; Kuo, Timothy T; Kobayashi, Kanna; Claypool, Steven M; Takagawa, Tetsuya; Kutsumi, Hiromu; Azuma, Takeshi; Lencer, Wayne I; Blumberg, Richard S

    2006-12-01

    Mucosal secretions of the human gastrointestinal, respiratory, and genital tracts contain significant quantities of IgG. The neonatal Fc receptor for IgG (FcRn) plays a major role in regulating host IgG levels and transporting IgG and associated antigens across polarized epithelial barriers. The FcRn can then recycle the IgG/antigen complex back across the intestinal barrier into the lamina propria for processing by dendritic cells and presentation to CD4(+) T cells in regional organized lymphoid structures. FcRn, through its ability to secrete and absorb IgG, thus integrates luminal antigen encounters with systemic immune compartments and, as such, provides essential host defense and immunoregulatory functions at the mucosal surfaces. PMID:17051393

  18. Frequency of Wra antigen and anti-Wra in Brazilian blood donors

    PubMed Central

    Muniz, Janaína Guilhem; Arnoni, Carine Prisco; Gazito, Diana; de Medeiros Person, Rosangela; Vendrame, Tatiana Aparecida de Paula; Latini, Flavia Roche Moreira; Castilho, Lilian

    2015-01-01

    Background Wra is a low-incidence antigen, which is antithetical to the high prevalence red blood cell antigen, Wrb. Anti-Wra is a naturally occurring antibody that is found in approximately 1–2% of blood donors. The aim of this study was to determine the frequency of Wra and anti-Wra in Brazilian blood donors. Methods A total of 1662 Brazilian blood donors were molecularly analyzed using the SNaPshot methodology to determine the WR*A/B alleles and to predict the frequency of the Wra antigen. To detect the anti-Wra, samples from 1049 blood donors were analyzed using a gel test with Wr(a+) red blood cells. The serum was treated with dithiothreitol (DTT) to determine the immunoglobulin classes. Immunoglobulin (Ig)-G isotype classification was performed in a gel test using the IgG1/IgG3 card. A monocyte monolayer assay was employed to predict the clinical significance of IgG anti-Wra. Results Of the 1662 donors, only one sample had the DI*02.03 allele in heterozygous predicting the Wr(a+b+) phenotype. Anti-Wra was detected in 34 (3.24%) samples, 64.7% in females and 35.3% in males. Regarding the immunoglobulin class, eight (23.5%) cases of anti-Wra were classified as IgG and 26 (76.5%) as IgM. Of the eight cases of IgG anti-Wra, four were IgG1, two were IgG3 and three anti-Wra were not IgG3 or IgG1, and thus probably IgG2 or IgG4. The results of the monocyte monolayer assay showed that IgG anti-Wra might be of clinical significance. Conclusion This study shows a very low frequency (0.06%) of the Wra antigen in Brazilian blood donors. Additionally, it shows that the frequency of anti-Wra in this population is higher than previously reported. PMID:26408365

  19. IgG and IgM autoantibody differences in discoid and systemic lupus patients.

    PubMed

    Chong, Benjamin F; Tseng, Lin-chiang; Lee, Thomas; Vasquez, Rebecca; Li, Quan Z; Zhang, Song; Karp, David R; Olsen, Nancy J; Mohan, Chandra

    2012-12-01

    Systemic lupus erythematosus (SLE) patients with discoid lupus erythematosus (DLE) were reported to have milder disease. To test this observation, we used sandwich arrays containing 98 autoantigens to compare autoantibody profiles of SLE subjects without DLE (DLE-SLE+) (N=9), SLE subjects with DLE (DLE+SLE+) (N=10), DLE subjects without SLE (DLE+SLE-) (N=11), and healthy controls (N=11). We validated differentially expressed autoantibodies using immunoassays in DLE-SLE+ (N=18), DLE+SLE+ (N=17), DLE+SLE- (N=23), and healthy subjects (N=22). Arrays showed 15 IgG autoantibodies (10 against nuclear antigens) and 4 IgM autoantibodies that were differentially expressed (q-value<0.05). DLE-SLE+ subjects had higher IgG autoantibodies against double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), double-stranded RNA (dsRNA), histone H2A and H2B, and SS-A (52 kDa) compared with all other groups including DLE+SLE+ subjects (P<0.05). Immunoassays measuring anti-dsDNA, -ssDNA, and -SS-A (52 kDa) IgG autoantibodies showed similar trends (P<0.05). Healthy and DLE+SLE- subjects expressed higher IgM autoantibodies against alpha beta crystallin, lipopolysaccharide, heat-shock cognate 70, and desmoglein-3 compared with DLE+SLE+ and DLE-SLE+ subjects. IgG:IgM ratios of autoantibodies against nuclear antigens progressively rose from healthy to DLE-SLE+ subjects. In conclusion, lower IgG autoantibodies against nuclear antigens in DLE+SLE+ versus DLE-SLE+ subjects suggest that DLE indicates lower disease severity. Higher IgM autoantibodies against selected antigens in healthy and DLE+SLE- subjects may be nonpathogenic. PMID:22763789

  20. DNA-hydrolysing activity of IgG antibodies from the sera of patients with schizophrenia

    PubMed Central

    Ermakov, Evgeny A.; Smirnova, Ludmila P.; Parkhomenko, Taisiya A.; Dmitrenok, Pavel S.; Krotenko, Nina M.; Fattakhov, Nikolai S.; Bokhan, Nikolay A.; Semke, Arkadiy V.; Ivanova, Svetlana A.; Buneva, Valentina N.; Nevinsky, Georgy A.

    2015-01-01

    It is believed that damage to the membranes of brain cells of schizophrenia (SCZ) patients induces the formation of autoantigens and autoantibodies. Nevertheless, the importance of immunological changes leading to the loss of tolerance to self-antigens in the genesis of SCZ has not been established. The MALDI mass spectra of the IgG light chains of 20 healthy donors were relatively homogeneous and characterized by one peak with only one maximum. In contrast to the healthy donors, the MALDI mass spectra of IgG light chains corresponding to 20 SCZ patients demonstrated, similarly to 20 autoimmune systemic lupus erythematosus (SLE) patients, two maxima of a comparable intensity. In addition, the MALDI spectra of the IgG light chains of five SLE and four SCZ patients contained a small additional brightly pronounced peak with remarkably lower molecular mass compared with the main one. DNase autoantibodies (abzymes) can be found in the blood of patients with several autoimmune diseases, while the blood of healthy donors or patients with diseases without a significant disturbance of the immune status does not contain DNase abzymes. Here, we present the first analysis of anti-DNA antibodies and DNase abzymes in the sera of SCZ patients. Several strict criteria have been applied to show that the DNase activity is an intrinsic property of IgGs from the sera of SCZ patients. The sera of approximately 30% of SCZ patients displayed a higher content of antibodies (compared with 37% of SLE) interacting with single- and double-stranded DNA compared with healthy donors. Antibodies with DNase activity were revealed in 80% of the patients. These data indicate that some SCZ patients may show signs of typical autoimmune processes to a certain extent. PMID:26382278

  1. IgG and IgM autoantibody differences in discoid and systemic lupus patients

    PubMed Central

    Chong, Benjamin F.; Tseng, Lin-chiang; Lee, Thomas; Vasquez, Rebecca; Li, Quan Z.; Zhang, Song; Karp, David R.; Olsen, Nancy J.; Mohan, Chandra

    2012-01-01

    Systemic lupus (SLE) patients with discoid lupus (DLE) were reported to have milder disease. To test this observation, we employed sandwich arrays containing 98 autoantigens to compare autoantibody profiles of SLE subjects without DLE (DLE−SLE+) (N=9), SLE subjects with DLE (DLE+SLE+) (N=10), DLE subjects without SLE (DLE+SLE−) (N=11), and healthy controls (N=11). We validated differentially expressed autoantibodies using immunoassays in DLE−SLE+ (N=18), DLE+SLE+ (N=17), DLE+SLE− (N=23), and healthy subjects (N=22). Arrays showed 15 IgG autoantibodies (ten against nuclear antigens) and four IgM autoantibodies that were differentially expressed (q-value<0.05). DLE−SLE+ subjects had higher IgG autoantibodies against dsDNA, ssDNA, dsRNA, histone H2A and H2B, and SS-A (52 kDa) than all other groups including DLE+SLE+ subjects (p<0.05). Immunoassays measuring anti-dsDNA, -ssDNA, and -SS-A (52 kDa) IgG autoantibodies showed similar trends (p<0.05). Healthy and DLE+SLE−subjects expressed higher IgM autoantibodies against alpha beta crystallin, lipopolysaccharide, heat shock cognate 70, and desmoglein-3 than DLE+SLE+ and DLE−SLE+ subjects. IgG:IgM ratios of autoantibodies against nuclear antigens progressively rose from healthy to DLE−SLE+ subjects. In conclusion, lower IgG autoantibodies against nuclear antigens in DLE+SLE+ versus DLE−SLE+ subjects suggest that DLE indicates lower disease severity. Higher IgM autoantibodies against selected antigens in healthy and DLE+SLE−subjects may be non-pathogenic. PMID:22763789

  2. Relative stabilities of IgG1 and IgG4 Fab domains: Influence of the light–heavy interchain disulfide bond architecture

    PubMed Central

    Heads, James T; Adams, Ralph; D'Hooghe, Lena E; Page, Matt J T; Humphreys, David P; Popplewell, Andrew G; Lawson, Alastair D; Henry, Alistair J

    2012-01-01

    The stability of therapeutic antibodies is a prime pharmaceutical concern. In this work we examined thermal stability differences between human IgG1 and IgG4 Fab domains containing the same variable regions using the thermofluor assay. It was found that the IgG1 Fab domain is up to 11°C more stable than the IgG4 Fab domain containing the same variable region. We investigated the cause of this difference with the aim of developing a molecule with the enhanced stability of the IgG1 Fab and the biological properties of an IgG4 Fc. We found that replacing the seven residues, which differ between IgG1 CH1 and IgG4 CH1 domains, while retaining the native IgG1 light-heavy interchain disulfide (L–H) bond, did not affect thermal stability. Introducing the IgG1 type L–H interchain disulfide bond (DSB) into the IgG4 Fab resulted in an increase in thermal stability to levels observed in the IgG1 Fab with the same variable region. Conversely, replacement of the IgG1 L–H interchain DSB with the IgG4 type L–H interchain DSB reduced the thermal stability. We utilized the increased stability of the IgG1 Fab and designed a hybrid antibody with an IgG1 CH1 linked to an IgG4 Fc via an IgG1 hinge. This construct has the expected biophysical properties of both the IgG4 Fc and IgG1 Fab domains and may therefore be a pharmaceutically relevant format. PMID:22761163

  3. Cytomegalovirus IgG Level and Avidity in Breastfeeding Infants of HIV-Infected Mothers in Malawi

    PubMed Central

    Wiener, Jeffrey; Chang, Tiffany S.; Dollard, Sheila C.; Amin, Minal M.; Ellington, Sascha; Kayira, Dumbani; van der Horst, Charles; Jamieson, Denise J.

    2015-01-01

    Cytomegalovirus (CMV) infection is common among infants of HIV-infected mothers in resource-limited settings. We examined the prevalence and timing of infant CMV infection during the first year of life using IgG antibody and avidity among HIV-exposed infants in Malawi and correlated the results with the presence of detectable CMV DNA in the blood. The Breastfeeding, Antiretrovirals and Nutrition (BAN) study randomized 2,369 mothers and their infants to maternal antiretrovirals, infant nevirapine, or neither for 28 weeks of breastfeeding, followed by weaning. Stored plasma specimens were tested for CMV IgG and antibody avidity from a random subset of infants who had been previously tested with blood CMV PCR and had available specimens at birth and at 24 and 48 weeks of age. Ninety-four of 127 infants (74.0%) tested at 24 weeks of age had CMV IgG of low or intermediate avidity, signifying primary CMV infections. An additional 22 infants (17.3%) had IgG of high avidity; 19 of them had CMV DNA detected in their blood, indicating infant infections. Taken together, these results show that the estimated prevalence of CMV infection at 24 weeks was 88.9%. By 48 weeks of age, 81.3% of infants had anti-CMV IgG; most of them (70.9%) had IgG of high avidity. The CMV serology and avidity testing, combined with the PCR results, confirmed a high rate of primary CMV infection by 6 months of life among breastfeeding infants of HIV-infected mothers. The CMV PCR in blood detected most, but not all, infant CMV infections. PMID:26424831

  4. Structural characterization of anti-inflammatory Immunoglobulin G Fc proteins

    PubMed Central

    Ahmed, Alysia A.; Giddens, John; Pincetic, Andrew; Lomino, Joseph V.; Ravetch, Jeffrey V.; Wang, Lai-Xi; Bjorkman, Pamela J.

    2014-01-01

    Immunoglobulin G (IgG) is a central mediator of host defense due to its ability to recognize and eliminate pathogens. The recognition and effector responses are encoded on distinct regions of IgGs. The diversity of the antigen recognition Fab domains accounts for IgG's ability to bind with high specificity to essentially any antigen. Recent studies have indicated that the Fc effector domain also displays considerable heterogeneity, accounting for its complex effector functions of inflammation, modulation and immune suppression. Therapeutic anti-tumor antibodies, for example, require the pro-inflammatory properties of the IgG Fc to eliminate tumor cells, while the anti-inflammatory activity of Intravenous Immunoglobulin G (IVIG) requires specific Fc glycans for activity. In particular, the anti-inflammatory activity of IVIG is ascribed to a small population of IgGs in which the Asn297-linked complex N-glycans attached to each Fc CH2 domain include terminal α2,6-linked sialic acids. We used chemoenzymatic glycoengineering to prepare fully di-sialylated IgG Fc and solved its crystal structure. Comparison of the structures of asialylated Fc, sialylated Fc, and F241A Fc, a mutant that displays increased glycan sialylation, suggests that increased conformational flexibility of the CH2 domain is associated with the switch from pro- to anti-inflammatory activity of the Fc. PMID:25036289

  5. Soluble Monomeric IgG1 Fc*

    PubMed Central

    Ying, Tianlei; Chen, Weizao; Gong, Rui; Feng, Yang; Dimitrov, Dimiter S.

    2012-01-01

    Antibody fragments are emerging as promising biopharmaceuticals because of their relatively small size and other unique properties. However, compared with full-size antibodies, these antibody fragments lack the ability to bind the neonatal Fc receptor (FcRn) and have reduced half-lives. Fc engineered to bind antigens but preserve interactions with FcRn and Fc fused with monomeric proteins currently are being developed as candidate therapeutics with prolonged half-lives; in these and other cases, Fc is a dimer of two CH2-CH3 chains. To further reduce the size of Fc but preserve FcRn binding, we generated three human soluble monomeric IgG1 Fcs (mFcs) by using a combination of structure-based rational protein design combined with multiple screening strategies. These mFcs were highly soluble and retained binding to human FcRn comparable with that of Fc. These results provide direct experimental evidence that efficient binding to human FcRn does not require human Fc dimerization. The newly identified mFcs are promising for the development of mFc fusion proteins and for novel types of mFc-based therapeutic antibodies of small size and long half-lives. PMID:22518843

  6. IgG4-related disease of the rectum

    PubMed Central

    Choi, Sung-Bong; Lim, Chul-Hyun; Cha, Myung-Guen

    2016-01-01

    IgG4-related disease is a relatively new disease entity characterized by elevated serum IgG4 levels and marked infiltration of IgG4-positive plasma cells in lesions. Organ enlargement or nodular lesions consisting of abundant infiltration of lymphocytes and IgG4-positive plasma cells and fibrosis are seen in various organs throughout. We encountered a patient with an inflammatory pseudotumor of the rectum, which was histopathologically confirmed to be an IgG4-related disease. The patient was a 28-year-old woman who had constipation for 3 months. The endoluminal ultrasonography showed a lesion that was heterogeneous and low echogenic in lower rectum. The result of colonoscopic biopsy findings was of chronic proctitis with lymphoid aggregates. For a confirmative diagnosis, excision was performed. Histopathological examination represented plasma cell infiltration and fibrosis. Immunohistochemistry revealed prominence of IgG4-positive plasma cells and confirmed the diagnosis of IgG4-related disease. The patient is currently under observation on low-dose oral prednisolone without relapse. PMID:27186575

  7. Abnormal regulation of IgG production in multiple sclerosis.

    PubMed

    Goust, J M; Hogan, E L; Arnaud, P

    1982-03-01

    After stimulation with pokeweed mitogen (PWM), peripheral blood mononuclear cells (MNC) from patients with active multiple sclerosis (MS) produced significantly more IgG (8595 ng per milliliter, p less than 0.01) then MNC from normal age-matched controls (5477 ng per milliliter), whereas those tested during stable periods produced less IgG (4076 ng per milliliter, p less than 0.01). Treatment of MNC with sodium periodate (SP) generated suppressor cells for PWM-driven IgG production in normal controls and in most of the stable MS patients but in only 26% of those during active disease, in whom an increase in IgG production was often seen. This suggests a deficiency of inducible suppressor T cells associated with a supranormal B-cell response to polyclonal activation; T lymphocytes obtained from MS patients during active episodes strongly suppressed IgG production by normal B lymphocytes, whereas their B cells often produced more IgG in the presence of normal T cells. In active MS, a relative B-cell unresponsiveness to activated suppressor T cells would leave helper signals unbalanced, thus leading to increased B-cell activation, which might deplete the pool of inducible suppressor cells for IgG production. PMID:6460946

  8. Cysteine Racemization on IgG Heavy and Light Chains

    PubMed Central

    Zhang, Qingchun; Flynn, Gregory C.

    2013-01-01

    Under basic pH conditions, the heavy chain 220-light chain 214 (H220-L214) disulfide bond, found in the flexible hinge region of an IgG1, can convert to a thioether. Similar conditions also result in racemization of the H220 cysteine. Here, we report that racemization occurs on both H220 and L214 on an IgG1 with a λ light chain (IgG1λ) but almost entirely on H220 of an IgGl with a κ light chain (IgG1κ) under similar conditions. Likewise, racemization was detected at significant levels on H220 and L214 on endogenous human IgG1λ but only at the H220 position on IgG1κ. Low but measurable levels of d-cysteines were found on IgG2 cysteines in the hinge region, both with monoclonal antibodies incubated under basic pH conditions and on antibodies isolated from human serum. A simplified reaction mechanism involving reversible β-elimination on the cysteine is presented that accounts for both base-catalyzed racemization and thioether formation at the hinge disulfide. PMID:24142697

  9. Glycosylation of plasma IgG in colorectal cancer prognosis

    PubMed Central

    Theodoratou, Evropi; Thaçi, Kujtim; Agakov, Felix; Timofeeva, Maria N.; Štambuk, Jerko; Pučić-Baković, Maja; Vučković, Frano; Orchard, Peter; Agakova, Anna; Din, Farhat V. N.; Brown, Ewan; Rudd, Pauline M.; Farrington, Susan M.; Dunlop, Malcolm G.; Campbell, Harry; Lauc, Gordan

    2016-01-01

    In this study we demonstrate the potential value of Immunoglobulin G (IgG) glycosylation as a novel prognostic biomarker of colorectal cancer (CRC). We analysed plasma IgG glycans in 1229 CRC patients and correlated with survival outcomes. We assessed the predictive value of clinical algorithms and compared this to algorithms that also included glycan predictors. Decreased galactosylation, decreased sialylation (of fucosylated IgG glycan structures) and increased bisecting GlcNAc in IgG glycan structures were strongly associated with all-cause (q < 0.01) and CRC mortality (q = 0.04 for galactosylation and sialylation). Clinical algorithms showed good prediction of all-cause and CRC mortality (Harrell’s C: 0.73, 0.77; AUC: 0.75, 0.79, IDI: 0.02, 0.04 respectively). The inclusion of IgG glycan data did not lead to any statistically significant improvements overall, but it improved the prediction over clinical models for stage 4 patients with the shortest follow-up time until death, with the median gain in the test AUC of 0.08. These glycan differences are consistent with significantly increased IgG pro-inflammatory activity being associated with poorer CRC prognosis, especially in late stage CRC. In the absence of validated biomarkers to improve upon prognostic information from existing clinicopathological factors, the potential of these novel IgG glycan biomarkers merits further investigation. PMID:27302279

  10. Glycosylation of plasma IgG in colorectal cancer prognosis.

    PubMed

    Theodoratou, Evropi; Thaçi, Kujtim; Agakov, Felix; Timofeeva, Maria N; Štambuk, Jerko; Pučić-Baković, Maja; Vučković, Frano; Orchard, Peter; Agakova, Anna; Din, Farhat V N; Brown, Ewan; Rudd, Pauline M; Farrington, Susan M; Dunlop, Malcolm G; Campbell, Harry; Lauc, Gordan

    2016-01-01

    In this study we demonstrate the potential value of Immunoglobulin G (IgG) glycosylation as a novel prognostic biomarker of colorectal cancer (CRC). We analysed plasma IgG glycans in 1229 CRC patients and correlated with survival outcomes. We assessed the predictive value of clinical algorithms and compared this to algorithms that also included glycan predictors. Decreased galactosylation, decreased sialylation (of fucosylated IgG glycan structures) and increased bisecting GlcNAc in IgG glycan structures were strongly associated with all-cause (q < 0.01) and CRC mortality (q = 0.04 for galactosylation and sialylation). Clinical algorithms showed good prediction of all-cause and CRC mortality (Harrell's C: 0.73, 0.77; AUC: 0.75, 0.79, IDI: 0.02, 0.04 respectively). The inclusion of IgG glycan data did not lead to any statistically significant improvements overall, but it improved the prediction over clinical models for stage 4 patients with the shortest follow-up time until death, with the median gain in the test AUC of 0.08. These glycan differences are consistent with significantly increased IgG pro-inflammatory activity being associated with poorer CRC prognosis, especially in late stage CRC. In the absence of validated biomarkers to improve upon prognostic information from existing clinicopathological factors, the potential of these novel IgG glycan biomarkers merits further investigation. PMID:27302279