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Sample records for cytotoxic-t-lymphocyte memory induction

  1. A new theory of cytotoxic T-lymphocyte memory: implications for HIV treatment.

    PubMed Central

    Wodarz, D; Page, K M; Arnaout, R A; Thomsen, A R; Lifson, J D; Nowak, M A

    2000-01-01

    We use simple mathematical models to examine the dynamics of primary and secondary cytotoxic T-lymphocyte (CTL) responses to viral infections. In particular, we are interested in conditions required to resolve the infection and to protect the host upon secondary challenge. While protection against reinfection is only effective in a restricted set of circumstances, we find that resolution of the primary infection requires persistence of CTL precursors (GTLp), as well as a fast rate of activation of the CTLp. Since these are commonly the defining characteristics of CTL memory, we propose that CTL memory may have evolved in order to clear the virus during primary challenge. We show experimental data from lymphocytic choriomeningitis virus infection in mice, supporting our theory on CTL memory. We adapt our models to HIV and find that immune impairment during the primary phase of the infection may result in the failure to establish CTL memory which in turn leads to viral persistence. Based on our models we suggest conceptual treatment regimes which ensure establishment of CTL memory. This would allow the immune response to control HIV in the long term in the absence of continued therapy. PMID:10794051

  2. Induction of cytotoxic T-lymphocytes by electroporation-enhanced needle-free skin immunization.

    PubMed

    Zhao, Y L; Murthy, S N; Manjili, M H; Guan, L J; Sen, A; Hui, S W

    2006-02-27

    A needle-free method based on transcutaneous electroporation is described for delivering peptide vaccines. The K(b)-binding OVA-peptide SIINFEKL was used as an example to induce the peptide-specific cytotoxic T-lymphocytes (CTL) response in mice. A saturated anionic lipid was added during electroporation, and post-pulse electro-osmosis was applied to enhance the vaccine delivery. Electroporation was found to stimulate the exodus of Langerhans cells (LC) from the skin. The peptide transported into and through murine skin was measured using a Franz diffusion apparatus. Most peptide was retained in the skin rather than passing through the skin in the process. The peptide was delivered to the dorsal skin of mice by in vivo electroporation. An electroporation-transportable oligonucleotide with CpG motif was used as adjuvant. The efficacy of peptide delivery was comparable to that of intradermally injected with Freund's complete adjuvant (FCA). Peptide-specific CTL response to the vaccine delivered by needle-free electroporation/electro-osmosis was equivalent to that delivered by intradermal injection, as determined by production of the peptide-specific IFN-gamma in ELISPOT assay.

  3. The Suppressed Induction of Human Mature Cytotoxic T Lymphocytes Caused by Asbestos Is Not due to Interleukin-2 Insufficiency.

    PubMed

    Kumagai-Takei, Naoko; Nishimura, Yasumitsu; Matsuzaki, Hidenori; Lee, Suni; Yoshitome, Kei; Hayashi, Hiroaki; Otsuki, Takemi

    2016-01-01

    We previously reported that exposure to chrysotile B (CB) asbestos suppressed the induction of mature cytotoxic T lymphocytes (CTLs) during mixed lymphocyte reaction assays (MLRs) with a decrease in the proliferation of immature CTLs. However, the mechanism responsible for the effect of asbestos fibers on the differentiation of CTLs remains unclear. Since interleukin-2 (IL-2) is a regulator of T lymphocyte proliferation, we examined the effect of IL-2 addition on suppressed CTL differentiation in CB-exposed cultures using flow cytometry (FCM). When IL-2 was added at 1 ng/mL on the second day of MLRs, the asbestos-caused decreases in the proliferation and percentages of CD25(+) and CD45RO(+) cells in CD8(+) lymphocytes were not recovered by IL-2 addition, although the decrease in percentage of granzyme B(+) cells was partially recovered. CD8(+) lymphocytes from the IL-2-treated culture with asbestos showed the same degree of cytotoxicity as those in cultures without IL-2 or asbestos. These findings indicate that IL-2 insufficiency is not the main cause for the suppressed induction of CTLs by asbestos exposure, although they suggest a potential for the improvement of such suppressed CTL functions. Secretory factors other than IL-2 in addition to membrane-bound stimulatory molecules may play a role in asbestos-caused suppressed CTL differentiation.

  4. The Suppressed Induction of Human Mature Cytotoxic T Lymphocytes Caused by Asbestos Is Not due to Interleukin-2 Insufficiency

    PubMed Central

    Kumagai-Takei, Naoko; Lee, Suni; Yoshitome, Kei; Hayashi, Hiroaki

    2016-01-01

    We previously reported that exposure to chrysotile B (CB) asbestos suppressed the induction of mature cytotoxic T lymphocytes (CTLs) during mixed lymphocyte reaction assays (MLRs) with a decrease in the proliferation of immature CTLs. However, the mechanism responsible for the effect of asbestos fibers on the differentiation of CTLs remains unclear. Since interleukin-2 (IL-2) is a regulator of T lymphocyte proliferation, we examined the effect of IL-2 addition on suppressed CTL differentiation in CB-exposed cultures using flow cytometry (FCM). When IL-2 was added at 1 ng/mL on the second day of MLRs, the asbestos-caused decreases in the proliferation and percentages of CD25+ and CD45RO+ cells in CD8+ lymphocytes were not recovered by IL-2 addition, although the decrease in percentage of granzyme B+ cells was partially recovered. CD8+ lymphocytes from the IL-2-treated culture with asbestos showed the same degree of cytotoxicity as those in cultures without IL-2 or asbestos. These findings indicate that IL-2 insufficiency is not the main cause for the suppressed induction of CTLs by asbestos exposure, although they suggest a potential for the improvement of such suppressed CTL functions. Secretory factors other than IL-2 in addition to membrane-bound stimulatory molecules may play a role in asbestos-caused suppressed CTL differentiation. PMID:27975069

  5. Induction of Bcl-xL-specific cytotoxic T lymphocytes in mice.

    PubMed

    Larsen, H L; Andersen, M H; Wandall, H H; Madsen, C B; Christensen, R E; Petersen, T R; Pedersen, A E

    2014-08-01

    The induction of active immunity against tumour-associated antigens to prevent relapse of cancer is a promising approach but has so far shown only low efficacy. This low efficacy may in part be due to clonal escape of tumour cell variants by the downregulation of antigen expression or inflammation-induced dedifferentiation. Identification of novel tumour-associated antigens that at the same time are essential for continued tumour cell survival is thus critical for the development of active cancer vaccinations. At the same time, identification of novel endogenous murine tumour antigens will help improve preclinical development of cancer immunotherapy. The anti-apoptotic protein Bcl-xL has been suggested to be such an essential tumour antigen, but the lack of well-defined murine epitopes have delayed preclinical studies of Bcl-xL-targeting cancer vaccines. Here, we report the identification of two novel murine tumour-associated epitopes TAYQSFEQV and AFFSFGGAL derived from mouse Bcl-xL. Dendritic cell (DC)-based vaccination induced CD8(+) T cells capable of producing IFN-γ upon restimulation with these epitopes. Thus, our data may benefit the design of future immunotherapy strategies by providing a preclinical model for cancer vaccination with an endogenous tumour antigen that can be combined with other cancer treatments.

  6. Induction of cytotoxic T lymphocyte response against Mycobacterial antigen using domain I of anthrax edema factor as antigen delivery system

    SciTech Connect

    Chandra, Subhash; Kaur, Manpreet; Midha, Shuchi; Gorantala, Jyotsna; Bhatnagar, Rakesh . E-mail: rakbhat01@yahoo.com

    2007-05-25

    We have investigated the efficiency of N-terminal 1-260 residues of Edema factor (EFn) as a delivery system for ESAT-6, an antigenic protein of Mycobacterium tuberculosis H{sub 37}R{sub v}, into the cytosol of mammalian cells. The EFn.ESAT-6 recombinant protein was obtained by genetic fusion of EFn and ESAT-6 DNA. Our data shows that in the presence of PA, EFn.ESAT-6 fusion protein is internalized into the cytosol of antigen presenting cells, and the splenocytes produced both Th1 and Th2 cytokines in vitro. Further, EFn.ESAT-6 elicited effective cytotoxicT lymphocyte (CTL) response in an in vitro CTL assay. This study for the first time demonstrates that EFn can be used as a vehicle to deliver heterologous proteins of therapeutic importance.

  7. Heteroclitic XBP1 peptides evoke tumor-specific memory cytotoxic T lymphocytes against breast cancer, colon cancer, and pancreatic cancer cells

    PubMed Central

    Bae, Jooeun; Samur, Mehmet; Munshi, Aditya; Hideshima, Teru; Keskin, Derin; Kimmelman, Alec; Lee, Ann-Hwee; Dranoff, Glen; Anderson, Kenneth C; Munshi, Nikhil C

    2015-01-01

    XBP1 is a critical transcriptional activator of the unfolded protein response (UPR), which increases tumor cell survival under prolonged endoplasmic reticulum (ER) stress and hypoxic conditions.This study was designed to evaluate the immunogenicity of heteroclitic XBP1 unspliced (US)184–192 (YISPWILAV) and heteroclictic XBP1 spliced (SP)367–375 (YLFPQLISV) HLA-A2 peptides, and to characterize the specific activities of XBP1 peptides-specific cytotoxic T lymphocytes (XBP1-CTL) against breast cancer, colon cancer, and pancreatic cancer cells.The XBP1-CTL had upregulated expression of critical T cell markers and displayed HLA-A2-restricted and antigen-specific activities against breast cancer, colon cancer and pancreatic cancer cells. XBP1-CTL were enriched withCD45RO+ memory CTL, which showed high expression of critical T cell markers (CD28, ICOS, CD69, CD40L), cell proliferation and antitumor activities as compared to CD45RO− non-memory CTL. The effector memory (EM: CD45RO+CCR7−) subset had the highest level of cell proliferation while the central memory (CM: CD45RO+CCR7+) subset demonstrated enhanced functional activities (CD107a degranulation, IFNγ/IL-2 production) upon recognition of the respective tumor cells. Furthermore, both the EM and CM XBP1-CTL subsets expressed high levels of Th1 transcription regulators Tbet and Eomes. The highest frequencies of IFNγ or granzyme B producing cells were detected within CM XBP1-CTL subset that were either Tbet+ or Eomes+ in responding to the tumor cells.These results demonstrate the immunotherapeutic potential of a cocktail of immunogenic HLA-A2 specific heteroclitic XBP1 US184–192 and heteroclictic XBP1 SP367–375 peptides to induce CD3+CD8+ CTL enriched for CM and EM cells with specific antitumor activities against a variety of solid tumors. PMID:25941601

  8. The Memory Cytotoxic T-Lymphocyte (CTL) Response to Human Cytomegalovirus Infection Contains Individual Peptide-Specific CTL Clones That Have Undergone Extensive Expansion In Vivo

    PubMed Central

    Weekes, Michael P.; Wills, Mark R.; Mynard, Kim; Carmichael, Andrew J.; Sissons, J. G. Patrick

    1999-01-01

    Human cytomegalovirus (HCMV)-specific CD8+ cytotoxic T lymphocytes (CTL) appear to play an important role in the control of virus replication and in protection against HCMV-related disease. We have previously reported high frequencies of memory CTL precursors (CTLp) specific to the HCMV tegument protein pp65 in the peripheral blood of healthy virus carriers. In some individuals, the CTL response to this protein is focused on only a single epitope, whereas in other virus carriers CTL recognized multiple epitopes which we identified by using synthetic peptides. We have analyzed the clonal composition of the memory CTL response to four of these pp65 epitopes by sequencing the T-cell receptors (TCR) of multiple independently derived epitope-specific CTL clones, which were derived by formal single-cell cloning or from clonal CTL microcultures. In all cases, we have observed a high degree of clonal focusing: the majority of CTL clones specific to a defined pp65 peptide from any one virus carrier use only one or two different TCRs at the level of the nucleotide sequence. Among virus carriers who have the same major histocompatibility complex (MHC) class I allele, we observed that CTL from different donors that recognize the same peptide-MHC complex often used the same Vβ segment, although other TCR gene segments and CDR3 length were not in general conserved. We have also examined the clonal composition of CTL specific to pp65 peptides in asymptomatic human immunodeficiency virus-infected individuals. We have observed a similarly focused peptide-specific CTL response. Thus, the large population of circulating HCMV peptide-specific memory CTLp in virus carriers in fact contains individual CTL clones that have undergone extensive clonal expansion in vivo. PMID:9971792

  9. Human Memory Cytotoxic T-Lymphocyte (CTL) Responses to Hantaan Virus Infection: Identification of Virus-Specific and Cross-Reactive CD8+ CTL Epitopes on Nucleocapsid Protein

    PubMed Central

    Van Epps, Heather L.; Schmaljohn, Connie S.; Ennis, Francis A.

    1999-01-01

    Hantaan virus, the prototypic member of the Hantavirus genus, causes hemorrhagic fever with renal syndrome in humans. We examined the human memory T-lymphocyte responses of three donors who had previous laboratory-acquired infections with Hantaan virus. We demonstrated virus-specific responses in bulk cultures of peripheral blood mononuclear cells (PBMC) from all donors. Bulk T-cell responses were directed against either Hantaan virus nucleocapsid (N) or G1 protein, and these responses varied between donors. We established both CD4+ and CD8+ N-specific cell lines from two donors and CD4+ G1-specific cell lines from a third donor. All CD8+ cytotoxic T-lymphocyte (CTL) lines recognized one of two epitopes on the nucleocapsid protein: one epitope spanning amino acids 12 to 20 and the other spanning amino acids 421 to 429. The CTL lines specific for amino acids 12 to 20 were restricted by HLA B51, and those specific for amino acids 421 to 429 were restricted by HLA A1. The N-specific CTL lines isolated from these two donors included both Hantaan virus-specific CTLs and hantavirus cross-reactive CTLs. Responses to both epitopes are detectable in short-term bulk cultures of PBMC from one donor, and precursor frequency analysis confirms that CTLs specific for these epitopes are present at relatively high precursor frequencies in the peripheral T-cell pool. These data suggest that infection with Hantaan virus results in the generation of CTL to limited epitopes on the nucleocapsid protein and that infection also results in the generation of cross-reactive T-cell responses to distantly related hantaviruses which cause the distinct hantavirus pulmonary syndrome. This is the first demonstration of human T-lymphocyte responses to Hantaan virus. PMID:10364276

  10. [Cytotoxic T lymphocytes in cancer and autoimmunity].

    PubMed

    Prado-García, Heriberto; Avila-Moreno, Federico; López-González, José Sullivan

    2004-01-01

    Cytotoxic T lymphocytes (CTLs) are cells of the immune system that recognize and kill cells that have been infected with intracellular pathogens, allogenic cells or tumor cells. It has been reported that CTLs participate in the pathogenesis of some autoimmune diseases. After stimulation with the antigen, CTLs undergo an activation process highly regulated, which leads to the cell to acquire an effector or memory function. In this review, we indicate the cellular markers associated with the different stages of CTL-differentiation (naive, memory and effector); we indicate the distinct models of CTLs differentiation; also, the mechanisms of CTLs cytotoxicity are mentioned. Furthermore, we describe the participation of CTLs in cancer and autoimmunity; the implications of CTLs in the progression of these diseases are discussed.

  11. Protective Role of Cytotoxic T Lymphocytes in Filovirus Hemorrhagic Fever

    PubMed Central

    Warfield, Kelly Lyn; Olinger, Gene Garrard

    2011-01-01

    Infection with many emerging viruses, such as the hemorrhagic fever disease caused by the filoviruses, Marburg (MARV), and Ebola virus (EBOV), leaves the host with a short timeframe in which to mouse a protective immune response. In lethal cases, uncontrolled viral replication and virus-induced immune dysregulation are too severe to overcome, and mortality is generally associated with a lack of notable immune responses. Vaccination studies in animals have demonstrated an association of IgG and neutralizing antibody responses against the protective glycoprotein antigen with survival from lethal challenge. More recently, studies in animal models of filovirus hemorrhagic fever have established that induction of a strong filovirus-specific cytotoxic T lymphocyte (CTL) response can facilitate complete viral clearance. In this review, we describe assays used to discover CTL responses after vaccination or live filovirus infection in both animal models and human clinical trials. Unfortunately, little data regarding CTL responses have been collected from infected human survivors, primarily due to the low frequency of disease and the inability to perform these studies in the field. Advancements in assays and technologies may allow these studies to occur during future outbreaks. PMID:22253531

  12. Role of vitamin D in cytotoxic T lymphocyte immunity to pathogens and cancer.

    PubMed

    Sarkar, Surojit; Hewison, Martin; Studzinski, George P; Li, Yan Chun; Kalia, Vandana

    2016-01-01

    The discovery of vitamin D receptor (VDR) expression in immune cells has opened up a new area of research into immunoregulation by vitamin D, a niche that is distinct from its classical role in skeletal health. Today, about three decades since this discovery, numerous cellular and molecular targets of vitamin D in the immune system have been delineated. Moreover, strong clinical associations between vitamin D status and the incidence/severity of many immune-regulated disorders (e.g. infectious diseases, cancers and autoimmunity) have prompted the idea of using vitamin D supplementation to manipulate disease outcome. While much is known about the effects of vitamin D on innate immune responses and helper T (T(H)) cell immunity, there has been relatively limited progress on the frontier of cytotoxic T lymphocyte (CTL) immunity--an arm of host cellular adaptive immunity that is crucial for the control of such intracellular pathogens as human immunodeficiency virus (HIV), tuberculosis (TB), malaria, and hepatitis C virus (HCV). In this review, we discuss the strong historical and clinical link between vitamin D and infectious diseases that involves cytotoxic T lymphocyte (CTL) immunity, present our current understanding as well as critical knowledge gaps in the realm of vitamin D regulation of host CTL responses, and highlight potential regulatory connections between vitamin D and effector and memory CD8 T cell differentiation events during infections.

  13. Protection against lethal Sendai virus infection by in vivo priming of virus-specific cytotoxic T lymphocytes with a free synthetic peptide.

    PubMed Central

    Kast, W M; Roux, L; Curren, J; Blom, H J; Voordouw, A C; Meloen, R H; Kolakofsky, D; Melief, C J

    1991-01-01

    The only peptide of Sendai virus that is recognized by cytotoxic T lymphocytes (CTL) in B6 mice was found with (i) the use of recombinant vaccinia virus constructs containing separate genes of Sendai virus and (ii) a set of overlapping peptides completely spanning the identified nucleoprotein (NP) gene product. This immunodominant NP peptide is recognized by Sendai virus-specific CTL that are known to have therapeutic effects in vivo. By subcutaneous immunization, this peptide induced Sendai virus and NP peptide-specific CTL memory responses in vivo. Most importantly, mice that had been immunized with this peptide were protected against a lethal virus dose, indicating that viral peptides can be used as antiviral T-cell vaccines. The induction of T-cell memory by free peptide immunization potentially has wide applicability in biology and medicine, including protection against infectious disease. PMID:1848698

  14. Protection Against Lethal Sendai Virus Infection by in vivo Priming of Virus-Specific Cytotoxic T Lymphocytes with a Free Synthetic Peptide

    NASA Astrophysics Data System (ADS)

    Kast, W. Martin; Roux, Laurent; Curren, Joseph; Blom, Hendrika J. J.; Voordouw, Arie C.; Meloen, Rob H.; Kolakofsky, Daniel; Melief, Cornelis J. M.

    1991-03-01

    The only peptide of Sendai virus that is recognized by cytotoxic T lymphocytes (CTL) in B6 mice was found with (i) the use of recombinant vaccinia virus constructs containing separate genes of Sendai virus and (ii) a set of overlapping peptides completely spanning the identified nucleoprotein (NP) gene product. This immunodominant NP peptide is recognized by Sendai virus-specific CTL that are known to have therapeutic effects in vivo. By subcutaneous immunization, this peptide induced Sendai virus and NP peptide-specific CTL memory responses in vivo. Most importantly, mice that had been immunized with this peptide were protected against a lethal virus dose, indicating that viral peptides can be used as antiviral T-cell vaccines. The induction of T-cell memory by free peptide immunization potentially has wide applicability in biology and medicine, including protection against infectious disease.

  15. Cross reactive antibody and cytotoxic T lymphocytes from avian influenza H9N2 infected chickens against homologous and heterologous avian influenza isolates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Immunity against avian influenza (AI) is largely based on the induction of neutralizing antibodies produced against the hemagglutinin, although cytotoxic T lymphocytes (CTL’s) have been reported as critical for clearance of virus from infected cells. Antibody production against a particular virus ...

  16. Antigen receptor-regulated exocytosis in cytotoxic T lymphocytes

    PubMed Central

    1987-01-01

    We demonstrate here that T cell receptor for antigen (TCR)-triggered exocytosis in cytotoxic T lymphocytes (CTL) is not constitutive and is regulated through crosslinking of the TCR by antigen or monoclonal anti- TCR antibodies. Morphological and biochemical data using three different biochemical markers of granules and Percoll gradient fractionation analysis are presented, suggesting that TCR-triggered exocytosis is accompanied by the loss of granules from CTL and appearance of intragranular proteins and enzymatic activities in the incubation medium. The strict requirement for crosslinking of the TCR in exocytosis triggering could be bypassed by protein kinase C activators (phorbol esters or bryostatin I and II) acting in synergy with Ca2+ ionophores. It is shown that external Ca2+ is obligatory for both the TCR-triggered and for the PMA/A23187-triggered exocytosis, since Ca2+ chelators and divalent cations that compete with Ca2+ for A23187 can inhibit exocytosis of granules. These data suggest that Ca2+ from intracellular stores is not sufficient to support exocytosis in CTL. Ca2+ channel blockers and calmodulin antagonists significantly inhibited TCR-triggered exocytosis without affecting the basal level of secretion. The described results are consistent with a model in which exocytosis of granules in CTL is triggered by the crosslinking of TCR, transmembrane protein kinase C activation, and external Ca2+ translocation through CTL plasma membrane Ca2+ channels and modulation of activity of Ca2+, calmodulin-dependent enzymes, and cytoskeletal proteins. PMID:2442289

  17. Clonotype analysis of cytomegalovirus-specific cytotoxic T lymphocytes.

    PubMed

    Babel, Nina; Brestrich, Gordon; Gondek, Lukasz P; Sattler, Arne; Wlodarski, Marcin W; Poliak, Nina; Bethke, Nicole; Thiel, Andreas; Hammer, Markus H; Reinke, Petra; Maciejewski, Jaroslaw P

    2009-02-01

    Cytotoxic T lymphocytes (CTL) control the replication of human cytomegalovirus (CMV). Previous studies assessed the clonotypic composition of CTL specific for individual immunodominant peptides within a certain HLA context. Such an approach has inherent limitations and may not assess the true clonal CTL response in vivo. Here, the clonotypic composition of CMV-specific CTL was determined in HLA-A2, CMV-seropositive kidney transplant recipients and healthy blood donors after stimulation of peripheral blood mononuclear cells with either a pp65 whole-peptide pool or a single immunodominant peptide. Even after stimulation with the whole peptide pool, CMV-specific CTL remained monoclonal or oligoclonal. Regarding intraindividual variation, the CDR3 motifs of the dominant clones were identical to those observed in CTL generated by the single immunodominant peptide. Sequencing of the CDR3 regions demonstrated significant interindividual variation; however, structural homology was observed for immunodominant clonotypes in three individuals. In conclusion, the highly focused T cell receptor repertoire found after stimulation with either a single immunodominant peptide or a peptide pool demonstrates a pivotal role for immunodominant epitopes in the generation of a clonal repertoire. These results provide new insights into the regulation of CMV clonal dominance and may contribute to the design and monitoring of adoptive immunotherapy.

  18. Cytotoxic T lymphocytes specific for the simian immunodeficiency virus.

    PubMed

    Letvin, N L; Schmitz, J E; Jordan, H L; Seth, A; Hirsch, V M; Reimann, K A; Kuroda, M J

    1999-08-01

    A non-human primate model for acquired immunodeficiency syndrome (AIDS), the simian immunodeficiency virus (SIV)-infected rhesus monkey, was used to explore the role of the AIDS virus-specific cytotoxic T-lymphocyte (CTL) response in disease pathogenesis. This CTL response was measured using the major histocompatibility complex (MHC) class I/peptide tetramer technology. Large numbers of tetramer-binding CD8+ T lymphocytes were demonstrable not only in the peripheral blood, but in lymph nodes and even in semen of chronically SIV-infected monkeys. The central role of these effector T lymphocytes in containing SIV spread during primary infection was demonstrated by showing that early SIV clearance during primary infection correlated with the emergence of the tetramer binding CD8+ T lymphocytes and that in vivo depletion of CD8+ lymphocytes eliminated the ability of the infected monkeys to contain SIV replication. These observations suggest that an effective AIDS vaccine should elicit a potent virus-specific CTL response. In fact, a live, recombinant SIV vaccine constructed using the attenuated pox virus vector modified vaccinia Ankara (MVA) elicited a high-frequency CTL response, comparable in magnitude to that elicited by SIV infection itself. This suggests that vaccine modalities such as MVA may prove useful in creating an effective human immunodeficiency virus (HIV) vaccine. These studies also indicate the power of both the SIV/macaque model and MHC class I/peptide tetramers for assessing AIDS vaccine strategies.

  19. Physiological changes induced in cardiac myocytes by cytotoxic T lymphocytes

    SciTech Connect

    Hassin, D.; Fixler, R.; Shimoni, Y.; Rubinstein, E.; Raz, S.; Gotsman, M.S.; Hasin, Y.

    1987-01-01

    The lethal hit induced by viral specific, sensitized, cytotoxic T lymphocytes (CTL) attacking virus-infected heart cells is important in the pathogenesis of viral myocarditis and reflects the key role of CTL in this immune response. The mechanisms involved are incompletely understood. Studies of the physiological changes induced in mengovirus-infected, cultured, neonatal, rat heart cells by CTL that had been previously sensitized by the same virus are presented. The CTL were obtained from spleens of mengovirus-infected, major histocompatibility complex (MHC) matched adult rats. Cell wall motion was measured by an optical method, action potentials with intracellular microelectrodes, and total exchangeable calcium content by /sup 45/Ca tracer measurements after loading the myocytes with /sup 45/Ca and then exposing them to CTL. After 50 min (mean time) of exposing mengovirus-infected myocytes to the CTL, the mechanical relaxation of the myocyte was slowed, with a subsequent slowing of beating rate and a reduced amplitude of contraction. Impaired relaxation progressed, and prolonged oscillatory contractions lasting up to several seconds appeared, with accompanying oscillations in the prolonged plateau phase of the action potentials. Arrest of the myocyte contractions appeared 98 min (mean time) after exposure to CTL. It is concluded that infection of cultured myocytes with mengovirus predisposes them to attack by mengovirus specific CTL, and that persistent dysfunction of the myocyte is preceded by reversible changes in membrane potential and contraction. This is suggestive of an altered calcium handling by the myocytes possibly resulting in the cytotoxic effect.

  20. Common antiviral cytotoxic t-lymphocyte epitope for diverse arenaviruses.

    PubMed

    Oldstone, M B; Lewicki, H; Homann, D; Nguyen, C; Julien, S; Gairin, J E

    2001-07-01

    Members of the Arenaviridae family have been isolated from mammalian hosts in disparate geographic locations, leading to their grouping as Old World types (i.e., lymphocytic choriomeningitis virus [LCMV], Lassa fever virus [LFV], Mopeia virus, and Mobala virus) and New World types (i.e., Junin, Machupo, Tacaribe, and Sabia viruses) (C. J. Peters, M. J. Buchmeier, P. E. Rollin, and T. G. Ksiazek, p. 1521-1551, in B. N. Fields, D. M. Knipe, and P. M. Howley [ed.], Fields virology, 3rd ed., 1996; P. J. Southern, p. 1505-1519, in B. N. Fields, D. M. Knipe, and P. M. Howley [ed.], Fields virology, 3rd ed., 1996). Several types in both groups-LFV, Junin, Machupo, and Sabia viruses-cause severe and often lethal human diseases. By sequence comparison, we noted that eight Old World and New World arenaviruses share several amino acids with the nucleoprotein (NP) that consists of amino acids (aa) 118 to 126 (NP 118-126) (RPQASGVYM) of LCMV that comprise the immunodominant cytotoxic T-lymphocyte (CTL) epitope for H-2(d) mice (32). This L(d)-restricted epitope constituted >97% of the total bulk CTLs produced in the specific antiviral or clonal responses of H-2(d) BALB mice. NP 118-126 of the Old World arenaviruses LFV, Mopeia virus, and LCMV and the New World arenavirus Sabia virus bound at high affinity to L(d). The primary H-2(d) CTL anti-LCMV response as well as that of a CTL clone responsive to LCMV NP 118-126 recognized target cells coated with NP 118-126 peptides derived from LCMV, LFV, and Mopeia virus but not Sabia virus, indicating that a common functional NP epitope exists among Old World arenaviruses. Use of site-specific amino acid exchanges in the NP CTL epitope among these arenaviruses identified amino acids involved in major histocompatibility complex binding and CTL recognition.

  1. Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocyte activity in HIV-exposed seronegative persons.

    PubMed

    Bernard, N F; Yannakis, C M; Lee, J S; Tsoukas, C M

    1999-03-01

    Repeated exposure to human immunodeficiency virus (HIV) does not always result in seroconversion. Understanding the conditions that permit or protect against progressive infection with HIV is important for vaccine development. Nineteen subjects at risk for HIV infection were CCR-5 genotyped and screened for virus-specific memory cytotoxic T lymphocytes (CTL). None had the Delta32CCR-5/Delta32CCR-5 genotype associated with HIV resistance. HIV-specific CTL were detected in 7 (41.1%) of 17 exposed uninfected subjects versus 0 of 14 seronegative subjects with no HIV risk factors (P=.006, chi2 test). Recognition of virus by CTL in exposed uninfected subjects was major histocompatibility complex class I-restricted and multispecific, and specificity could change with time. Activity could persist up to 34 months after the last virus exposure. The presence of HIV-specific CTL in a greater proportion of seronegative HIV-exposed versus unexposed subjects supports the notion that in some cases, virus exposure induces HIV immunity without seroconversion or disease progression.

  2. An antigenic threshold for maintaining human immunodeficiency virus type 1-specific cytotoxic T lymphocytes.

    PubMed Central

    Jin, X.; Ogg, G.; Bonhoeffer, S.; Safrit, J.; Vesanen, M.; Bauer, D.; Chen, D.; Cao, Y.; Demoitie, M. A.; Zhang, L.; Markowitz, M.; Nixon, D.; McMichael, A.; Ho, D. D.

    2000-01-01

    BACKGROUND: Using the lymphocytic choriomeningitis virus (LCMV) model in mice, a number of studies show that memory cytotoxic T-lymphocyte (CTL) responses are maintained in the presence of continuous antigenic stimulation. Yet, other groups found that memory CTL specific for LCMV could last for a lifetime in mice without viral antigens. Thus, the extent to which an antigen is required for the maintenance of virus-specific CTL remains controversial. In humans, very few studies have been conducted to investigate the relationship between the quantity of antigen and the magnitude of CTL responses. MATERIALS AND METHODS: We quantified CTL precursors (CTLp) using a limiting-dilution analysis (LDA) and CTL effectors (CTLe) using a new Major Histocompatibility Complex (MHC) class I tetramer technology in six long-term nonprogressors (LTNPs) with human immunodeficiency virus type-1 (HIV-1) infection, as well as in eight patients whose viral loads were well suppressed by antiretroviral therapy. The viremia levels in these patients were measured using an reverse transcription polymerase chain reaction (RT-PCR) assay. The proviral DNA load in peripheral blood mononuclear cell (PBMC) was also measured by PCR in four LTNPs. RESULTS: The LTNPs had high levels of HIV-1-specific memory CTLp and CTLe, while maintaining a low plasma viral load. Despite also having low viral loads, patients whose plasma viremia was well-suppressed by effective therapy had low levels of CTLe. CONCLUSIONS: Our findings suggest that a complex, rather than a monotonic, relationship exists between CTL levels and HIV-1 viremia, including what appears to be an antigenic threshold for the maintenance of CTL at a measurable level. Under conditions of "antigen excess,", CTLe levels correlate inversely with viral load. On the other hand, under conditions that are "antigen limited," the correlation appears to be direct. PMID:11071274

  3. Cytotoxic T lymphocyte-mediated cytolysis: an example of programmed cell death in the immune system

    SciTech Connect

    Duke, R.C.

    1985-01-01

    Target cells are programmed to die following interaction with cytotoxic T lymphocytes (CTLs). Within minutes of exposure to CTL the target cell's nuclear DNA is fragmented. Target cell lysis, as measured by /sup 51/Cr release, occurs about 60 minutes after induction of DNA fragmentation. DNA fragmentation results from the action of an endonuclease which cleaves DNA in the linker region between nucleosomes. The origin of this nuclease, whether transferred to the target by the CTL or endogenous to the target cell, has not been resolved. DNA fragmentation occurs only when appropriately sensitized CTL are used and is not merely the result of cell death because killing of target cells by extreme deviation from homeostasis, by interruption of energy production, or by lysis with antibody and complement does not induce DNA cleavage. When Triton X-100 is added to target cells which have interacted with CTL, the DNA fragments do not remain in association with the nucleus. This observation suggests that breakdown of overall nuclear structure is induced concomitantly with DNA fragmentation. Morphologically, disruption of nuclear structure and DNA fragmentation are observed as widespread chromatin condensation (apoptosis). Apoptosis is observed in metabolically active target cells and is not a consequence of cell death. A cell whose DNA is extensively fragmented is condemmed to die. Induction of oligonucleosome-sized DNA is also an early event in glucocorticoid-induced thymocyte death and death of T cells upon removal of growth factor. Several similarities exist between these systems and CTL-mediated cytolysis suggesting a final common biochemical pathway for all three types of cell death.

  4. Thymic influence on the T-lymphocyte self MHC repertoire. II. Cytotoxic T-lymphocyte precursors.

    PubMed

    Jenski, L J; Miller, B A

    1988-01-01

    We measured the frequency and specificity of thymic alloantigen-reactive cytotoxic T-lymphocyte precursors in spleens of allogeneic thymus-grafted nude mice tolerant to thymic alloantigens. Under our conditions of limiting dilution analysis we found no selective loss of cytotoxic T-lymphocyte precursors in allogeneic thymus-grafted mice. Upon analysis of individual cytotoxic T-lymphocyte clones, we found that lysis of specific and third party targets was mediated by distinct clones specific for H-2 antigens. Precursors from allogeneic thymus-grafted nudes stimulated at limiting dilutions with thymic alloantigens tended to lyse fewer targets than were lysed by normal cytotoxic T-lymphocytes or allogeneic thymus-grafted nude precursors stimulated with third party alloantigens, but the reduction in lytic activity was not statistically significant. Specific suppression was not demonstrated, but could not be ruled out unequivocally. We conclude that intrathymic deletion of thymic alloantigen-reactive pCTL is not necessary to achieve specific tolerance to thymic alloantigens.

  5. In vitro generation of cytotoxic T lymphocyte response using dendritic cell immunotherapy in osteosarcoma

    PubMed Central

    He, Ye-Teng; Zhang, Qing-Min; Kou, Quan-Chun; Tang, Bo

    2016-01-01

    Immunotherapy with tumor lysate-pulsed dendritic cells (DCs) is one of the breakthrough strategies used in the treatment of cancer. However, DC-based immunotherapies for osteosarcoma are limited. In the present study, preclinical studies of a C3H osteosarcoma mouse model (produced by subcutaneous injection of LM8 murine osteosarcoma cells) validated the concept that LM8 cell lysate-pulsed bone marrow-derived DCs may evoke a more potent immune response compared with DCs that have been matured using polyinosinic:polycytidylic acid (poly I:C). A cytotoxic T lymphocyte (CTL) response was established using two groups of C3H mice (n=9) with osteosarcoma; the treatment group consisted of LM8 cell lysate-pulsed DCs and the control group consisted of DCs matured using poly I:C. Each group was immunized with doses of 1×106 cells twice per week for 3 weeks. No difference in the expression of cluster of differentiation markers was identified in the two groups. DCs pulsed with LM8 cell lysate were associated with the increased induction of CTL activity. Serum interferon-γ levels were increased in mice that received DCs pulsed with LM8 cell lysate compared with that in the poly I:C-matured DC group (P<0.041). Serum interleukin-4 was decreased in the treatment group vs. the control group (P<0.033). A mixed lymphocyte reaction assay confirmed that LM8-DC immunotherapy may evoke a significant antigen-specific immune response in a mouse model. The present study reveals promising data on efficacy of a DC-based immunotherapy in the treatment of osteosarcoma; however, further clinical studies are warranted. PMID:27446401

  6. Variant antigenic peptide promotes cytotoxic T lymphocyte adhesion to target cells without cytotoxicity

    PubMed Central

    Shotton, David M.; Attaran, Amir

    1998-01-01

    Timelapse video microscopy has been used to record the motility and dynamic interactions between an H-2Db-restricted murine cytotoxic T lymphocyte clone (F5) and Db-transfected L929 mouse fibroblasts (LDb) presenting normal or variant antigenic peptides from human influenza nucleoprotein. F5 cells will kill LDb target cells presenting specific antigen (peptide NP68: ASNENMDAM) after “browsing” their surfaces for between 8 min and many hours. Cell death is characterized by abrupt cellular rounding followed by zeiosis (vigorous “boiling” of the cytoplasm and blebbing of the plasma membrane) for 10–20 min, with subsequent cessation of all activity. Departure of cytotoxic T lymphocytes from unkilled target cells is rare, whereas serial killing is sometimes observed. In the absence of antigenic peptide, cytotoxic T lymphocytes browse target cells for much shorter periods, and readily leave to encounter other targets, while never causing target cell death. Two variant antigenic peptides, differing in nonamer position 7 or 8, also act as antigens, albeit with lower efficiency. A third variant peptide NP34 (ASNENMETM), which differs from NP68 in both positions and yet still binds Db, does not stimulate F5 cytotoxicity. Nevertheless, timelapse video analysis shows that NP34 leads to a significant modification of cell behavior, by up-regulating F5–LDb adhesive interactions. These data extend recent studies showing that partial agonists may elicit a subset of the T cell responses associated with full antigen stimulation, by demonstrating that TCR interaction with variant peptide antigens can trigger target cell adhesion and surface exploration without activating the signaling pathway that results in cytotoxicity. PMID:9861010

  7. Generation of cytotoxic T lymphocytes and cytostatic acting cells in T. annulata-immune cattle.

    PubMed

    Ahmed, J S; Wiegers, P; Ritz, H; Hartwig, H; Schein, E; Schnittger, L

    2000-01-01

    Cattle immunized against Theileria annulata with schizont containing autologous cell lines are immune to challenge with a homologous parasite strain. Two cell types have been detected in the peripheral blood of the immunized animals: cytotoxic T lymphocytes (CTL) and cytostatic acting cells (CAC). Killing the target cells by CTL is infection associated and is MHC class I restricted. Hence, no cytotoxicity was observed against target cells that were treated with the theilericidal drug buparvaquone or autologous Con A-blasts. The growth inhibition of CAC is MHC unrestricted, and not mediated by cytokine interferon gamma (IFN-gamma).

  8. Ex vivo analysis of cytotoxic T lymphocytes to measles antigens during infection and after vaccination in Gambian children.

    PubMed Central

    Jaye, A; Magnusen, A F; Sadiq, A D; Corrah, T; Whittle, H C

    1998-01-01

    The study of cytotoxic T cell responses to measles antigens during infection and after vaccination may provide insight into the immunopathology of the infection. It will also provide a knowledge of the immunity conferred by wild or attenuated virus, which will help in the design of new vaccines. Direct cytotoxic T cell responses, which did not require in vitro restimulation, were measured from peripheral blood by a standard 51Cr-release assay in 35 patients with acute measles, using HLA class I matched allogeneic B cells as targets. 77% showed specific responses to measles fusion protein, 69% to the hemagglutinin, and 50% to the nucleoprotein. These responses, which were related to severity of disease and history of previous vaccination, had waned by 14-24 wk after measles when memory responses to the same antigens could be elicited by restimulation in 71% of the 13 patients tested. A similar pattern followed vaccination: direct cytotoxic responses to fusion and hemagglutinin proteins were shown in 70% of the 20 children tested while 50% responded to the nucleoprotein. These responses, which were mediated by both CD8(+) and CD4(+) cells, faded over 6 wk when memory responses could be restimulated. Thus, a vigorous cytotoxic T lymphocyte response to fusion, hemagglutinin, and nucleoproteins is important in both natural and vaccine-induced immunity to measles. PMID:9835622

  9. Polymer nanoparticles for cross-presentation of exogenous antigens and enhanced cytotoxic T-lymphocyte immune response

    PubMed Central

    Song, Chanyoung; Noh, Young-Woock; Lim, Yong Taik

    2016-01-01

    Effective induction of an antigen-specific cytotoxic T lymphocyte (CTL) immune response is one of the key goals of cancer immunotherapy. We report the design and fabrication of polyethylenimine (PEI)-coated polymer nanoparticles (NPs) as efficient antigen-delivery carriers that can induce antigen cross-presentation and a strong CTL response. After synthesis of poly(d,l-lactide-co-glycolide) (PLGA) NPs containing ovalbumin (OVA) by the double-emulsion solvent-evaporation method, cationic-charged PLGA NPs were generated by coating them with PEI. In a methyl tetrazolium salt assay, no discernible cytotoxic effect of PEI-coated PLGA (OVA) NPs was observed. The capacity and mechanism of PEI-coated PLGA (OVA) NPs for antigen delivery and cross-presentation on dendritic cells (DCs) were determined by fluorescence microscopy and flow cytometry. PEI-coated PLGA (OVA) NPs were internalized efficiently via phagocytosis or macropinocytosis in DCs and induced efficient cross-presentation of the antigen on MHC class I molecules via both endosome escape and a lysosomal processing mechanism. The DCs treated with PEI-coated PLGA (OVA) NPs induced a release of IL-2 cytokine from OVA-specific CD8-OVA1.3 T cells more efficiently than DCs treated with PLGA (OVA) NPs. Therefore, the PEI-coated PLGA (OVA) NPs can induce antigen cross-presentation and are expected to be used for induction of a strong CTL immune response and for efficient anticancer immunotherapy. PMID:27540289

  10. Hepatitis B surface antigen vector delivers protective cytotoxic T-lymphocyte responses to disease-relevant foreign epitopes.

    PubMed

    Woo, Wai-Ping; Doan, Tracy; Herd, Karen A; Netter, Hans-Jürgen; Tindle, Robert W

    2006-04-01

    Although hepatitis B surface antigen (HBsAg) per se is highly immunogenic, its use as a vector for the delivery of foreign cytotoxic T-lymphocyte (CTL) epitopes has met with little success because of constraints on HBsAg stability and secretion imposed by the insertion of foreign sequence into critical hydrophobic/amphipathic regions. Using a strategy entailing deletion of DNA encoding HBsAg-specific CTL epitopes and replacement with DNA encoding foreign CTL epitopes, we have derived chimeric HBsAg DNA immunogens which elicited effector and memory CTL responses in vitro, and pathogen- and tumor-protective responses in vivo, when the chimeric HBsAg DNAs were used to immunize mice. We further show that HBsAg DNA recombinant for both respiratory syncytial virus and human papillomavirus CTL epitopes elicited simultaneous responses to both pathogens. These data demonstrate the efficacy of HBsAg DNA as a vector for the delivery of disease-relevant protective CTL responses. They also suggest the applicability of the approach of deriving chimeric HBsAg DNA immunogens simultaneously encoding protective CTL epitopes for multiple diseases. The DNAs we tested formed chimeric HBsAg virus-like particles (VLPs). Thus, our results have implications for the development of vaccination strategies using either chimeric HBsAg DNA or VLP vaccines. HBsAg is the globally administered vaccine for hepatitis B virus infection, inviting its usage as a vector for the delivery of immunogens from other diseases.

  11. Functional Alteration of Natural Killer Cells and Cytotoxic T Lymphocytes upon Asbestos Exposure and in Malignant Mesothelioma Patients.

    PubMed

    Nishimura, Yasumitsu; Kumagai-Takei, Naoko; Matsuzaki, Hidenori; Lee, Suni; Maeda, Megumi; Kishimoto, Takumi; Fukuoka, Kazuya; Nakano, Takashi; Otsuki, Takemi

    2015-01-01

    Malignant mesothelioma is caused by exposure to asbestos, which is known to have carcinogenic effects. However, the development of mesothelioma takes a long period and results from a low or intermediate dose of exposure. These findings have motivated us to investigate the immunological effects of asbestos exposure and analyze immune functions of patients with mesothelioma and pleural plaque, a sign of exposure to asbestos. Here, we review our knowledge concerning natural killer (NK) cells and cytotoxic T lymphocytes (CTL). NK cells showed impaired cytotoxicity with altered expression of activating receptors upon exposure to asbestos, while induction of granzyme(+) cells in CD8(+) lymphocytes was suppressed by asbestos exposure. It is interesting that a decrease in NKp46, a representative activating receptor, is common between NK cells in PBMC culture with asbestos and those of mesothelioma patients. Moreover, it was observed that CD8(+) lymphocytes may be stimulated by some kind of "nonself" cells in plaque-positive individuals and in mesothelioma patients, whereas CTL in mesothelioma is impaired by poststimulation maintenance of cytotoxicity. These findings suggest that analysis of immunological parameters might contribute to the evaluation of health conditions of asbestos-exposed individuals and to a greater understanding of the pathology of malignant mesothelioma.

  12. Inhibitory effects of various oxygenated sterols on the differentiation and function of tumor-specific cytotoxic T lymphocytes

    SciTech Connect

    Spangrude, G.J.; Sherris, D.; Daynes, R.A.

    1982-05-01

    Irradiation of skin with ultraviolet light (UVL) is capable of causing many biological and biochemical changes in this complex organ. One early consequence is the oxidation of epidermal plasma membrane cholesterol, causing the induction of a wide variety of photoproducts. It is well recognized that some oxygenated sterols possess potent biological activity on mammalian cells by their ability to inhibit endogeneous mevalonate and cholesterol biosynthesis. In the few immunological systems that have been studied, there is general agreement that lymphocyte function is altered in the presence of certain oxygenated sterols. Insight into the biochemical basis for altered lymphocyte function is lacking, as both afferent and efferent blockades have been suggested. These studies were undertaken to determine the effect of various oxygenated sterols (representing a number of known cholesterol-derived photoproducts) on the generation (afferent) and function (efferent) of cytotoxic T lymphocytes (CTLs). Cell-mediated immune responses which result in the generation of both alloantigen-specific and syngeneic tumor-specific CTLs were evaluated. (JMT)

  13. Functional Alteration of Natural Killer Cells and Cytotoxic T Lymphocytes upon Asbestos Exposure and in Malignant Mesothelioma Patients

    PubMed Central

    Nishimura, Yasumitsu; Kumagai-Takei, Naoko; Matsuzaki, Hidenori; Lee, Suni; Maeda, Megumi; Kishimoto, Takumi; Fukuoka, Kazuya; Nakano, Takashi; Otsuki, Takemi

    2015-01-01

    Malignant mesothelioma is caused by exposure to asbestos, which is known to have carcinogenic effects. However, the development of mesothelioma takes a long period and results from a low or intermediate dose of exposure. These findings have motivated us to investigate the immunological effects of asbestos exposure and analyze immune functions of patients with mesothelioma and pleural plaque, a sign of exposure to asbestos. Here, we review our knowledge concerning natural killer (NK) cells and cytotoxic T lymphocytes (CTL). NK cells showed impaired cytotoxicity with altered expression of activating receptors upon exposure to asbestos, while induction of granzyme+ cells in CD8+ lymphocytes was suppressed by asbestos exposure. It is interesting that a decrease in NKp46, a representative activating receptor, is common between NK cells in PBMC culture with asbestos and those of mesothelioma patients. Moreover, it was observed that CD8+ lymphocytes may be stimulated by some kind of “nonself” cells in plaque-positive individuals and in mesothelioma patients, whereas CTL in mesothelioma is impaired by poststimulation maintenance of cytotoxicity. These findings suggest that analysis of immunological parameters might contribute to the evaluation of health conditions of asbestos-exposed individuals and to a greater understanding of the pathology of malignant mesothelioma. PMID:26161391

  14. Aloe QDM complex enhances specific cytotoxic T lymphocyte killing in vivo in metabolic disease mice.

    PubMed

    Lee, Youngjoo; Kim, Jiyeon; An, Jinho; Lee, Heetae; Kong, Hyunseok; Song, Youngcheon; Shin, Eunju; Do, Seon-Gil; Lee, Chong-Kil; Kim, Kyungjae

    2017-03-01

    We developed spontaneous diet-induced metabolic disease in mice by feeding them a high-fat diet for 23 weeks and administered Aloe QDM complex for 16 weeks to examine its restorative effect on immune disorders and metabolic syndrome. A series of immune functional assays indicated Aloe QDM complex enhanced lymphocyte proliferation and antigen-specific immunity as determined by the restored functions of cytotoxic T lymphocytes (CTL) and IgG production. The elevated serum TNF-α level was also regulated by Aloe QDM complex treatment, which suggested its complex therapeutic potential. As for metabolic phenotypes, oral administration of Aloe QDM complex significantly improved diabetic symptoms, including high fasting glucose levels and glucose tolerance, and distinctly alleviated lipid accumulation in adipose and hepatic tissue. The simultaneous restoration of Aloe QDM complex on metabolic syndrome and host immune dysfunction, especially on the specific CTL killing was first elucidated in our study.

  15. Cytotoxic T lymphocytes against disease-associated determinant(s) in ankylosing spondylitis

    PubMed Central

    1986-01-01

    Cytotoxic T lymphocytes, induced by stimulating the PBMC of an HLA-B27+ normal individual (B27+, AS-) with the PBMC of an HLA-identical sibling suffering from ankylosing spondylitis (AS) (B27+, AS+), specifically lyse B27+, AS+ PBMC but not PBMC from HLA-27+ or B27-, AS- normal controls, or from HLA-B27- AS patients (B27-,AS+). CTL of similar specificity can also be raised by immunizing in vitro B27+,AS- cells with autologous cells modified by cross-reactive bacterial antigens. These results suggest that CTL can recognize certain bacterial antigens in association with HLA-B27 and that this interaction may lead to an inflammatory episode during the initial stages of the disease. PMID:3528379

  16. Effective Cytotoxic T Lymphocyte Targeting of Persistent HIV-1 during Antiretroviral Therapy Requires Priming of Naive CD8+ T Cells

    PubMed Central

    Smith, Kellie N.; Mailliard, Robbie B.; Piazza, Paolo A.; Fischer, Will; Korber, Bette T.; Fecek, Ronald J.; Ratner, Deena; Gupta, Phalguni; Mullins, James I.

    2016-01-01

    ABSTRACT Curing HIV-1 infection will require elimination of persistent cellular reservoirs that harbor latent virus in the face of combination antiretroviral therapy (cART). Proposed immunotherapeutic strategies to cure HIV-1 infection include enhancing lysis of these infected cells by cytotoxic T lymphocytes (CTL). A major challenge in this strategy is overcoming viral immune escape variants that have evaded host immune control. Here we report that naive CD8+ T cells from chronic HIV-1-infected participants on long-term cART can be primed by dendritic cells (DC). These DC must be mature, produce high levels of interleukin 12p70 (IL-12p70), be responsive to CD40 ligand (CD40L), and be loaded with inactivated, autologous HIV-1. These DC-primed CD8+ T cell responders produced high levels of gamma interferon (IFN-γ) in response to a broad range of both conserved and variable regions of Gag and effectively killed CD4+ T cell targets that were either infected with the autologous latent reservoir-associated virus or loaded with autologous Gag peptides. In contrast, HIV-1-specific memory CD8+ T cells stimulated with autologous HIV-1-loaded DC produced IFN-γ in response to a narrow range of conserved and variable Gag peptides compared to the primed T cells and most notably, displayed significantly lower cytolytic function. Our findings highlight the need to selectively induce new HIV-1-specific CTL from naive precursors while avoiding activation of existing, dysfunctional memory T cells in potential curative immunotherapeutic strategies for HIV-1 infection. PMID:27247230

  17. Cathepsin L coexists with Cytotoxic T-lymphocyte Antigen-2 alpha in distinct regions of the mouse brain.

    PubMed

    Luziga, Claudius; Nga, Bui Thi To; Mbassa, Gabriel; Yamamoto, Yoshimi

    2016-09-01

    Cathepsins B and L are two prominent members of cystein proteases with broad substrate specificity and are known to be involved in the process of intra- and extra-cellular protein degradation and turnover. The propeptide region of cathepsin L is identical to Cytotoxic T-lymphocyte antigen-2α (CTLA-2α) discovered in mouse activated T-cells and mast cells. CTLA-2α exhibits selective inhibitory activities against papain and cathepsin L. We previously demonstrated the distribution pattern of the CTLA-2α protein in mouse brain by immunohistochemistry, describing that it is preferentially localized within nerve fibre bundles than neuronal cell bodies. In the present study we report colocalization of cathepsin L and CTLA-2α by double labeling immunofluorescence analysis in the mouse brain. In the telencephalon, immunoreactivity was identified in cerebral cortex and subcortical structures, hippocampus and amygdala. Within the diencephalon intense colocalization was detected in stria medullaris of thalamus, mammillothalamic tract, medial habenular nucleus and choroid plexus. Colocalization signals in the mesencephalon were strong in the hypothalamus within supramammillary nucleus and lateroanterior hypothalamic nucleus while in the cerebellum was in the deep white matter, granule cell layer and Purkinje neurons but moderately in stellate, and basket cells of cerebellar cortex. The distribution pattern indicates that the fine equilibrium between synthesis and secretion of cathespin L and CTLA-2α is part of the brain processes to maintain normal growth and development. The functional implication of cathespin L coexistence with CTLA-2α in relation to learning, memory and disease mechanisms is discussed.

  18. Tumor vessel-injuring ability improves antitumor effect of cytotoxic T lymphocytes in adoptive immunotherapy

    PubMed Central

    Kanagawa, N; Yanagawa, T; Nakagawa, T; Okada, N; Nakagawa, S

    2013-01-01

    Angiogenesis is required for normal physiologic processes, but it is also involved in tumor growth, progression and metastasis. Here, we report the development of an immune-based antiangiogenic strategy based on the generation of T lymphocytes that possess killing specificity for cells expressing vascular endothelial growth factor receptor 2 (VEGFR2). To target VEGFR2-expressing cells, we engineered cytotoxic T lymphocyte (CTL) expressing chimeric T-cell receptors (cTCR–CTL) comprised of a single-chain variable fragment (scFv) against VEGFR2 linked to an intracellular signaling sequence derived from the CD3ζ chain of the TCR and CD28 by retroviral gene transduction methods. The cTCR–CTL exhibited efficient killing specificity against VEGFR2 and a tumor-targeting function in vitro and in vivo. Reflecting such abilities, we confirmed that the cTCR–CTL strongly inhibited the growth of a variety of syngeneic tumors after adoptive transfer into tumor-bearing mice without consequent damage to normal tissue. In addition, CTL expressing both cTCR and tumor-specific TCR induced complete tumor regression due to enhanced tumor infiltration by the CTL and long-term antigen-specific function. These findings provide evidence that the tumor vessel-injuring ability improved the antitumor effect of CTLs in adoptive immunotherapy for a broad range of cancers by inducing immune-mediated destruction of the tumor neovasculature. PMID:23175243

  19. Evolution of viral life-cycle in response to cytotoxic T lymphocyte-mediated immunity.

    PubMed

    Louzoun, Yoram; Ganusov, Vitaly V

    2012-10-07

    Viruses in mammals are constantly faced with the problem of elimination by the host immunity. Cytotoxic T lymphocyte (CTL) responses are thought to play a major role in the control and clearance of several viral infections in mice and humans. It is therefore expected that over evolutionary time, viruses would be forced to evolve to avoid recognition by CTLs. Indeed, a number of studies have documented the accumulation of viral variants with escape mutations. These mutations allow viruses to hide from CTL responses common in the host population. CTLs recognize viruses by short protein sequences, named epitopes, derived from viral proteins. The efficiency of viral recognition by epitope-specific CTL responses depends on the expression pattern of the proteins carrying these epitopes, and the total amount of that protein (and thus epitopes) in the cell. When a virus replicates in a cell, some viral genes are expressed early in the life cycle of the virus, while other proteins are expressed late. For example, HIV infected cells first express Rev and Tat proteins, and the Gag proteins are expressed late. Here we propose a dynamical model of the viral life cycle to study how expression level of early vs. late genes may affect viral dynamics within the host and virus transmission over the course of infection. We find that for acute and chronic viral infections lower expression of early genes than that of the late genes is expected to give selective advantage and higher transmission to viruses.

  20. A Gene Encoding Antigenic Peptides of Human Squamous Cell Carcinoma Recognized by Cytotoxic T Lymphocytes

    PubMed Central

    Shichijo, Shigeki; Nakao, Masanobu; Imai, Yasuhisa; Takasu, Hideo; Kawamoto, Mayumi; Niiya, Fumihiko; Yang, Damu; Toh, Yuji; Yamana, Hideaki; Itoh, Kyogo

    1998-01-01

    Except for melanomas, tumor antigens recognized by cytotoxic T lymphocytes (CTLs) are yet unidentified. We have identified a gene encoding antigenic peptides of human squamous cell carcinomas (SCCs) recognized by human histocompatibility leukocyte antigens (HLA)- A2601–restricted CTLs. This gene showed no similarity to known sequences, and encoded two (125- and 43-kilodalton [kD]) proteins. The 125-kD protein with the leucine zipper motif was expressed in the nucleus of the majority of proliferating cells tested, including normal and malignant cells. The 43-kD protein was expressed in the cytosol of most SCCs from various organs and half of lung adenocarcinomas, but was not expressed in other cancers nor in a panel of normal tissues. The three nonapeptides shared by the two proteins were recognized by the KE4 CTLs, and one of the peptides induced in vitro from peripheral blood mononuclear cells (PBMCs) the CTLs restricted to the autologous tumor cells. The 43-kD protein and this nonapeptide (KGSGKMKTE) may be useful for the specific immunotherapy of HLA-A2601+ epithelial cancer patients. PMID:9449708

  1. Development of a cytotoxic T-lymphocyte-based, broadly protective influenza vaccine.

    PubMed

    Uchida, Tetsuya

    2011-01-01

    The current vaccination strategy against influenza is to induce production of antibodies directed against the surface antigens of these viruses. However, frequent changes in the surface antigens of influenza viruses allow them to avoid antibody-mediated immunity. On the other hand, it is known that cytotoxic T-lymphocyte (CTL) populations directed against internal antigens of influenza A virus are broadly cross-reactive to influenza virus subtypes. The present authors have previously demonstrated that antigens chemically coupled to the surface of liposomes made using unsaturated fatty acids are cross-presented by APCs via MHC class I to CD8(+) T cells and induce antigen-specific CTLs. Based on this finding, a liposome vaccine that is capable of inducing CTL response against internal antigens of influenza viruses and removing virus-infected cells in the host has been developed. The CTL-based liposomal technique might be applicable for developing vaccines against influenza and other viruses, such as hepatitis C, HIV, and severe acute respiratory syndrome corona virus, which frequently change their surface antigenic molecules.

  2. Tissue Dimensionality Influences the Functional Response of Cytotoxic T Lymphocyte-Mediated Killing of Targets

    PubMed Central

    Gadhamsetty, Saikrishna; Marée, Athanasius F. M.; de Boer, Rob J.; Beltman, Joost B.

    2017-01-01

    Cytotoxic T lymphocyte (CTL)-mediated killing of virus infections and tumors occurs over a wide range of conditions. The spatial environments in which CTLs encounter target cells vary from narrow vessels, to two-dimensional epithelial tissues, to densely populated 3-dimensional (3D) T cell areas within lymphoid tissues. How such spatial environments alter the functional response of CTL-mediated killing, i.e., how the killing efficiency depends on cell densities, is unclear. In this study, we perform cellular Potts model simulations in different spatial configurations to investigate how the dimensionality of the space affects the functional response of CTL-mediated killing. Irrespective of the spatial configuration, the function with separate saturation constants for CTL and for target cell densities that we previously proposed can in all cases describe the response, demonstrating its generality. However, the tissue dimensionality determines at which cell densities the killing rate starts to saturate. We show that saturation in a fully 3D environment is stronger than in a “flat” 3D environment, which is largely due to accompanying differences in the CTL–target encounter rates. PMID:28123385

  3. Cytotoxic T-lymphocyte-mediated killing of human pancreatic islet cells in vitro.

    PubMed

    Campbell, Peter D; Estella, Eugene; Dudek, Nadine L; Jhala, Gaurang; Thomas, Helen E; Kay, Thomas W H; Mannering, Stuart I

    2008-09-01

    Cytotoxic T lymphocytes (CTL) are believed to play an essential role in beta-cell destruction leading to development of type 1 diabetes and allogeneic islet graft failure. We aimed to identify the mechanisms used by CTL to kill human beta cells. CTL clones that recognize epitopes from influenza virus and Epstein-Barr virus restricted by human leukocyte antigen (HLA)-A0201 and -B0801, respectively, were used to investigate the susceptibility of human beta cells to CTL. In a short-term (5-hour) assay, CTL killed human islet cells of the appropriate major histocompatibility complex (MHC) class I type that had been pulsed with viral peptides. Killing was increased by pretreating islets with interferon gamma that increases MHC class I on target cells. Killing was abolished by incubation of CTL with the perforin inhibitor concanamycin A. The Fas pathway did not contribute to killing because blocking with neutralizing anti-Fas ligand antibody did not significantly reduce beta-cell killing. In conclusion, we report a novel way of investigating the interaction between CTL and human islets. Human islets were rapidly killed in vitro by MHC class I-restricted CTL predominantly by the granule exocytosis pathway.

  4. Dengue virus protein recognition by virus-specific murine CD8+ cytotoxic T lymphocytes.

    PubMed Central

    Rothman, A L; Kurane, I; Lai, C J; Bray, M; Falgout, B; Men, R; Ennis, F A

    1993-01-01

    The identification of the protein targets for dengue virus-specific T lymphocytes may be useful for planning the development of subunit vaccines against dengue. We studied the recognition by murine dengue virus-specific major histocompatibility complex class I-restricted, CD8+ cytotoxic T lymphocytes (CTL) of dengue virus proteins using recombinant vaccinia viruses containing segments of the dengue virus genome. CTL from H-2k mice recognized a single serotype-cross-reactive epitope on the nonstructural (NS) protein NS3. CTL from H-2b mice recognized a serotype-cross-reactive epitope that was localized to NS4a or NS4b. CTL from H-2d mice recognized at least three epitopes: a serotype-specific epitope on one of the structural proteins, a serotype-cross-reactive epitope on NS3, and a serotype-cross-reactive epitope on NS1 or NS2a. Our findings demonstrate the limited recognition of dengue virus proteins by CTL from three inbred mouse strains and the predominance of CTL epitopes on dengue virus nonstructural proteins, particularly NS3. Since human dengue virus-specific CTL show similar patterns of recognition, these findings suggest that nonstructural proteins should be considered in designing vaccines against dengue. PMID:7678307

  5. A General Functional Response of Cytotoxic T Lymphocyte-Mediated Killing of Target Cells

    PubMed Central

    Gadhamsetty, Saikrishna; Marée, Athanasius F.M.; Beltman, Joost B.; de Boer, Rob J.

    2014-01-01

    Cytotoxic T lymphocytes (CTLs) kill virus-infected cells and tumor cells, and play a critical role in immune protection. Our knowledge of how the CTL killing efficiency varies with CTL and target cell numbers is limited. Here, we simulate a region of lymphoid tissue using a cellular Potts model to characterize the functional response of CTL killing of target cells, and find that the total killing rate saturates both with the CTL and the target cell densities. The relative saturation in CTL and target cell densities is determined by whether a CTL can kill multiple target cells at the same time, and whether a target cell can be killed by many CTLs together. We find that all the studied regimes can be well described by a double-saturation (DS) function with two different saturation constants. We show that this DS model can be mechanistically derived for the cases where target cells are killed by a single CTL. For the other cases, a biological interpretation of the parameters is still possible. Our results imply that this DS function can be used as a tool to predict the cellular interactions in cytotoxicity data. PMID:24739177

  6. Tissue Dimensionality Influences the Functional Response of Cytotoxic T Lymphocyte-Mediated Killing of Targets.

    PubMed

    Gadhamsetty, Saikrishna; Marée, Athanasius F M; de Boer, Rob J; Beltman, Joost B

    2016-01-01

    Cytotoxic T lymphocyte (CTL)-mediated killing of virus infections and tumors occurs over a wide range of conditions. The spatial environments in which CTLs encounter target cells vary from narrow vessels, to two-dimensional epithelial tissues, to densely populated 3-dimensional (3D) T cell areas within lymphoid tissues. How such spatial environments alter the functional response of CTL-mediated killing, i.e., how the killing efficiency depends on cell densities, is unclear. In this study, we perform cellular Potts model simulations in different spatial configurations to investigate how the dimensionality of the space affects the functional response of CTL-mediated killing. Irrespective of the spatial configuration, the function with separate saturation constants for CTL and for target cell densities that we previously proposed can in all cases describe the response, demonstrating its generality. However, the tissue dimensionality determines at which cell densities the killing rate starts to saturate. We show that saturation in a fully 3D environment is stronger than in a "flat" 3D environment, which is largely due to accompanying differences in the CTL-target encounter rates.

  7. A general functional response of cytotoxic T lymphocyte-mediated killing of target cells.

    PubMed

    Gadhamsetty, Saikrishna; Marée, Athanasius F M; Beltman, Joost B; de Boer, Rob J

    2014-04-15

    Cytotoxic T lymphocytes (CTLs) kill virus-infected cells and tumor cells, and play a critical role in immune protection. Our knowledge of how the CTL killing efficiency varies with CTL and target cell numbers is limited. Here, we simulate a region of lymphoid tissue using a cellular Potts model to characterize the functional response of CTL killing of target cells, and find that the total killing rate saturates both with the CTL and the target cell densities. The relative saturation in CTL and target cell densities is determined by whether a CTL can kill multiple target cells at the same time, and whether a target cell can be killed by many CTLs together. We find that all the studied regimes can be well described by a double-saturation (DS) function with two different saturation constants. We show that this DS model can be mechanistically derived for the cases where target cells are killed by a single CTL. For the other cases, a biological interpretation of the parameters is still possible. Our results imply that this DS function can be used as a tool to predict the cellular interactions in cytotoxicity data.

  8. HDAC6 regulates the dynamics of lytic granules in cytotoxic T lymphocytes

    PubMed Central

    Núñez-Andrade, Norman; Iborra, Salvador; Trullo, Antonio; Moreno-Gonzalo, Olga; Calvo, Enrique; Catalán, Elena; Menasche, Gaël; Sancho, David; Vázquez, Jesús; Yao, Tso-Pang

    2016-01-01

    HDAC6 is a tubulin deacetylase involved in many cellular functions related to cytoskeleton dynamics including cell migration and autophagy. In addition, HDAC6 affects antigen-dependent CD4+ T cell activation. In this study, we show that HDAC6 contributes to the cytotoxic function of CD8+ T cells. Immunization studies revealed defective cytotoxic activity in vivo in the absence of HDAC6. Adoptive transfer of wild-type or Hdac6-/- CD8+ T cells to Rag1-/- mice demonstrated specific impairment in CD8+ T cell responses against vaccinia infection. Mechanistically, HDAC6-deficient cytotoxic T lymphocytes (CTLs) showed defective in vitro cytolytic activity related to altered dynamics of lytic granules, inhibited kinesin 1 – dynactin mediated terminal transport of lytic granules to the immune synapse and deficient exocytosis, but not to target cell recognition, T cell receptor (TCR) activation or interferon (IFNγ) production. Our results establish HDAC6 as an effector of the immune cytotoxic response that acts by affecting the dynamics, transport and secretion of lytic granules by CTLs. PMID:26869226

  9. Analysis of the mechanisms of human cytotoxic T lymphocyte response inhibition by NO.

    PubMed

    Blesson, Séverine; Thiery, Jérôme; Gaudin, Catherine; Stancou, Rodica; Kolb, Jean-Pierre; Moreau, Jean-Louis; Theze, Jacques; Mami-Chouaib, Fathia; Chouaib, Salem

    2002-10-01

    NO is a potent cellular mediator which has been shown to modulate several immune mechanisms. Using human T lymphocytes as responder cells in a primary mixed lymphocyte reaction, we demonstrated that, at the initiation of the culture, exogenously provided NO via sodium nitroprusside, in non-toxic concentrations, inhibited both allogeneic proliferative and primary cytotoxic responses in a dose-dependent manner. In contrast, it had no effect on the cytotoxic activity of established human TCR (alpha)beta and TCR (gamma)delta cytotoxic T lymphocyte (CTL) clones. The NO inhibitory effect on primary cytotoxic T cell response correlates with inhibition of T cell blastogenesis. Furthermore, under our stimulation conditions, NO induced an inhibition of IL-2 production, an alteration of IL-2R(alpha) expression, and a down-regulation of NF-AT translocation in CD4(+) and CD8(+)allostimulated T cells. Furthermore, we demonstrate that the inhibition of allospecific CTL activity by the NO donor was at least in part related to an inhibition of granzyme B and Fas ligand transcription as revealed respectively by RNase protection and RT-PCR analysis. These results suggest that NO may function to fine tune human CD3(+) T cell activation and subsequent CTL generation.

  10. Peptide microarrays for the profiling of cytotoxic T-lymphocyte activity using minimum numbers of cells.

    PubMed

    Hoff, Antje; Bagû, Ana-Cristina; André, Thomas; Roth, Günter; Wiesmüller, Karl-Heinz; Gückel, Brigitte; Brock, Roland

    2010-09-01

    The identification of epitopes that elicit cytotoxic T-lymphocyte activity is a prerequisite for the development of cancer-specific immunotherapies. However, especially the parallel characterization of several epitopes is limited by the availability of T cells. Microarrays have enabled an unprecedented miniaturization and parallelization in biological assays. Here, we developed peptide microarrays for the detection of CTL activity. MHC class I-binding peptide epitopes were pipetted onto polymer-coated glass slides. Target cells, loaded with the cell-impermeant dye calcein, were incubated on these arrays, followed by incubation with antigen-expanded CTLs. Cytotoxic activity was detected by release of calcein and detachment of target cells. With only 200,000 cells per microarray, CTLs could be detected at a frequency of 0.5% corresponding to 1,000 antigen-specific T cells. Target cells and CTLs only settled on peptide spots enabling a clear separation of individual epitopes. Even though no physical boundaries were present between the individual spots, peptide loading only occurred locally and cytolytic activity was confined to the spots carrying the specific epitope. The peptide microarrays provide a robust platform that implements the whole process from antigen presentation to the detection of CTL activity in a miniaturized format. The method surpasses all established methods in the minimum numbers of cells required. With antigen uptake occurring on the microarray, further applications are foreseen in the testing of antigen precursors that require uptake and processing prior to presentation.

  11. Polyomavirus DNA is damaged in target cells during cytotoxic T-lymphocyte-mediated killing

    SciTech Connect

    Sellins, K.S.; Cohen, J.J.

    1989-02-01

    Target cell DNA damage is an early event in cytotoxic T-lymphocyte (CTS)-mediated killing. It has been hypothesized that this DNA damage may serve as one mechanism of destroying viral genetic material inside infected cells. The authors directly examined the fate of viral DNA in target cells during CTL-mediated lysis. Polyomavirus DNA in transfected murine P815 mastocytoma targets was digested along with cellular DNA into oligonucleosome-sized fragments, although intact forms, possibly virion-associated DNA, were also present. In infected BALB/3T3 murine fibroblasts, which normally undergo single-stranded nicks when killed by CTL, polyomavirus DNA was converted to relaxed forms in the presence of CTL. These results suggest that the fate of the viral DNA depends on the stage of the viral life cycle and corresponds to the fate of the host cell DNA. Cleavage of the viral genome prior to assembly may thus be an important mechanism in specific antiviral immunity.

  12. A High Throughput Phenotypic Screen of Cytotoxic T Lymphocyte Lytic Granule Exocytosis Reveals Candidate Immunosuppressants

    PubMed Central

    Zhao, Ziyan; Haynes, Mark K.; Ursu, Oleg; Edwards, Bruce S.; Sklar, Larry A.; Zweifach, Adam

    2015-01-01

    We screened the NIH’s Molecular Libraries Small Molecule Repository for inhibitors of cytotoxic T lymphocyte (CTL) lytic granule exocytosis by measuring binding of an antibody in the extracellular solution to a lysosomal membrane protein (LAMP-1) that is transferred to the plasma membrane by exocytosis. We used TALL-104 human leukemic CTLs stimulated with soluble chemicals. Using high-throughput cluster cytometry to screen 364202 compounds in 1536-well plate format, identifying 2404 initial hits. 161 were confirmed on retesting, and dose-response measurements were performed. 75 of those compounds were obtained, and 48 were confirmed active. Experiments were conducted to determine the molecular mechanism of action (MMOA) of the active compounds. Fifteen blocked increases in intracellular calcium >50%. Seven blocked phosphorylation of ERK by upstream MAP kinase kinases >50%. One completely blocked the activity of the calcium-dependent phosphatase calcineurin. None blocked ERK catalytic activity. Eight blocked more than one pathway. For eight compounds, we were unable to determine an MMOA. The activity of one of these compounds was confirmed from powder resupply. We conclude that a screen based on antibody binding to CTLs is a good means of identifying novel candidate immunosuppressants with either known or unknown MMOA. PMID:25381253

  13. In vitro selection of lymphocytic choriomeningitis virus escape mutants by cytotoxic T lymphocytes.

    PubMed Central

    Aebischer, T; Moskophidis, D; Rohrer, U H; Zinkernagel, R M; Hengartner, H

    1991-01-01

    Cytotoxic T lymphocyte (CTL)-mediated cytolysis is induced via the interaction of the specific T-cell antigen receptor and the peptidic viral antigen associated with the major histocompatibility complex class I antigen. Here we demonstrate in vitro that lymphocytic choriomeningitis virus (LCMV) can escape the cytotoxic activity of LCMV-specific cloned CTLs by single amino acid changes within the recognized T-cell epitope defined by residues 275-289 of the LCMV glycoprotein [LCMV-GP-(275-289)]. LCMV-infected fibroblasts at a multiplicity of infection of 10(-3) exposed to virus-specific CTL at an effector-to-target cell ratio of 4:1 4 hr after infection was optimal for virus mutant selection. The selections were carried out with three LCMV-GP-(275-289)-specific CTL clones expressing T-cell antigen receptors containing the identical variable gene segments V alpha 4 and V beta 10 but different junctional regions; selection was also possible with LCMV-GP-(275-289)-specific cytotoxic polyclonal T cells. The most common escape mutation was an amino acid change of asparagine (AAT) to aspartic acid (GAT) at position 280; an additional mutation was glycine (GGT) to aspartic acid (GAT) at position 282. The results presented show that relevant point mutations within the T-cell epitope of LCMV-GP-(275-289) occur frequently and that they are selectable in vitro by CTLs. Images PMID:1722316

  14. Identification of genes and pathways associated with cytotoxic T lymphocyte infiltration of serous ovarian cancer

    PubMed Central

    Leffers, N; Fehrmann, R S N; Gooden, M J M; Schulze, U R J; ten Hoor, K A; Hollema, H; Boezen, H M; Daemen, T; de Jong, S; Nijman, H W; van der Zee, A G J

    2010-01-01

    Background: Tumour-infiltrating lymphocytes (TILs) are predictors of disease-specific survival (DSS) in ovarian cancer. It is largely unknown what factors contribute to lymphocyte recruitment. Our aim was to evaluate genes and pathways contributing to infiltration of cytotoxic T lymphocytes (CTLs) in advanced-stage serous ovarian cancer. Methods: For this study global gene expression was compared between low TIL (n=25) and high TIL tumours (n=24). The differences in gene expression were evaluated using parametric T-testing. Selectively enriched biological pathways were identified with gene set enrichment analysis. Prognostic influence was validated in 157 late-stage serous ovarian cancer patients. Using immunohistochemistry, association of selected genes from identified pathways with CTL was validated. Results: The presence of CTL was associated with 320 genes and 23 pathways (P<0.05). In addition, 54 genes and 8 pathways were also associated with DSS in our validation cohort. Immunohistochemical evaluation showed strong correlations between MHC class I and II membrane expression, parts of the antigen processing and presentation pathway, and CTL recruitment. Conclusion: Gene expression profiling and pathway analyses are valuable tools to obtain more understanding of tumour characteristics influencing lymphocyte recruitment in advanced-stage serous ovarian cancer. Identified genes and pathways need to be further investigated for suitability as therapeutic targets. PMID:20664601

  15. Engineered cytotoxic T lymphocytes with AFP-specific TCR gene for adoptive immunotherapy in hepatocellular carcinoma.

    PubMed

    Sun, Longhao; Guo, Hao; Jiang, Ruoyu; Lu, Li; Liu, Tong; He, Xianghui

    2016-01-01

    Alpha-fetoprotein (AFP) is overexpressed in hepatocellular carcinoma (HCC) and could serve as a tumor-associated antigen (TAA) and potential target for adoptive immunotherapy. However, low frequency and severe functional impairment of AFP-specific T cells in vivo hamper adoptive infusion. TAA-specific T cell receptor (TCR) gene transfer could be an efficient and reliable alternation to generate AFP-specific cytotoxic T lymphocytes (CTLs). Autologous dendritic cells (DC) pulsed with AFP158-166 peptides were used to stimulate AFP-specific CTLs. TCR α/β chain genes of AFP-specific CTLs were cloned and linked by 2A peptide to form full-length TCR coding sequence synthesized into a lentiviral vector. Nonspecific activated T cells were engineered by lentivirus infection. Transgenetic CTLs were evaluated for transfection efficiency, expression of AFP158-166-specific TCR, interferon (IFN)-γ secretion, and specific cytotoxicity toward AFP+ HCC cells in vitro and in vivo. Flow cytometry revealed the AFP158-166-MHC-Pentamer positive transgenetic CTLs was 9.86 %. The number of IFN-γ secretion T cells and the specific cytotoxicity toward HpeG2 in vitro and in tumor-bearing NOD/SCID mice were significantly raised in transgenetic CTLs than that of AFP158-166-specific CTLs obtained by peptide-pulsed DCs or control group. TCR gene transfer is a promising strategy to generate AFP158-166-specific CTLs for the treatment of HCC.

  16. Cytotoxic T lymphocytes established by seasonal human influenza cross-react against 2009 pandemic H1N1 influenza virus.

    PubMed

    Tu, Wenwei; Mao, Huawei; Zheng, Jian; Liu, Yinping; Chiu, Susan S; Qin, Gang; Chan, Ping-Lung; Lam, Kwok-Tai; Guan, Jing; Zhang, Lijuan; Guan, Yi; Yuen, Kwok-Yung; Peiris, J S Malik; Lau, Yu-Lung

    2010-07-01

    While few children and young adults have cross-protective antibodies to the pandemic H1N1 2009 (pdmH1N1) virus, the illness remains mild. The biological reasons for these epidemiological observations are unclear. In this study, we demonstrate that the bulk memory cytotoxic T lymphocytes (CTLs) established by seasonal influenza viruses from healthy individuals who have not been exposed to pdmH1N1 can directly lyse pdmH1N1-infected target cells and produce gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha). Using influenza A virus matrix protein 1 (M1(58-66)) epitope-specific CTLs isolated from healthy HLA-A2(+) individuals, we further found that M1(58-66) epitope-specific CTLs efficiently killed both M1(58-66) peptide-pulsed and pdmH1N1-infected target cells ex vivo. These M1(58-66)-specific CTLs showed an effector memory phenotype and expressed CXCR3 and CCR5 chemokine receptors. Of 94 influenza A virus CD8 T-cell epitopes obtained from the Immune Epitope Database (IEDB), 17 epitopes are conserved in pdmH1N1, and more than half of these conserved epitopes are derived from M1 protein. In addition, 65% (11/17) of these epitopes were 100% conserved in seasonal influenza vaccine H1N1 strains during the last 20 years. Importantly, seasonal influenza vaccination could expand the functional M1(58-66) epitope-specific CTLs in 20% (4/20) of HLA-A2(+) individuals. Our results indicated that memory CTLs established by seasonal influenza A viruses or vaccines had cross-reactivity against pdmH1N1. These might explain, at least in part, the unexpected mild pdmH1N1 illness in the community and also might provide some valuable insights for the future design of broadly protective vaccines to prevent influenza, especially pandemic influenza.

  17. Cytotoxic T Lymphocyte Antigen-4 Gene Variants in Type 2 Diabetic Patients with or without Neuropathy.

    PubMed

    Kiani, Javad; Khadempar, Saedeh; Hajilooi, Mehrdad; Rezaei, Hamzeh; Keshavarzi, Fatemeh; Solgi, Ghasem

    2016-06-01

    Many studies have shown that cytotoxic T lymphocyte antigen-4 (CTLA-4) gene variants are associated with several autoimmune diseases particularly type 1 diabetes. Due to the lack of consistent data for this association with type 2 diabetes (T2D), this study explored the possible influence of CTLA-4 gene polymorphisms at -1722 (T/C), -318 (C/T), and +49 (G/A) positions for susceptibility to T2D in relation with neuropathy. One hundred and eleven unrelated patients with T2D [49 patients with diabetic peripheral neuropathy (DPN) and 62 patients without PDN] and 100 healthy ethnic- and gender-matched controls were included in this study. The dimorphisms at -1722 (C/T), -318 (C/T) and +49 (A/G) for CTLA-4 gene were determined using ARMS-PCR. The CTLA-4 (+49 G/G) and (+49 A/A) genotypes were found to be positively and negatively associated with T2D, respectively (p=0.03). The -318 C/T and T/T genotypes were more frequent in patients than controls and -318 C/C genotype was shown to be protective for T2D (p=0.003). ACT and GTT Haplotypes were less and more frequent in controls and patients, respectively (p=3.86×10-7 and p=2.29×10-5). Genotypes distribution among T2D patients with and without DPN compared to healthy controls showed significantly lower frequencies for -318 C/C and +49 A/A genotypes and significantly higher frequencies for -318 C/T and T/T genotypes as well. Our findings indicate that CTLA-4 (+49 A/G) and (-318 C/T) genotypes could be considered as genetic risk factors associated with susceptibility or protection for T2D.

  18. Effect of prolactin on carcinoembryonic antigen-specific cytotoxic T lymphocyte response induced by dendritic cells.

    PubMed

    Matera, L; Beltramo, E; Martinuzzi, E; Buttiglieri, S

    2004-08-01

    The cytokine hormone prolactin (PRL) has been shown previously to modulate native cellular responses and maturation of antigen-presenting cells. Here we have addressed its effect on the antigen-specific response of cytotoxic T lymphocytes (CTL). CTL were generated from HLA-A2 lymphocytes after three rounds of stimulation with autologous dendritic cells loaded with HLA-A2-restricted carcinoembrionic antigen (CEA) Cap-1 (YLSGANLNL) peptide. Selected cultures were expanded on cytokine-supplemented feeder-layers, enriched for CD8+ lymphocytes and analysed for PRL-receptor (PRL-R) expression and PRL responsiveness. Resting CD8+ lymphocytes were negative for PRL-R, whereas antigen-activated CD8+ lymphocytes derived from long-term cultures were highly positive. Results of a 51Cr release assay showed CTL killing of CEA-loaded, but not unloaded, T2 cell line and the CEA-positive gastric carcinoma cell line KATO, but not of the CEA-negative T leukaemia cell line Jurkat. Interferon (IFN)-gamma release, evaluated in an ELISPOT assay against CEA-loaded T2, was enhanced (P < 0.05) by concentrations of PRL (12-25 ng/ml) very close to the physiological levels (6-20 ng/ml), but was decreased (P < 0.05) by high concentrations (200 ng/ml). Pre-incubation of the stimulators with the anti-MHC class I MoAb W6.32 induced a 40-60% decrease of the PRL-boosted IFN-gamma release, thus proving the MHC restriction of the lymphocyte response. Cytotoxicity against CEA-loaded T2 and KATO cell lines was also increased by 12-25 ng (P < 0.05) and decreased (P < 0.05) by 200 ng PRL. Pre-incubation of CTL with an antibody specific for the PRL-R almost completely abrogated this effect.

  19. Immunological potential of cytotoxic T lymphocyte antigen 4 immunoglobulin in murine autoimmune cholangitis.

    PubMed

    Tanaka, H; Yang, G-X; Tomiyama, T; Tsuneyama, K; Zhang, W; Leung, P S C; Coppel, R L; Joh, T; Nadler, S G; Ansari, A A; Bowlus, C; Gershwin, M E

    2015-06-01

    Cytotoxic T lymphocyte antigen 4 (CTLA-4) immunoglobulin (Ig) is an important regulator of T cell activation and a fusion protein directed at CD80 and CD86; it blocks co-stimulatory signalling and T cell activation. We have taken advantage of a murine model of human primary biliary cirrhosis (PBC), mice expressing a transforming growth factor (TGF)-β receptor II dominant negative (dnTGF-βRII) transgene to address the potential therapeutic efficacy of CTLA-4 Ig. To mimic patients with PBC at different stages or duration of disease, we treated mice with either CTLA-4 Ig or control IgG three times weekly from 3 to 12 or 24 weeks of age, or from 12 to 24 weeks of age. CTLA-4 Ig treatment from 3 weeks of age significantly reduced liver inflammation to 12 weeks of age. Treatment initiated at 12 weeks of age also ameliorated the autoimmune cholangitis at 24 weeks of age. However, in mice treated at 3 weeks of age, suppression of liver inflammation was not sustained and colitis was aggravated when treatment was extended to 24 weeks of age. Our data indicate that, in dnTGF-βRII mice, CTLA-4 Ig treatment has short-term beneficial effects on autoimmune cholangitis, but the effect varies according to duration of treatment and the time in which therapy was initiated. Further dissection of the events that lead to the reduction in therapeutic effectiveness of CTLA-4 Ig will be critical to determining whether such efforts can be applied to human PBC.

  20. Behavior and Properties of Mature Lytic Granules at the Immunological Synapse of Human Cytotoxic T Lymphocytes

    PubMed Central

    Ming, Min; Schirra, Claudia; Becherer, Ute; Stevens, David R.; Rettig, Jens

    2015-01-01

    Killing of virally infected cells or tumor cells by cytotoxic T lymphocytes requires targeting of lytic granules to the junction between the CTL and its target. We used whole-cell patch clamp to measure the cell capacitance at fixed intracellular [Ca2+] to study fusion of lytic granules in human CTLs. Expression of a fluorescently labeled human granzyme B construct allowed identification of lytic granule fusion using total internal reflection fluorescence microscopy. In this way capacitance steps due to lytic granule fusion were identified. Our goal was to determine the size of fusing lytic granules and to describe their behavior at the plasma membrane. On average, 5.02 ± 3.09 (mean ± s.d.) lytic granules were released per CTL. The amplitude of lytic granule fusion events was ~ 3.3 fF consistent with a diameter of about 325 nm. Fusion latency was biphasic with time constants of 15.9 and 106 seconds. The dwell time of fusing lytic granules was exponentially distributed with a mean dwell time of 28.5 seconds. Fusion ended in spite of the continued presence of granules at the immune synapse. The mobility of fusing granules at the membrane was indistinguishable from that of lytic granules which failed to fuse. While dwelling at the plasma membrane lytic granules exhibit mobility consistent with docking interspersed with short periods of greater mobility. The failure of lytic granules to fuse when visible in TIRF at the membrane may indicate that a membrane-confined reaction is rate limiting. PMID:26296096

  1. Expression of structurally diverse Qa-2-encoded molecules on the surface of cloned cytotoxic T lymphocytes

    PubMed Central

    1984-01-01

    Extracts of 125I-labeled cloned murine cytotoxic T lymphocytes (CTL) were immunoprecipitated with alloantisera to the cloned CTL and rabbit antisera to beta-2 microglobulin. Polyacrylamide gel electrophoresis (PAGE) of the specific precipitates revealed, as expected, 125I-labeled components that corresponded to products of class I genes of the major histocompatibility complex (MHC). However, additional class I gene products of relatively low apparent molecular weight (Mr) were also observed. Similar analyses of spleen cells from a variety of MHC- congenic mouse strains suggested that the class I molecules of relatively low Mr are encoded in the Qa-2 region of the MHC, and this was confirmed by immunoprecipitation with a monoclonal antibody to Qa- 2. Surprisingly, however, the cell surface Qa-2 molecules of different CTL clones differed in Mr, in isoelectric focusing (IEF) pattern, and in the number of distinguishable molecules expressed per clone: some clones seemed to express only a single Qa-2-encoded molecule while others expressed two distinct ones. Treatment of the immunoprecipitated Qa-2 with endoglycosidase F (Endo F) resulted in a decrease in Mr of approximately 5,000-6,000, corresponding to the expected loss of N- linked oligosaccharides, but the decrease did not eliminate structural variability among the clones. Structural diversity of the Qa-2-encoded molecules expressed on CTL could arise because CTL clones differ (a) in the particular Qa-2 genes they express, (b) in the way they splice Qa-2 gene transcripts or, perhaps, (c) in Endo F-resistant oligosaccharides on their Qa-2 molecules. PMID:6333483

  2. Generation of cytotoxic T lymphocytes (CTL) with phorbol ester and calcium ionophore

    SciTech Connect

    Tuttle, T.M.; Bear, H.D. )

    1991-03-15

    Stimulation of lymphocytes with viable tumor cells can induce cytotoxic T lymphocytes (CTL) against autologous tumor. However, sufficient numbers of tumor cells are not always available for such stimulation, and high dose interleukin-2 (IL-2) is often required for growth. Using the weakly immunogenic methylcholanthrene-induced sarcoma MCA105, the authors demonstrate here that CTLs can be expected by pharmacologic manipulation of protein kinase C (PKC) and intracellular calcium with phorbol dibutyrate (PD-Bu) and ionomycin (Io), respectively. Lymphocytes were obtained from the spleens and ipsilateral popliteal draining lymph nodes (DLN) 10 days after the footpad injection of viable MCA105 tumor cells. The cells were stimulated with autologous tumor and 20U/ml IL-2 for 7 days and then treated with PDBu and Io and expanded in culture with 20U/ml IL-2 for an additional 14 days. The lymphocytes from the spleens and DLNs demonstrated significant expansion and marked cytotoxicity against MCA105. In another regimen, lymphocytes from the DLNs of tumor-bearing mice were stimulated directly with PDBu and Io without prior in vitro exposure to autologous tumor and expanded in culture with 20U/ml IL-2. The expansion of these lymphocytes was 500 fold and the cytotoxicity against MCA 105 remained high. Lymphocytes expanded with PDBu and Io also killed MCA102, but normal spleen cells expanded in the same way had no cytotoxic activity. The authors conclude that PKC activators coupled with calcium ionophores and low-dose IL-2 can generate CTL when little or no antigen is available.

  3. Mathematical modeling of escape of HIV from cytotoxic T lymphocyte responses

    NASA Astrophysics Data System (ADS)

    Ganusov, Vitaly V.; Neher, Richard A.; Perelson, Alan S.

    2013-01-01

    Human immunodeficiency virus (HIV-1 or simply HIV) induces a persistent infection, which in the absence of treatment leads to AIDS and death in almost all infected individuals. HIV infection elicits a vigorous immune response starting about 2-3 weeks postinfection that can lower the amount of virus in the body, but which cannot eradicate the virus. How HIV establishes a chronic infection in the face of a strong immune response remains poorly understood. It has been shown that HIV is able to rapidly change its proteins via mutation to evade recognition by virus-specific cytotoxic T lymphocytes (CTLs). Typically, an HIV-infected patient will generate 4-12 CTL responses specific for parts of viral proteins called epitopes. Such CTL responses lead to strong selective pressure to change the viral sequences encoding these epitopes so as to avoid CTL recognition. Indeed, the viral population ‘escapes’ from about half of the CTL responses by mutation in the first year. Here we review experimental data on HIV evolution in response to CTL pressure, mathematical models developed to explain this evolution, and highlight problems associated with the data and previous modeling efforts. We show that estimates of the strength of the epitope-specific CTL response depend on the method used to fit models to experimental data and on the assumptions made regarding how mutants are generated during infection. We illustrate that allowing CTL responses to decay over time may improve the model fit to experimental data and provides higher estimates of the killing efficacy of HIV-specific CTLs. We also propose a novel method for simultaneously estimating the killing efficacy of multiple CTL populations specific for different epitopes of HIV using stochastic simulations. Lastly, we show that current estimates of the efficacy at which HIV-specific CTLs clear virus-infected cells can be improved by more frequent sampling of viral sequences and by combining data on sequence evolution with

  4. Immunization with a replication-deficient mutant of herpes simplex virus type 1 (HSV-1) induces a CD8+ cytotoxic T-lymphocyte response and confers a level of protection comparable to that of wild-type HSV-1.

    PubMed Central

    Brehm, M A; Bonneau, R H; Knipe, D M; Tevethia, S S

    1997-01-01

    Replication-deficient viruses provide an attractive alternative to conventional approaches used in the induction of antiviral immunity. We have quantitatively evaluated both the primary and memory cytotoxic T-lymphocyte (CTL) responses elicited by immunization with a replication-deficient mutant of herpes simplex virus type 1 (HSV-1). In addition, we have examined the potential role of these CTL in protection against HSV infection. Using bulk culture analysis and limiting-dilution analysis, we have shown that a replication-deficient virus, d301, generates a strong primary CTL response that is comparable to the response induced by the wild type-strain, KOS1.1. Furthermore, the CTL induced by d301 immunization recognized the immunodominant, H-2Kb-restricted, CTL recognition epitope gB498-505 to a level similar to that for CTL from KOS1.1-immunized mice. The memory CTL response evoked by d301 was strong and persistent, even though the frequencies of CTL were slightly lower than the frequencies of CTL induced by KOS1.1. Adoptive transfer studies indicated that both the CD8+ and the CD4+ T-cell responses generated by immunization with d301 and KOS1.1 were able to limit the extent of a cutaneous HSV infection to comparable levels. Overall, these results indicate that viral replication is not necessary to elicit a potent and durable HSV-specific immune response and suggest that replication-deficient viruses may be effective in eliciting protection against viral pathogens. PMID:9094625

  5. Dendritic cells are accessory cells for the development of anti- trinitrophenyl cytotoxic T lymphocytes

    PubMed Central

    1980-01-01

    This study establishes that dendritic cells (DC) are the critical accessory cells for the development of anti-trinitrophenol (TNP) cytotoxic T lymphocytes (CTL) in vitro. We developed a model in which nylon wool-nonadherent spleen cells were used both as the responding and stimulating cells, the latter having been TNP-modified and x- irradiated. Thy-1-bearing CTL developed in C57BL/6, B6D2F1, and CBA mice only when small numbers of DC were added. Maximal responses in 5-d cultures were achieved with 0.5-1 DC/100 responding T cells. The DC did not have to be TNP modified directly. Anti-Ia and complement inactivated accessory cells, whereas similar treatment of the responders had no effect. DC exposed to ultraviolet radiation were ineffective, but x-irradiated DC were fully active. Culture media from DC, or from DC-nylon wool-passed spleen T cell cocultures that contained abundant CTL, would not substitute for viable DC. Enriched preparations of macrophages (M phi) were obtained from blood, peritoneal cavity, and spleens of BCG-immune and unprimed mice. M phi added at doses of 0.2-4% were weak or inactive as accessory cells. The level of Ia antigens on test M phi populations was quantitated and visualized by binding of a radioiodinated monoclonal anti-I-Ab,d antibody, clone B-21. M phi that bore substantial amounts of Ia from all organs were weak accessory cells. Addition of M phi to DC-T cell cocultures produced inhibitory effects, usually at a dose of 2% M phi. In contrast, 0.5% Ia-bearing M phi from BCG-immune boosted mice inhibited > 80% of the DC-mediated CTL response. Addition of indomethacin reversed M phi inhibition, and 10(-9) M prostaglandin E2 in turn blocked the indomethacin effect. Indomethacin also restored a low level of accessory cell function in immune-boosted adherent peritoneal cells, but not in preparations of monocytes and spleen M phi. Small numbers of DC were identified in preparations of immune- boosted peritoneal cells and may have accounted

  6. Identification of cytotoxic T lymphocyte epitopes in dengue virus serotype 1.

    PubMed

    Duan, Zhiliang; Guo, Jianglong; Huang, Xi; Liu, Huifang; Chen, Xinyu; Jiang, Minghua; Wen, Jinsheng

    2015-07-01

    Dengue virus (DENV) has a serious and growing impact on global health and the exact role of DENV-specific CD8(+) T-cells in DENV infection is still uncertain. In the present study, SYFPEITHI algorithm was used to screen the amino acid sequence of Dengue virus serotype 1 (DENV-1) for potential epitopes, and seven putative HLA-A*1101-restricted and five putative HLA-A*2402-restricted epitopes conserved in hundreds of DENV-1 strains were synthesized. The binding affinity of these epitope candidates to corresponding HLA molecules was evaluated using competitive peptide-binding assay. The immunogenicity and specificity of peptides were further tested in HLA-A*1101 transgenic mice, HLA-A*2402 transgenic mice and peripheral blood mononuclear cells (PBMCs) of patients infected with DENV-1. Percentage inhibition (PI) values calculated in competitive peptide-binding assay showed that six peptides (E39-47 PTLDIELLK, NS5(505-513) GVEGEGLHK, NS2b(15-23) SILLSSLLK, NS5(561-569) ALLATSIFK, NS3(99-107) AVEPGKNPK, and NS4b(159-167) VVYDAKFEK) could bind to HLA-A*1101 molecule with high affinity and five peptides (NS3472-480 QYIYMGQPL, NS4a40-48 AYRHAMEEL, NS5(880-888) DYMTSMKRF, NS3(548-556) SYKVASEGF, and NS3(22-30) IYRILQRGL) have a high affinity for HLA-A*2402 molecule. Enzyme-linked immunospot (ELISPOT) results indicated that these high-affinity peptides were recognized by splenocytes of DENV-1-infected transgenic mice and high-affinity peptide-immunized transgenic mice displayed high levels of peptide-specific IFN-γ-secreting cells. In addition, both peptide-pulsed splenocytes and DENV-1-infected splenic monocytes were efficiently killed by these peptide-specific cytotoxic T lymphocytes. Finally, except NS2b(15-23), 10 high-affinity peptides were recognized by PBMCs of patients infected with DENV-1. These identified epitopes would contribute to the understanding of the function of DENV-specific CD8(+) T-cells.

  7. MUC1-specific cytotoxic T lymphocytes in cancer therapy: induction and challenge.

    PubMed

    Roulois, David; Grégoire, Marc; Fonteneau, Jean-François

    2013-01-01

    MUC1 glycoprotein is often found overexpressed and hypoglycosylated in tumor cells from numerous cancer types. Since its discovery MUC1 has been an attractive target for antitumor immunotherapy. Indeed, in vitro and in vivo experiments have shown T-cell-specific responses against MUC1 in an HLA-restricted and HLA-unrestricted manner, although some animal models have highlighted the possible development of tolerogenic responses against this antigen. These observations permit the development of new T-cell vaccine strategies capable of inducing an MUC1-specific cytotoxic T cell response in cancer patients. Some of these strategies are now being tested in clinical trials against different types of cancer. To date, encouraging clinical responses have been observed with some MUC1 vaccines in phase II/III clinical trials. This paper compiles knowledge regarding MUC1 as a promising tumor antigen for antitumor therapeutic vaccines applicable to numerous cancers. We also summarize the results of MUC1-vaccine-based clinical trials.

  8. Oral vaccination with attenuated Salmonella enterica strains encoding T-cell epitopes from tumor antigen NY-ESO-1 induces specific cytotoxic T-lymphocyte responses.

    PubMed

    Meng, Jia-Zi; Dong, Yu-Jun; Huang, He; Li, Shuang; Zhong, Yi; Liu, Shu-Lin; Wang, Yue-Dan

    2010-06-01

    Bacterial fimbriae can accept foreign peptides and display them on the cell surface. A highly efficient gene replacement method was used to generate peptide vaccines based on Salmonella enterica serovar Typhimurium SL3261. The T-cell epitopes (NY-ESO-1 p157-165 and p157-167) from NY-ESO-1, which is a promising target antigen in patients for the specific immune recognition of cancer, were incorporated into the gene encoding AgfA (the major subunit protein of thin aggregative fimbriae of Salmonella) by replacing an equal length of the DNA segment. To improve cytotoxic T-lymphocyte recognition, both termini of the peptide were flanked by double alanine (AA) residues. Immunofluorescence microscopy with AgfA-specific antiserum verified the expression of chimeric AgfA, which was also proved by a Congo red binding assay. Oral immunizations of HLA-A*0201 transgenic mice with recombinant SL3261 strains encoding NY-ESO-1 p157-165 or p157-167 induced NY-ESO-1 p157-165-specific CD8(+) T cells, detected by an HLA-A*0201 pentamer, and induced a T-cell response detected by an enzyme-linked immunospot assay. The Salmonella fimbrial display system was efficient at the induction of an antitumor cellular immune response in vivo, providing a new strategy for the development of efficient cancer vaccinations.

  9. Dynamic visualization the whole process of cytotoxic T lymphocytes killing the B16 tumor cells in vitro

    NASA Astrophysics Data System (ADS)

    Qi, Shuhong; Zhang, Zhihong

    2016-03-01

    Cytotoxic T lymphocytes (CTLs) played a key role in the immune system to destroy the tumor cells. Although some mechanisms of CTLs killing the tumor cells are revealed already, the dynamic information of CTLs interaction with tumor cells are still not known very clearly. Here we used confocal microscopy to visualize the whole process of CTLs killing the tumor cells in vitro. The imaging data showed that CTLs destroyed the target tumor cells rapidly and efficiently. Several CTLs surrounded one or some tumor cells and the average time for CTLs destroying one tumor cell is just a few minutes in vitro. The study displayed the temporal events of CTLs interacting with tumor cells at the beginning and finally killing them and directly presented the efficient tumor cell cytotoxicity of the CTLs. The results helped us to deeply understand the mechanism of the CTLs destroying the tumor cells and to develop the cancer immunotherapy.

  10. Revival of the identification of cytotoxic T-lymphocyte epitopes for immunological diagnosis, therapy and vaccine development.

    PubMed

    Liu, Jun; Zhang, Shihong; Tan, Shuguang; Zheng, Beiwen; Gao, George F

    2011-03-01

    Immunogenic T-cell epitopes have a central role in the cellular immunity against pathogens and tumors. However, in the early stage of cellular immunity studies, it was complicated and time-consuming to identify and characterize T-cell epitopes. Currently, the epitope screening is experiencing renewed enthusiasm due to advances in novel techniques and theories. Moreover, the application of T-cell epitope-based diagnoses for tuberculosis and new data on epitope-based vaccine development have also revived the field. There is a growing knowledge on the emphasis of epitope-stimulated T-cell immune responses in the elimination of pathogens and tumors. In this review, we outline the significance of the identification and characterization of T-cell epitopes. We also summarize the methods and strategies for epitope definition and, more importantly, address the relevance of cytotoxic T-lymphocyte epitopes to clinical diagnoses, therapy and vaccine development.

  11. Selection, Transmission, and Reversion of an Antigen-Processing Cytotoxic T-Lymphocyte Escape Mutation in Human Immunodeficiency Virus Type 1 Infection

    PubMed Central

    Allen, Todd M.; Altfeld, Marcus; Yu, Xu G.; O'Sullivan, Kristin M.; Lichterfeld, Mathias; Le Gall, Sylvie; John, Mina; Mothe, Bianca R.; Lee, Paul K.; Kalife, Elizabeth T.; Cohen, Daniel E.; Freedberg, Kenneth A.; Strick, Daryld A.; Johnston, Mary N.; Sette, Alessandro; Rosenberg, Eric S.; Mallal, Simon A.; Goulder, Philip J. R.; Brander, Christian; Walker, Bruce D.

    2004-01-01

    Numerous studies now support that human immunodeficiency virus type 1 (HIV-1) evolution is influenced by immune selection pressure, with population studies showing an association between specific HLA alleles and mutations within defined cytotoxic T-lymphocyte epitopes. Here we combine sequence data and functional studies of CD8 T-cell responses to demonstrate that allele-specific immune pressures also select for mutations flanking CD8 epitopes that impair antigen processing. In persons expressing HLA-A3, we demonstrate consistent selection for a mutation in a C-terminal flanking residue of the normally immunodominant Gag KK9 epitope that prevents its processing and presentation, resulting in a rapid decline in the CD8 T-cell response. This single amino acid substitution also lies within a second HLA-A3-restricted epitope, with the mutation directly impairing recognition by CD8 T cells. Transmission of the mutation to subjects expressing HLA-A3 was shown to prevent the induction of normally immunodominant acute-phase responses to both epitopes. However, subsequent in vivo reversion of the mutation was coincident with delayed induction of new CD8 T-cell responses to both epitopes. These data demonstrate that mutations within the flanking region of an HIV-1 epitope can impair recognition by an established CD8 T-cell response and that transmission of these mutations alters the acute-phase CD8+ T-cell response. Moreover, reversion of these mutations in the absence of the original immune pressure reveals the potential plasticity of immunologically selected evolutionary changes. PMID:15194783

  12. Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas’ sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation

    PubMed Central

    Malamas, Anthony S.; Gameiro, Sofia R.; Knudson, Karin M.; Hodge, James W.

    2016-01-01

    Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients’ endogenous antigen-specific T-cell populations against specific tumor antigens. PMID:27893426

  13. Immunization with antigenic peptides complexed with β-glucan induces potent cytotoxic T-lymphocyte activity in combination with CpG-ODNs.

    PubMed

    Mochizuki, Shinichi; Morishita, Hiromi; Kobiyama, Kouji; Aoshi, Taiki; Ishii, Ken J; Sakurai, Kazuo

    2015-12-28

    The induction of antigen-specific immune responses requires immunization with not only antigens, but also adjuvants. CpG oligonucleotides (CpG-ODNs) are well-known ligands for Toll-like receptor 9 and a potent adjuvant that induces both Th1-type humoral and cellular immune responses including cytotoxic T-lymphocyte responses. We previously demonstrated that β-glucan schizophyllan (SPG) can form complexes with CpG-ODNs with attached dA40 (CpG-dA/SPG), which can accumulate in macrophages in the draining inguinal lymph nodes and induce strong immune responses by co-administration of antigenic proteins, namely ovalbumin (OVA). Immunization with antigenic peptides, OVA257-264, did not induce these antigen-specific immune responses even in combination with CpG-dA/SPG, indicating that peptides require a carrier to antigen presenting cells. In this study, we prepared conjugates comprising OVA257-264 and dA40, and made complexes with SPG. Immunization with OVA257-264-dA/SPG induced peptide-specific immune responses in combination with CpG-dA regardless of complexation with SPG both in vitro and in vivo. When splenocytes from immunized mice were incubated with E.G7-OVA tumor model cells presenting OVA peptides, the number of cells drastically decreased after 24h. Furthermore, mice pre-immunized with OVA257-264-dA/SPG and CpG-ODNs exhibited a long delay in tumor growth after tumor inoculation. Therefore, these peptide-dA/SPG and CpG-dA/SPG complexes could be used as a potent vaccine for the treatment of cancers and infectious diseases.

  14. Sublethal exposure to alpha radiation (223Ra dichloride) enhances various carcinomas' sensitivity to lysis by antigen-specific cytotoxic T lymphocytes through calreticulin-mediated immunogenic modulation.

    PubMed

    Malamas, Anthony S; Gameiro, Sofia R; Knudson, Karin M; Hodge, James W

    2016-12-27

    Radium-223 dichloride (Xofigo®; 223Ra) is an alpha-emitting radiopharmaceutical FDA-approved for the treatment of bone metastases in patients with advanced castration-resistant prostate cancer. It is also being examined clinically in patients with breast and lung carcinoma and patients with multiple myeloma. As with other forms of radiation, the aim of 223Ra is to reduce tumor burden by directly killing tumor cells. External beam (photon) and proton radiation have been shown to augment tumor sensitivity to antigen-specific CD8+ cytotoxic T lymphocytes (CTLs). However, little is known about whether treatment with 223Ra can also induce such immunogenic modulation in tumor cells that survive irradiation. We examined these effects in vitro by exposing human prostate, breast, and lung carcinoma cells to sublethal doses of 223Ra. 223Ra significantly enhanced T cell-mediated lysis of each tumor type by CD8+ CTLs specific for MUC-1, brachyury, and CEA tumor antigens. Immunofluorescence analysis revealed that the increase in CTL killing was accompanied by augmented protein expression of MHC-I and calreticulin in each tumor type, molecules that are essential for efficient antigen presentation. Enhanced tumor-cell lysis was facilitated by calreticulin surface translocation following 223Ra exposure. The phenotypic changes observed after treatment appear to be mediated by induction of the endoplasmic reticulum stress response pathway. By rendering tumor cells more susceptible to T cell-mediated lysis, 223Ra may potentially be effective in combination with various immunotherapies, particularly cancer vaccines that are designed to generate and expand patients' endogenous antigen-specific T-cell populations against specific tumor antigens.

  15. Dendritic cells engineered to secrete anti-DcR3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

    PubMed Central

    Chen, Jiang; Guo, Xiao-Zhong; Li, Hong-Yu; Zhao, Jia-Jun; Xu, Wen-Da

    2017-01-01

    AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs’ viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a 51Cr releasing test. T cell responses induced by RNA-loaded DCs were analyzed by measuring cytokine levels, including IFN-γ, IL-10, IL4, TNF-α and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DC-tumor-anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses

  16. Recombinant Salmonella typhimurium strains that invade nonphagocytic cells are resistant to recognition by antigen-specific cytotoxic T lymphocytes.

    PubMed Central

    Gao, X M; Tite, J P; Lipscombe, M; Rowland-Jones, S; Ferguson, D J; McMichael, A J

    1992-01-01

    To address the question of whether Salmonella-infected nonphagocytic cells could serve as target cells for recognition by antigen-specific, major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTL), four recombinant Salmonella typhimurium constructs that expressed full-length, or fragments of, influenza A virus nucleoprotein (NP) were made. The bacteria were shown to infect Chinese hamster ovary (CHO) cells. Appropriate major histocompatibility complex restriction molecules, HLA-B27 and H-2 Db, were transfected into CHO cells, which were then infected with recombinant S. typhimurium and used as targets for NP-specific CTL. The cells in which NP was expressed by intracellularly replicating bacteria were not lysed by NP-specific CTL, although they were killed when appropriate influenza A virus or peptides were used. Thus, S.typhimurium bacteria within nonphagocytic cells were resistant to CTL recognition. In contrast to these results, mice infected with recombinant S.typhimurium that expressed fragments of NP in the periplasm were primed for NP-specific CTL responses. The results indicate that CTL responses specific to Salmonella antigens can be generated, but the bacteria may be safe from the CTL attack once they have entered the nonphagocytic cells. Images PMID:1500187

  17. New insights into HIV-1 specific cytotoxic T-lymphocyte responses in exposed, persistently seronegative Kenyan sex workers.

    PubMed

    Kaul, R; Rowland-Jones, S L; Kimani, J; Fowke, K; Dong, T; Kiama, P; Rutherford, J; Njagi, E; Mwangi, F; Rostron, T; Onyango, J; Oyugi, J; MacDonald, K S; Bwayo, J J; Plummer, F A

    2001-11-01

    A clearer understanding of HIV-1 specific immune responses in highly-exposed, persistently seronegative (HEPS) subjects is important in developing models of HIV-1 protective immunity. HIV-1 specific cytotoxic T-lymphocytes (CTL) have been described in a cohort of HEPS Kenyan sex workers, and recent work has further elucidated these responses. CTL specific for HIV-1 Env were found in the blood of over half the sex workers meeting criteria for HIV resistance, and in some women recognized unmapped epitopes. The proportion of women with Env-specific CTL increased with the duration of uninfected HIV exposure, suggesting that these responses were acquired over time. CD8+ lymphocyte responses directed against predefined HIV-1 CTL epitopes from various HIV-1 genes were found in the blood and genital tract of >50% resistant sex workers, at a ten-fold lower frequency than in infected subjects. The epitope specificity of CD8+ responses differs between HEPS and HIV infected women, and in HEPS the maintenance of responses appears to be dependent on persistent HIV exposure. Several HIV-1 'resistant' sex workers have become HIV infected over the past 6 years, possibly related to waning of pre-existing HIV-specific CTL, and infection has often been associated with a switch in the epitope specificity of CD8+ responses. These findings suggest that vaccine-induced protective HIV immunity is a realistic goal, but that vaccine strategies of boosting or persistent antigen may be necessary for long-lived protection.

  18. Identification of HLA-A*1101-restricted cytotoxic T lymphocyte epitopes derived from epidermal growth factor pathway substrate number 8

    PubMed Central

    Lu, Huifang; Tang, Baishan; He, Yanjie; Zhou, Weijun; Qiu, Jielei; Li, Yuhua

    2016-01-01

    Epidermal growth factor receptor pathway substrate 8 (EPS8) is critical in the proliferation, progression and metastasis of solid and hematological types of cancer, and thus constitutes an ideal target for cancer immunotherapy. The present study aimed to identify human leukocyte antigen (HLA)-A*1101-restricted cytotoxic T lymphocyte (CTL) epitopes from EPS8 and characterize their immunotherapeutic efficacy in vitro. Two computer-based algorithms were used to predict native EPS8 epitopes with potential high binding affinity to the HLA-A*1101 molecule, which is the HLA-A allele with the highest frequency in the Chinese population. The peptide-induced cytokine production from the CTLs was examined using enzyme-linked immunosorbent spot analysis. The cytotoxic effects on cancer cells by CTLs primed with the identified peptides were examined using flow cytometry. A total of five peptides, designated as P380, P70, P82, P30 and P529, presented with high affinity towards the HLA-A*1101 molecule. In response to stimulation by these five peptides, enhanced secretion of interferon-γ from the CTLs and increased cytolytic capabilities of the CTLs toward cancer cells were noted, with the most potent effects observed from the P380 peptide. Taken together, the present study identified five potential CTL epitopes from EPS8. Among these, P380 presented with the highest therapeutic efficacy in vitro. These peptides may benefit the development of EPS8-based immunotherapy for the treatment of HLA-A*1101-positive hematological malignancies. PMID:27840923

  19. Dendritic cells transduced with Rsf-1/HBXAP gene generate specific cytotoxic T lymphocytes against ovarian cancer in vitro

    SciTech Connect

    Sun, Li; Kong, Beihua; Sheng, Xiugui; Sheu, Jim Jinn-Chyuan; Shih, Ie-Ming

    2010-04-09

    Recently, some studies have indicated that Rsf-1/HBXAP plays a role in chromatin remodeling and transcriptional regulation that may contribute to tumorigenesis in ovarian cancer. The present study demonstrates that using dendritic cells (DCs) from human cord blood CD34{sup +} cells transduced with Rsf-1/HBXAP DNA plasmids by nucleofection generate specific cytotoxic T lymphocytes (CTL) against ovarian cancer in vitro. After transfection, DCs were analyzed for Rsf-1/HBXAP mRNA expression by RT-PCR and protein expression by Western blot. Then the DC phenotypes, T-cell stimulatory capacity, endocytic activity and migration capacity were explored by flow cytometry analysis, allogeneic mixed lymphocyte reaction, endocytosis and transwell chemotaxis assay, respectively. After transfection, Rsf-1/HBXAP expression was detected at mRNA and protein levels. Allogeneic T-cell proliferation induced by transfected DCs was obviously higher than non-transfected DCs, but the endocytosis capacity and migratory ability were not different. Rsf-1/HBXAP gene-transduced DCs could induce antigen-specific CTL and generate a very potent cytotoxicity to OVCAR3 cells. These data suggest that Rsf-1/HBXAP gene-transduced DCs may be a potential adjuvant immunotherapy for ovarian cancer in clinical applications.

  20. Treatment of solid organ transplant recipients with autologous Epstein Barr virus–specific cytotoxic T lymphocytes (CTLs)

    PubMed Central

    Savoldo, Barbara; Goss, John A.; Hammer, Markus M.; Zhang, Lan; Lopez, Teresita; Gee, Adrian P.; Lin, Yu-Feng; Quiros-Tejeira, Ruben E.; Reinke, Petra; Schubert, Stephan; Gottschalk, Stephen; Finegold, Milton J.; Brenner, Malcolm K.; Rooney, Cliona M.; Heslop, Helen E.

    2006-01-01

    We have investigated the in vivo safety, efficacy, and persistence of autologous Epstein Barr virus (EBV)–specific cytotoxic T lymphocytes (CTLs) for the treatment of solid organ transplant (SOT) recipients at high risk for EBV-associated posttransplantation lymphoproliferative disease (PTLD). EBV-CTLs generated from 35 patients expanded with normal kinetics contained both CD8 and CD4 lymphocytes and produced significant specific killing of autologous EBV-transformed B lymphoblastoid cell lines (LCLs). Twelve SOT recipients at high risk for PTLD, or with active disease, received autologous CTL infusions without toxicity. Real-time polymerase chain reaction (PCR) monitoring of EBV-DNA showed a transient increase in plasma EBV-DNA suggestive of lysis of EBV-infected cells, although there was no consistent decrease in virus load in peripheral-blood mononuclear cells. Interferon-γ enzyme-linked immunospot (ELISPOT) assay and tetramer analysis showed an increase in the frequency of EBV-responsive T cells, which returned to preinfusion levels after 2 to 6 months. None of the treated patients developed PTLD. One patient with liver PTLD showed a complete response, and one with ocular disease has had a partial response stable for over one year. These data are consistent with an expansion and persistence of adoptively transferred EBV-CTLs that is limited in the presence of continued immunosuppression but that nonetheless produces clinically useful antiviral activity. PMID:16835376

  1. Neonatal mycobacterial specific cytotoxic T-lymphocyte and cytokine profiles in response to distinct BCG vaccination strategies

    PubMed Central

    Hussey, Gregory D; Watkins, Marcia L V; Goddard, Elizabeth A; Gottschalk, Sean; Hughes, Elizabeth J; Iloni, Karen; Kibel, Maurice A; Ress, Stanley R

    2002-01-01

    This study evaluated whether different bacillus Calmette–Gue´rin (BCG) strains, routes of administration, vaccination age and percutaneous tools influenced immune responses to BCG vaccination in infants. Proliferative responses, cytokine production and cell-mediated cytotoxicity obtained in post-vaccinated children were compared to baseline cord bloods and unvaccinated 10-week-old infants. BCG vaccination generally induced strong lymphoproliferative and T helper type 1 (Th1)-type cytokine responses. There was a trend for greater responsiveness following the intradermal route of vaccination, with Japanese-172 strain and with delaying vaccination until 10 weeks. Cord mononuclear cells differentially stimulated the Th2-type cytokines interleukin-5 (IL-5) and IL-10 selectively in response to BCG, as compared to H37Rv or purified protein derivative stimulation. We document for the first time the generation of mycobacterium-specific cytotoxic T lymphocytes in neonates, following BCG vaccination. Cytotoxic activity correlated with the ratio of interferon-γ to IL-5, aside from a single instance where use of the Biovac® tool resulted in a striking dissociation selectively against H37Rv targets. These data have implications for correlates of protective immunity in design of vaccine studies. PMID:11918693

  2. Cytotoxic T lymphocytes recognize an HLA-A2-restricted epitope within the hepatitis B virus nucleocapsid antigen

    PubMed Central

    1991-01-01

    The absence of readily manipulable experimental systems to study the cytotoxic T lymphocyte (CTL) response against hepatitis B virus (HBV) antigens has thus far precluded a definitive demonstration of the role played by this response in the pathogenesis of liver cell injury and viral clearance during HBV infection. To circumvent the problem that HBV infection of human cells in vitro for production of stimulator/target systems for CTL analysis is not feasible, a panel of 22 overlapping synthetic peptides covering the entire amino acid sequence of the HBV core (HBcAg) and e (HBeAg) antigens were used to induce and to analyze the HBV nucleocapsid-specific CTL response in nine patients with acute hepatitis B, six patients with chronic active hepatitis B, and eight normal controls. By using this approach, we have identified an HLA-A2-restricted CTL epitope, located within the NH2- terminal region of the HBV core molecule, which is shared with the e antigen and is readily recognized by peripheral blood mononuclear cells from patients with self-limited acute hepatitis B but less efficiently in chronic HBV infection. Our study provides the first direct evidence of HLA class I-restricted T cell cytotoxicity against HBV in humans. Furthermore, the different response in HBV-infected subjects who successfully clear the virus (acute patients) in comparison with patients who do not succeed (chronic patients) suggests a pathogenetic role for this CTL activity in the clearance of HBV infection. PMID:1720813

  3. Identification of cytotoxic T lymphocyte epitopes on swine viruses: multi-epitope design for universal T cell vaccine.

    PubMed

    Liao, Yu-Chieh; Lin, Hsin-Hung; Lin, Chieh-Hua; Chung, Wen-Bin

    2013-01-01

    Classical swine fever (CSF), foot-and-mouth disease (FMD) and porcine reproductive and respiratory syndrome (PRRS) are the primary diseases affecting the pig industry globally. Vaccine induced CD8(+) T cell-mediated immune response might be long-lived and cross-serotype and thus deserve further attention. Although large panels of synthetic overlapping peptides spanning the entire length of the polyproteins of a virus facilitate the detection of cytotoxic T lymphocyte (CTL) epitopes, it is an exceedingly costly and cumbersome approach. Alternatively, computational predictions have been proven to be of satisfactory accuracy and are easily performed. Such a method enables the systematic identification of genome-wide CTL epitopes by incorporating epitope prediction tools in analyzing large numbers of viral sequences. In this study, we have implemented an integrated bioinformatics pipeline for the identification of CTL epitopes of swine viruses including the CSF virus (CSFV), FMD virus (FMDV) and PRRS virus (PRRSV) and assembled these epitopes on a web resource to facilitate vaccine design. Identification of epitopes for cross protections to different subtypes of virus are also reported in this study and may be useful for the development of a universal vaccine against such viral infections among the swine population. The CTL epitopes identified in this study have been evaluated in silico and possibly provide more and wider protection in compared to traditional single-reference vaccine design. The web resource is free and open to all users through http://sb.nhri.org.tw/ICES.

  4. Cancer-induced defective cytotoxic T lymphocyte effector function: another mechanism how antigenic tumors escape immune-mediated killing.

    PubMed Central

    Radoja, S.; Frey, A. B.

    2000-01-01

    BACKGROUND: The notion that a deficit in immune cell functions permits tumor growth has received experimental support with the discovery of several different biochemical defects in T lymphocytes that infiltrate cancers. Decreased levels of enzymes involved with T-cell signal transduction have been reported by several laboratories, suggesting that tumors or host cells recruited to the tumor site actively down-regulate antitumor T-cell immune response. This permits tumor escape from immune-mediated killing. The possibility that defects in T-cell signal transduction can be reversed, which would potentially permit successful vaccination or adoptive immunotherapy, motivates renewed interest in the field. Summarizing the literature concerning tumor-induced T-cell dysfunction, we focus on the end stage of immune response to human cancer, that of defective cytotoxic T lymphocyte killing function. Based on the data from several laboratories, we hypothesize a biochemical mechanism that accounts for the unusual phenotype of antitumor T-cell accumulation in tumors, but with defective killing function. PMID:10972084

  5. Clearance of HSV-2 from recurrent genital lesions correlates with infiltration of HSV-specific cytotoxic T lymphocytes.

    PubMed Central

    Koelle, D M; Posavad, C M; Barnum, G R; Johnson, M L; Frank, J M; Corey, L

    1998-01-01

    The mechanisms involved in host clearance of symptomatic mucocutaneous herpes simplex virus (HSV) infection are unclear. We studied the functional properties of bulk cultures of skin-infiltrating lymphocytes from normal skin and serial biopsies of recurrent genital HSV-2 lesions, and compared HSV-specific and NK responses with viral clearance. HSV-specific CD4+ or CD8+ T cells were rarely detected in lymphocytes cultured from normal skin. The total lymphocyte count and HSV-specific and NK-like effector cell activities were markedly higher in cultures derived from lesional skin. HSV-specific CD4+ proliferative responses and NK-like cytotoxic responses were present at all stages of herpetic lesions, including biopsies early in the disease course. In contrast, cytotoxic T lymphocyte activity was generally low among cells derived from early culture-positive lesions, and increased during lesion evolution. Viral clearance from the lesion site was associated with a high level of local cytolytic activity towards HSV-infected cells. The phenotypes of cells with HSV-specific cytotoxic responses varied between patients, having CD4+ and CD8+ components. Immunotherapeutic approaches to HSV should be directed at improving in vivo cytolytic activity to HSV. PMID:9525993

  6. Trivalent live attenuated influenza-simian immunodeficiency virus vaccines: efficacy and evolution of cytotoxic T lymphocyte escape in macaques.

    PubMed

    Reece, Jeanette C; Alcantara, Sheilajen; Gooneratne, Shayarana; Jegaskanda, Sinthujan; Amaresena, Thakshila; Fernandez, Caroline S; Laurie, Karen; Hurt, Aeron; O'Connor, Shelby L; Harris, Max; Petravic, Janka; Martyushev, Alexey; Grimm, Andrew; Davenport, Miles P; Stambas, John; De Rose, Robert; Kent, Stephen J

    2013-04-01

    There is an urgent need for a human immunodeficiency virus (HIV) vaccine that induces robust mucosal immunity. CD8(+) cytotoxic T lymphocytes (CTLs) apply substantial antiviral pressure, but CTLs to individual epitopes select for immune escape variants in both HIV in humans and SIV in macaques. Inducing multiple simian immunodeficiency virus (SIV)-specific CTLs may assist in controlling viremia. We vaccinated 10 Mane-A1*08401(+) female pigtail macaques with recombinant influenza viruses expressing three Mane-A1*08401-restricted SIV-specific CTL epitopes and subsequently challenged the animals, along with five controls, intravaginally with SIV(mac251). Seroconversion to the influenza virus vector resulted and small, but detectable, SIV-specific CTL responses were induced. There was a boost in CTL responses after challenge but no protection from high-level viremia or CD4 depletion was observed. All three CTL epitopes underwent a coordinated pattern of immune escape during early SIV infection. CTL escape was more rapid in the vaccinees than in the controls at the more dominant CTL epitopes. Although CTL escape can incur a "fitness" cost to the virus, a putative compensatory mutation 20 amino acids upstream from an immunodominant Gag CTL epitope also evolved soon after the primary CTL escape mutation. We conclude that vaccines based only on CTL epitopes will likely be undermined by rapid evolution of both CTL escape and compensatory mutations. More potent and possibly broader immune responses may be required to protect pigtail macaques from SIV.

  7. A specific cytotoxic T-lymphocyte epitope presentation system for antitumor immunity.

    PubMed

    Wu, Ying; Liu, Changzhen; Sun, Meiyi; Shen, Hexiao; Guo, Deyin; Gao, Bin

    2010-05-15

    The magnitude of CTL-mediated immunity response is highly dependent on the density of antigenic peptide-MHC I complexes at the cell surface. In this study, we adopt a novel strategy to promote the surface level of specific peptide-MHC I complexes. The strategy combines the inhibition of transporter associated with antigen processing (TAP) with the delivery of specific peptide into endoplasmic reticulum directly without the help of TAP. First, RNA interference (RNAi) technology was used to inhibit TAP expression for blocking endogenous epitope-assembled MHC class I on cell surface. Second, a peptide epitope of interest was covalently linked onto human beta-2-microglobulin (beta2m). Both TAP-specific siRNA and the peptide-linked beta2m were delivered into antigen-presentation cells sequentially or simultaneously using a retrovirus delivery system. The combined strategy produces a significant amount of MHC I loaded with specific epitopes on the surface while reducing endogenously peptide-assembled MHC class I both in vitro and in vivo. The efficacy of induction of specific immune response with the strategy against tumor cells is demonstrated in both tumor cell lines and a syngenic graft tumor model.

  8. Discovery of a Good Responder Subtype of Esophageal Squamous Cell Carcinoma with Cytotoxic T-Lymphocyte Signatures Activated by Chemoradiotherapy

    PubMed Central

    Komatsuzaki, Rie; Komatsu, Masayuki; Chiwaki, Fumiko; Tamaoki, Masashi; Nishimura, Takao; Takahashi, Naoki; Oda, Ichiro; Tachimori, Yuji; Arao, Tokuzo; Nishio, Kazuto; Kitano, Shigehisa; Narumi, Kenta; Aoki, Kazunori; Fujii, Satoshi; Ochiai, Atsushi; Yoshida, Teruhiko; Muto, Manabu; Yamada, Yasuhide; Sasaki, Hiroki

    2015-01-01

    Definitive chemoradiotherapy (CRT) is a less invasive therapy for esophageal squamous cell carcinoma (ESCC). Five-year survival rate of locally advanced ESCC patients by definitive CRT were 37%. We previously reported that tumor-specific cytotoxic T-lymphocyte (CTL) activation signatures were preferentially found in long-term survivors. However, it is unknown whether the CTL activation is actually driven by CRT. We compared gene expression profiles among pre- and post-treatment biopsy specimens of 30 ESCC patients and 121 pre-treatment ESCC biopsy specimens. In the complete response (CR) cases, 999 overexpressed genes including at least 234 tumor-specific CTL-activation associated genes such as IFNG, PRF1, and GZMB, were found in post-treatment biopsy specimens. Clustering analysis using expression profiles of these 234 genes allowed us to distinguish the immune-activated cases, designating them as I-type, from other cases. However, despite the better CR rate in the I-type, overall survival was not significantly better in both these 30 cases and another 121 cases. Further comparative study identified a series of epithelial to mesenchymal transition-related genes overexpressed in the early relapse cases. Importantly, the clinical outcome of CDH2-negative cases in the I-type was significantly better than that of the CDH2-positive cases in the I-type. Furthermore, NK cells, which were activated by neutrophils-producing S100A8/S100A9, and CTLs were suggested to cooperatively enhance the effect of CRT in the CDH2-negative I-type. These results suggested that CTL gene activation may provide a prognostic advantage in ESCCs with epithelial characteristics. PMID:26625258

  9. Enhanced function of cytotoxic T lymphocytes induced by dendritic cells modified with truncated PSMA and 4-1BBL.

    PubMed

    Youlin, Kuang; Li, Zhang; Xin, Gou; Mingchao, Xiao; Xiuheng, Liu; Xiaodong, Weng

    2013-04-01

    Interactions between costimulatory molecules and their receptors are vital for Ag-presenting dendritic cells (DCs) to initiate T cells activation, expansion and their antitumor immune responses. Augmentation of costimulatory signal due to the interaction of DCs and T cells may amplify, sustain and drive diversity of cytotoxic T lymphocytes (CTLs) and consequently enhance the antitumor response. 4-1BBL/4-1BB is such a pair of costimulatory ligand and receptor, playing an important role in the co-stimulation of CTLs. Previously, we demonstrated that DCs transduced with recombinant adenovirus encoding truncated PSMA (tPSMA) and m4-1BBL could induce prostate cancer regression in mouse models. In the present study, we further explored the adjuvant role of 4-1BBL in modulating CTLs activation induced by tPSMA gene-pulsed DCs. The apoptosis and cytotoxicity against tPSMA expressing RM-1 cells of CTLs were determined. Results showed that tPSMA gene-pulsed DCs effectively induced T lymphocyte activation and cytotoxicity, which was enhanced by upregulated expression of 4-1BBL, displaying better cell viability, lower CTLs apoptosis, higher expression anti-apoptotic protein of Bcl-xL and phosphorylation of P38, enhanced NF-κB activation, as well as more IFN-γ production. These results demonstrated that 4-1BBL may play a significant role in the co-stimulation pathway for Ag-presenting DCs-mediated CTLs activity, which might be a beneficial adjuvant factor for DCs-based cancer immunotherapy.

  10. HLA-A2-restricted cytotoxic T lymphocyte epitopes from human hepsin as novel targets for prostate cancer immunotherapy.

    PubMed

    Guo, J; Li, G; Tang, J; Cao, X-B; Zhou, Q-Y; Fan, Z-J; Zhu, B; Pan, X-H

    2013-09-01

    Hepsin is a type II transmembrane serine protease that is overexpressed in prostate cancer, and it is associated with prostate cancer cellular migration and invasion. Therefore, HPN is a biomarker for prostate cancer. CD8(+) T cells play an important role in tumour immunity. This study predicted and identified HLA-A2-restricted cytotoxic T lymphocyte (CTL) epitopes in human hepsin protein. HLA-A2-restricted CTL epitopes were identified using the following four-step procedure: (1) a computer program generated predicted epitopes from the amino acid sequence of human hepsin; (2) an HLA-A2-binding assay detected the affinity of the predicted epitopes to the HLA-A2 molecule; (3) the primary T cell response against the predicted epitopes was stimulated in vitro; and (4) the induced CTLs towards different types of hepsin- or HLA-A2-expressing prostate cancer cells were detected. Five candidate peptides were identified. The effectors that were induced by human hepsin epitopes containing residues 229 to 237 (Hpn229; GLQLGVQAV), 268 to 276 (Hpn268; PLTEYIQPV) and 191 to 199 (Hpn199; SLLSGDWVL) effectively lysed LNCaP prostate cancer cells that were hepsin-positive and HLA-A2 matched. These peptide-specific CTLs did not lyse normal liver cells with low hepsin levels. Hpn229, Hpn268 and Hpn199 increased the frequency of IFN-γ-producing T cells compared with the negative peptide. These results suggest that the Hpn229, Hpn268 and Hpn199 epitopes are novel HLA-A2-restricted CTL epitopes that are capable of inducing hepsin-specific CTLs in vitro. Hpn229, Hpn268 and Hpn199 peptide-based vaccines may be useful for immunotherapy in patients with prostate cancer.

  11. Immune checkpoints programmed death 1 ligand 1 and cytotoxic T lymphocyte associated molecule 4 in gastric adenocarcinoma

    PubMed Central

    Schlößer, Hans A.; Drebber, Uta; Kloth, Michael; Thelen, Martin; Rothschild, Sacha I.; Haase, Simon; Garcia-Marquez, Maria; Wennhold, Kerstin; Berlth, Felix; Urbanski, Alexander; Alakus, Hakan; Schauss, Astrid; Shimabukuro-Vornhagen, Alexander; Theurich, Sebastian; Warnecke-Ebertz, Ute; Stippel, Dirk L.; Zippelius, Alfred; Büttner, Reinhard; Hallek, Michael; Hölscher, Arnulf H.; Zander, Thomas; Mönig, Stefan P.; von Bergwelt-Baildon, Michael

    2016-01-01

    ABSTRACT Remarkable efficacy of immune checkpoint inhibition has been reported for several types of solid tumors and early studies in gastric adenocarcinoma are promising. A detailed knowledge about the natural biology of immune checkpoints in gastric adenocarcinoma is essential for clinical and translational evaluation of these drugs. This study is a comprehensive analysis of cytotoxic T lymphocyte associated molecule 4 (CTLA-4) and programmed death 1 ligand 1 (PD-L1) expression in gastric adenocarcinoma. PD-L1 and CTLA-4 were stained on tumor sections of 127 Caucasian patients with gastric adenocarcinoma by immunohistochemistry (IHC) and somatic mutation profiling was performed using targeted next-generation sequencing. Expression of PD-L1 and CTLA-4 on lymphocytes in tumor sections, tumor-draining lymph nodes (TDLN) and peripheral blood were studied by flow-cytometry and immune-fluorescence microscopy in an additional cohort. PD-L1 and CTLA-4 were expressed in 44.9% (57/127) and 86.6% (110/127) of the analyzed gastric adenocarcinoma samples, respectively. Positive tumor cell staining for PD-L1 or CTLA-4 was associated with inferior overall survival. Somatic mutational analysis did not reveal a correlation to expression of PD-L1 or CTLA-4 on tumor cells. Expression of PD-1 (52.2%), PD-L1 (42.2%) and CTLA-4 (1.6%) on tumor infiltrating T cells was significantly elevated compared to peripheral blood. Of note, PD-1 and PD-L1 were expressed far higher by tumor-infiltrating lymphocytes than CTLA-4. In conclusion, specific immune checkpoint-inhibitors should be evaluated in this disease and the combination with molecular targeted therapies might be of benefit. An extensive immune monitoring should accompany these studies to better understand their mode of action in the tumor microenvironment. PMID:27467911

  12. Modulation of MUC1 mucin as an escape mechanism of breast cancer cells from autologous cytotoxic T-lymphocytes

    PubMed Central

    Kontani, K; Taguchi, O; Narita, T; Izawa, M; Hiraiwa, N; Zenita, K; Takeuchi, T; Murai, H; Miura, S; Kannagi, R

    2001-01-01

    MUC1 mucin is known to serve as a target molecule in the killing of breast cancer cells by cytotoxic T-lymphocytes (CTLs). We searched for a possible mechanism allowing tumour cells to escape from autologous CTLs. When the killing of breast cancer cells by autologous lymphocytes was examined in 26 patients with breast cancer, significant tumour cell lysis was observed in 8 patients, whereas virtually no autologous tumour cell lysis was detected in as many as 18 patients. In the patients who showed negligible tumour cell lysis, the autologous tumour cells expressed MUC1-related antigenic epitopes much more weakly than the tumour cells in the patients who exhibited strong cytotoxicity (significant statistically at P< 0.0005–0.0045), suggesting that the unresponsiveness of cancer cells to CTLs observed in these patients was mainly due to loss of MUC1 expression or modulation of its antigenicity. A breast cancer cell line, NZK-1, established from one of the cytotoxicity-negative patients, did not express MUC1 and was resistant to killing by CTLs, while control breast cancer cell lines expressing MUC-1 were readily killed by CTLs. Transfection of NZK-1 cells with MUC1 cDNA induced significant lysis by autologous T-lymphocytes. These results supported the importance of MUC1 mucin in autologous anti-tumour immunity, but suggested that the major escape mechanism of tumour cells from autologous T-lymphocytes is the loss and/or modulation of MUC1 antigenicity on tumour cells, which would limit the effectiveness of possible immunotherapy designed to target the MUC1 mucin. © 2001 Cancer Research Campaign http://www.bjcancer.com PMID:11336479

  13. Cytotoxic T lymphocyte-dependent tumor growth inhibition by a vascular endothelial growth factor-superantigen conjugate

    SciTech Connect

    Sun, Qingwen; Jiang, Songmin; Han, Baohui; Sun, Tongwen; Li, Zhengnan; Zhao, Lina; Gao, Qiang; Sun, Jialin

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer We construct and purify a fusion protein VEGF-SEA. Black-Right-Pointing-Pointer VEGF-SEA strongly repressed the growth of murine solid sarcoma 180 (S180) tumors. Black-Right-Pointing-Pointer T cells driven by VEGF-SEA were accumulated around tumor cells bearing VEGFR by mice image model. Black-Right-Pointing-Pointer VEGF-SEA can serve as a tumor targeting agent and sequester CTLs into the tumor site. Black-Right-Pointing-Pointer The induced CTLs could release the cytokines, perforins and granzyme B to kill the tumor cells. -- Abstract: T cells are major lymphocytes in the blood and passengers across the tumor vasculature. If these T cells are retained in the tumor site, a therapeutic potential will be gained by turning them into tumor-reactive cytotoxic T lymphocytes (CTLs). A fusion protein composed of human vascular endothelial growth factor (VEGF) and staphylococcal enterotoxin A (SEA) with a D227A mutation strongly repressed the growth of murine solid sarcoma 180 (S180) tumors (control versus VEGF-SEA treated with 15 {mu}g, mean tumor weight: 1.128 g versus 0.252 g, difference = 0.876 g). CD4{sup +} and CD8{sup +} T cells driven by VEGF-SEA were accumulated around VEGFR expressing tumor cells and the induced CTLs could release the tumoricidal cytokines, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Meanwhile, intratumoral CTLs secreted cytolytic pore-forming perforin and granzyme B proteins around tumor cells, leading to the death of tumor cells. The labeled fusion proteins were gradually targeted to the tumor site in an imaging mice model. These results show that VEGF-SEA can serve as a tumor targeting agent and sequester active infiltrating CTLs into the tumor site to kill tumor cells, and could therefore be a potential therapeutical drug for a variety of cancers.

  14. Novel plant virus-based vaccine induces protective cytotoxic T-lymphocyte-mediated antiviral immunity through dendritic cell maturation.

    PubMed

    Lacasse, Patrick; Denis, Jérôme; Lapointe, Réjean; Leclerc, Denis; Lamarre, Alain

    2008-01-01

    Currently used vaccines protect mainly through the production of neutralizing antibodies. However, antibodies confer little or no protection for a majority of chronic viral infections that require active involvement of cytotoxic T lymphocytes (CTLs). Virus-like particles (VLPs) have been shown to be efficient inducers of cell-mediated immune responses, but administration of an adjuvant is generally required. We recently reported the generation of a novel VLP system exploiting the self-assembly property of the papaya mosaic virus (PapMV) coat protein. We show here that uptake of PapMV-like particles by murine splenic dendritic cells (DCs) in vivo leads to their maturation, suggesting that they possess intrinsic adjuvant-like properties. DCs pulsed with PapMV-like particles displaying the lymphocytic choriomeningitis virus (LCMV) p33 immunodominant CTL epitope (PapMV-p33) efficiently process and cross-present the viral epitope to p33-specific transgenic T cells. Importantly, the CTL epitope is also properly processed and presented in vivo, since immunization of p33-specific T-cell receptor transgenic mice with PapMV-p33 induces the activation of large numbers of specific CTLs. C57BL/6 mice immunized with PapMV-p33 VLPs in the absence of adjuvant develop p33-specific effector CTLs that rapidly expand following LCMV challenge and protect vaccinated mice against LCMV infection in a dose-dependent manner. These results demonstrate the efficiency of this novel plant virus-based vaccination platform in inducing DC maturation leading to protective CTL responses.

  15. Δ9-tetrahydrocannabinol suppresses cytotoxic T lymphocyte function independent of CB1 and CB 2, disrupting early activation events.

    PubMed

    Karmaus, Peer W F; Chen, Weimin; Kaplan, Barbara L F; Kaminski, Norbert E

    2012-12-01

    Previously, CD8(+) T cells were found to be a sensitive target for suppression by Δ(9)-tetrahydrocannabinol (Δ(9)-THC) in a murine model of influenza infection. To study the effect of Δ(9)-THC on CD8(+) cytotoxic T lymphocytes (CTL), an allogeneic model of MHC I mismatch was used to elicit CTL. In addition, to determine the requirement for the cannabinoid receptors 1 (CB(1)) and 2 (CB(2)) in Δ(9)-THC-mediated CTL response modulation, mice null for both receptors were used (CB(1) (-/-)CB(2) (-/-)). Δ(9)-THC suppressed CTL function independent of CB(1) and CB(2) as evidenced by reduction of (51)Cr release by CTL generated from CB(1) (-/-)CB(2) (-/-) mice. Furthermore, viability in CD4(+) and CD8(+) cells was reduced in a concentration-dependent manner with Δ(9)-THC, independent of CB(1) and CB(2), but no effect of Δ(9)-THC on proliferation was observed, suggesting that Δ(9)-THC decreases the number of T cells initially activated. Δ(9)-THC increased expression of the activation markers, CD69 in CD8(+) cells and CD25 in CD4(+) cells in a concentration-dependent manner in cells derived from WT and CB(1) (-/-)CB(2) (-/-) mice. Furthermore, Δ(9)-THC synergized with the calcium ionophore, ionomycin, to increase CD69 expression on both CD4(+) and CD8(+) cells. In addition, without stimulation, Δ(9)-THC increased CD69 expression in CD8(+) cells from CB(1) (-/-)CB(2) (-/-) and WT mice. Overall, these results suggest that CB(1) and CB(2) are dispensable for Δ(9)-THC-mediated suppression and that perturbation of Ca(2+) signals during T cell activation plays an important role in the mechanism by which Δ(9)-THC suppresses CTL function.

  16. Human immunodeficiency virus (HIV) nef-specific cytotoxic T lymphocytes in noninfected heterosexual contact of HIV-infected patients.

    PubMed Central

    Langlade-Demoyen, P; Ngo-Giang-Huong, N; Ferchal, F; Oksenhendler, E

    1994-01-01

    We report on the detection of HIV-specific cytotoxic T lymphocytes (CTL) among 23 regular partners of HIV-infected individuals. 15 of the 46 individuals enrolled in the study were positive for HLA-A2.1 typing. Among the 23 contacts studied, 7 were seropositive and 16 were seronegative on repeated tests. None of the 16 seronegative contacts were positive for p24 antigenemia nor were they positive by the lymphocytes coculture assay, although, in two instances HIV-1 DNA could be detected by PCR (in one case using a gag SK 38/39 primer, and in the other using a primer for the pol P3/P4 primer). These two individuals remained seronegative for 18 and 36 mo, respectively. HIV-specific cytotoxicity was performed in the 15 HLA-A2.1 subjects (7 indexes, 2 seropositive contacts, and 6 seronegative contacts) and in 4 HLA-matched HIV negative donors. CTL specific for env, gag, or nef proteins could not be detected in unstimulated bulk cultures of peripheral blood lymphocytes in any of the six seronegative contacts. However, using a limiting dilution assay we found an usually high frequency of HIV nef-specific CTL precursors (CTLp) for HIV env and gag was very similar to that observed in seronegative HLA-matched healthy donors. Because no presence of HIV could be demonstrated in these individuals, these findings argue against the possibility of a silent HIV infection and suggest that a CTL response against nef may be involved in a rapid and effective clearance of the virus after sexual exposure. PMID:8132769

  17. Cytotoxic T lymphocytes and natural killer cells display impaired cytotoxic functions and reduced activation in patients with alcoholic hepatitis.

    PubMed

    Støy, Sidsel; Dige, Anders; Sandahl, Thomas Damgaard; Laursen, Tea Lund; Buus, Christian; Hokland, Marianne; Vilstrup, Hendrik

    2015-02-15

    The dynamics and role of cytotoxic T lymphocytes (CTLs), natural killer (NK) cells, and NKT cells in the life-threatening inflammatory disease alcoholic hepatitis is largely unknown. These cells directly kill infected and damaged cells through, e.g., degranulation and interferon-γ (IFNγ) production, but cause tissue damage if overactivated. They also assist tissue repair via IL-22 production. We, therefore, aimed to investigate the frequency, functionality, and activation state of such cells in alcoholic hepatitis. We analyzed blood samples from 24 severe alcoholic hepatitis patients followed for 30 days after diagnosis. Ten healthy abstinent volunteers and 10 stable abstinent alcoholic cirrhosis patients were controls. Using flow cytometry we assessed cell frequencies, NK cell degranulation capacity following K562 cell stimulation, activation by natural killer group 2 D (NKG2D) expression, and IL-22 and IFNγ production. In alcoholic hepatitis we found a decreased frequency of CTLs compared with healthy controls (P < 0.001) and a similar trend for NK cells (P = 0.089). The NK cell degranulation capacity was reduced by 25% compared with healthy controls (P = 0.02) and by 50% compared with cirrhosis patients (P = 0.04). Accordingly, the NKG2D receptor expression was markedly decreased on NK cells, CTLs, and NKT cells (P < 0.05, all). The frequencies of IL-22-producing CTLs and NK cells were doubled compared with healthy controls (P < 0.05, all) but not different from cirrhosis patients. This exploratory study for the first time showed impaired cellular cytotoxicity and activation in alcoholic hepatitis. This is unlikely to cause hepatocyte death but may contribute toward the severe immune incompetence. The results warrant detailed and mechanistic studies.

  18. Immune privilege and FasL: two ways to inactivate effector cytotoxic T lymphocytes by FasL-expressing cells

    PubMed Central

    Li, Jie-Hui; Rosen, Dalia; Sondel, Paul; Berke, Gideon

    2002-01-01

    The theory that Fas ligand (FasL)-expressing tumours are immune-privileged and can directly counterattack Fas-expressing effector T lymphocytes has recently been questioned and several alternative mechanisms have been proposed. To address this controversial issue, we analysed the impact of FasL-expressing tumours on in vivo-primed cytotoxic T lymphocytes (CTLs) and the mechanisms involved. CTLs were obtained from the peritoneal cavity (PEL) after in vivo priming with syngeneic or allogeneic murine tumour cells. We have found that PEL populations undergo Fas-based apoptotic cell death when co-cultured with FasL-expressing tumour cells and that PEL destruction of cognate targets in a 51Cr-release assay was markedly inhibited by the pre-exposure to either cognate or non-cognate tumour cells expressing FasL. Furthermore, cytocidal function of PEL was markedly inhibited by preincubation with FasL-negative tumour cells, if and only if they were the cognate targets of the CTL; this CTL inhibition involved FasL–Fas interactions. The killing function of ‘bystander’ PELs, reactive to a third-party target cell, was inhibited by co-cultivation with PELs mixed with their cognate target. This activation-induced CTL fratricide was not influenced by the expression of FasL on the cognate target cells. These studies demonstrate the existence of two distinct pathways whereby FasL-expressing cells inhibit in vivo-primed FasL- and Fas-expressing CTLs: first, by FasL-based direct tumour counterattack, and second, by FasL-mediated activation-induced cell death of the CTLs, which is consistent with the concept that FasL expression in vivo could play a role in inducing immune privilege. PMID:11918688

  19. Dominant recognition by human CD8+ cytotoxic T lymphocytes of dengue virus nonstructural proteins NS3 and NS1.2a.

    PubMed Central

    Mathew, A; Kurane, I; Rothman, A L; Zeng, L L; Brinton, M A; Ennis, F A

    1996-01-01

    A severe complication of dengue virus infection, dengue hemorrhagic fever (DHF), is hypothesized to be immunologically mediated and virus-specific cytotoxic T lymphocytes (CTLs) may trigger DHF. It is also likely that dengue virus-specific CTLs are important for recovery from dengue virus infections. There is little available information on the human CD8+ T cell responses to dengue viruses. Memory CD8+CTL responses were analyzed to determine the diversity of the T cell response to dengue virus and to identify immunodominant proteins using PBMC from eight healthy adult volunteers who had received monovalent, live-attenuated candidate vaccines of the four dengue serotypes. All the donors had specific T cell proliferation to dengue and to other flaviviruses that we tested. CTLs were generated from the stimulated PBMC of all donors, and in the seven donors tested, dengue virus-specific CD8+CTL activity was demonstrated. The nonstructural (NS3 and NS1.2a) and envelope (E) proteins were recognized by CD8+CTLs from six, five, and three donors, respectively. All donors recognized either NS3 or NS1.2a. In one donor who received a dengue 4 vaccine, CTL killing was seen in bulk culture against the premembrane protein (prM). This is the first demonstration of a CTL response against the prM protein. The CTL responses using the PBMC of two donors were serotype specific, whereas all other donors had serotype-cross-reactive responses. For one donor, CTLs specific for E, NS1.2a, and NS3 proteins were all HLA-B44 restricted. For three other donors tested, the potential restricting alleles for recognition of NS3 were B38, A24, and/or B62 and B35.These results indicate that the CD8+CTL responses of humans after immunization with one serotype of dengue virus are diverse and directed against a variety of proteins. The NS3 and NS1.2a proteins should be considered when designing subunit vaccines for dengue. PMID:8833919

  20. Association of Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) and Thyroglobulin (TG) Genetic Variants with Autoimmune Hypothyroidism.

    PubMed

    Patel, Hinal; Mansuri, Mohmmad Shoab; Singh, Mala; Begum, Rasheedunnisa; Shastri, Minal; Misra, Ambikanandan

    2016-01-01

    Autoimmune hypothyroidism is known to be caused by immune responses related to the thyroid gland and its immunological feature includes presence of autoimmune antibodies. Therefore the aim was to analyze presence of anti-TPO antibodies in hypothyroidism patients in Gujarat. Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) is one of the susceptibility genes for various autoimmune diseases. Hence, exon1 +49A/G and 3'UTR CT60A/G single nucleotide polymorphisms (SNPs) in CTLA4 and its mRNA expression levels were investigated in autoimmune hypothyroidism patients. Thyroglobulin (TG) is known to be associated with autoimmune thyroid disorders and thus exon 33 (E33) SNP in TG was investigated. We analyzed the presence of anti-TPO antibodies in the plasma samples of 84 hypothyroidism patients and 62 controls by ELISA. PCR-RFLP technique was used for genotyping of polymorphisms. sCTLA4 and flCTLA4 mRNA expression levels were assessed by real time PCR. 59.52% of hypothyroid patients had anti-TPO antibodies in their circulation. The genotype and allele frequencies differed significantly for +49A/G (p = 0.0004 for +49AG, p = 0.0019 for +49GG & p = 0.0004 for allele), CT60 (p = 0.0110 for CT60AG, p = 0.0005 for CT60GG & p<0.0001 for allele) and TG E33 (p = 0.0003 for E33TC p<0.0001 for E33CC& p<0.0001 for allele) SNPs between patients and controls. Patients had significantly decreased mRNA levels of both sCTLA4 (p = 0.0017) and flCTLA4 (p<0.0001) compared to controls. +49A/G and CT60 polymorphisms of CTLA4 were in moderate linkage disequilibrium. Logistic regression analysis indicated significant association of CT49A/G, CT60A/G and TG exon 33 polymorphisms with susceptibility to autoimmune hypothyroidism when adjusted for age and gender. Our results suggest +49A/G and CT60 polymorphism of CTLA4 and E33 polymorphism of TG may be genetic risk factors for autoimmune hypothyroidism susceptibility and down regulation of both forms of CTLA4 advocates the crucial role of CTLA4 in pathogenesis

  1. Consequences of cytotoxic T lymphocyte interaction with major histocompatibility complex class I-expressing neurons in vivo

    PubMed Central

    1995-01-01

    Neurons have evolved strategies to evade immune surveillance that include an inability to synthesize the heavy chain of the class I major histocompatibility complex (MHC), proteins that are necessary for cytotoxic T lymphocyte (CTL) recognition of target cells. Multiple viruses have taken advantage of the lack of CTL-mediated recognition and killing of neurons by establishing persistent neuronal infections and thereby escaping attack by antiviral CTL. We have expressed a class I MHC molecule (Db) in neurons of transgenic mice using the neuron- specific enolase (NSE) promoter to determine the pathogenic consequences of CTL recognition of virally infected, MHC-expressing central nervous system (CNS) neurons. The NSE-Db transgene was expressed in H-2b founder mice, and transgene-derived messenger RNA was detected by reverse transcriptase-polymerase chain reaction in transgenic brains from several lines. Purified primary neurons from transgenic but not from nontransgenic mice adhered to coverslips coated with a conformation-dependent monoclonal antibody directed against the Dv molecule and presented viral peptide to CTL in an MHC-restricted manner, indicating that the Db molecule was expressed on transgenic neurons in a functional form. Transgenic mice infected with the neurotropic lymphocytic choriomeningitis virus (LCMV) and given anti- LCMV, MHC-restricted CTL displayed a high morbidity and mortality when compared with controls receiving MHC-mismatched CTL or expressing alternative transgenes. After CTL transfer, transgenic brains showed an increased number of CD8+ cells compared with nontransgenic controls as well as an increased rate of clearance of infectious virus from the CNS. Additionally, an increase in blood-brain barrier permeability was detected during viral clearance in NSE-Db transgenic mice and lasted several months after clearance of virus from neurons. In contrast, LCMV- infected, nontransgenic littermates and mice expressing other gene products from

  2. Large-scale preparation of human anti-third-party veto cytotoxic T lymphocytes depleted of graft-versus-host reactivity: a new source for graft facilitating cells in bone marrow transplantation.

    PubMed

    Aviner, Shraga; Yao, Xin; Krauthgamer, Rita; Gan, Yehudit; Goren-Arbel, Rinat; Klein, Tirza; Tabilio, Antonio; McMannis, John D; Champlin, Richard; Martelli, Massimo F; Bachar-Lustig, Esther; Reisner, Yair

    2005-06-01

    Induction of donor type chimerism in mildly prepared hosts without graft-versus-host disease (GvHD) is a most desirable goal in bone morrow transplantation. We have recently demonstrated in a mouse model that donor veto cytotoxic T lymphocytes (CTLs) can facilitate the induction of donor type chimerism in sublethally irradiated recipients without causing GvHD if they are effectively depleted of alloreactivity against host cells by means of stimulation against a third party. We extend this approach to human cells, by preparing CTLs in two major steps: primary culture in the absence of interleukin 2, leading to death by neglect of antihost clones, and addition of interleukin 2 and subsequent dilution of antihost clones as a consequence of the expansion of the anti-third-party clones. CTLs prepared in this way specifically suppress host cytotoxic T cells directed against antigens of the donor, but not against fourth-party antigens, as demonstrated in a standard (51)Cr release assay. We conclude that human anti-third-party CTLs afford a new source of veto cells that are depleted of potential graft-versus-host-reactive clones. The cells generated by this approach could potentially be used to facilitate engraftment of allogeneic hematopoietic stem cells.

  3. Human cytotoxic T-lymphocyte membrane-camouflaged nanoparticles combined with low-dose irradiation: a new approach to enhance drug targeting in gastric cancer

    PubMed Central

    Zhang, Lianru; Li, Rutian; Chen, Hong; Wei, Jia; Qian, Hanqing; Su, Shu; Shao, Jie; Wang, Lifeng; Qian, Xiaoping; Liu, Baorui

    2017-01-01

    Cell membrane-derived nanoparticles are becoming more attractive because of their ability to mimic many features of their source cells. This study reports on a biomimetic delivery platform based on human cytotoxic T-lymphocyte membranes. In this system, the surface of poly-lactic-co-glycolic acid nanoparticles was camouflaged using T-lymphocyte membranes, and local low-dose irradiation (LDI) was used as a chemoattractant for nanoparticle targeting. The T-lymphocyte membrane coating was verified using dynamic light scattering, transmission electron microscopy, and confocal laser scanning microscopy. This new platform reduced nanoparticle phagocytosis by macrophages to 23.99% (P=0.002). Systemic administration of paclitaxel-loaded T-lymphocyte membrane-coated nanoparticles inhibited the growth of human gastric cancer by 56.68% in Balb/c nude mice. Application of LDI at the tumor site significantly increased the tumor growth inhibition rate to 88.50%, and two mice achieved complete remission. Furthermore, LDI could upregulate the expression of adhesion molecules in tumor vessels, which is important in the process of leukocyte adhesion and might contribute to the localization of T-lymphocyte membrane-encapsulated nanoparticles in tumors. Therefore, this new drug-delivery platform retained both the long circulation time and tumor site accumulation ability of human cytotoxic T lymphocytes, while local LDI could significantly enhance tumor localization. PMID:28360520

  4. The importance of local mucosal HIV-specific CD8(+) cytotoxic T lymphocytes for resistance to mucosal viral transmission in mice and enhancement of resistance by local administration of IL-12.

    PubMed Central

    Belyakov, I M; Ahlers, J D; Brandwein, B Y; Earl, P; Kelsall, B L; Moss, B; Strober, W; Berzofsky, J A

    1998-01-01

    Although crucial to mucosal vaccine development, the mechanisms of defense against mucosal viral infection are still poorly understood. Protection, cytotoxic T lymphocytes (CTL), and neutralizing antibodies have all been observed, but cause and effect have been difficult to determine. The ability of CTL in the mucosa to mediate protection against mucosal viral transmission has never been proven. Here, we use an HIV peptide immunogen and an HIV-1 gp160-expressing recombinant vaccinia viral intrarectal murine challenge system, in which neutralizing antibodies do not play a role, to demonstrate for the first time that long-lasting immune resistance to mucosal viral transmission can be accomplished by CD8(+) CTL that must be present in the mucosal site of exposure. The resistance is ablated by depleting CD8(+) cells in vivo and requires CTL in the mucosa, whereas systemic (splenic) CTL are shown to be unable to protect against mucosal challenge. Furthermore, the resistance as well as the CTL response can be increased by local mucosal delivery of IL-12 with the vaccine. These results imply that induction of local mucosal CTL may be critical for success of a vaccine against viruses transmitted through a mucosal route, such as HIV. PMID:9854042

  5. Alphavirus-Specific Cytotoxic T Lymphocytes Recognize a Cross-Reactive Epitope from the Capsid Protein and Can Eliminate Virus from Persistently Infected Macrophages

    PubMed Central

    Linn, May La; Mateo, L.; Gardner, J.; Suhrbier, A.

    1998-01-01

    Persistent alphavirus infections in synovial and neural tissues are believed to be associated with chronic arthritis and encephalitis, respectively, and represent likely targets for CD8+ αβ cytotoxic T lymphocytes (CTL). Here we show that the capsid protein is a dominant target for alphavirus-specific CTL in BALB/c mice and that capsid-specific CTL from these mice recognize an H-2Kd restricted epitope, QYSGGRFTI. This epitope lies in the highly conserved region of the capsid protein, and QYSGGRFTI-specific CTL were cross reactive across a range of Old World alphaviruses. In vivo the acute primary viraemia of these highly cytopathic viruses was unaffected by QYSGGRFTI-specific CTL. However, in vitro these CTL were able to completely clear virus from macrophages persistently and productively infected with the arthrogenic alphavirus Ross River virus. PMID:9573286

  6. Patterns of Immunodominance in HIV-1–specific Cytotoxic T Lymphocyte Responses in Two Human Histocompatibility Leukocyte Antigens (HLA)-identical Siblings with HLA-A*0201 Are Influenced by Epitope Mutation

    PubMed Central

    Goulder, P.J.R.; Sewell, A.K.; Lalloo, D.G.; Price, D.A.; Whelan, J.A.; Evans, J.; Taylor, G.P.; Luzzi, G.; Giangrande, P.; Phillips, R.E.; McMichael, A.J.

    1997-01-01

    Primary human immunodeficiency virus (HIV) infection is controlled principally by HIV-specific cytotoxic T lymphocytes (CTL) to a steady-state level of virus load, which strongly influences the ultimate rate of progression to disease. Epitope selection by CTL may be an important determinant of the degree of immune control over the virus. This report describes the CTL responses of two HLA-identical hemophiliac brothers who were exposed to identical batches of Factor VIII and became seropositive within 10 wk of one another. Both have HLA-A*0201. The CTL responses of the two siblings were very dissimilar, one donor making strong responses to two epitopes within p17 Gag (HLA-A*0201–restricted SLYNTVATL and HLA-A3–restricted RLRPGGKKK). The sibling responded to neither epitope, but made strong responses to two epitopes presented by HLA-B7. This was not the result of differences in presentation of the epitopes. However, mutations in both immunodominant epitopes of the p17 Gag responder were seen in proviral sequences of the nonresponder. We then documented the CTL responses to two HLA-A*0201–restricted epitopes, in Gag (SLYNTVATL) and Pol (ILKEPVHGV) in 22 other HIV-infected donors with HLA-A*0201. The majority (71%) generated responses to the Gag epitope. In the 29% of donors failing to respond to the Gag epitope in standard assays, there was evidence of low frequency memory CTL responses using peptide stimulation of PBMC, and most of these donors also showed mutations in or around the Gag epitope. We concluded that HLA class I genotype determines epitope selection initially but that mutation in immunodominant epitopes can profoundly alter the pattern of CTL response. PMID:9126923

  7. Prediction of cross-recognition of peptide-HLA A2 by Melan-A-specific cytotoxic T lymphocytes using three-dimensional quantitative structure-activity relationships.

    PubMed

    Fagerberg, Theres; Zoete, Vincent; Viatte, Sebastien; Baumgaertner, Petra; Alves, Pedro M; Romero, Pedro; Speiser, Daniel E; Michielin, Olivier

    2013-01-01

    The cross-recognition of peptides by cytotoxic T lymphocytes is a key element in immunology and in particular in peptide based immunotherapy. Here we develop three-dimensional (3D) quantitative structure-activity relationships (QSARs) to predict cross-recognition by Melan-A-specific cytotoxic T lymphocytes of peptides bound to HLA A*0201 (hereafter referred to as HLA A2). First, we predict the structure of a set of self- and pathogen-derived peptides bound to HLA A2 using a previously developed ab initio structure prediction approach [Fagerberg et al., J. Mol. Biol., 521-46 (2006)]. Second, shape and electrostatic energy calculations are performed on a 3D grid to produce similarity matrices which are combined with a genetic neural network method [So et al., J. Med. Chem., 4347-59 (1997)] to generate 3D-QSAR models. The models are extensively validated using several different approaches. During the model generation, the leave-one-out cross-validated correlation coefficient (q (2)) is used as the fitness criterion and all obtained models are evaluated based on their q (2) values. Moreover, the best model obtained for a partitioned data set is evaluated by its correlation coefficient (r = 0.92 for the external test set). The physical relevance of all models is tested using a functional dependence analysis and the robustness of the models obtained for the entire data set is confirmed using y-randomization. Finally, the validated models are tested for their utility in the setting of rational peptide design: their ability to discriminate between peptides that only contain side chain substitutions in a single secondary anchor position is evaluated. In addition, the predicted cross-recognition of the mono-substituted peptides is confirmed experimentally in chromium-release assays. These results underline the utility of 3D-QSARs in peptide mimetic design and suggest that the properties of the unbound epitope are sufficient to capture most of the information to determine the

  8. Carthamus tinctorius Enhances the Antitumor Activity of Dendritic Cell Vaccines via Polarization toward Th1 Cytokines and Increase of Cytotoxic T Lymphocytes

    PubMed Central

    Chang, Jia-Ming; Hung, Le-Mei; Chyan, Yau-Jan; Cheng, Chun-Ming; Wu, Rey-Yuh

    2011-01-01

    Carthamus tinctorius (CT), also named safflower, is a traditional Chinese medicine widely used to improve blood circulation. CT also has been studied for its antitumor activity in certain cancers. To investigate the effects of CT on the dendritic cell (DC)-based vaccine in cancer treatment, cytokine secretion of mouse splenic T lymphocytes and the maturation of DCs in response to CT were analyzed. To assess the antitumor activity of CT extract on mouse CD117+ (c-kit)-derived DCs pulsed with JC mammal tumor antigens, the JC tumor was challenged by the CT-treated DC vaccine in vivo. CT stimulated IFN-γ and IL-10 secretion of splenic T lymphocytes and enhanced the maturation of DCs by enhancing immunological molecule expression. When DC vaccine was pulsed with tumor antigens along with CT extract, the levels of TNF-α and IL-1β were dramatically increased with a dose-dependent response and more immunologic and co-stimulatory molecules were expressed on the DC surface. In addition, CT-treated tumor lysate-pulsed DC vaccine reduced the tumor weight in tumor-bearing mice by 15.3% more than tumor lysate-pulsed DC vaccine without CT treatment. CT polarized cytokine secretion toward the Th1 pathway and also increased the population of cytotoxic T lymphocytes ex vivo. In conclusion, CT activates DCs might promote the recognition of antigens and facilitate antigen presentation to Th1 immune responses. PMID:19001481

  9. Association between cytotoxic T-lymphocyte antigen-4 +49A/G polymorphism and colorectal cancer risk: a meta-analysis.

    PubMed

    He, Lei; Deng, Tao; Luo, He-Sheng

    2015-01-01

    The Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) gene has been implicated in the development of colorectal cancer (CRC). However, the results are inconsistent. In this study, we performed a meta-analysis to assess the associations between the CTLA-4 +49A/G polymorphism and risk of CRC. Relevant studies were identified using PubMed, Web of Science, CNKI and WanFang databases up to November 10, 2014. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association using the fixed or random effect model. A total of 8 case-control studies, including 1180 cases and 2110 controls, were included. Overall, a significant association between the CTLA-4 +49A/G polymorphism and CRC risk was found (dominant model: OR=1.63, 95% CI: 1.09-2.43; AG vs. AA: OR=1.69, 95% CI: 1.15-2.48). In the subgroup analysis by ethnicity, we observed a significant association in Asian descent (dominant model: OR=2.42, 95% CI: 1.40-4.16; AG vs. AA: OR=2.39, 95% CI: 1.52-3.76), but not among Europeans; when stratified by source of control, no significant association was detected in both population-based and hospital-based populations. This meta-analysis demonstrated that the CTLA-4 +49A/G polymorphism significantly increases the risk of CRC, especially for Asians.

  10. Generation of leukemia-reactive cytotoxic T lymphocytes from HLA-identical donors of patients with chronic myeloid leukemia using modifications of a limiting dilution assay.

    PubMed

    Smit, W M; Rijnbeek, M; van Bergen, C A; Willemze, R; Falkenburg, J H

    1998-03-01

    Donor leukocyte transfusions (DLT) have an anti-leukemic effect in most patients with a relapse of chronic myeloid leukemia (CML) after allogeneic stem cell transplantation. However, DLT are often complicated by graft-versus-host disease. Selection of donor lymphocytes with a relative specificity for leukemic cells is desirable. The generation of leukemia-reactive cytotoxic T lymphocyte (CTL) responses between HLA-identical donors and patients in bulk cultures showed major variations, and false negative results were observed. In a modification of a limiting dilution analysis (LDA) two-fold serial dilutions of HLA-identical donor mononuclear cells (MNC) were cultured in the presence of CML cells. The anti-leukemic CTL precursor frequencies in these donors varied between <1 and 9 per 106 MNC. HLA-restricted CD4+ or CD8+ lymphocytes as well as MHC non-restricted gammadelta T cells were responsible for the anti-leukemic responses. A positive correlation between cytotoxicity in the various wells after 3, 4 and 5 weeks of culture could be found. The LDA may be superior to bulk cultures in selecting stable immune responses and in separating multiple different anti-leukemic T cell responses in each donor-patient combination.

  11. A β-tubulin 5-derived peptide induces cytotoxic T lymphocytes restricted to the HLA-A24 allele in prostate cancer patients.

    PubMed

    Komatsu, Nobukazu; Terasaki, Yasunobu; Moriya, Fukuko; Suekane, Shigetaka; Noguchi, Masanori; Todo, Satoru; Itoh, Kyogo; Shichijo, Shigeki

    2010-09-01

    To facilitate the development of a peptide-based cancer vaccine for prostate cancer patients, we examined whether any of the 13 peptides previously reported to induce HLA-class I-restricted cytotoxic T lymphocyte (CTL) activity in HLA-A3 supertype (-A3, -A11, -A31 and -A33)-positive prostate cancer patients are also capable of inducing CTLs restricted to HLA-A2, HLA-A24 or HLA-A26 alleles. Among the 13 peptides tested, a peptide at positions 309 to 318 of β-tubulin 5 exhibited binding activity to the HLA-A(*)2402 molecule and induced HLA-A24-restricted CTL activity against prostate cancer cells derived from peripheral blood mononuclear cells of prostate cancer patients. The CTL activity was determined to be specific to this peptide and was mediated by CD8(+) T cells in an HLA-class I-restricted manner. These results suggest that this peptide could be applicable as a peptide vaccine, not only for HLA-A3 supertype-positive, but also for HLA-A24-positive prostate cancer patients.

  12. Identification of SART3-derived peptides having the potential to induce cancer-reactive cytotoxic T lymphocytes from prostate cancer patients with HLA-A3 supertype alleles.

    PubMed

    Minami, Takafumi; Matsueda, Satoko; Takedatsu, Hiroko; Tanaka, Masahiro; Noguchi, Masanori; Uemura, Hirotsugu; Itoh, Kyogo; Harada, Mamoru

    2007-05-01

    SART3-derived peptides applicable to prostate cancer patients with HLA-A3 supertype alleles were identified in order to expand the possibility of an anti-cancer vaccine, because the peptide vaccine candidates receiving the most attention thus far have been the HLA-A2 and HLA-A24 alleles. Twenty-nine SART3-derived peptides that were prepared based on the binding motif to the HLA-A3 supertype alleles (HLA-A11, -A31, and -A33) were first screened for their recognizability by immunoglobulin G (IgG) of prostate cancer patients and subsequently for the potential to induce peptide-specific cytotoxic T lymphocytes (CTLs) from HLA-A3 supertype(+) prostate cancer patients. As a result, five SART3 peptides were frequently recognized by IgG, and two of them-SART3 (511-519) and SART3 (734-742)-efficiently induced peptide-specific and cancer-reactive CTLs. Their cytotoxicity toward prostate cancer cells was ascribed to peptide-specific and CD8(+) T cells. These results indicate that these two SART3 peptides could be promising candidates for peptide-based immunotherapy for HLA-A3 supertype(+) prostate cancer patients.

  13. Effect of mutations and variations of HLA-A2 on recognition of a virus peptide epitope by cytotoxic T lymphocytes.

    PubMed Central

    McMichael, A J; Gotch, F M; Santos-Aguado, J; Strominger, J L

    1988-01-01

    Cytotoxic T lymphocytes (CTL) specific for influenza A virus were prepared from 15 donors. Those with HLA-A2 recognized autologous or HLA-A2-matched B-lymphoblastoid cells in the presence of synthetic peptide representing residues 55-73 or 56-68 of the virus matrix protein sequence. Influenza A virus-specific CTL from donors without HLA-A2 or with an HLA-A2 variant type failed to respond to this peptide. CTL lines specific for HLA-A2 plus peptide did not lyse peptide-treated target cells from HLA-A2 variant donors. They also failed to lyse peptide-treated cells with point mutations that had been inserted into HLA-A2 at positions 62-63, 66, 152, and 156 and, in some instances, mutations at positions 9 and 70. CTL lysed peptide-treated target cells with mutations in HLA-A2 at positions 43, 74, and 107. The results imply that this defined peptide epitope therefore interacts with HLA-A2 in the binding groove so that the long alpha-helices of HLA-A2 make important contact with the peptide at positions 66, 152, and 156. Different amino acids at position 9, which is in the floor of the peptide binding groove of HLA-A2 and the closely related position 70, modulate the peptide interaction so that some T-cell clones react and some do not. PMID:2461564

  14. Cytotoxic T lymphocyte-associated antigen 4 plays an essential role in the function of CD25(+)CD4(+) regulatory cells that control intestinal inflammation.

    PubMed

    Read, S; Malmström, V; Powrie, F

    2000-07-17

    It is now clear that functionally specialized regulatory T (Treg) cells exist as part of the normal immune repertoire, preventing the development of pathogenic responses to both self- and intestinal antigens. Here, we report that the Treg cells that control intestinal inflammation express the same phenotype (CD25(+)CD45RB(low)CD4(+)) as those that control autoimmunity. Previous studies have failed to identify how CD25(+) Treg cells function in vivo. Our studies reveal that the immune-suppressive function of these cells in vivo is dependent on signaling via the negative regulator of T cell activation cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), as well as secretion of the immune-suppressive cytokine transforming growth factor beta. Strikingly, constitutive expression of CTLA-4 among CD4(+) cells was restricted primarily to Treg cells, suggesting that CTLA-4 expression by these cells is involved in their immune-suppressive function. These findings raise the possibility that Treg cell function contributes to the immune suppression characteristic of CTLA-4 signaling. Identification of costimulatory molecules involved in the function of Treg cells may facilitate further characterization of these cells and development of new therapeutic strategies for the treatment of inflammatory diseases.

  15. An initial and rapid step of lytic granule secretion precedes microtubule organizing center polarization at the cytotoxic T lymphocyte/target cell synapse

    PubMed Central

    Bertrand, Florie; Müller, Sabina; Roh, Kyung-Ho; Laurent, Camille; Dupré, Loïc; Valitutti, Salvatore

    2013-01-01

    It is presently assumed that lethal hit delivery by cytotoxic T lymphocytes (CTLs) is mechanistically linked to centrosome polarization toward target cells, leading to dedicated release of lytic granules within a confined secretory domain. Here we provide three lines of evidence showing that this mechanism might not apply as a general paradigm for lethal hit delivery. First, in CTLs stimulated with immobilized peptide–MHC complexes, lytic granules and microtubule organizing center localization into synaptic areas are spatio-temporally dissociated, as detected by total internal reflection fluorescence microscopy. Second, in many CTL/target cell conjugates, lytic granule secretion precedes microtubule polarization and can be detected during the first minute after cell–cell contact. Third, inhibition of microtubule organizing center and centrosome polarization impairs neither lytic granule release at the CTL synapse nor killing efficiency. Our results broaden current views of CTL biology by revealing an extremely rapid step of lytic granule secretion and by showing that microtubule organizing center polarization is dispensable for efficient lethal hit delivery. PMID:23536289

  16. Association of cytotoxic T-lymphocyte antigen 4 +49A/G gene polymorphism with acute rejection risk in renal transplantation.

    PubMed

    Yang, Chun-Hua; Chen, Xue-Xia; Chen, Li; Zheng, Dong-Hua; Liu, Qiong-Shan; Xie, Wen-Feng

    2017-03-23

    The conclusions on the association between cytotoxic T-lymphocyte antigen 4 (CTLA4) +49A/G gene polymorphism and acute rejection risk in renal transplantation are still debated. This meta-analysis was performed to update the association between CTLA4 +49A/G and acute rejection risk in renal transplantation. The association investigations were identified from PubMed and Cochrane Library, and eligible studies were included and synthesized using meta-analysis method. Fourteen reports were included into this meta-analysis for the association of CTLA4 A/G gene polymorphism and acute rejection risk in renal transplantation, consisting of 962 acute rejection patients and 2084 non-acute rejection controls. The association between CTLA4 G allele/GG genotype and acute rejection risk in renal transplantation was found in this meta-analysis (G allele: OR=1.21, 95% CI: 1.03-1.44, P=.02; GG genotype: OR=1.37, 95% CI: 1.10-1.69, P=.004). However, the AA genotype was not associated with acute rejection risk in renal transplantation. In conclusion, CTLA4 G allele/GG genotype is associated with the acute rejection risk in renal transplantation.

  17. Development of an Enhanced Phenotypic Screen of Cytotoxic T-Lymphocyte Lytic Granule Exocytosis Suitable for Use with Synthetic Compound and Natural Product Collections.

    PubMed

    Zhao, Ziyan; deMayo, James A; West, Ashley M; Balunas, Marcy J; Zweifach, Adam

    2016-07-01

    We previously developed an assay of cytotoxic T-lymphocyte lytic granule exocytosis based on externalization of LAMP-1/CD107A using nonphysiological stimuli to generate maximal levels of exocytosis. Here, we used polystyrene beads coated with anti-CD3 antibodies to stimulate cells. Light scatter let us distinguish cells that contacted beads from cells that had not, allowing comparison of signaling events and exocytosis from stimulated and unstimulated cells in one sample. Bead stimulation resulted in submaximal exocytosis, making it possible to detect compounds that either augment or inhibit lytic granule exocytosis. Coupled with the assay's ability to distinguish responses in cells that have and have not contacted a stimulatory bead, it is possible to detect three kinds of compounds: inhibitors, stimulators, which cause exocytosis, and augmenters, which enhance receptor-stimulated exocytosis. To validate the assay, we screened a set of synthetic compounds identified using our previous assay and a library of 320 extracts prepared from tunicate-associated bacteria. One of the extracts augmented exocytosis threefold. Activity-guided fractionation and structure elucidation revealed that this compound is the known PKC activator teleocidin A-1. We conclude that our modified assay is suitable for screening synthetic compound plates and natural product collections, and will be useful for identifying immunologically active small molecules.

  18. Association of cytotoxic T-lymphocyte antigen 4 genetic polymorphism, hepatitis C viral infection and B-cell non-Hodgkin lymphoma: an Egyptian study.

    PubMed

    Khorshied, Mervat Mamdooh; Gouda, Heba Mahmoud; Khorshid, Ola M Reda

    2014-05-01

    Abstract Genetic and environmental factors are involved in the pathogenesis of non-Hodgkin lymphoma (NHL). The present study aimed to investigate the association between cytotoxic T-lymphocyte antigen 4 (CTLA-4) genetic polymorphism, hepatitis C virus (HCV) infection and B-cell NHL risk in Egypt. Genotyping of CTLA-4 single nucleotide polymorphisms (SNPs) was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay for 181 adult patients with B-NHL and 200 controls. Our study revealed that CTLA-4 + 49 A/G polymorphism conferred increased risk of B-NHL (odds ratio [OR] = 1.7, 95% confidence interval [CI] = 1.36-2.565). The prevalence of HCV infection in individuals harboring the mutant genotype + 49 A/G and - 318 C/T SNPs was higher in patients with B-NHL and was associated with increased risk of B-NHL (OR = 2.79, 95% CI = 1.24-6.93 for + 49 A/G and OR = 3.9, 95% CI = 1.01-15.98 for - 318 C/T). In conclusion, some SNPs of CTLA-4 are genetic risk factors for B-NHL. Moreover, this study identified an association of CTLA-4 + 49 A/G and - 318 C/T promoter polymorphisms with HCV infection.

  19. Identification of CD8+ cytotoxic T lymphocyte epitopes from porcine reproductive and respiratory syndrome virus matrix protein in BALB/c mice

    PubMed Central

    2011-01-01

    Twenty-seven nanopeptides derived from the matrix (M) protein of porcine reproductive and respiratory syndrome virus (PRRSV) were screened for their ability to elicit a recall interferon-γ (IFN-γ) response from the splenocytes of BALB/c mice following DNA vaccination and a booster vaccination with recombinant vaccinia virus rWR-PRRSV-M. We identified two peptides (amino acid residues K93FITSRCRL and F57GYMTFVHF) as CD8+ cytotoxic T lymphocyte (CTL) epitopes. These peptides elicited significant numbers of IFN-γ secreting cells, compared with other M nonapeptides and one irrelevant nonapeptide. Bioinformatics analysis showed that the former is an H-2Kd-restricted CTL epitope, and the latter is an H-2Dd-restricted CTL epitope. Multiple amino acid sequence alignment among different PRRSV M sequences submitted to GenBank indicated that these two CTL epitopes are strongly conserved, and they should therefore be considered for further research on the mechanisms of cellular immune responses to PRRSV. PMID:21619712

  20. Dendritic cells pulsed with alpha-fetoprotein and mutant P53 fused gene induce bi-targeted cytotoxic T lymphocyte response against hepatic carcinoma.

    PubMed

    Ren, Jun; Jia, Jun; Zhang, Hongmei; Zhang, Liwang; Ma, Bo; Jiang, Hanfang; Di, Lijun; Song, Guohong; Yu, Jing

    2008-07-01

    Dendritic cell (DC)-based immunotherapy is rapidly emerging as a promising treatment in cancer therapy. We had previously shown that DC pulsed with either defined mRNA of tumor antigen (Ag) such as alpha-fetoprotein (AFP), or total RNA of hepatocellular carcinoma (HCC) could elicit Ag-specific cytotoxic T lymphocyte (CTL) response. Therefore, we suggested a novel DC-based therapeutic method, in which DCs derived from CD34(+) cells enriched peripheral blood mononuclear cells were pulsed with liposome-coated AFP and mutant P53 (mtP53) fused gene pEGFP-C3/AFP-mtP53 to induce bi-targeted specific CTL responses against HCC. Three different genotype HCC cell lines, HepG2 (human histocompatibility leukocyte antigens (HLA) A2 positive, AFP expressing positive, P53 expressing negative), SMMC7721 (HLA A2 positive, neither AFP nor P53 expressing positive), and HMCC97 (HLA A2 positive, both AFP and P53 expressing positive) were selected as targets for CTL responses. An important finding was that DCs pulsed with the liposome-coated fused gene could evoke more intensive bi-targeted Ag-specific CTL responses against HMCC97 than DCs pulsed with either AFP or P53 single gene (P < 0.05). This experimental therapeutic model provides a new promising cytotherapeutic approach, in that DCs pulsed with the fused gene of different Ags might induce more extensive multitargeted antitumor immunity.

  1. Interferon-gamma Inhibits Melanogenesis and Induces Apoptosis in Melanocytes: A Pivotal Role of CD8+ Cytotoxic T Lymphocytes in Vitiligo.

    PubMed

    Yang, Lili; Wei, Yi; Sun, Yue; Shi, Weimin; Yang, Ji; Zhu, Lubing; Li, Ming

    2015-07-01

    Increased expression of the cytokine interferon (IFN)-γ plays a pivotal role in vitiligo-induced depigmentation. However, the major source of IFN-γ in vitiligo patients and the mechanisms underlying melanocyte destruction are unknown. In this study, a large number of skin infiltrating IFN-γ+ cells and CD8+ T cells were detected in progressive vitiligo. Among the peripheral blood mononuclear cells (PBMCs) of vitiligo patients, CD8+ cytotoxic T lymphocytes (CTLs) that express IFN-γ exhibited significant expansion, which suggests that activated CTLs are the main source of increased IFN-γ in progressive vitiligo. An in vitro analysis demonstrated that IFN-γ inhibits melanogenesis in primary cultured human melanocytes by altering melanogenic enzyme mRNA expression and, more importantly, that IFN-γ directly induces melanocyte apoptosis. Our data indicate that vitiligo pathophysiology may be linked to globally activated CD8+ CTL subpopulations, which produce increased IFN-γ and induce melanocyte dysfunction and apoptosis.

  2. Vaccination of rhesus monkeys with synthetic peptide in a fusogenic proteoliposome elicits simian immunodeficiency virus-specific CD8+ cytotoxic T lymphocytes

    PubMed Central

    1992-01-01

    An effective vaccine against the human immunodeficiency virus should be capable of eliciting both an antibody and a cytotoxic T lymphocyte (CTL) response. However, when viral proteins and peptides are formulated with traditional immunological adjuvants and inoculated via a route acceptable for use in humans, they have not been successful at eliciting virus-specific, major histocompatibility complex (MHC) class I-restricted CTL. We have designed a novel viral subunit vaccine by encapsulating a previously defined synthetic peptide CTL epitope of the simian immunodeficiency virus (SIV) gag protein within a proteoliposome capable of attaching to and fusing with plasma membranes. Upon fusing, the encapsulated contents of this proteoliposome can enter the MHC class I processing pathway through the cytoplasm. In this report, we show that after a single intramuscular vaccination, rhesus monkeys develop a CD8+ cell-mediated, MHC class I-restricted CTL response that recognizes the synthetic peptide immunogen. The induced CTL also demonstrate antiviral immunity by recognizing SIV gag protein endogenously processed by target cells infected with SIV/vaccinia recombinant virus. These results demonstrate that virus-specific, MHC class I-restricted, CD8+ CTL can be elicited by a safe, nonreplicating viral subunit vaccine in a primate model for acquired immune deficiency syndrome. Moreover, the proteoliposome vaccine formation described can include multiple synthetic peptide epitopes, and, thus, offers a simple means of generating antiviral cell-mediated immunity in a genetically heterogeneous population. PMID:1460429

  3. Allospecific cytotoxic T lymphocytes recognize an H-2 peptide in the context of a murine major histocompatibility complex class I molecule.

    PubMed Central

    Song, E S; Linsk, R; Olson, C A; McMillan, M; Goodenow, R S

    1988-01-01

    We have isolated cytotoxic T lymphocytes (CTL) preferentially reactive with the alpha 1 external domain of the H-2Ld antigen by selecting for T cells capable of recognizing a variant major histocompatibility complex (MHC) class I antigen sharing alpha 1 sequences with H-2Ld. Using these CTL, we demonstrate that a synthetic alpha 1 peptide corresponding to one of the helices derived from the H-2Ld molecule can be presented by a class I restriction element to reconstitute a CTL determinant borne by intact H-2Ld. Moreover, several other H-2L-reactive CTL generated independently were also able to recognize H-2Ld either as an intact alloantigen or as a peptide in conjunction with appropriate class I restriction elements. These data demonstrate that an H-2 peptide can reconstitute a CTL target structure and suggest that some alloreactive T cells in fact might be directed against allogeneic class I peptides in the context of a class I framework. PMID:3258067

  4. Flavivirus-cross-reactive, HLA-DR15-restricted epitope on NS3 recognized by human CD4+ CD8- cytotoxic T lymphocyte clones.

    PubMed

    Kurane, I; Okamoto, Y; Dai, L C; Zeng, L L; Brinton, M A; Ennis, F A

    1995-09-01

    The role of flavivirus-cross-reactive T lymphocytes in recovery from and pathogenesis of flavivirus infections is not known. In the present paper, we have defined a flavivirus-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK4 and JK43. The T cell clones were established from the peripheral blood T lymphocytes of a dengue-4-immune donor, using a limiting-dilution method with dengue-4 antigen. These two T cell clones were cross-reactive for dengue virus types 1, 2, 3 and 4, yellow fever virus and West Nile virus, and recognized NS3 protein. The smallest synthetic peptide recognized by these T cell clones was an identical 9 amino acid peptide which contains amino acids 146 to 154 (VIGLYGNGV) of dengue-4 NS3. HLA-DR15 was the restriction allele for recognition of this epitope by JK4 and JK43. JK4 and JK43 both used T cell receptor V alpha 8, but JK4 used V beta 8 and JK43 used V beta 2. This result indicates that this epitope is recognized by two flavivirus-cross-reactive CD4+ T cell clones which originated from different T cells in vivo.

  5. Definition of an epitope on NS3 recognized by human CD4+ cytotoxic T lymphocyte clones cross-reactive for dengue virus types 2, 3, and 4.

    PubMed

    Kurane, I; Zeng, L; Brinton, M A; Ennis, F A

    1998-01-20

    The role of dengue virus-specific serotype-cross-reactive T lymphocytes in recovery from and pathogenesis of dengue virus infections is not known. In the present paper, we have defined a dengue serotype-cross-reactive epitope recognized by two CD4+ CD8- cytotoxic T lymphocyte (CTL) clones, JK36 and JK46. These T cell clones were established from the peripheral blood T lymphocytes of a dengue-3-immune donor, using a limiting dilution method. JK36 and JK46 were cross-reactive for dengue virus types 2, 3, and 4, but not for type 1, and recognized the NS3 protein. The smallest synthetic peptide recognized by JK36 was an 8-amino acid peptide that contains amino acids (aa) 226 to 233 (VVAAEMEE) of NS3. The smallest peptide recognized by JK46 was an 11-amino acid peptide that contains aa 224 to 234 (TRVVAAEMEEA). HLA-DR15 was the restriction allele for recognition of these peptides by both JK36 and JK46. This is the first epitope to be defined that is recognized by human CD4+ CTL cross-reactive for dengue virus types 2, 3, and 4.

  6. Artificial antigen-presenting cells expressing AFP(158-166) peptide and interleukin-15 activate AFP-specific cytotoxic T lymphocytes.

    PubMed

    Sun, Longhao; Guo, Hao; Jiang, Ruoyu; Lu, Li; Liu, Tong; Zhang, Zhixiang; He, Xianghui

    2016-04-05

    Professional antigen-presenting cells (APCs) are potent generators of tumor antigen-specific cytotoxic T lymphocytes (CTLs) for adoptive immunotherapy; however, generation of APCs is cumbersome, expensive, and subject to the tumor microenvironment. Artificial APCs (aAPCs) have been developed as a cost-effective alternative to APCs. We developed a cellular aAPC that efficiently generated alpha-fetoprotein (AFP)-specific CTLs. We genetically modified the human B cell lymphoma cell line BJAB with a lentiviral vector to establish an aAPC called BA15. The expression of AFP(158-166)-HLA-A*02:01 complex, CD80, CD86, and interleukin (IL)-15 in BA15 cells was assessed. The efficiency of BA15 at generating AFP-specific CTLs and the specific cytotoxicity of CTLs against AFP+ cells were also determined. BA15 cells expressed high levels of AFP(158-166) peptide, HLA-A2, CD80, CD86, and IL-15. BA15 cells also exhibited higher efficiency in generating AFP-specific CTLs than did dendritic cells. These CTLs had greater cytotoxicity against AFP+ hepatocellular carcinoma cells than did CTLs obtained from dendritic cells in vitro and in vivo. Our novel aAPC system could provide a robust platform for the generation of functional AFP-specific CTLs for adoptive immunotherapy of hepatocellular carcinoma.

  7. Linking Pig-Tailed Macaque Major Histocompatibility Complex Class I Haplotypes and Cytotoxic T Lymphocyte Escape Mutations in Simian Immunodeficiency Virus Infection

    PubMed Central

    Gooneratne, Shayarana L.; Alinejad-Rokny, Hamid; Ebrahimi, Diako; Bohn, Patrick S.; Wiseman, Roger W.; O'Connor, David H.; Davenport, Miles P.

    2014-01-01

    ABSTRACT The influence of major histocompatibility complex class I (MHC-I) alleles on human immunodeficiency virus (HIV) diversity in humans has been well characterized at the population level. MHC-I alleles likely affect viral diversity in the simian immunodeficiency virus (SIV)-infected pig-tailed macaque (Macaca nemestrina) model, but this is poorly characterized. We studied the evolution of SIV in pig-tailed macaques with a range of MHC-I haplotypes. SIVmac251 genomes were amplified from the plasma of 44 pig-tailed macaques infected with SIVmac251 at 4 to 10 months after infection and characterized by Illumina deep sequencing. MHC-I typing was performed on cellular RNA using Roche/454 pyrosequencing. MHC-I haplotypes and viral sequence polymorphisms at both individual mutations and groups of mutations spanning 10-amino-acid segments were linked using in-house bioinformatics pipelines, since cytotoxic T lymphocyte (CTL) escape can occur at different amino acids within the same epitope in different animals. The approach successfully identified 6 known CTL escape mutations within 3 Mane-A1*084-restricted epitopes. The approach also identified over 70 new SIV polymorphisms linked to a variety of MHC-I haplotypes. Using functional CD8 T cell assays, we confirmed that one of these associations, a Mane-B028 haplotype-linked mutation in Nef, corresponded to a CTL epitope. We also identified mutations associated with the Mane-B017 haplotype that were previously described to be CTL epitopes restricted by Mamu-B*017:01 in rhesus macaques. This detailed study of pig-tailed macaque MHC-I genetics and SIV polymorphisms will enable a refined level of analysis for future vaccine design and strategies for treatment of HIV infection. IMPORTANCE Cytotoxic T lymphocytes select for virus escape mutants of HIV and SIV, and this limits the effectiveness of vaccines and immunotherapies against these viruses. Patterns of immune escape variants are similar in HIV type 1-infected human

  8. Cytotoxic-T-lymphocyte-mediated elimination of target cells transduced with engineered adeno-associated virus type 2 vector in vivo.

    PubMed

    Li, Chengwen; Hirsch, Matt; DiPrimio, Nina; Asokan, Aravind; Goudy, Kevin; Tisch, Roland; Samulski, R Jude

    2009-07-01

    A recent clinical trial in patients with hemophilia B has suggested that adeno-associated virus (AAV) capsid-specific cytotoxic T lymphocytes (CTLs) eliminated AAV-transduced hepatocytes and resulted in therapeutic failure. AAV capsids elicit a CTL response in animal models; however, these capsid-specific CTLs fail to kill AAV-transduced target cells in mice. To better model the human clinical trial data in mice, we introduced an immunodominant epitope derived from ovalbumin (OVA; SIINFEKL) into the AAV capsid and tested CTL-mediated killing of AAV2-transduced target tissues in vivo. Initially, in vitro experiments demonstrated both classical class I and cross-presentation of the OVA antigen, following endogenous expression or AAV2-OVA vector transduction, respectively. Furthermore, an OVA-specific CTL response was elicited after muscular or systemic injection of the AAV2-OVA vector. Finally, CTL reactivity was enhanced in mice with established SIINFEKL-specific immunity after AAV2-OVA/alpha1 anti-trypsin (AAT) administration. Most importantly, these OVA-specific CTLs decreased AAT expression in mice treated with AAV2-OVA/AAT vector that followed a time course mimicking uncoating kinetics of AAV2 transduction in OVA-immunized mice. These results demonstrate that AAV capsid-derived antigens elicit CD8(+) CTL reactivity, and these CTLs eliminated AAV-transduced target cells in mice. Notably, this model system can be exploited to study the kinetics of capsid presentation from different serotypes of AAV and permit the design of novel strategies to block CTL-mediated killing of AAV-transduced cells.

  9. Cytotoxic-T-Lymphocyte-Mediated Elimination of Target Cells Transduced with Engineered Adeno-Associated Virus Type 2 Vector In Vivo▿

    PubMed Central

    Li, Chengwen; Hirsch, Matt; DiPrimio, Nina; Asokan, Aravind; Goudy, Kevin; Tisch, Roland; Samulski, R. Jude

    2009-01-01

    A recent clinical trial in patients with hemophilia B has suggested that adeno-associated virus (AAV) capsid-specific cytotoxic T lymphocytes (CTLs) eliminated AAV-transduced hepatocytes and resulted in therapeutic failure. AAV capsids elicit a CTL response in animal models; however, these capsid-specific CTLs fail to kill AAV-transduced target cells in mice. To better model the human clinical trial data in mice, we introduced an immunodominant epitope derived from ovalbumin (OVA; SIINFEKL) into the AAV capsid and tested CTL-mediated killing of AAV2-transduced target tissues in vivo. Initially, in vitro experiments demonstrated both classical class I and cross-presentation of the OVA antigen, following endogenous expression or AAV2-OVA vector transduction, respectively. Furthermore, an OVA-specific CTL response was elicited after muscular or systemic injection of the AAV2-OVA vector. Finally, CTL reactivity was enhanced in mice with established SIINFEKL-specific immunity after AAV2-OVA/α1 anti-trypsin (AAT) administration. Most importantly, these OVA-specific CTLs decreased AAT expression in mice treated with AAV2-OVA/AAT vector that followed a time course mimicking uncoating kinetics of AAV2 transduction in OVA-immunized mice. These results demonstrate that AAV capsid-derived antigens elicit CD8+ CTL reactivity, and these CTLs eliminated AAV-transduced target cells in mice. Notably, this model system can be exploited to study the kinetics of capsid presentation from different serotypes of AAV and permit the design of novel strategies to block CTL-mediated killing of AAV-transduced cells. PMID:19369348

  10. Shifting immunodominance pattern of two cytotoxic T-lymphocyte epitopes in the F glycoprotein of the Long strain of respiratory syncytial virus.

    PubMed

    Johnstone, Carolina; de León, Patricia; Medina, Francisco; Melero, José A; García-Barreno, Blanca; Del Val, Margarita

    2004-11-01

    Human respiratory syncytial virus (RSV) is a major cause of respiratory infection in children and in the elderly. The RSV fusion (F) glycoprotein has long been recognized as a vaccine candidate as it elicits cytotoxic T-lymphocyte (CTL) and antibody responses. Two murine H-2K(d)-restricted CTL epitopes (F85-93 and F92-106) are known in the F protein of the A2 strain of RSV. F-specific CTL lines using BCH4 fibroblasts that are persistently infected with the Long strain of human RSV as stimulators were generated, and it was found that in this strain only the F85-93 epitope is conserved. Motif based epitope prediction programs and an F2 chain deleted F protein encoded in a recombinant vaccinia virus enabled identification of a new epitope in the Long strain, F249-258, which is presented by K(d) as a 9-mer (TYMLTNSEL) or a 10-mer (TYMLTNSELL) peptide. The results suggest that the 10-mer might be a naturally processed endogenous K(d) ligand. The CD8(+) T-lymphocyte responses to epitopes F85-93 and F249-258 present in the F protein of RSV Long were found to be strongly skewed to F85-93 in in vitro multispecific CTL lines and in vivo during a secondary response to a recombinant vaccinia virus that expresses the entire F protein. However, no hierarchy in CD8(+) T-lymphocyte responses to F85-93 and F249-258 epitopes was observed in vivo during a primary response.

  11. Generation of tumor-specific cytotoxic T-lymphocytes from the peripheral blood of colorectal cancer patients for adoptive T-cell transfer.

    PubMed

    Carluccio, Silvia; Delbue, Serena; Signorini, Lucia; Setola, Elisabetta; Bagliani, Anna; Della Valle, Alberto; Galli, Andrea; Ferrante, Pasquale; Bregni, Marco

    2015-07-01

    This study designs a strategy for an adoptive cellular therapy (ACT) protocol based on the ex-vivo selection of autologous peripheral blood-derived CD8-enriched T-cells, stimulated with dendritic cells (DCs) that had been pulsed with apoptotic tumor cells to generate cytotoxic T lymphocytes (CTLs) with anti-tumor activity. Seventy-eight colorectal cancer (CRC) patients were enrolled in this study. Tumor tissues and peripheral blood (PB) were obtained at surgery. Tissues were mechanically dissociated and cultured to obtain a primary tumor cell line from each patient. DCs were derived from peripheral blood mononuclear cells (PBMCs) using magnetic positive selection of CD14+ monocytes. Anti-tumor CTLs were elicited in co-/micro-cultures using DCs as antigen-presenting cells, autologous apoptotic tumor cells as a source of antigens, and CD8+ T lymphocytes as effectors. Interferon-γ (IFN-γ) secretion was assessed by ELISpot assays to evaluate the activation of the CTLs against the autologous tumor cells. Primary tumor cell lines were obtained from 20 of 78 patients (25.6%). DCs were generated from 26 patients, and of them, corresponding tumor cell lines were derived from six patients. ELISpot results showed that significant IFN-γ secretion was detected after different numbers of stimulations for two patients, whereas weak secretion was observed for three patients. Despite difficulties due to contamination of several primary tumor cell lines with gut intestinal flora, the results suggest that the generation of tumor-specific CTLs is feasible from patients with CRC, and could be useful for supporting an ACT approach in CRC.

  12. Therapeutic effect of interleukin 12 on mouse haemangiosarcomas is not associated with an increased anti-tumour cytotoxic T-lymphocyte activity.

    PubMed Central

    Vizler, C.; Rosato, A.; Calderazzo, F.; Quintieri, L.; Fruscella, P.; Wainstok de Calmanovici, R.; Mantovani, A.; Vecchi, A.; Zanovello, P.; Collavo, D.

    1998-01-01

    In syngeneic mice, the H5V polyoma middle-T oncogene-transformed endothelioma cell line induces Kaposi's sarcoma-like cavernous haemangiomas that regress transiently, probably because of an anti-tumour immune response, but eventually grow progressively and kill the host. To evaluate the generation of tumour-specific cytotoxic T lymphocytes (CTLs), spleen cells of tumour-bearing mice were restimulated with irradiated H5V cells in mixed leucocyte-tumour cell cultures. Tumour-specific CTLs were demonstrable only when low numbers of H5V stimulator cells were used (<1 H5V cell per 50 splenocytes). We found that H5V cells secrete immunosuppressive mediators because CTL generation was blocked when H5V cells culture supernatants were added to allogeneic mixed leucocyte cultures. As numerous tumour-derived immunosuppressive mediators may interfere with interleukin 12 (IL-12) production, we tested whether IL-12 treatment of the tumour-bearing mice would augment their immune response and thus suppress tumour growth. Indeed, IL-12 inhibited tumour growth and prevented mortality, but did not increase anti-H5V CTL generation either in vitro or in vivo. Moreover, the anti-tumour activity in IL-12-treated mice was abrogated by anti-interferon (IFN)-gamma monoclonal antibody (MAb) co-administration. These results strongly suggest that the anti-tumour effect of IL-12 is principally mediated by IFN-gamma release that in turn blocks H5V cell proliferation and induces the release of factors that suppress angiogenesis. PMID:9484826

  13. Identification of Immunogenic Cytotoxic T Lymphocyte Epitopes Containing Drug Resistance Mutations in Antiretroviral Treatment-Naïve HIV-Infected Individuals

    PubMed Central

    Blanco-Heredia, Juan; Lecanda, Aarón; Valenzuela-Ponce, Humberto; Brander, Christian; Ávila-Ríos, Santiago; Reyes-Terán, Gustavo

    2016-01-01

    Background Therapeutic HIV vaccines may prove helpful to intensify antiretroviral treatment (ART) efficacy and may be an integral part of future cure strategies. Methods We examined IFN-gamma ELISpot responses to a panel of 218 HIV clade B consensus-based HIV protease-reverse transcriptase peptides, designed to mimic previously described and predicted cytotoxic T lymphocyte epitopes overlapping drug resistance (DR) positions, that either included the consensus sequence or the DR variant sequence, in 49 ART-naïve HIV-infected individuals. Next generation sequencing was used to assess the presence of minority DR variants in circulating viral populations. Results Although a wide spectrum of differential magnitudes of response to DR vs. WT peptide pairs was observed, responses to DR peptides were frequent and strong in the study cohort. No difference between the median magnitudes of response to DR vs. WT peptides was observed. Interestingly, of the 22 peptides that were recognized by >15% of the participants, two-thirds (64%) corresponded to DR peptides. When analysing responses per peptide pair per individual, responses to only WT (median 4 pairs/individual) or DR (median 6 pairs/individual) were more common than responses to both WT and DR (median 2 pairs/individual; p<0.001). While the presence of ELISpot responses to WT peptides was frequently associated with the presence of the corresponding peptide sequence in the patient’s virus (mean 68% of cases), responses to DR peptides were generally not associated with the presence of DR mutations in the viral population, even at low frequencies (mean 1.4% of cases; p = 0.0002). Conclusions Our data suggests that DR peptides are frequently immunogenic and raises the potential benefit of broadening the antigens included in a therapeutic vaccine approach to immunogenic epitopes containing common DR sequences. Further studies are needed to assess the quality of responses elicited by DR peptides. PMID:26808823

  14. Target cell death triggered by cytotoxic T lymphocytes: a target cell mutant distinguishes passive pore formation and active cell suicide mechanisms.

    PubMed Central

    Ucker, D S; Wilson, J D; Hebshi, L D

    1994-01-01

    The role of the target cell in its own death mediated by cytotoxic T lymphocytes (CTL) has been controversial. The ability of the pore-forming granule components of CTL to induce target cell death directly has been taken to suggest an essentially passive role for the target. This view of CTL-mediated killing ascribes to the target the single role of providing an antigenic stimulus to the CTL; this signal results in the vectoral degranulation and secretion of pore-forming elements onto the target. On the other hand, by a number of criteria, target cell death triggered by CTL appears fundamentally different from death resulting from membrane damage and osmotic lysis. CTL-triggered target cell death involves primary internal lesions of the target cell that reflect a physiological cell death process. Orderly nuclear disintegration, including lamin phosphorylation and solubilization, chromatin condensation, and genome digestion, are among the earliest events, preceding the loss of plasma membrane integrity. We have tested directly the involvement of the target cell in its own death by examining whether we could isolate mutants of target cells that have retained the ability to be recognized by and provide an antigenic stimulus to CTL while having lost the capacity to respond by dying. Here, we describe one such mutant, BW87. We have used this CTL-resistant mutant to analyze the mechanisms of CTL-triggered target cell death under a variety of conditions. The identification of a mutable target cell element essential for the cell death response to CTL provides genetic evidence that target cell death reflects an active cell suicide process similar to other physiological cell deaths. PMID:8264610

  15. A vaccine-elicited, single viral epitope-specific cytotoxic T lymphocyte response does not protect against intravenous, cell-free simian immunodeficiency virus challenge.

    PubMed Central

    Yasutomi, Y; Koenig, S; Woods, R M; Madsen, J; Wassef, N M; Alving, C R; Klein, H J; Nolan, T E; Boots, L J; Kessler, J A

    1995-01-01

    Protection against simian immunodeficiency virus (SIV) challenge was assessed in rhesus monkeys with a vaccine-elicited, single SIV epitope-specific cytotoxic T-lymphocyte (CTL) response in the absence of SIV-specific antibody. Strategies were first explored for eliciting an optimal SIV Gag epitope-specific CTL response. These studies were performed in rhesus monkeys expressing the major histocompatibility complex (MHC) class I gene Mamu-A*01, a haplotype associated with a predominant SIV CTL epitope mapped to residues 182 to 190 of the Gag protein (p11C). We demonstrated that a combined modality immunization strategy using a recombinant Mycobacterium bovis BCG-SIV Gag construct for priming, and peptide formulated in liposome for boosting, elicited a greater p11C-specific CTL response than did a single immunization with peptide-liposome alone. Vaccinated and control monkeys were then challenged with cell-free SIVmne by an intravenous route of inoculation. Despite a vigorous p11C-specific CTL response at the time of virus inoculation, all monkeys became infected with SIV. gag gene sequencing of the virus isolated from these monkeys demonstrated that the established viruses had no mutations in the p11C-coding region. Thus, the preexisting CTL response did not select for a viral variant that might escape T-cell immune recognition. These studies demonstrate that a potent SIV-specific CTL response can be elicited by combining live vector and peptide vaccine modalities. However, a single SIV Gag epitope-specific CTL response in the absence of SIV-specific antibody did not provide protection against a cell-free, intravenous SIV challenge. PMID:7884874

  16. Human cytotoxic T lymphocytes directed to seasonal influenza A viruses cross-react with the newly emerging H7N9 virus.

    PubMed

    van de Sandt, Carolien E; Kreijtz, Joost H C M; de Mutsert, Gerrie; Geelhoed-Mieras, Martina M; Hillaire, Marine L B; Vogelzang-van Trierum, Stella E; Osterhaus, Albert D M E; Fouchier, Ron A M; Rimmelzwaan, Guus F

    2014-02-01

    In February 2013, zoonotic transmission of a novel influenza A virus of the H7N9 subtype was reported in China. Although at present no sustained human-to-human transmission has been reported, a pandemic outbreak of this H7N9 virus is feared. Since neutralizing antibodies to the hemagglutinin (HA) globular head domain of the virus are virtually absent in the human population, there is interest in identifying other correlates of protection, such as cross-reactive CD8(+) T cells (cytotoxic T lymphocytes [CTLs]) elicited during seasonal influenza A virus infections. These virus-specific CD8(+) T cells are known to recognize conserved internal proteins of influenza A viruses predominantly, but it is unknown to what extent they cross-react with the newly emerging H7N9 virus. Here, we assessed the cross-reactivity of seasonal H3N2 and H1N1 and pandemic H1N1 influenza A virus-specific polyclonal CD8(+) T cells, obtained from HLA-typed study subjects, with the novel H7N9 virus. The cross-reactivity of CD8(+) T cells to H7N9 variants of known influenza A virus epitopes and H7N9 virus-infected cells was determined by their gamma interferon (IFN-γ) response and lytic activity. It was concluded that, apart from recognition of individual H7N9 variant epitopes, CD8(+) T cells to seasonal influenza viruses display considerable cross-reactivity with the novel H7N9 virus. The presence of these cross-reactive CD8(+) T cells may afford some protection against infection with the new virus.

  17. Human Cytotoxic T Lymphocytes Directed to Seasonal Influenza A Viruses Cross-React with the Newly Emerging H7N9 Virus

    PubMed Central

    van de Sandt, Carolien E.; Kreijtz, Joost H. C. M.; de Mutsert, Gerrie; Geelhoed-Mieras, Martina M.; Hillaire, Marine L. B.; Vogelzang-van Trierum, Stella E.; Osterhaus, Albert D. M. E.; Fouchier, Ron A. M.

    2014-01-01

    In February 2013, zoonotic transmission of a novel influenza A virus of the H7N9 subtype was reported in China. Although at present no sustained human-to-human transmission has been reported, a pandemic outbreak of this H7N9 virus is feared. Since neutralizing antibodies to the hemagglutinin (HA) globular head domain of the virus are virtually absent in the human population, there is interest in identifying other correlates of protection, such as cross-reactive CD8+ T cells (cytotoxic T lymphocytes [CTLs]) elicited during seasonal influenza A virus infections. These virus-specific CD8+ T cells are known to recognize conserved internal proteins of influenza A viruses predominantly, but it is unknown to what extent they cross-react with the newly emerging H7N9 virus. Here, we assessed the cross-reactivity of seasonal H3N2 and H1N1 and pandemic H1N1 influenza A virus-specific polyclonal CD8+ T cells, obtained from HLA-typed study subjects, with the novel H7N9 virus. The cross-reactivity of CD8+ T cells to H7N9 variants of known influenza A virus epitopes and H7N9 virus-infected cells was determined by their gamma interferon (IFN-γ) response and lytic activity. It was concluded that, apart from recognition of individual H7N9 variant epitopes, CD8+ T cells to seasonal influenza viruses display considerable cross-reactivity with the novel H7N9 virus. The presence of these cross-reactive CD8+ T cells may afford some protection against infection with the new virus. PMID:24257602

  18. Computer-based design of an HLA-haplotype and HIV-clade independent cytotoxic T-lymphocyte assay for monitoring HIV-specific immunity.

    PubMed Central

    Amicosante, Massimo; Gioia, Cristiana; Montesano, Carla; Casetti, Rita; Topino, Simone; D'Offizi, Gianpiero; Cappelli, Giulia; Ippolito, Giuseppe; Colizzi, Vittorio; Poccia, Fabrizio; Pucillo, Leopoldo P.

    2002-01-01

    BACKGROUND: Human immunodeficiency virus (HIV)- specific CD8-positive cytotoxic T-lymphocytes (CTL) play a key role in controlling HIV infection. Monitoring CTL response could be clinically relevant during structured therapy interruption (STI), HIV exposure, and vaccine trials. However, HLA patients' restriction and HIV variability limited the development of a CTL assay with broad specificity. MATERIALS AND METHODS: We designed an HLA-class I/HIV-1 clade independent assay for assessing HIV- specific CTL by using a computer-assisted selection ofthe CTL epitopes. Twenty-eight 15-mers were selected by peptide-binding motifs analysis using different databases (HIV-Immunology Database, SYFPEITHI, BIMAS). Altogether they putatively bind to more than 90% of HLA haplotypes in different populations, with an overall HIV-1 variability below 9%. The peptide pool was used as an antigen in an intracellular cytokine staining (ICS) assay for quantifying HIV-specific CTL response. RESULTS: The test can be performed using both fresh and cryopreserved peripheral blood mononuclear cells (PBMC), whereas GAG protein as antigen works only on fresh PBMC. A significantly higher CTL response with respect to HIV-negative controls was detected in all HIV-1 infected subjects of two groups of patients with different ethnicities (Caucasians and Africans) and coming from areas with different HIV-1 clade prevalences (clade B and A/G, respectively). In Caucasian patients, after month of STI, the number of HIV-1 specific CTL (2,896 +/- 2,780 IFN-gamma specific CD8 cells/ml) was significantly higher than that found at enrolment (2,125 +/- 4,426 IFN-gamma specific CD8 cells/ml, p< 0.05). CONCLUSIONS: These data indicate that this CTL assay is broadly specific and could represent a useful clinical tool for HIV immunodiagnostic independent of HLA-haplotype and HIV-clade variabilities. PMID:12606814

  19. Enhanced in vivo gene expression mediated by listeriolysin O incorporated anionic LPDII: Its utility in cytotoxic T lymphocyte-inducing DNA vaccine.

    PubMed

    Sun, Xun; Provoda, Chester; Lee, Kyung-Dall

    2010-12-01

    Enhanced in vivo gene expression using non-viral vectors is a critical issue in gene therapy in general. Among the many potential utilities of non-viral vector-mediated gene delivery, its application in DNA-based vaccination is an attractive approach with several practical advantages over conventional vaccination. We have previously shown that the endosomolytic bacterial protein listeriolysin O (LLO) is capable of facilitating transfection in vitro using the LPDII (anionic liposome-polycation-DNA complexes) delivery system. In the present study we have extended and investigated the DNA delivery of LLO-containing LPDII to in vivo and evaluated its utility in DNA vaccination in mice. We further investigated the ability of this non-viral gene delivery system to elicit an immune response to a model antigen ovalbumin (OVA), particularly focusing on the OVA-specific CD8(+) cytotoxic T lymphocyte (CTL) response, after delivery of a plasmid containing the OVA cDNA. A DNA prime and protein boost protocol was employed to generate cytotoxic T cell responses. Our results show that increased in vitro and in vivo transfection efficiencies were observed when LLO was incorporated into LPDII. This LLO-LPDII formulation produced an enhanced functional antigen-specific CD8(+) T cell response in vivo compared to the heat-inactivated LLO-containing LPDII (HI-LLO-LPDII) formulation. Furthermore, a significantly higher CTL frequency was observed in the splenocytes isolated from the mice primed with LLO-LPDII by an enzyme-linked immunosorbent spot assay. Interferon-γ production upon specific stimulation by OVA-specific CD8(+) peptide was also significantly stronger with the inclusion of LLO into LPDII. These findings suggest that the LLO-containing LPDII system possesses noteworthy potential as a candidate carrier for DNA vaccine delivery.

  20. A Novel CD8-Independent High-Avidity Cytotoxic T-Lymphocyte Response Directed against an Epitope in the Phosphoprotein of the Paramyxovirus Simian Virus 5

    PubMed Central

    Gray, Peter M.; Parks, Griffith D.; Alexander-Miller, Martha A.

    2001-01-01

    Adoptive transfer studies have shown that cytotoxic T lymphocytes (CTL) of high avidity, capable of recognizing low levels of peptide-MHC I molecules, are more efficient at reducing viral titers than are low-avidity CTL, thus establishing CTL avidity as a critical parameter for the ability of a CTL to clear virus in vivo. It has been well documented that CTL of high avidity are relatively CD8 independent, whereas low-avidity CTL require CD8 engagement in order to become activated. In this study we have analyzed the antiviral CTL response elicited following infection with the paramyxovirus simian virus 5 (SV5). We have identified the immunodominant and subdominant CTL responses and subsequently assessed the avidity of these responses by their CD8 dependence. This is the first study in which the relationship between immunodominance and CTL avidity has been investigated. The immunodominant response was directed against an epitope present in the viral M protein, and subdominant responses were directed against epitopes present in the P, F, and HN proteins. Similarly to other CTL responses we have analyzed, the immunodominant response and the subdominant F and HN responses were comprised of both high- and low-avidity CTL. However, the subdominant response directed against the epitope present in the P protein is novel, as it is exclusively high avidity. This high-avidity response is independent of both the route of infection and expression by recombinant SV5. A further understanding of the inherent properties of P that elicit only high-avidity CTL may allow for the design of more efficacious vaccine vectors that preferentially elicit high-avidity CTL in vivo. PMID:11581375

  1. Functional profile of human influenza virus-specific cytotoxic T lymphocyte activity is influenced by interleukin-2 concentration and epitope specificity

    PubMed Central

    Boon, ACM; de Mutsert, G; Fouchier, RAM; Osterhaus, ADME; Rimmelzwaan, GF

    2005-01-01

    The ability of influenza A virus-specific cytotoxic T lymphocytes (CTL) to degranulate and produce cytokines upon antigenic restimulation was studied in four HLA-A*0101 and HLA-A*0201 positive subjects. Peripheral blood mononuclear cells of these subjects were stimulated with influenza A virus in the presence of high or low interleukin (IL)-2 concentrations. CD8+ T cell populations specific for the HLA-A*0101 restricted epitope NP44–52 and the HLA-A*0201 restricted epitope M158–66 were identified by positive staining with tetramers of peptide major histocompatibility complexes (MHC) (NP-Tm and M1-Tm, respectively). Within these populations, the proportion of cells mobilizing CD107a, or expressing interferon (IFN)-γ and tumour necrosis factor-(TNF)-α upon short-term peptide restimulation was determined by flow cytometry. Independent of IL-2 concentrations, large subject-dependent differences in the mobilization of CD107a and expression of IFN-γ and TNF-α by both NP- and M1-specific T cells were observed. In two of the four subjects, the functional profile of NP-Tm+ and M1-Tm+ cells differed considerably. Overall, no difference in the proportion of NP-Tm+ or M1-Tm+ cells expressing CD107a was observed. The proportion of M1-Tm+ cells that produced IFN-γ (P < 0·05) was larger than for NP-Tm+ cells, independent of IL-2 concentration. When cultured under IL-2hi concentrations higher TNF-α expression was also observed in M1-Tm+ cells (P < 0·05). The IL-2 concentration during expansion of virus-specific cells had a profound effect on the functionality of both M1-Tm+ and NP-Tm+ cells. PMID:16178855

  2. Identification of Programmed Death Ligand 1-derived Peptides Capable of Inducing Cancer-reactive Cytotoxic T Lymphocytes From HLA-A24+ Patients With Renal Cell Carcinoma.

    PubMed

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu

    2015-09-01

    Molecular therapy targeting tumor angiogenesis has been the standard treatment for metastatic renal cell carcinoma (mRCC). However, despite their significant antitumor effects, most of patients with mRCC have not been cured. Under such circumstances, anticancer immunotherapy has been considered a promising treatment modality for mRCC, and cancer-reactive cytotoxic T lymphocytes (CTLs) are the most powerful effectors among several immune cells. However, anticancer CTLs can be inhibited by several immune inhibitory mechanisms, including the interaction between programmed death 1 (PD-1) and its ligand PD-L1, on T cells and cancer cells, respectively. Alternatively, this also means that PD-L1 could be a promising target for anticancer immunotherapy. Therefore, we searched for PD-L1-derived peptides that are applicable for anticancer vaccine for HLA-A24(+) RCC patients. Among 5 peptides derived from PD-L1, which were prepared based on the binding motif to the HLA-A24(+) allele, both PD-L1(11-19) and PD-L1(41-50) peptides induced peptide-specific CTLs from peripheral blood mononuclear cells of HLA-A24(+) RCC patients. Such PD-L1 peptide-stimulated CD8 T cells showed cytotoxicity against HLA-A24(+) and PD-L1-expressing RCC cells. Although IFN-γ treatment increased PD-L1 expression on PD-L1(low) RCC cells, their sensitivity to cytotoxicity of PD-L1 peptide-stimulated CD8(+) T cells varied between patients. Altogether, these results indicate that both PD-L1(11-19) and PD-L1(41-50) peptides could be candidates for peptide-based anticancer vaccines for HLA-A24(+) mRCC patients.

  3. Identification of erythropoietin receptor-derived peptides having the potential to induce cancer-reactive cytotoxic T lymphocytes from HLA-A24(+) patients with renal cell carcinoma.

    PubMed

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu

    2014-05-01

    Molecular targeting therapy with anti-angiogenic agents, including sunitinib and sorafenib, has been proven to be the first- and second-line standard treatments for metastatic renal cell carcinoma (mRCC) worldwide. Despite their significant antitumor effects, most of the patients with mRCC have not been cured. Under such circumstances, anti-cancer immunotherapy has been considered as a promising treatment modality for mRCC, and cytotoxic T lymphocytes (CTLs) are the most powerful effectors among several immune cells and molecules. Therefore, we previously conducted anti-cancer vaccine therapy with peptides derived from carbonic anhydrase-9 and vascular endothelial growth factor receptor-1 as phase-I/II trials for mRCC patients and reported their clinical benefits. Alternatively, up-regulated expression of erythropoietin (Epo) and its receptor (EpoR) in RCC has been reported, and their co-expression is involved in tumorigenesis. In order to increase options for peptide-based vaccination therapy, we searched for novel EpoR-peptides for HLA-A24(+) RCC patients. Among 5 peptides derived from EpoR, which were prepared based on the binding motif to the HLA-A24 allele, EpoR52-60 peptide had the potential to induce peptide-specific CTLs from peripheral blood mononuclear cells of HLA-A24(+) RCC patients. Cytotoxicity toward HLA-A24(+) and EpoR-expressing RCC cells was ascribed to peptide-specific CD8(+) T cells. These results indicate that the EpoR52-60 peptide could be a promising candidate for a peptide-based anti-cancer vaccine for HLA-A24(+) mRCC patients.

  4. Multiple mechanisms underlie defective recognition of melanoma cells cultured in three-dimensional architectures by antigen-specific cytotoxic T lymphocytes

    PubMed Central

    Feder-Mengus, C; Ghosh, S; Weber, W P; Wyler, S; Zajac, P; Terracciano, L; Oertli, D; Heberer, M; Martin, I; Spagnoli, G C; Reschner, A

    2007-01-01

    Cancer cells' growth in three-dimensional (3D) architectures promotes resistance to drugs, cytokines, or irradiation. We investigated effects of 3D culture as compared to monolayers (2D) on melanoma cells' recognition by tumour-associated antigen (TAA)-specific HLA-A*0201-restricted cytotoxic T-lymphocytes (CTL). Culture of HBL, D10 (both HLA-A*0201+, TAA+) and NA8 (HLA-A*0201+, TAA−) melanoma cells on polyHEMA-coated plates, resulted in generation of 3D multicellular tumour spheroids (MCTS). Interferon-gamma (IFN-γ) production by HLA-A*0201-restricted Melan-A/MART-127–35 or gp100280–288-specific CTL clones served as immunorecognition marker. Co-culture with melanoma MCTS, resulted in defective TAA recognition by CTL as compared to 2D as witnessed by decreased IFN-γ production and decreased Fas Ligand, perforin and granzyme B gene expression. A multiplicity of mechanisms were potentially involved. First, MCTS per se limit CTL capacity of recognising HLA class I restricted antigens by reducing exposed cell surfaces. Second, expression of melanoma differentiation antigens is downregulated in MCTS. Third, expression of HLA class I molecules can be downregulated in melanoma MCTS, possibly due to decreased interferon-regulating factor-1 gene expression. Fourth, lactic acid production is increased in MCTS, as compared to 2D. These data suggest that melanoma cells growing in 3D, even in the absence of immune selection, feature characteristics capable of dramatically inhibiting TAA recognition by specific CTL. PMID:17342088

  5. Virus-specific HLA-restricted lysis of herpes simplex virus-infected human monocytes and macrophages mediated by cytotoxic T lymphocytes

    SciTech Connect

    Torpey, D.J. III

    1987-01-01

    Freshly-isolated peripheral blood human monocytes and 5 day in vitro cultured macrophages were infected with herpes simplex virus type 1 (HSV-1), labeled with /sup 51/Cr, and used as target cells in a 12-14 hour cell-mediated cytotoxicity assay. Mononuclear leukocytes (MNL) from HSV-1 non-immune individuals, whether unstimulated or stimulated with HSV-1 antigen, did not mediate significant lysis of either target cell. HSV-immune MNL, both freshly-isolated and cultured for 5 days without antigen, demonstrated only low levels of natural killer (NK) cell-mediate lysis. MNL from HSV-immune individuals incubated for 5 days in vitro with HSV-1 antigen mediated significant virus-specific lysis of both target cells. Mean virus-specific lysis of autologous monocytes was 8.5(/+-/2.0)% compared to a three-fold greater virus-specific lysis of autologous macrophages. Greater than 70% of this lytic activity was mediated by Leu-11-negative, T3-positive cytotoxic T lymphocytes (CTL). Allogeneic target cells lacking a common HLA determinant were not significantly lysed while T8-positive CTL mediated infrequent lysis of target cells sharing a common HLA-A and/or HLA-B determinant. T4-positive lymphocytes were demonstrated to be the predominant cell mediating lysis of autologous target cells and allogeneic target cells sharing both HLA-A and/or HLA-B plus HLA-DR determinants with the CTL; the T4-positive cell was the sole CTL mediator of lysis of allogeneic target cells having a common HLA-DR determinant.

  6. The life span of major histocompatibility complex-peptide complexes influences the efficiency of presentation and immunogenicity of two class I-restricted cytotoxic T lymphocyte epitopes in the Epstein-Barr virus nuclear antigen 4

    PubMed Central

    1996-01-01

    We have investigated the reactivity to two human histocompatibility leukocyte antigen (HLA) A11-restricted cytotoxic T lymphocyte (CTL) epitopes derived from amino acids 416-424 (IVTDFSVIK, designated IVT) and 399-408 (AVFDRKSVAK, designated AVF) of the Epstein-Barr virus (EBV) nuclear antigen (EBNA) 4. A strong predominance of CTL clones specific for the IVT epitope was demonstrated in polyclonal cultures generated by stimulation of lymphocytes from the EBV-seropositive donor BK with the autologous B95.8 virus-transformed lymphoblastoid cell line (LCL). This was not due to intrinsic differences of CTL efficiency since clones specific for the two epitopes lysed equally well A11- positive phytohemagglutinin blasts and LCLs pulsed with the relevant synthetic peptide. Irrespective of the endogenous levels of EBNA4 expression, untreated LCLs were lysed more efficiently by the IVT- specific effectors, suggesting that a higher density of A11-IVT complexes is presented at the cell surface. In accordance, 10-50-fold higher amounts of IVT peptides were found in high-performance liquid chromatography fractions of acid extracts corresponding to an abundance of about 350-12,800 IVT and 8-760 AVF molecules per cell. Peptide- mediated competition of CTL sensitization, transport assays in streptolysin-O permeabilized cells, and induction of A11 expression in the transporter associated with antigen presentation-deficient T2/A11 transfectant demonstrated that the IVT and AVF peptides bind with similar affinities to A11, are translocated with equal efficiency to the endoplasmic reticulum, and form complexes of comparable stability over a wide range of temperature and pH conditions. A rapid surface turnover of A11 molecules containing the AVF peptide was demonstrated in metabolically active T2/A11 cells corresponding to a half-life of approximately 3.5 as compared to approximately 2 h for molecules induced at 26 degrees C in the absence of exogenous peptides and >12 h for IVT

  7. Regulatory B cells inhibit cytotoxic T lymphocyte (CTL) activity and elimination of infected CD4 T cells after in vitro reactivation of HIV latent reservoirs.

    PubMed

    Siewe, Basile; Wallace, Jennillee; Rygielski, Sonya; Stapleton, Jack T; Martin, Jeffrey; Deeks, Steven G; Landay, Alan

    2014-01-01

    During HIV infection, IL-10/IL-10 receptor and programmed death-1 (PD-1)/programmed death-1-ligand (PD-L1) interactions have been implicated in the impairment of cytotoxic T lymphocyte (CTL) activity. Despite antiretroviral therapy (ART), attenuated anti-HIV CTL functions present a major hurdle towards curative measures requiring viral eradication. Therefore, deeper understanding of the mechanisms underlying impaired CTL is crucial before HIV viral eradication is viable. The generation of robust CTL activity necessitates interactions between antigen-presenting cells (APC), CD4+ and CD8+ T cells. We have shown that in vitro, IL-10hiPD-L1hi regulatory B cells (Bregs) directly attenuate HIV-specific CD8+-mediated CTL activity. Bregs also modulate APC and CD4+ T cell function; herein we characterize the Breg compartment in uninfected (HIVNEG), HIV-infected "elite controllers" (HIVEC), ART-treated (HIVART), and viremic (HIVvir), subjects, and in vitro, assess the impact of Bregs on anti-HIV CTL generation and activity after reactivation of HIV latent reservoirs using suberoylanilide hydroxamic acid (SAHA). We find that Bregs from HIVEC and HIVART subjects exhibit comparable IL-10 expression levels significantly higher than HIVNEG subjects, but significantly lower than HIVVIR subjects. Bregs from HIVEC and HIVART subjects exhibit comparable PD-L1 expression, significantly higher than in HIVVIR and HIVNEG subjects. SAHA-treated Breg-depleted PBMC from HIVEC and HIVART subjects, displayed enhanced CD4+ T-cell proliferation, significant upregulation of antigen-presentation molecules, increased frequency of CD107a+ and HIV-specific CD8+ T cells, associated with efficient elimination of infected CD4+ T cells, and reduction in integrated viral DNA. Finally, IL-10-R and PD-1 antibody blockade partially reversed Breg-mediated inhibition of CD4+ T-cell proliferation. Our data suggest that, possibly, via an IL-10 and PD-L1 synergistic mechanism; Bregs likely inhibit APC function

  8. Attachment of an anti-receptor antibody to non-target cells renders them susceptible to lysis by a clone of cytotoxic T lymphocytes.

    PubMed

    Kranz, D M; Tonegawa, S; Eisen, H N

    1984-12-01

    The molecular basis for the dependence of antigen recognition by T cells on products of the major histocompatibility complex (MHC) is unknown, and the antigenic structures that are actually bound by T-cell receptors are ill-defined. In this study, we asked whether a monoclonal antibody (mAb) that reacts with the T-cell receptor of a clone of murine cytotoxic T lymphocytes (CTL) and not with the receptors of other CTL clones can substitute for that clone's natural ligand in specific cytolytic reactions. To answer the question, a mAb (1B2) to the receptor of a CTL clone (2C) was attached covalently to 51Cr-labeled cells that were not otherwise susceptible to lysis by clone 2C, and the cells thus modified were then tested as targets for clone 2C and other CTL clones of similar specificity. All labeled cells modified in this way, including a murine cell line that expresses no cell-surface MHC class I molecules and a human cell line, were lysed by clone 2C but not by other CTL clones. If, however, instead of attaching the mAb to the receptor of clone 2C, the cells were modified by attaching to them mAbs to other surface antigens on CTL [lymphocyte function-associated antigen (LFA-1), Thy-1.2], they were not lysed. In cytolytic titrations, the cells that had been converted by attachment of mAb 1B2 into specific targets for clone 2C were just as susceptible to lysis by that clone as the clone's natural H-2d targets (e.g., P815 cells). However, some accessory surface molecules (LFA-1, Lyt-2) that are required for clone 2C to lyse its natural H-2d targets seemed not to be required for this clone to lyse the mAb-converted target cells. By demonstrating that a variety of different cell types can be thus converted into target cells for CTL, the approach described in this study may provide opportunities to analyze further the mechanisms by which CTL destroy target cells.

  9. Cytotoxic T lymphocyte response to a wild type hepatitis B virus epitope in patients chronically infected by variant viruses carrying substitutions within the epitope

    PubMed Central

    1994-01-01

    Mutations that abrogate recognition of a viral epitope by class I- restricted cytotoxic T lymphocyte (CTL) can lead to viral escape if the CTL response against that epitope is crucial for viral clearance. The likelihood of this type of event is low when the CTL response is simultaneously directed against multiple viral epitopes, as has been recently reported for patients with acute self-limited hepatitis B virus (HBV) infection. The CTL response to HBV is usually quite weak, however, during chronic HBV infection, and it is generally acknowledged that this is a major determinant of viral persistence in this disease. If such individuals were to produce a mono- or oligospecific CTL response, however, negative selection of the corresponding mutant viruses might occur. We have recently studied two HLA-A2-positive patients with chronic hepatitis B who, atypically, developed a strong HLA-A2-restricted CTL response against an epitope (FLPSDFFPSV) that contains an HLA-A2-binding motif located between residues 18-27 of the viral nucleocapsid protein, hepatitis B core antigen (HBcAg). These patients failed, however, to respond to any of other HLA-A2-restricted HBV-derived peptides that are generally immunogenic in acutely infected patients who successfully clear the virus. Interestingly, DNA sequence analysis of HBV isolates from these two patients demonstrated alternative residues at position 27 (V --> A and V --> I) and position 21 (S --> N, S --> A, and S --> V) that reduced the HLA and T cell receptor-binding capacities of the variant sequences, respectively. Synthetic peptides containing these alternative sequences were poorly immunogenic compared to the prototype HBc18-27 sequence, and they could not be recognized by CTL clones specific for the prototype peptide. While we do not know if the two patients were originally infected by these variant viruses or if the variants emerged subsequent to infection because of immune selection, the results are most consistent with

  10. Prognostic impact of the tumor-infiltrating regulatory T-cell (Foxp3+)/activated cytotoxic T lymphocyte (granzyme B+) ratio on resected left-sided pancreatic cancer

    PubMed Central

    Hwang, Ho Kyoung; Kim, Hyoung-Il; Kim, Se Hoon; Choi, Junjeong; Kang, Chang Moo; Kim, Kyung Sik; Lee, Woo Jung

    2016-01-01

    Among the subsets of tumor-infiltrating lymphocytes (TILs), activated cytotoxic T lymphocytes (granzyme B+) have an antitumor effect, while regulatory T lymphocytes [forkhead box P3 (Foxp3)+] suppress the antitumor immune response. The aim of the present study was to investigate the possible associations between TIL subsets and survival outcomes in patients with left-sided pancreatic ductal adenocarcinoma (PDAC). From January 2000 to December 2008, 30 patients who underwent curative distal pancreatectomy without neoadjuvant chemoradiotherapy due to left-sided PDAC were enrolled in the present study. TIL subsets were enumerated by immunohistochemical staining for cluster of differentiation (CD)3, CD4, CD8, Foxp3 and granzyme B in the intra-tumoral areas of tissue blocks. Patients were divided into two groups according to the median value of the absolute counts and relative ratios of TIL subsets. In the univariate analysis, age, gender, tumor size, nodal stage, tumor differentiation and lymphovascular/perineural invasion were not significantly associated with survival outcome. However, low levels of preoperative cancer antigen (CA) 19–9 were associated with a longer overall survival (OS), although the association was not significant (37 vs. 18 months; P=0.061). A high level of granzyme B+ was associated with enhanced disease-free survival (DFS) (25 vs. 10 months; P=0.023), and a low Foxp3+/granzyme B+ ratio was associated with a favorable prognosis in terms of DFS (25 vs. 8 months; P=0.008) and OS (47 vs. 17 months; P=0.003). In the multivariate analysis, the ratio of Foxp3+/granzyme B+ was an independent prognostic factor for determining DFS [Exp(B), 3.060; 95% confidence interval (CI), 1.259–47.436; P=0.014] and OS [Exp(B), 3.580; 95% CI, 1.460–8.780; P=0.005]. Among the clinicopathological factors, low levels of CA 19–9 were significantly associated with a low Foxp3+/granzyme B+ ratio (P=0.016). The results of the present study suggested that a low Foxp3

  11. Pseudorabies virus glycoprotein gIII is a major target antigen for murine and swine virus-specific cytotoxic T lymphocytes.

    PubMed Central

    Zuckermann, F A; Zsak, L; Mettenleiter, T C; Ben-Porat, T

    1990-01-01

    Pseudorabies virus (PrV) is the etiological agent of Aujeszky's disease, a disease that causes heavy economic losses in the swine industry. A rational approach to the generation of an effective vaccine against this virus requires an understanding of the immune response induced by it and of the role of the various viral antigens in inducing such a response. We have constructed mutants of PrV [strain PrV (Ka)] that differ from each other only in expression of the viral nonessential glycoproteins gI, gp63, gX, and gIII (i.e., are otherwise isogenic). These mutants were used to ascertain the importance of each of the nonessential glycoproteins in eliciting a PrV-specific cytotoxic T-lymphocyte (CTL) response in mice and pigs. Immunization of DBA/2 mice and pigs with a thymidine kinase-deficient (TK-) mutant of PrV elicits the formation of cytotoxic cells that specifically lyse syngeneic infected target cells. These PrV-specific cytolytic cells have the phenotype of major histocompatibility complex class I antigen-restricted CTLs. The relative number of CTLs specific for glycoproteins gI, gp63, gX, and gIII induced in mice vaccinated with a TK- mutant of PrV was ascertained by comparing their levels of cytotoxicity against syngeneic cells infected with either wild-type virus or gI-/gp63-, gX-, or gIII- virus deletion mutants. The PrV-specific CLTs were significantly less effective in lysing gIII(-)-infected targets than in lysing gI-/gp63-, gX-, or wild-type-infected targets. The in vitro secondary CTL response of lymphocytes obtained from either mice or pigs 6 or more weeks after immunization with a TK- mutant of PrV was also tested. Lymphocytes obtained from these animals were cultured with different glycoprotein-deficient mutants of PrV, and their cytolytic activities against wild-type-infected targets were ascertained. The importance of each of the nonessential viral glycoproteins in eliciting CTLs was assessed from the effectiveness of each of the virus mutants to

  12. Capability of SART3(109-118) peptide to induce cytotoxic T lymphocytes from prostate cancer patients with HLA class I-A11, -A31 and -A33 alleles.

    PubMed

    Mohamed, Elnisr Rashed; Naito, Masayasu; Terasaki, Yasunobu; Niu, Yamei; Gohara, Shojiro; Komatsu, Nobukazu; Shichijo, Shigeki; Itoh, Kyogo; Noguchi, Masanori

    2009-02-01

    We previously reported the SART3 gene to be a tumor-rejection antigen gene encoding a peptide at positions 109-118 (SART3(109-118)) with the ability to induce HLA-A24-restricted cytotoxic T lymphocytes. In this study, we investigated both humoral and cellular responses to this peptide in cancer patients with alleles other than HLA-A24 to explore the possibility of using this peptide as a cancer vaccine for these patients. IgG reactive to SART3(109-118) peptide was identified in sera of the vast majority of non-cancer subjects (n=50) and all cancer patients (n=50) tested without apparent HLA-A association. Levels of anti-SART3(109-118) peptide antibody in cancer patients were significantly higher than those of non-cancer subjects, but no difference was found between HLA-A24+A2- and HLA-A24-A2+ cancer patients. This peptide induced cancer cell-reactive cytotoxic T lymphocytes from peripheral blood mononuclear cells of both healthy donors and prostate cancer patients with HLA-A11, HLA-A31 and HLA-A33 alleles, but not with HLA-A2. These results suggest that this peptide can be applicable as a cancer vaccine not only for HLA-A24+, but also for HLA-A11+, HLA-A31+ and HLA-A33+ prostate cancer patients.

  13. New peptides of the polycomb group protein enhancer of zeste homolog 2 with the potential to induce cancer-reactive cytotoxic T lymphocytes in human leukocyte antigen-A2+ prostate cancer patients.

    PubMed

    Itoh, Yukoh; Komohara, Yoshihiro; Komatsu, Nobukazu; Minami, Takafumi; Saito, Koujiro; Noguchi, Masanori; Itoh, Kyogo; Harada, Mamoru

    2007-11-01

    The polycomb group protein enhancer of zeste homolog 2 (EZH2) is linked to aggressive prostate cancer and could be an appropriate target in specific immunotherapy. In this study, we attempted to identify EZH2-derived peptides that have the potential to generate cancer-reactive cytotoxic T lymphocytes (CTLs) in human leukocyte antigen (HLA)-A2+ prostate cancer patients. Twelve EZH2-derived peptides were prepared based on the HLA-A2 binding motif. These peptide candidates were screened first by their ability to be recognized by immunoglobulin G (IgG), and then by their ability to induce peptide-specific cytotoxic T lymphocytes (CTLs). As a result, five EZH2 peptides recognized by IgG (EZH2 120-128, EZH2 165-174, EZH2 569-577, EZH2 665-674, and EZH2 699-708) were frequently detected in the plasma of prostate cancer patients. Among them, the EZH2 120-128 and EZH2 165-174 peptides effectively induced HLA-A2-restricted and cancer-reactive CTLs from prostate cancer patients. The cytotoxicity was mainly dependent on EZH2 peptide-specific and HLA-A2-restricted CD8+ T cells. These results indicate that these EZH2 120-128 and EZH2 165-174 peptides could be promising candidates in peptide-based immunotherapy for HLA-A2+ prostate cancer patients.

  14. Induction of CD8+ cytotoxic T lymphocytes by immunization with syngeneic irradiated HIV-1 envelope derived peptide-pulsed dendritic cells.

    PubMed

    Takahashi, H; Nakagawa, Y; Yokomuro, K; Berzofsky, J A

    1993-08-01

    Based on the evidence that CD8+ cytotoxic T cells (CTL) precursors do not appear to distinguish between virus-infected cells and viral peptide-pulsed syngeneic cells, we have developed methods for priming class I MHC molecule restricted CD8+ CTL with such peptides without using any adjuvant. We were able to prime in vivo such CTL immunity lasting at least 6 months with a single i.v. injection of syngeneic 2200-3300 rad irradiated peptide-pulsed spleen cells, and even more efficiently with a very small number of irradiated class II MHC molecule expressing splenic dendritic cells (DC). No foreign serum source was necessary during the pulsing. Interestingly, we could not generate significant CTL activity with unirradiated or low dose (< 1100 rad) irradiated spleen cells. Because even purified DC required irradiation for optimal activity, because unirradiated B cells did not significantly inhibit the immunization with DC, and because B cell depletion did not substitute for irradiation, we believe that the effect of irradiation is more to determine homing of the cells than to eliminate interference by B cells. Intravenous immunization was much more effective than s.c. or i.p. immunization. CTL generated by this method could kill both peptide-pulsed syngeneic targets and targets endogenously expressing the whole gp160 gene. Moreover, we found that we could prime CD8+ CTL with the minimal 10-residue core peptide (RGPGRAFVTI) for optimal presentation by class I MHC molecules as efficiently as the original p18. These results suggested that DC bearing antigenic peptide may prime antigen-specific CD8+ CTL in vivo. These results offer useful information for development of synthetic peptide vaccines and immunotherapy.

  15. CD40 stimulation leads to effective therapy of CD40− tumors through induction of strong systemic cytotoxic T lymphocyte immunity

    PubMed Central

    van Mierlo, Geertje J. D.; den Boer, Annemieke Th.; Medema, Jan Paul; van der Voort, Ellen I. H.; Fransen, Marieke F.; Offringa, Rienk; Melief, Cornelis J. M.; Toes, Rene E. M.

    2002-01-01

    Adequate spontaneous activation of tumor-specific T lymphocytes in tumor-bearing hosts is rare, despite the expression of tumor antigens that are potentially highly immunogenic. For example, failure of the immune system to raise competent responses against established tumors expressing the human adenovirus E1A-antigen allows this tumor to grow in immunocompetent mice. We show that systemic in vivo administration of agonistic anti-CD40 antibodies into tumor-bearing mice results in tumor eradication mediated by CD8+ T cells. Treatment resulted in a strong expansion and systemic accumulation of E1A-specific CTL and depended on CD40 expression on host cells, as the tumor was CD40−, and therapy failed in CD40-deficient mice. Local intratumoral administration of anti-CD40 mAb is equally effective in licensing strong, systemic CTL immunity, resulting in the clearance of distant tumor nodules. Our data indicate that the immune response after cancer–host interactions can be directed toward competence, leading to the cure of established tumors merely by delivery of a CD40-dependent “license to kill” signal. PMID:11929985

  16. Identification of Two New HLA-A*1101-Restricted Tax Epitopes Recognized by Cytotoxic T Lymphocytes in an Adult T-Cell Leukemia Patient after Hematopoietic Stem Cell Transplantation

    PubMed Central

    Harashima, Nanae; Tanosaki, Ryuji; Shimizu, Yukiko; Kurihara, Kiyoshi; Masuda, Takao; Okamura, Jun; Kannagi, Mari

    2005-01-01

    We previously reported that Tax-specific CD8+ cytotoxic T lymphocytes (CTLs), directed to single epitopes restricted by HLA-A2 or A24, expanded in vitro and in vivo in peripheral blood mononuclear cells (PBMC) from some adult T-cell leukemia (ATL) patients after but not before allogeneic hematopoietic stem cell transplantation (HSCT). Here, we demonstrated similar Tax-specific CTL expansion in PBMC from another post-HSCT ATL patient without HLA-A2 or A24, whose CTLs equally recognized two newly identified epitopes, Tax88-96 and Tax272-280, restricted by HLA-A11, suggesting that these immunodominant Tax epitopes are present in the ATL patient in vivo. PMID:16014972

  17. Identification of two new HLA-A*1101-restricted tax epitopes recognized by cytotoxic T lymphocytes in an adult T-cell leukemia patient after hematopoietic stem cell transplantation.

    PubMed

    Harashima, Nanae; Tanosaki, Ryuji; Shimizu, Yukiko; Kurihara, Kiyoshi; Masuda, Takao; Okamura, Jun; Kannagi, Mari

    2005-08-01

    We previously reported that Tax-specific CD8(+) cytotoxic T lymphocytes (CTLs), directed to single epitopes restricted by HLA-A2 or A24, expanded in vitro and in vivo in peripheral blood mononuclear cells (PBMC) from some adult T-cell leukemia (ATL) patients after but not before allogeneic hematopoietic stem cell transplantation (HSCT). Here, we demonstrated similar Tax-specific CTL expansion in PBMC from another post-HSCT ATL patient without HLA-A2 or A24, whose CTLs equally recognized two newly identified epitopes, Tax88-96 and Tax272-280, restricted by HLA-A11, suggesting that these immunodominant Tax epitopes are present in the ATL patient in vivo.

  18. TLR agonists are highly effective at eliciting functional memory CTLs of effector memory phenotype in peptide immunization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Given the importance of memory cytotoxic T lymphocytes (CTLs) in eliminating altered self-cells, including virus-infected and tumor cells, devising effective vaccination strategies for generating memory CTLs is a priority in the field of immunology. Herein, we elaborate upon a novel boosting approac...

  19. Detailed analysis of immunologic effects of the cytotoxic T lymphocyte-associated antigen 4-blocking monoclonal antibody tremelimumab in peripheral blood of patients with melanoma

    PubMed Central

    Comin-Anduix, Begoña; Lee, Yohan; Jalil, Jason; Algazi, Alain; de la Rocha, Pilar; Camacho, Luis H; Bozon, Viviana A; Bulanhagui, Cecile A; Seja, Elisabeth; Villanueva, Arturo; Straatsma, Bradley R; Gualberto, Antonio; Economou, James S; Glaspy, John A; Gomez-Navarro, Jesus; Ribas, Antoni

    2008-01-01

    Background CTLA4-blocking antibodies induce tumor regression in a subset of patients with melanoma. Analysis of immune parameters in peripheral blood may help define how responses are mediated. Methods Peripheral blood from HLA-A*0201-positive patients with advanced melanoma receiving tremelimumab (formerly CP-675,206) at 10 mg/kg monthly was repeatedly sampled during the first 4 cycles. Samples were analyzed by 1) tetramer and ELISPOT assays for reactivity to CMV, EBV, MART1, gp100, and tyrosinase; 2) activation HLA-DR and memory CD45RO markers on CD4+/CD8+ cells; and 3) real-time quantitative PCR of mRNA for FoxP3 transcription factor, preferentially expressed by T regulatory cells. The primary endpoint was difference in MART1-specific T cells by tetramer assay. Immunological data were explored for significant trends using clustering analysis. Results Three of 12 patients eligible for immune monitoring had tumor regression lasting > 2 years without relapse. There was no significant change in percent of MART1-specific T cells by tetramer assay. Additionally, there was no generalized trend toward postdosing changes in other antigen-specific CD8+ cell populations, FoxP3 transcripts, or overall changes in surface expression of T-cell activation or memory markers. Unsupervised hierarchical clustering based on immune monitoring data segregated patients randomly. However, clustering according to T-cell activation or memory markers separated patients with clinical response and most patients with inflammatory toxicity into a common subgroup. Conclusion Administration of CTLA4-blocking antibody tremelimumab to patients with advanced melanoma results in a subset of patients with long-lived tumor responses. T-cell activation and memory markers served as the only readout of the pharmacodynamic effects of this antibody in peripheral blood. Clinical trial registration number NCT00086489 PMID:18452610

  20. Ceramide mediates FasL-induced caspase 8 activation in colon carcinoma cells to enhance FasL-induced cytotoxicity by tumor-specific cytotoxic T lymphocytes

    PubMed Central

    Coe, Genevieve L.; Redd, Priscilla S.; Paschall, Amy V.; Lu, Chunwan; Gu, Lilly; Cai, Houjian; Albers, Thomas; Lebedyeva, Iryna O.; Liu, Kebin

    2016-01-01

    FasL-mediated cytotoxicity is one of the mechanisms that CTLs use to kill tumor cells. However, human colon carcinoma often deregulates the Fas signaling pathway to evade host cancer immune surveillance. We aimed at testing the hypothesis that novel ceramide analogs effectively modulate Fas function to sensitize colon carcinoma cells to FasL-induced apoptosis. We used rational design and synthesized twenty ceramide analogs as Fas function modulators. Five ceramide analogs, IG4, IG7, IG14, IG17, and IG19, exhibit low toxicity and potent activity in sensitization of human colon carcinoma cells to FasL-induced apoptosis. Functional deficiency of Fas limits both FasL and ceramide analogs in the induction of apoptosis. Ceramide enhances FasL-induced activation of the MAPK, NF-κB, and caspase 8 despite induction of potent tumor cell death. Finally, a sublethal dose of several ceramide analogs significantly increased CTL-mediated and FasL-induced apoptosis of colon carcinoma cells. We have therefore developed five novel ceramide analogs that act at a sublethal dose to enhance the efficacy of tumor-specific CTLs, and these ceramide analogs hold great promise for further development as adjunct agents in CTL-based colon cancer immunotherapy. PMID:27487939

  1. Construction of a fusion plasmid containing the PSCA gene and cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and its anti-tumor effect in an animal model of prostate cancer

    PubMed Central

    Mai, T.J.; Ma, R.; Li, Z.; Bi, S.C.

    2016-01-01

    Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is a negative regulator of T cell activation, which competes with CD28 for B7.1/B7.2 binding, and which has a greater affinity. Fusion of specific antigens to extracellular domain of CTLA4 represents a promising approach to increase the immunogenicity of DNA vaccines. In this study, we evaluated this interesting approach for CTLA4 enhancement on prostate stem cell antigen (PSCA)-specific immune responses and its anti-tumor effects in a prostate cancer mouse model. Consequently, we constructed a DNA vaccine containing the PSCA and the CTLA-4 gene. Vaccination with the CTLA4-fused DNA not only induced a much higher level of anti-PSCA antibody, but also increased PSCA-specific T cell response in mice. To evaluate the anti-tumor efficacy of the plasmids, murine models with PSCA-expressing tumors were generated. After injection of the tumor-bearing mouse model, the plasmid carrying the CTLA4 and PSCA fusion gene showed stronger inhibition of tumor growth than the plasmid expressing PSCA alone. These observations emphasize the potential of the CTLA4-fused DNA vaccine, which could represent a promising approach for tumor immunotherapy. PMID:27783810

  2. T cell receptor genes in a series of class I major histocompatibility complex-restricted cytotoxic T lymphocyte clones specific for a Plasmodium berghei nonapeptide: implications for T cell allelic exclusion and antigen-specific repertoire

    PubMed Central

    1991-01-01

    We report here the first extensive study of a T cell repertoire for a class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocyte (CTL) response. We have found that the T cell receptors (TCRs) carried by 28 H-2Kd-restricted CTL clones specific for a single Plasmodium berghei circumsporozoite nonapeptide are highly diverse in terms of V alpha, J alpha, and J beta segments and aminoacid composition of the junctional regions. However, despite this extensive diversity, a high proportion of the TCRs contain the same V beta segment. These results are in contrast to most previously reported T cell responses towards class II MHC-peptide complexes, where the TCR repertoires appeared to be much more limited. In our study, the finding of a dominant V beta in the midst of otherwise highly diverse TCRs suggests the importance of the V beta segment in shaping the T cell repertoire specific for a given MHC-peptide complex. As an additional finding, we observed that nearly all clones have rearranged both TCR alpha loci. Moreover, as many as one-third of the CTL clones that we analyzed apparently display two productive alpha rearrangements. This argues against a regulated model of sequential recombination at the alpha locus and consequently raises the question of whether allelic exclusion of the TCR alpha chain is achieved at all. PMID:1836010

  3. Evaluation of the ability of N-terminal fragment of lethal factor of Bacillus anthracis for delivery of Mycobacterium T cell antigen ESAT-6 into cytosol of antigen presenting cells to elicit effective cytotoxic T lymphocyte response

    SciTech Connect

    Chandra, Subhash; Kaur, Manpreet; Midha, Shuchi; Bhatnagar, Rakesh . E-mail: rakbhat01@yahoo.com; Banerjee-Bhatnagar, Nirupama . E-mail: nirupama@icgeb.res.in

    2006-12-22

    We report the ability of N-terminal fragment of lethal factor of Bacillus anthracis to deliver genetically fused ESAT-6 (early secretory antigen target), a potent T cell antigen of Mycobacterium tuberculosis, into cytosol to elicit Cytotoxic T lymphocyte (CTL) response. In vitro Th1 cytokines data and CTL assay proved that efficient delivery of LFn.ESAT-6 occurs in cytosol, in the presence of protective antigen (PA), and leads to generation of effective CTL response. Since CTL response is essential for protection against intracellular pathogens and, it is well known that only single T cell epitope or single antigenic protein is not sufficient to elicit protective CTL response due to variation or polymorphism in MHC-I alleles among the individuals, we suggest that as a fusion protein LFn can be used to deliver multiepitopes of T cells or multiproteins which can generate effective CTLs against intracellular pathogens like M. tuberculosis. It can be used to enhance the protective efficacy of BCG vaccine.

  4. Novel immunodominant peptide presentation strategy: a featured HLA-A*2402-restricted cytotoxic T-lymphocyte epitope stabilized by intrachain hydrogen bonds from severe acute respiratory syndrome coronavirus nucleocapsid protein.

    PubMed

    Liu, Jun; Wu, Peng; Gao, Feng; Qi, Jianxun; Kawana-Tachikawa, Ai; Xie, Jing; Vavricka, Christopher J; Iwamoto, Aikichi; Li, Taisheng; Gao, George F

    2010-11-01

    Antigenic peptides recognized by virus-specific cytotoxic T lymphocytes (CTLs) are presented by major histocompatibility complex (MHC; or human leukocyte antigen [HLA] in humans) molecules, and the peptide selection and presentation strategy of the host has been studied to guide our understanding of cellular immunity and vaccine development. Here, a severe acute respiratory syndrome coronavirus (SARS-CoV) nucleocapsid (N) protein-derived CTL epitope, N1 (QFKDNVILL), restricted by HLA-A*2402 was identified by a series of in vitro studies, including a computer-assisted algorithm for prediction, stabilization of the peptide by co-refolding with HLA-A*2402 heavy chain and β(2)-microglobulin (β(2)m), and T2-A24 cell binding. Consequently, the antigenicity of the peptide was confirmed by enzyme-linked immunospot (ELISPOT), proliferation assays, and HLA-peptide complex tetramer staining using peripheral blood mononuclear cells (PBMCs) from donors who had recovered from SARS donors. Furthermore, the crystal structure of HLA-A*2402 complexed with peptide N1 was determined, and the featured peptide was characterized with two unexpected intrachain hydrogen bonds which augment the central residues to bulge out of the binding groove. This may contribute to the T-cell receptor (TCR) interaction, showing a host immunodominant peptide presentation strategy. Meanwhile, a rapid and efficient strategy is presented for the determination of naturally presented CTL epitopes in the context of given HLA alleles of interest from long immunogenic overlapping peptides.

  5. An immunodominant class I-restricted cytotoxic T lymphocyte determinant of human immunodeficiency virus type 1 induces CD4 class II-restricted help for itself

    PubMed Central

    1990-01-01

    We have observed that a peptide corresponding to an immunodominant epitope of the HIV-1 envelope protein recognized by class I MHC- restricted CD8+ CTL can also induce T cell help for itself. The help is necessary for restimulation of CTL precursors in vitro with peptide alone in the absence of exogenous lymphokines, can be removed by depletion of CD4+ T cells, and can be replaced by exogenous IL-2. Whereas the CTL in BALB/c or B10. D2 mice are restricted by the class I molecule Dd, the Th cells are restricted by the class II molecule Ad, and the help can be blocked by anti-Ad mAb. To examine the genetic regulation of the induction of help, we studied B10.A mice that share the class I Dd molecule, but have different class II molecules, Ak and Ek. Spleen cells of immune B10.A mice behave like CD4-depleted BALB/c spleen cells in that they cannot be restimulated in vitro by the peptide alone, but can with peptide plus IL-2. Therefore, in the absence of exogenous lymphokines, peptide-specific help is necessary for restimulation with this immunodominant CTL epitope peptide, and in H-2d mice, this peptide stimulates help for itself as well as CTL. We speculate on the implications of these findings for the immunodominance of this peptide in H-2d mice, and for the selective advantage of pairing certain class I and class II molecules in an MHC haplotype. PMID:1689366

  6. Enhancement of the antigen-specific cytotoxic T lymphocyte-inducing ability in the PMDC11 leukemic plasmacytoid dendritic cell line via lentiviral vector-mediated transduction of the caTLR4 gene.

    PubMed

    Iwabuchi, Minami; Narita, Miwako; Uchiyama, Takayoshi; Iwaya, Shunpei; Oiwa, Eri; Nishizawa, Yoshinori; Hashimoto, Shigeo; Bonehill, Aude; Kasahara, Noriyuki; Takizawa, Jun; Takahashi, Masuhiro

    2015-08-01

    The aim of the present study was to enhance the efficiency of leukemia immunotherapy by increasing the antigen-specific cytotoxic T lymphocyte-inducing ability of leukemia cells. The leukemic plasmacytoid dendritic cell line PMDC05 containing the HLA-A02/24 antigen, which was previously established in our laboratory (Laboratory of Hematology and Oncology, Graduate School of Health Sciences, Niigata University, Niigata, Japan), was used in the present study. It exhibited higher expression levels of CD80 following transduction with lentiviruses encoding the CD80 gene. This CD80-expressing PMDC05 was named PMDC11. In order to establish a more potent antigen-presenting cell for cellular immunotherapy of tumors or severe infections, PMDC11 cells were transduced with a constitutively active (ca) toll-like receptor 4 (TLR4) gene using the Tet-On system (caTLR4-PMDC11). CD8(+) T cells from healthy donors with HLA-A02 were co-cultured with mutant WT1 peptide-pulsed PMDC11, lipopolysaccharide (LPS)-stimulated PMDC11 or caTLR4-PMDC11 cells. Interleukin (IL)-2 (50 IU/ml) and IL-7 (10 ng/ml) were added on day three of culture. Priming with mutant WT1 peptide-pulsed PMDC11, LPS-stimulated PMDC11 or caTLR4-PMDC11 cells was conducted once per week and two thirds of the IL-2/IL-7 containing medium was replenished every 3-4 days. Immediately prior to the priming with these various PMDC11 cells, the cultured cells were analyzed for the secretion of interferon (IFN)-γ in addition to the percentage and number of CD8(+)/WT1 tetramer(+) T cells using flow cytometry. caTLR4-PMDC11 cells were observed to possess greater antigen-presenting abilities compared with those of PMDC11 or LPS-stimulated PMDC11 cells in a mixed leukocyte culture. CD8 T cells positive for the WT1 tetramer were generated following 3-4 weeks of culture and CD8(+)/WT1 tetramer+ T cells were markedly increased in caTLR4-PMDC11-primed CD8(+) T cell culture compared with PMDC11 or LPS-stimulated PMDC11-primed CD8(+) T

  7. New polycomb group protein enhancer of zeste homolog (EZH) 2-derived peptide with the potential to induce cancer-reactive cytotoxic T lymphocytes in prostate cancer patients with HLA-A3 supertype alleles.

    PubMed

    Minami, Takafumi; Minami, Tomoko; Shimizu, Nobutaka; Yamamoto, Yutaka; De Velasco, Marco A; Nozawa, Masahiro; Yoshimura, Kazuhiro; Harashima, Nanae; Harada, Mamoru; Uemura, Hirotsugu

    2015-05-01

    Analyses on reactivity of anti-cancer cytotoxic T lymphocytes (CTLs) and clinical application of peptide-based anti-cancer vaccine have been mainly focused on patients with HLA-A2 or -A24 alleles. In this study, we identified an enhancer of zeste homolog (EZH) 2-derived peptide applicable for anti-cancer vaccine for prostate cancer patients with HLA-A3 supertype alleles. Five EZH2-derived peptides that were prepared based on the binding motif to the HLA-A3 supertype alleles (HLA-A11, -A31, and -A33) were functionally screened for their potential to induce peptide-specific CTLs from peripheral blood mononuclear cells (PBMCs) of HLA-A3 supertype allele(+) prostate cancer patients. As a result, EZH2733-741 peptide was found to efficiently induce peptide-specific CTLs. The EZH2733-741 peptide-stimulated and purified CD8(+) T cells from PBMCs of HLA-A3 supertype allele(+) prostate cancer patients showed higher cytotoxicity against HLA-A3 supertype allele-expressing LNCaP prostate cancer cells than against parental LNCaP cells. This cytotoxicity against HLA-A3 supertype allele-expressing LNCaP cells was partially but significantly inhibited by the addition of EZH2733-741 peptide-pulsed competitive cells. These results indicate that the EZH2733-741 peptide could be a promising candidate for peptide-based immunotherapy for HLA-A3 supertype allele(+) prostate cancer patients.

  8. Accumulation of Pol Mutations Selected by HLA-B*52:01-C*12:02 Protective Haplotype-Restricted Cytotoxic T Lymphocytes Causes Low Plasma Viral Load Due to Low Viral Fitness of Mutant Viruses.

    PubMed

    Murakoshi, Hayato; Koyanagi, Madoka; Chikata, Takayuki; Rahman, Mohammad Arif; Kuse, Nozomi; Sakai, Keiko; Gatanaga, Hiroyuki; Oka, Shinichi; Takiguchi, Masafumi

    2017-02-15

    HLA-B*52:01-C*12:02, which is the most abundant haplotype in Japan, has a protective effect on disease progression in HIV-1-infected Japanese individuals, whereas HLA-B*57 and -B*27 protective alleles are very rare in Japan. A previous study on HLA-associated polymorphisms demonstrated that the number of HLA-B*52:01-associated mutations at four Pol positions was inversely correlated with plasma viral load (pVL) in HLA-B*52:01-negative individuals, suggesting that the transmission of HIV-1 with these mutations could modulate the pVL in the population. However, it remains unknown whether these mutations were selected by HLA-B*52:01-restricted CTLs and also reduced viral fitness. In this study, we identified two HLA-B*52:01-restricted and one HLA-C*12:02-restricted novel cytotoxic T-lymphocyte (CTL) epitopes in Pol. Analysis using CTLs specific for these three epitopes demonstrated that these CTLs failed to recognize mutant epitopes or more weakly recognized cells infected with mutant viruses than wild-type virus, supporting the idea that these mutations were selected by the HLA-B*52:01- or HLA-C*12:02-restricted T cells. We further showed that these mutations reduced viral fitness, although the effect of each mutation was weak. The present study demonstrated that the accumulation of these Pol mutations selected by HLA-B*52:01- or HLA-C*12:02-restricted CTLs impaired viral replication capacity and thus reduced the pVL. The fitness cost imposed by the mutations partially accounted for the effect of the HLA-B*52:01-C*12:02 haplotype on clinical outcome, together with the effect of HLA-B*52:01-restricted CTLs on viral replication, which had been previously demonstrated.

  9. Cytotoxic T lymphocyte-associated antigen 4 inhibition increases the antitumor activity of adoptive T-cell therapy when carried out with naïve rather than differentiated T cells.

    PubMed

    Ishikawa, Takeshi; Adachi, Satoko; Okayama, Tetsuya; Kokura, Satoshi; Mizushima, Katsura; Doi, Toshifumi; Matsuyama, Tatsuzo; Sakamoto, Naoyuki; Katada, Kazuhiro; Kamada, Kazuhiro; Uchiyama, Kazuhiko; Handa, Osamu; Takagi, Tomohisa; Naito, Yuji; Itoh, Yoshito; Yoshikawa, Toshikazu

    2015-05-01

    Although treatment with an antibody against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) combined with multiple therapeutic interventions has been explored, the effect of combination therapy with CTLA-4 inhibition and adoptive T-cell therapy has not been determined. In the present study, our aim was to determine whether CTLA-4 inhibition, combined with adoptive transfer of T cells at different stages of differentiation, exhibits synergistic antitumor effects in a murine colon cancer model. Mice bearing subcutaneous tumors were administered adoptive T-cell transfer of CD62Lhigh or CD62Llow cells combined with an anti-CTLA-4 antibody (α-CTLA-4) or control immunoglobulin G. Subcutaneous tumors were harvested, and the antitumor effects and helper T-cell polarization were analyzed. CTLA-4 inhibition combined with CD62Lhigh cell administration showed the strongest antitumor effect. Combination therapy increased the number of CD3+ cells within the tumor. Moreover, CTLA-4 inhibition induced polarization of T cells infiltrating the tumor toward the T helper 1 lineage, and suppressed the frequency of regulatory T cells within the tumor, particularly in combination with CD62Lhigh T-cell transfer. This is the first report demonstrating that the efficacy of α-CTLA-4 and adoptive T-cell transfer combination therapy depends on the state of differentiation of the transferred T cells. Our data support the notion that a combination of α-CTLA-4 and adoptive T-cell transfer containing an abundance of naïve phenotype cells could potentially exert antitumor effects in a clinical setting.

  10. The Contributory Roles of Th17 Lymphocyte and Cytotoxic T Lymphocyte at the Hair Bulge Region as Well as the Hair Bulb Area in the Chronic Alopecia Areata Patients

    PubMed Central

    Hong, Jin-Woo; Lee, Chae-Young; Ha, Seung-Min; Choi, Seung-Hwan; Kim, Tae-Hoon; Song, Ki-Hoon

    2017-01-01

    Background Alopecia areata (AA) is a T cell-mediated autoimmune disease that targets hair follicles and interrupts hair regrowth. The microenvironment of the effector T cells and their related cytokines may affect immunopathogenesis around the hair bulb/bulge. Objective To determine the contributory roles of the effector T cell subsets and related cytokines to the pathogenesis of AA. Methods We investigated the correlation between histopathological grades and four clinical prognostic factors in 331 patients with AA, and analyzed the topography of T cell infiltrates and related cytokines around the hair bulb/bulge according to histopathological grades through immunohistochemical and double immunofluorescence studies on a subset of AA specimens. Results First, the groups with more severe histopathological grades were associated with earlier onset, longer duration, more hair loss, as well as poorer therapeutic outcomes. Second, the pattern of CD4 and CD8 expression around the hair bulb/bulge varied by histopathological grade, with staining density decreasing in the following order: type 1>type 2>type 3. In addition, interferon-γ and transforming growth factor-β1 expression appeared denser in the peribulbar area. Interestingly, the denser CCR6+ cells (Th17 cells) showed more infiltration than CCR5+ cells (Th1 cells) around the hair bulb/bulge as histopathological grade worsened. Conclusion The insidious destruction of bulge stem cells and hair bulb matrix stem cells results in more severe hair loss in patients with chronic AA, which is mediated by Th17 lymphocyte and cytotoxic T lymphocyte infiltration. Furthermore, Th17 lymphocytes may play an even more important role than cytotoxic T cells in the development of AA.

  11. Crystal structure of swine major histocompatibility complex class I SLA-1 0401 and identification of 2009 pandemic swine-origin influenza A H1N1 virus cytotoxic T lymphocyte epitope peptides.

    PubMed

    Zhang, Nianzhi; Qi, Jianxun; Feng, Sijia; Gao, Feng; Liu, Jun; Pan, Xiaocheng; Chen, Rong; Li, Qirun; Chen, Zhaosan; Li, Xiaoying; Xia, Chun; Gao, George F

    2011-11-01

    The presentation of viral epitopes to cytotoxic T lymphocytes (CTLs) by swine leukocyte antigen class I (SLA I) is crucial for swine immunity. To illustrate the structural basis of swine CTL epitope presentation, the first SLA crystal structures, SLA-1 0401, complexed with peptides derived from either 2009 pandemic H1N1 (pH1N1) swine-origin influenza A virus (S-OIV(NW9); NSDTVGWSW) or Ebola virus (Ebola(AY9); ATAAATEAY) were determined in this study. The overall peptide-SLA-1 0401 structures resemble, as expected, the general conformations of other structure-solved peptide major histocompatibility complexes (pMHC). The major distinction of SLA-1 0401 is that Arg(156) has a "one-ballot veto" function in peptide binding, due to its flexible side chain. S-OIV(NW9) and Ebola(AY9) bind SLA-1 0401 with similar conformations but employ different water molecules to stabilize their binding. The side chain of P7 residues in both peptides is exposed, indicating that the epitopes are "featured" peptides presented by this SLA. Further analyses showed that SLA-1 0401 and human leukocyte antigen (HLA) class I HLA-A 0101 can present the same peptides, but in different conformations, demonstrating cross-species epitope presentation. CTL epitope peptides derived from 2009 pandemic S-OIV were screened and evaluated by the in vitro refolding method. Three peptides were identified as potential cross-species influenza virus (IV) CTL epitopes. The binding motif of SLA-1 0401 was proposed, and thermostabilities of key peptide-SLA-1 0401 complexes were analyzed by circular dichroism spectra. Our results not only provide the structural basis of peptide presentation by SLA I but also identify some IV CTL epitope peptides. These results will benefit both vaccine development and swine organ-based xenotransplantation.

  12. Crystal Structure of Swine Major Histocompatibility Complex Class I SLA-1*0401 and Identification of 2009 Pandemic Swine-Origin Influenza A H1N1 Virus Cytotoxic T Lymphocyte Epitope Peptides ▿

    PubMed Central

    Zhang, Nianzhi; Qi, Jianxun; Feng, Sijia; Gao, Feng; Liu, Jun; Pan, Xiaocheng; Chen, Rong; Li, Qirun; Chen, Zhaosan; Li, Xiaoying; Xia, Chun; Gao, George F.

    2011-01-01

    The presentation of viral epitopes to cytotoxic T lymphocytes (CTLs) by swine leukocyte antigen class I (SLA I) is crucial for swine immunity. To illustrate the structural basis of swine CTL epitope presentation, the first SLA crystal structures, SLA-1*0401, complexed with peptides derived from either 2009 pandemic H1N1 (pH1N1) swine-origin influenza A virus (S-OIVNW9; NSDTVGWSW) or Ebola virus (EbolaAY9; ATAAATEAY) were determined in this study. The overall peptide–SLA-1*0401 structures resemble, as expected, the general conformations of other structure-solved peptide major histocompatibility complexes (pMHC). The major distinction of SLA-1*0401 is that Arg156 has a “one-ballot veto” function in peptide binding, due to its flexible side chain. S-OIVNW9 and EbolaAY9 bind SLA-1*0401 with similar conformations but employ different water molecules to stabilize their binding. The side chain of P7 residues in both peptides is exposed, indicating that the epitopes are “featured” peptides presented by this SLA. Further analyses showed that SLA-1*0401 and human leukocyte antigen (HLA) class I HLA-A*0101 can present the same peptides, but in different conformations, demonstrating cross-species epitope presentation. CTL epitope peptides derived from 2009 pandemic S-OIV were screened and evaluated by the in vitro refolding method. Three peptides were identified as potential cross-species influenza virus (IV) CTL epitopes. The binding motif of SLA-1*0401 was proposed, and thermostabilities of key peptide–SLA-1*0401 complexes were analyzed by circular dichroism spectra. Our results not only provide the structural basis of peptide presentation by SLA I but also identify some IV CTL epitope peptides. These results will benefit both vaccine development and swine organ-based xenotransplantation. PMID:21900158

  13. Cytotoxic T lymphocytes elicited by dendritic cell-targeted delivery of human papillomavirus type-16 E6/E7 fusion gene exert lethal effects on CaSki cells.

    PubMed

    Wu, Xiang-Mei; Liu, Xing; Jiao, Qing-Fang; Fu, Shao-Yue; Bu, You-Quan; Song, Fang-Zhou; Yi, Fa-Ping

    2014-01-01

    Human papillomavirus (HPV) is the primary etiologic agent of cervical cancer. Consideration of safety and non human leukocyte antigen restriction, protein vaccine has become the most likely form of HPV therapeutic vaccine, although none have so far been reported as effective. Since tumor cells consistently express the two proteins E6 and E7, most therapeutic vaccines target one or both of them. In this study, we fabricated DC vaccines by transducing replication-defective recombinant adenoviruses expressing E6/E7 fusion gene of HPV-16, to investigate the lethal effects of specific cytotoxic T lymphocytes (CTL) against CaSki cells in vitro. Mouse immature dendritic cells (DC) were generated from bone marrow, and transfected with pAd-E6/E7 to prepare a DC vaccine and to induce specific CTL. The surface expression of CD40, CD68, MHC II and CD11c was assessed by flow cytometry (FCM), and the lethal effects of CTL against CaSki cells were determined by DAPI, FCM and CCK-8 methods. Immature mouse DC was successfully transfected by pAd-E6/E7 in vitro, and the transfecting efficiency was 40%-50%. A DC vaccine was successfully prepared and was used to induce specific CTL. Experimental results showed that the percentage of apoptosis and killing rate of CaSki cells were significantly increased by coculturing with the specific CTL (p <0.05). These results illustrated that a DC vaccine modified by HPV-16 E6/E7 gene can induce apoptosis of CaSki cells by inducing CTL, which may be used as a new strategy for biological treatment of cervical cancer.

  14. Molecular basis of viral persistence: a single amino acid change in the glycoprotein of lymphocytic choriomeningitis virus is associated with suppression of the antiviral cytotoxic T-lymphocyte response and establishment of persistence.

    PubMed Central

    Salvato, M; Borrow, P; Shimomaye, E; Oldstone, M B

    1991-01-01

    Isolates of lymphocytic choriomeningitis virus (LCMV) that elicit a cytotoxic T-lymphocyte response (CTL+) have been compared with isolates that suppress the CTL response (CTL-) in an effort to map this phenotype. A single amino acid change in the glycoprotein of the LCMV Armstrong (ARM) strain is consistently associated with the CTL- trait and the ability of the virus to persist (P+). The CTL+ P- parental strain spontaneously gives rise to CTL- P+ variants within lymphoid tissues of mice persistently infected from birth. To map the structural basis of the phenotype, the complete RNA sequence of LCMV ARM 53b (CTL+) was compared with that of its variant ARM clone 13 (CTL-). Differences in 5 of 10,600 nucleotides were found. Three changes are noted in the large L RNA segment, and two are noted in the small S RNA segment. Only two of the changes distinguishing CTL+ from CTL- isolates affect amino acid coding: lysine to glutamine at amino acid 1079 of the polymerase protein, and phenylalanine to leucine at amino acid 260 of the envelope glycoprotein (GP). We also analyzed two additional CTL- variants and four spontaneous CTL+ revertants. All three CTL- variants differ from the original CTL+ parental strain at GP amino acid 260, indicating that this amino acid change is consistently associated with the CTL- phenotype. By contrast the other four mutations in LCMV are not associated with the CTL- phenotype. Sequence analysis of the coding regions of four CTL+ revertants of ARM clone 13 did not reveal back mutations at the GP 260 locus. This finding indicates that the GP 260 mutation is necessary but not sufficient for a CTL- P+ phenotype and that the reversion to CTL+ P- is likely either due to secondary mutations in other regions of the viral genome or to quasispecies within the revertant population that make significant contributions to the phenotype. Images PMID:1840619

  15. Characterization of cloned class I MHC-restricted, CD8+ anti-Meth A cytotoxic T-lymphocytes: recognition of an epitope derived from the Meth A gp110 tumor rejection antigen.

    PubMed

    Fassanito, M A; Loftus, D; De Leo, R M; Law, L W; Appella, E; De Leo, A B

    1994-08-15

    Meth A gp110 has been tentatively identified as a tumor rejection antigen. Following isolation of a class I major histocompatibility complex (MHC)-restricted, CD8+ anti-Meth A cytotoxic T-lymphocyte (CTL), we sought to determine whether the determinant recognized by this CTL was: (a) functional in tumor rejection of Meth A sarcoma; and (b) derived from Meth A gp110. Initially, we isolated an anti-Meth A CTL-resistant variant of Meth A sarcoma, Meth A4R, by immunoselection. The results of the subsequent analysis of Meth A4R cells showed the CTL-defined determinant as having a functional role in transplantation rejection of Meth A sarcoma. Walker et al. (Proc. Natl. Acad. Sci. USA, 89: 7915-7918, 1993) showed that the cationic lipid, N-[1-(2,3-dioleoyloxy)propyl]-N,N,N- trimethylammonium-methyl sulfate, mediated delivery of a recombinant glycoprotein into the cytosol of target cells, making it available for processing and presentation by class I MHC molecules. As a result, the cells were sensitized for cytolysis by a class I MHC-restricted CD8+ CTL, which recognized an epitope expressed by the glycoprotein. In a similar manner, we treated the SV40-transformed BALB/c cell line, SVBalb, which is relatively insensitive to cytolysis by the anti-Meth A CTL, with Meth A gp110 and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl sulfate. The sensitivities of the treated cells and control cell lines to the anti-Meth A CTL were then examined. The results of these experiments permit us to conclude that the determinant recognized by the anti-Meth A CTL line is derived from Meth A gp110.

  16. Preinfection human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes failed to prevent HIV type 1 infection from strains genetically unrelated to viruses in long-term exposed partners.

    PubMed

    Liu, Yi; Woodward, Amanda; Zhu, Haiying; Andrus, Thomas; McNevin, John; Lee, Jean; Mullins, James I; Corey, Lawrence; McElrath, M Juliana; Zhu, Tuofu

    2009-10-01

    Understanding the mechanisms underlying potential altered susceptibility to human immunodeficiency virus type 1 (HIV-1) infection in highly exposed seronegative (ES) individuals and the later clinical consequences of breakthrough infection can provide insight into strategies to control HIV-1 with an effective vaccine. From our Seattle ES cohort, we identified one individual (LSC63) who seroconverted after over 2 years of repeated unprotected sexual contact with his HIV-1-infected partner (P63) and other sexual partners of unknown HIV-1 serostatus. The HIV-1 variants infecting LSC63 were genetically unrelated to those sequenced from P63. This may not be surprising, since viral load measurements in P63 were repeatedly below 50 copies/ml, making him an unlikely transmitter. However, broad HIV-1-specific cytotoxic T-lymphocyte (CTL) responses were detected in LSC63 before seroconversion. Compared to those detected after seroconversion, these responses were of lower magnitude and half of them targeted different regions of the viral proteome. Strong HLA-B27-restricted CTLs, which have been associated with disease control, were detected in LSC63 after but not before seroconversion. Furthermore, for the majority of the protein-coding regions of the HIV-1 variants in LSC63 (except gp41, nef, and the 3' half of pol), the genetic distances between the infecting viruses and the viruses to which he was exposed through P63 (termed the exposed virus) were comparable to the distances between random subtype B HIV-1 sequences and the exposed viruses. These results suggest that broad preinfection immune responses were not able to prevent the acquisition of HIV-1 infection in LSC63, even though the infecting viruses were not particularly distant from the viruses that may have elicited these responses.

  17. Differential T cell receptor photoaffinity labeling among H-2Kd restricted cytotoxic T lymphocyte clones specific for a photoreactive peptide derivative. Labeling of the alpha-chain correlates with J alpha segment usage

    PubMed Central

    1993-01-01

    Using a direct binding assay based on photoaffinity labeling, we studied the interaction of T cell receptor (TCR) with a Kd-bound photoreactive peptide derivative on living cells. The Kd-restricted Plasmodium berghei circumsporozoite (PbCS) peptide 253-260 (YIPSAEKI) was reacted NH2-terminally with biotin and at the TCR contact residue Lys259 with photoreactive iodo, 4-azido salicylic acid (IASA) to make biotin-YIPSAEK(IASA)I. Cytotoxic T lymphocyte (CTL) clones derived from mice immunized with this derivative recognized this conjugate, but not a related one lacking the IASA group nor the parental PbCS peptide. The clones were Kd restricted. Recognition experiments with variant conjugates, lacking substituents from IASA, revealed a diverse fine specificity pattern and indicated that this group interacted directly with the TCR. The TCR of four clones could be photoaffinity labeled by biotin-YIPSAEK(125IASA)I. This labeling was dependent on the conjugates binding to the Kd molecule and was selective for the TCR alpha (2 clones) or beta chain (1 clone), or was common for both chains (1 clone). TCR sequence analysis showed a preferential usage of J alpha TA28 containing alpha chains that were paired with V beta 1 expressing beta chains. The TCR that were photoaffinity labeled at the alpha chain expressed these J alpha and V beta segments. The tryptophan encoded by the J alpha TA28 segment is rarely found in other J alpha segments. Moreover, we show that the IASA group interacts preferentially with tryptophan in aqueous solution. We thus propose that for these CTL clones, labeling of the alpha chain occurs via the J alpha-encoded tryptophan residue. PMID:8478607

  18. Cytotoxic T-lymphocyte-associated protein 4 +49A/G polymorphisms contribute to the risk of type 1 diabetes in children: An updated systematic review and meta-analysis with trial sequential analysis.

    PubMed

    Wang, Bo; Du, Wei; Jia, Yutao; Zhang, Xiaobai; Ma, Guorui

    2017-02-07

    Type 1 diabetes (T1D) is a heritable disease associated with multiple genetic variants. This systematic review and meta-analysis assessed the correlation between cytotoxic T-lymphocyte-associated protein 4(CTLA-4) +49A/G polymorphisms and the risk of T1D in children. The random effects model was used to estimate the related odds ratios (ORs) and 95% confidence intervals (CIs). Trial sequential analysis (TSA) was used to determine whether the currently available evidence was sufficient and conclusive. Our results indicated that CTLA-4 gene polymorphisms significantly increased the risk of childhood T1D in an allelic model (G vs. A: OR=1.33, 95%CI=1.19-1.48; I2=44.0% and P=0.001for heterogeneity) and a codominant model (GG vs. AA: OR=1.75, 95%CI=1.37-2.24; I2=57.5% and P=0.001for heterogeneity; GA vs. AA: OR=1.26, 95%CI=1.09-1.46; I2=40.4% and P=0.036for heterogeneity). Subgroup analysis results indicated that the ORs were higher in the Asian population (ORallelic model=1.60, ORGG vs. AA=2.46 and ORGA vs. AA=1.58) than the Caucasian population (ORallelic model==1.24, ORGG vs. AA=1.55 and ORGA vs. AA=1.19). The TSA results indicated that the evidence of the effect was sufficient. In conclusion, CTLA4 +49A/G polymorphisms increased the risk of T1D in children, and CTLA4 +49A/G can be considered to be a genetic marker for T1D in children.

  19. Deletion mutation analysis of the adenovirus type 2 E3-gp19K protein: identification of sequences within the endoplasmic reticulum lumenal domain that are required for class I antigen binding and protection from adenovirus-specific cytotoxic T lymphocytes.

    PubMed Central

    Hermiston, T W; Tripp, R A; Sparer, T; Gooding, L R; Wold, W S

    1993-01-01

    Adenovirus E3-gp19K is a transmembrane glycoprotein, localized in the endoplasmic reticulum (ER), which forms a complex with major histocompatibility complex (MHC) class I antigens and retains them in the ER, thereby preventing cytolysis by cytotoxic T lymphocytes (CTL). The ER lumenal domain of gp19K, residues 1 to 107, is known to be sufficient for binding to class I antigens; the transmembrane and cytoplasmic ER retention domains are located at residues ca. 108 to 127 and 128 to 142, respectively. To identify more precisely which gp19K regions are involved in binding to class I antigens, we constructed 13 in-frame virus deletion mutants (4 to 12 amino acids deleted) in the ER lumenal domain of gp19K, and we analyzed the ability of the mutant proteins to form a complex with class I antigens, retain them in the ER, and prevent cytolysis by adenovirus-specific CTL. All mutant proteins except one (residues 102 to 107 deleted) were defective for these properties, indicating that the ability of gp19K to bind to class I antigens is highly sensitive to mutation. All mutant proteins were stable and were retained in the ER. Sequence comparisons among adenovirus serotypes reveal that the ER lumenal domain of gp19K consists of a variable region (residues 1 to 76) and a conserved region (residues 77 to 98). We show, using the mutant proteins, that the gp19K-specific monoclonal antibody Tw1.3 recognizes a noncontiguous epitope in the variable region and that disruption of the variable region by deletion destroys the epitope. The monoclonal antibody and class I antigen binding results, together with the serotype sequence comparisons, are consistent with the idea that the ER lumenal domain of gp19K has three subdomains that we have termed the ER lumenal variable domain (residues 1 to ca. 77 to 83), the ER lumenal conserved domain (residues ca. 84 to 98), and the ER lumenal spacer domain (residues 99 to 107). We suggest that the ER lumenal variable domain of gp19K has a specific

  20. Analysis of the human env-specific cytotoxic T-lymphocyte (CTL) response in natural human immunodeficiency virus type 1 infection: low prevalence of broadly cross-reactive env-specific CTL.

    PubMed Central

    Carmichael, A; Jin, X; Sissons, P

    1996-01-01

    Major histocompatibility complex-restricted cytotoxic T lymphocytes (CTL) are part of the cellular immune response to persistent virus infections. Candidate vaccines against human immunodeficiency virus type 1 (HIV-1) should elicit broad cross-reactive immunity to confer protection against different strains of HIV-1. As it is likely that candidate vaccines will include the envelope gene product Env, we determined the proportion of CTL clones which recognized variable and conserved determinants in three env variants during natural infection. Limiting dilution analysis was used to characterize numerous short-term CTL clones derived from peripheral blood of HIV-1-infected subjects, using split-well analysis to assay cytotoxicity against target cells expressing gp160env of HIV-1 strains IIIB, MN, and RF. In 9 of 12 HIV-1-infected subjects, at the clonal level most env-specific CTL recognized determinant(s) within one env variant but not in the other variants. In some subjects, CTL recognized multiple nonconserved determinants in different variants. The pattern of recognition of different env variants was relatively stable over time. In most of the patients studied, the proportion of CTL which showed cross-recognition of conserved determinants shared among the three strains was low. Two novel CTL epitopes within gp41 were identified by using 15-mer peptides of the HIV-SF2 sequence. When specific peptide was used to stimulate CTL precursors in vitro, the frequency of peptide-specific CTL precursors was very high, but the CTL elicited by this stimulation were highly strain specific. We conclude that the use of a single HIV env variant to detect CTL activity can underestimate the magnitude and complexity of the env-specific CTL response. The low prevalence of CTL clones which show cross-recognition of conserved determinants may have implications for immunization strategies based solely on env; to elicit broadly cross-reactive CTL other, more conserved viral antigens are

  1. Rapid induction of false memory for pictures.

    PubMed

    Weinstein, Yana; Shanks, David R

    2010-07-01

    Recognition of pictures is typically extremely accurate, and it is thus unclear whether the reconstructive nature of memory can yield substantial false recognition of highly individuated stimuli. A procedure for the rapid induction of false memories for distinctive colour photographs is proposed. Participants studied a set of object pictures followed by a list of words naming those objects, but embedded in the list were names of unseen objects. When subsequently shown full colour pictures of these unseen objects, participants consistently claimed that they had seen them, while discriminating with high accuracy between studied pictures and new pictures whose names did not appear in the misleading word list. These false memories can be reported with high confidence as well as the feeling of recollection. This new procedure allows the investigation of factors that influence false memory reports with ecologically valid stimuli and of the similarities and differences between true and false memories.

  2. Optogenetic Induction of Aversive Taste Memory

    PubMed Central

    C. Keene, Alex; Masek, Pavel

    2013-01-01

    The Drosophila melanogaster gustatory system consists of several neuronal pathways representing diverse taste modalities. The two predominant modalities are a sweet sensing pathway that mediates attraction, and a bitter sensing pathway that mediates avoidance. A central question is how flies integrate stimuli from these pathways and generate the appropriate behavioral response. We have developed a novel assay for induction of taste memories. We demonstrate that the gustatory response to fructose is suppressed when followed by the presence of bitter quinine. We employ optogenetic neural activation using infrared laser in combination with heat sensitive channel - TRPA1 to precisely activate gustatory neurons. This optogenetic system allows for spatially and temporally controlled activation of distinct neural classes in the gustatory circuit. We directly activated bitter-sensing neurons together with presentation of fructose for remote induction of aversive taste memories. Here we report that activation of bitter-sensing neurons in the proboscis suffices as a conditioning stimulus. Spatially restricted stimulation indicates that the conditioning stimulus is indeed a signal from the bitter neurons in the proboscis and it is independent of postingestive feedback. The coincidence of temporally specific activation of bitter-sensing neurons with fructose presentation is crucial for memory formation, establishing aversive taste learning in Drosophila as associative learning. Taken together, this optogenetic system provides a powerful new tool for interrogation of the central brain circuits that mediate memory formation. PMID:22820051

  3. Comparison of adjuvant formulations for cytotoxic T cell induction using synthetic peptides.

    PubMed

    Hioe, C E; Qiu, H; Chend, P D; Bian, Z; Li, M L; Li, J; Singh, M; Kuebler, P; McGee, P; O'Hagan, D; Zamb, T; Koff, W; Allsopp, C; Wang, C Y; Nixon, D F

    1996-04-01

    We have investigated the capacity of synthetic peptides delivered in different adjuvant formulations to induce cytotoxic T lymphocyte (CTL) responses to a class I H-2Kd-restricted Plasmodium berghei circumsporozoite epitope, CS 252-260. Using three immunogen formulations: soybean emulsion; Montanide ISA720; and lipopeptide (P3-CS), we first evaluated the effects of immunization routes on CTL induction. No CTL response was induced in mice immunized s.c. or i.p. with CS peptide formulated in soybean emulsion. In contrast, immunization with lipopeptide P3-CS either s.c. or i.p. effectively primed for CTL. Interestingly, CS peptide emulsified in Montanide ISA720 induced a CTL response only when delivered s.c. and not i.p., indicating the critical influence of immunization routes on CTL induction. We then compared the effectiveness of eight adjuvant formulations to induce CTL response following a single s.c. immunization. Notably, lipopeptide P3-CS and CS peptide admixed with P3 or POE lipid molecules stimulated a vigorous CTL response. However, only mice immunized with P3-CS and CS peptide admixed with P3 molecule generated long-lived CTL which persisted in vivo for 5 months. Thus, based on a simultaneous comparison of the different adjuvant formulations, we demonstrated that the conjugated and unconjugated P3 lipopeptides were the most effective immunogens for eliciting primary and memory CTL in mice.

  4. Nasal Immunization of Mice with Human Papillomavirus Type 16 (HPV-16) Virus-Like Particles or with the HPV-16 L1 Gene Elicits Specific Cytotoxic T Lymphocytes in Vaginal Draining Lymph Nodes

    PubMed Central

    Dupuy, Catherine; Buzoni-Gatel, Dominique; Touzé, Antoine; Bout, Daniel; Coursaget, Pierre

    1999-01-01

    Human papillomavirus type 16 (HPV-16) infects the genital tract and is closely associated with the development of cervical cancer. HPV-16 initiates infection at the genital mucosal surface; thus, mucosal immune responses are likely to contribute to defense against HPV-16 infection. However, little information is available regarding the induction of immune responses in the genital tract mucosa. In this study, we evaluated the potential of intranasally administered papillomavirus vaccines to elicit both systemic and vaginal immune responses. HPV-16 virus-like particles (VLPs) produced by self-assembly of L1 protein and the HPV-16 L1 gene cloned into a mammalian expression vector were used as vaccines. Intranasally administered VLPs induced serum immunoglobulin G (IgG) and vaginal IgA secretory antibodies. Very weak serum IgG and vaginal IgA responses were found after DNA immunization. Both splenic and vaginal lymphocytes could be activated by intranasal immunization with VLPs and the HPV-16 L1 gene. Activated CD4+ Th1-like T cells were shown to synthesize gamma interferon, and activated CD8+ T cells were demonstrated to be cytotoxic. PMID:10516012

  5. The Relationship between Memory and Inductive Reasoning: Does It Develop?

    ERIC Educational Resources Information Center

    Hayes, Brett K.; Fritz, Kristina; Heit, Evan

    2013-01-01

    In 2 studies, the authors examined the development of the relationship between inductive reasoning and visual recognition memory. In both studies, 5- to 6-year-old children and adults were shown instances of a basic-level category (dogs) followed by a test set containing old and new category members that varied in their similarity to study items.…

  6. How similar are recognition memory and inductive reasoning?

    PubMed

    Hayes, Brett K; Heit, Evan

    2013-07-01

    Conventionally, memory and reasoning are seen as different types of cognitive activities driven by different processes. In two experiments, we challenged this view by examining the relationship between recognition memory and inductive reasoning involving multiple forms of similarity. A common study set (members of a conjunctive category) was followed by a test set containing old and new category members, as well as items that matched the study set on only one dimension. The study and test sets were presented under recognition or induction instructions. In Experiments 1 and 2, the inductive property being generalized was varied in order to direct attention to different dimensions of similarity. When there was no time pressure on decisions, patterns of positive responding were strongly affected by property type, indicating that different types of similarity were driving recognition and induction. By comparison, speeded judgments showed weaker property effects and could be explained by generalization based on overall similarity. An exemplar model, GEN-EX (GENeralization from EXamples), could account for both the induction and recognition data. These findings show that induction and recognition share core component processes, even when the tasks involve flexible forms of similarity.

  7. The relationship between memory and inductive reasoning: does it develop?

    PubMed

    Hayes, Brett K; Fritz, Kristina; Heit, Evan

    2013-05-01

    In 2 studies, the authors examined the development of the relationship between inductive reasoning and visual recognition memory. In both studies, 5- to 6-year-old children and adults were shown instances of a basic-level category (dogs) followed by a test set containing old and new category members that varied in their similarity to study items. Participants were given either recognition instructions (memorize study items and discriminate between old and new test items) or induction instructions (learn about a novel property shared by the study items and decide whether it generalizes to test items). Across both tasks, children made a greater number of positive responses than did adults. Across both age groups, a greater number of positive responses were made in induction than in recognition. The application of a mathematical model, called GEN-EX for generalization from examples, showed that both memory and reasoning data could be explained by a single exemplar-based process that assumes task and age differences in generalization gradients. These results show considerable developmental continuity in the cognitive processes that underlie memory and inductive reasoning.

  8. Nicotine inhibits memory CTL programming.

    PubMed

    Sun, Zhifeng; Smyth, Kendra; Garcia, Karla; Mattson, Elliot; Li, Lei; Xiao, Zhengguo

    2013-01-01

    Nicotine is the main tobacco component responsible for tobacco addiction and is used extensively in smoking and smoking cessation therapies. However, little is known about its effects on the immune system. We confirmed that multiple nicotinic receptors are expressed on mouse and human cytotoxic T lymphocytes (CTLs) and demonstrated that nicotinic receptors on mouse CTLs are regulated during activation. Acute nicotine presence during activation increases primary CTL expansion in vitro, but impairs in vivo expansion after transfer and subsequent memory CTL differentiation, which reduces protection against subsequent pathogen challenges. Furthermore, nicotine abolishes the regulatory effect of rapamycin on memory CTL programming, which can be attributed to the fact that rapamycin enhances expression of nicotinic receptors. Interestingly, naïve CTLs from chronic nicotine-treated mice have normal memory programming, which is impaired by nicotine during activation in vitro. In conclusion, simultaneous exposure to nicotine and antigen during CTL activation negatively affects memory development.

  9. When development and learning decrease memory. Evidence against category-based induction in children.

    PubMed

    Sloutsky, Vladimir M; Fisher, Anna V

    2004-08-01

    Inductive inference is crucial for learning: If one learns that a cat has a particular biological property, one could expand this knowledge to other cats. We argue that young children perform induction on the basis of similarity of compared entities, whereas adults may induce on the basis of category information. If different processes underlie induction at different points in development, young children and adults would form different memory traces during induction, and would subsequently have different memory accuracy. Experiment 1 demonstrates that after performing an induction task, 5-year-olds exhibit more accurate memory than adults. Experiment 2 indicates that after 5-year-olds are trained to perform induction in an adultlike manner, their memory accuracy drops to the level of adults. These results, indicating that sometimes 5-year-olds exhibit better memory than adults, support the claim that, unlike adults, young children perform similarity-based rather than category-based induction.

  10. Induction of potent CD8+ T-cell responses by novel biodegradable nanoparticles carrying human immunodeficiency virus type 1 gp120.

    PubMed

    Wang, Xin; Uto, Tomofumi; Akagi, Takami; Akashi, Mitsuru; Baba, Masanori

    2007-09-01

    The mainstream of recent anti-AIDS vaccines is a prime/boost approach with multiple doses of the target DNA of human immunodeficiency virus type 1 (HIV-1) and recombinant viral vectors. In this study, we have attempted to construct an efficient protein-based vaccine using biodegradable poly(gamma-glutamic acid) (gamma-PGA) nanoparticles (NPs), which are capable of inducing potent cellular immunity. A significant expansion of CD8+ T cells specific to the major histocompatibility complex class I-restricted gp120 epitope was observed in mice intranasally immunized once with gp120-carrying NPs but not with gp120 alone or gp120 together with the B-subunit of cholera toxin. Both the gp120-encapsulating and -immobilizing forms of NPs could induce antigen-specific spleen CD8+ T cells having a functional profile of cytotoxic T lymphocytes. Long-lived memory CD8+ T cells could also be elicited. Although a substantial decay in the effector memory T cells was observed over time in the immunized mice, the central memory T cells remained relatively constant from day 30 to day 238 after immunization. Furthermore, the memory CD8+ T cells rapidly expanded with boosting with the same immunogen. In addition, gamma-PGA NPs were found to be a much stronger inducer of antigen-specific CD8+ T-cell responses than nonbiodegradable polystyrene NPs. Thus, gamma-PGA NPs carrying various HIV-1 antigens may have great potential as a novel priming and/or boosting tool in current vaccination regimens for the induction of cellular immune responses.

  11. Inductive reasoning and implicit memory: evidence from intact and impaired memory systems.

    PubMed

    Girelli, Luisa; Semenza, Carlo; Delazer, Margarete

    2004-01-01

    In this study, we modified a classic problem solving task, number series completion, in order to explore the contribution of implicit memory to inductive reasoning. Participants were required to complete number series sharing the same underlying algorithm (e.g., +2), differing in both constituent elements (e.g., 2468 versus 57911) and correct answers (e.g., 10 versus 13). In Experiment 1, reliable priming effects emerged, whether primes and targets were separated by four or ten fillers. Experiment 2 provided direct evidence that the observed facilitation arises at central stages of problem solving, namely the identification of the algorithm and its subsequent extrapolation. The observation of analogous priming effects in a severely amnesic patient strongly supports the hypothesis that the facilitation in number series completion was largely determined by implicit memory processes. These findings demonstrate that the influence of implicit processes extends to higher level cognitive domain such as induction reasoning.

  12. A Toll-like receptor 2 agonist-fused antigen enhanced antitumor immunity by increasing antigen presentation and the CD8 memory T cells population

    PubMed Central

    Wu, Chiao-Chieh; Liu, Shih-Jen; Chen, Hsin-Wei; Shen, Kuan-Yin; Leng, Chih-Hsiang

    2016-01-01

    The induction of long-lived effector CD8+ T cells is key to the development of efficient cancer vaccines. In this study, we demonstrated that a Toll-like receptor 2 (TLR2) agonist-fused antigen increased antigen presentation via TLR2 signaling and induced effector memory-like CD8+ T cells against cancer after immunization. The N-terminus of ovalbumin (OVA) was biologically fused with a bacterial lipid moiety TLR2 agonist to produce a recombinant lipidated ovalbumin (rlipo-OVA). We demonstrated that rlipo-OVA activated bone marrow-derived dendritic cells (BM-DCs) maturation and increased antigen presentation by major histocompatibility complex (MHC) class I via TLR2. After immunization, rlipo-OVA skewed the immune response towards T helper (Th) 1 and induced OVA-specific cytotoxic T lymphocyte (CTL) responses. Moreover, immunization with rlipo-OVA induced higher numbers of effector memory (CD44+CD62L−) CD8+ T cells compared with recombinant ovalbumin (rOVA) alone or rOVA mixed with the TLR2 agonist Pam3CSK4. Accordingly, the CD27+CD43+ effector memory CD8+ T cells expressed high levels of the long-lived CD127 marker. The administration of rlipo-OVA could inhibit tumor growth, but the anti-tumor effects were lost after the depletion of CD8 or CD127 cells in vivo. These findings suggested that the TLR2 agonist-fused antigen induced long-lived memory CD8+ T cells for efficient cancer therapy. PMID:27127171

  13. Inflammasome-Dependent Induction of Adaptive NK Cell Memory.

    PubMed

    van den Boorn, Jasper G; Jakobs, Christopher; Hagen, Christian; Renn, Marcel; Luiten, Rosalie M; Melief, Cornelis J M; Tüting, Thomas; Garbi, Natalio; Hartmann, Gunther; Hornung, Veit

    2016-06-21

    Monobenzone is a pro-hapten that is exclusively metabolized by melanocytes, thereby haptenizing melanocyte-specific antigens, which results in cytotoxic autoimmunity specifically against pigmented cells. Studying monobenzone in a setting of contact hypersensitivity (CHS), we observed that monobenzone induced a long-lasting, melanocyte-specific immune response that was dependent on NK cells, yet fully intact in the absence of T- and B cells. Consistent with the concept of "memory NK cells," monobenzone-induced NK cells resided in the liver and transfer of these cells conferred melanocyte-specific immunity to naive animals. Monobenzone-exposed skin displayed macrophage infiltration and cutaneous lymph nodes showed an inflammasome-dependent influx of macrophages with a tissue-resident phenotype, coinciding with local NK cell activation. Indeed, macrophage depletion or the absence of the NLRP3 inflammasome, the adaptor protein ASC or interleukin-18 (IL-18) abolished monobenzone CHS, thereby establishing a non-redundant role for the NLRP3 inflammasome as a critical proinflammatory checkpoint in the induction of hapten-dependent memory NK cells.

  14. Immunoproteasome induction is suppressed in hepatitis C virus-infected cells in a protein kinase R-dependent manner

    PubMed Central

    Oh, In Soo; Textoris-Taube, Kathrin; Sung, Pil Soo; Kang, Wonseok; Gorny, Xenia; Kähne, Thilo; Hong, Seon-Hui; Choi, Young Joon; Cammann, Clemens; Naumann, Michael; Kim, Jong Hoon; Park, Su-Hyung; Yoo, Ook Joon; Kloetzel, Peter M; Seifert, Ulrike; Shin, Eui-Cheol

    2016-01-01

    By changing the relative abundance of generated antigenic peptides through alterations in the proteolytic activity, interferon (IFN)-γ-induced immunoproteasomes influence the outcome of CD8+ cytotoxic T lymphocyte responses. In the present study, we investigated the effects of hepatitis C virus (HCV) infection on IFN-γ-induced immunoproteasome expression using a HCV infection cell culture system. We found that, although IFN-γ induced the transcriptional expression of mRNAs encoding the β1i/LMP2, β2i/MECL-1 and β5i/LMP7 immunoproteasome subunits, the formation of immunoproteasomes was significantly suppressed in HCV-infected cells. This finding indicated that immunoproteasome induction was impaired at the translational or posttranslational level by HCV infection. Gene silencing studies showed that the suppression of immunoproteasome induction is essentially dependent on protein kinase R (PKR). Indeed, the generation of a strictly immunoproteasome-dependent cytotoxic T lymphocyte epitope was impaired in in vitro processing experiments using isolated 20S proteasomes from HCV-infected cells and was restored by the silencing of PKR expression. In conclusion, our data point to a novel mechanism of immune regulation by HCV that affects the antigen-processing machinery through the PKR-mediated suppression of immunoproteasome induction in infected cells. PMID:27833096

  15. Creativity and Memory: Effects of an Episodic-Specificity Induction on Divergent Thinking.

    PubMed

    Madore, Kevin P; Addis, Donna Rose; Schacter, Daniel L

    2015-09-01

    People produce more episodic details when imagining future events and solving means-end problems after receiving an episodic-specificity induction-brief training in recollecting details of a recent event-than after receiving a control induction not focused on episodic retrieval. Here we show for the first time that an episodic-specificity induction also enhances divergent creative thinking. In Experiment 1, participants exhibited a selective boost on a divergent-thinking task (generating unusual uses of common objects) after a specificity induction compared with a control induction; by contrast, performance following the two inductions was similar on an object association task thought to involve little divergent thinking. In Experiment 2, we replicated the specificity-induction effect on divergent thinking using a different control induction, and also found that participants performed similarly on a convergent-thinking task following the two inductions. These experiments provide novel evidence that episodic memory is involved in divergent creative thinking.

  16. Creativity and Memory: Effects of an Episodic Specificity Induction on Divergent Thinking

    PubMed Central

    Madore, Kevin P.; Addis, Donna Rose; Schacter, Daniel L.

    2015-01-01

    After receiving an episodic specificity induction - brief training in recollecting details of a recent event - people produce more episodic details when imagining future events and solving means-end problems than after receiving a control induction not focused on episodic retrieval. Here we show for the first time that an episodic specificity induction also enhances divergent creative thinking. In Experiment 1, participants exhibited a selective boost on a divergent thinking task that involves generating unusual uses of common objects after a specificity induction compared with a control induction; by contrast, performance was similar on an object association task thought to involve little divergent thinking. In Experiment 2, we replicated the specificity induction effect on divergent thinking using a different control induction, and also found that participants performed similarly on a convergent thinking task following both inductions. These experiments provide novel evidence that episodic memory is involved in divergent creative thinking. PMID:26205963

  17. CSI (Crime Scene Induction): Creating False Memories of Committing Crime.

    PubMed

    Porter, Stephen B; Baker, Alysha T

    2015-12-01

    We describe two merging lines of empirical inquiry: entire false memories for autobiographical events and false confessions. A recent study showed that people can be led to remember, and confess to, perpetrating serious crimes that never occurred when confronted with suggestive interview tactics commonly used in police interrogations.

  18. Pharmacologic Induction of CD8+ T Cell Memory: Better Living Through Chemistry

    PubMed Central

    Gattinoni, Luca; Klebanoff, Christopher A.; Restifo, Nicholas P.

    2011-01-01

    The generation of a robust population of memory T cells is critical for effective vaccine and cell-based therapies to prevent and treat infectious diseases and cancer. A series of recent papers have established a new, cell-intrinsic approach in which small molecules target key metabolic and developmental pathways to enhance the formation and maintenance of highly functional CD8+ memory T cells. These findings raise the exciting new possibility of using small molecules, many of which are already approved for human use, for the pharmacologic induction of immunologic memory. PMID:20371454

  19. The Velten Mood Induction Procedure: Effects on Mood and Memory.

    ERIC Educational Resources Information Center

    Riskind, John H.; And Others

    1982-01-01

    Examined the hypothesis that the self-devaluative aspects of the Velton Mood Induction Procedure (VMIP) do not lower mood but that the depression-related somatic states of the VMIP do lower mood. Found that both aspects of the VMIP have a powerful impact on mood. (Author/RC)

  20. INFLUENCE OF EXPOSURE HISTORY ON VITELLOGENIN INDUCTION IN MEDAKA: A CASE OF "ESTROGEN MEMORY"?

    EPA Science Inventory

    Influence of Exposure History on Vitellogenin Induction in Medaka: a Case of "Estrogen Memory"? (Abstract). Mar. Environ. Res. 50(1-5):196.

    In this study, we exposed female medaka to aqueous solutions of o,p'-DDT until tissues residues reached approximately 100 g/g. Male...

  1. Noninvasive induction implant heating: an approach for contactless altering of mechanical properties of shape memory implants.

    PubMed

    Pfeifer, Ronny; Hustedt, Michael; Wesling, Volker; Hurschler, Christoph; Olender, Gavin; Mach, Martin; Gösling, Thomas; Müller, Christian W

    2013-01-01

    This article shows an approach to change the properties of an orthopaedic shape memory implant within biological tissue, using contactless induction heating. Due to inducing the one way-memory effect, triggered by the rise of temperature within the implant, the geometry and hence the mechanical properties of the implant itself, are altered. The power uptake of the implant, depending on the induction parameters as well as on its position within the induction coil, is shown. Thermographic measurements are carried out in order to determine the surface temperature distribution of the implant. In order to simulate biological tissue, the implant was embedded in agarose gel. Suitable heating parameters, in terms of a short heating process in combination with a reduced heat impact on the surrounding environment, were determined.

  2. Depressive symptoms moderate the effects of a self-discrepancy induction on overgeneral autobiographical memory.

    PubMed

    Smets, Jorien; Griffith, James W; Wessel, Ineke; Walschaerts, Dominique; Raes, Filip

    2013-01-01

    According to the CaRFAX model, rumination is one of the key underlying mechanisms of overgeneral autobiographical memory (OGM). The association between rumination and OGM is well established in clinical populations, but this relationship is not robust in nonclinical samples. A series of null findings is reported in the current paper. Additionally we followed up on recent findings suggesting that a state of rumination needs to be active in order to detect a relationship between trait-rumination and OGM. Secondary school students (N= 123) completed questionnaires assessing trait-rumination and depressive symptoms as well as two autobiographical memory tests (AMTs), one before and one after a self-discrepancy induction. This induction should trigger state-rumination, which would subsequently promote the retrieval of general rather than specific memories. Trait-rumination failed to predict increases in OGM. We did find, however, that higher BDI-II scores were positively related to an increase in OGM following the induction. This adds to the growing body of evidence that OGM reactivity might be more important than baseline memory specificity.

  3. Effective induction of anti-tumor immunity using p5 HER-2/neu derived peptide encapsulated in fusogenic DOTAP cationic liposomes co-administrated with CpG-ODN.

    PubMed

    Mansourian, Mercedeh; Badiee, Ali; Jalali, Seyed Amir; Shariat, Sheida; Yazdani, Mona; Amin, Mohamdreza; Jaafari, Mahmoud Reza

    2014-11-01

    Cationic liposomes have been used as efficient antigen delivery systems for cancer vaccination. The current study has investigated whether the incorporation of the helper-fusogenic lipid dioleoylphosphatidylethanolamine (DOPE) in cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium propane (DOTAP)-cholesterol enhances the cytosolic delivery of p5 HER-2/neu derived peptide (p5) and promotes cytotoxic T lymphocytes (CTL) response. The p5, which is a very hydrophobic peptide, was encapsulated into liposomes by using three different methods and characterized for their colloidal properties. A chaotropic loading method using 7 M urea provided the highest encapsulation yields. Mice were first immunized with encapsulated p5 in liposomes composed of either DOTAP-cholesterol or DOTAP-cholesterol-DOPE, alone or co-administered with CpG-ODN, as an immunoadjuvant, then, inoculated with a subcutaneous injection of TUBO tumor cells. Results obtained from enzyme-linked immunospot, cytotoxicity and intracellular cytokine assays as well as tumor sizes and animal survival analysis demonstrated that p5 encapsulated in DOTAP-cholesterol-DOPE liposomes co-administered with CpG-ODN greatly enhanced the cytotoxic T lymphocytes response and highly inhibited the tumor progression. The outperformance of DOTAP-cholesterol-DOPE liposomes+CpG-ODN was found to be attributed to its capability in induction of both CD8+ and CD4+ responses. This formulation could be a suitable vaccine candidate against Her2 positive cancers and merits further investigations.

  4. Do Development and Learning Really Decrease Memory? On Similarity and Category-Based Induction in Adults and Children

    ERIC Educational Resources Information Center

    Wilburn, Catherine; Feeney, Aidan

    2008-01-01

    In a recently published study, Sloutsky and Fisher [Sloutsky, V. M., & Fisher, A.V. (2004a). When development and learning decrease memory: Evidence against category-based induction in children. "Psychological Science", 15, 553-558; Sloutsky, V. M., & Fisher, A. V. (2004b). Induction and categorization in young children: A similarity-based model.…

  5. Electromagnetic induction heating of an orthopaedic nickel--titanium shape memory device.

    PubMed

    Müller, Christian W; Pfeifer, Ronny; El-Kashef, Tarek; Hurschler, Christof; Herzog, Dirk; Oszwald, Markus; Haasper, Carl; Krettek, Christian; Gösling, Thomas

    2010-12-01

    Shape memory orthopaedic implants made from nickel-titanium (NiTi) might allow the modulation of fracture healing, changing their cross-sectional shape by employing the shape memory effect. We aimed to show the feasibility and safety of contact-free electromagnetic induction heating of NiTi implants in a rat model. A water-cooled generator-oscillator combination was used. Induction characteristics were determined by measuring the temperature increase of a test sample in correlation to generator power and time. In 53 rats, NiTi implants were introduced into the right hind leg. The animals were transferred to the inductor, and the implant was electromagnetically heated to temperatures between 40 and 60°C. Blood samples were drawn before and 4 h after the procedure. IL-1, IL-4, IL-10, TNF-α, and IFN-γ were measured. Animals were euthanized at 3 weeks. Histological specimens from the hind leg and liver were retrieved and examined for inflammatory changes, necrosis, and corrosion pits. Cytokine measurements and histological specimens showed no significant differences among the groups. We concluded that electromagnetic induction heating of orthopedic NiTi implants is feasible and safe in a rat model. This is the first step in the development of new orthopedic implants in which stiffness or rigidity can be modified after implantation to optimize bone-healing.

  6. Identification of HLA-A*0201-restricted cytotoxic T lymphocyte epitope from proliferating cell nuclear antigen.

    PubMed

    Xu, Wei; Li, Hui-Zhong; Liu, Jun-Jie; Guo, Zhen; Zhang, Bao-Fu; Chen, Fei-Fei; Pei, Dong-Sheng; Zheng, Jun-Nian

    2011-02-01

    Peptide-based immunotherapy strategies appear promising as an approach to successfully induce an antitumor immune response and prolong survival in patients with various cancers. Protein antigens and their specific epitopes are formulation targets for anti-tumor vaccines. Bioinformatical approaches to predict major histocompatibility complex binding peptides can facilitate the resource-consuming effort of T cell epitope identification. Proliferating cell nuclear antigen including Ki-67 and PCNA, associated with the proliferation process of the cell, seems to be an attractive new target for tumor-specific immunotherapy. In this study, we predicted seven HLA-A*0201-restricted CTL candidate epitope of Ki-67 and eight epitope of PCNA by computer algorithm SYFPEITHI, BIMAS, and IEDB_ANN. Subsequently, biological functions of these peptides were tested by experiments in vitro. We found Ki-67((280-288)) (LQGETQLLV) had the strongest binding-affinity with HLA-A*0201. Further study revealed that Ki-67((280-288)) increased the frequency of IFN-γ-producing T cells compared to a negative peptide. Because Ki-67 was broadly expressed in most advanced malignant tumors, indicating a potential anti-tumor application in the future.

  7. Identification and Characterization of Ovarian Carcinoma Peptide Epitopes Recognized by Cytotoxic T Lymphocytes

    DTIC Science & Technology

    2006-11-01

    restricted response from two of six different donors. The peptide sensitized targets for lysis at 1 to 20 nM, indicating that these CTL had receptors ...Immunoediting. Annu Rev Immunol 2004;22(1):329-60. 2. Lollini PL, Cavallo F, Nanni P, Forni G . Vaccines for tumour prevention. Nature Reviews...number? Curr Opin Immunol 2005;17(3):320-5. 6. Parmiani G , Castelli C, Rivoltini L, et al. Immunotherapy of melanoma. Semin Cancer Biol 2003;13(6

  8. A Well-Controlled Experimental System to Study Interactions of Cytotoxic T Lymphocytes with Tumor Cells

    PubMed Central

    Neubert, Natalie J.; Soneson, Charlotte; Barras, David; Baumgaertner, Petra; Rimoldi, Donata; Delorenzi, Mauro; Fuertes Marraco, Silvia A.; Speiser, Daniel E.

    2016-01-01

    While T cell-based immunotherapies are steadily improving, there are still many patients who progress, despite T cell-infiltrated tumors. Emerging evidence suggests that T cells themselves may provoke immune escape of cancer cells. Here, we describe a well-controlled co-culture system for studying the dynamic T cell – cancer cell interplay, using human melanoma as a model. We explain starting material, controls, and culture parameters to establish reproducible and comparable cultures with highly heterogeneous tumor cells. Low passage melanoma cell lines and melanoma-specific CD8+ T cell clones generated from patient blood were cultured together for up to 3 days. Living melanoma cells were isolated from the co-culture system by fluorescence-activated cell sorting. We demonstrate that the characterization of isolated melanoma cells is feasible using flow cytometry for protein expression analysis as well as an Agilent whole human genome microarray and the NanoString technology for differential gene expression analysis. In addition, we identify five genes (ALG12, GUSB, RPLP0, KRBA2, and ADAT2) that are stably expressed in melanoma cells independent of the presence of T cells or the T cell-derived cytokines IFNγ and TNFα. These genes are essential for correct normalization of gene expression data by NanoString. Further to the characterization of melanoma cells after exposure to CTLs, this experimental system might be suitable to answer a series of questions, including how the affinity of CTLs for their target antigen influences the melanoma cell response and whether CTL-induced gene expression changes in melanoma cells are reversible. Taken together, our human T cell – melanoma cell culture system is well suited to characterize immune-related mechanisms in cancer cells. PMID:27625650

  9. Immunotherapy of cancer via mediation of cytotoxic T lymphocytes by methionine enkephalin (MENK).

    PubMed

    Li, Weiwei; Chen, Wenna; Herberman, Ronald B; Plotnikoff, Nicolas P; Youkilis, Gene; Griffin, Noreen; Wang, Enhua; Lu, Changlong; Shan, Fengping

    2014-03-28

    The aim of this study was to investigate the immunological mechanisms by which synthetic methionine enkephalin (MENK) exerts therapeutic effects on tumor growth. Our findings in vivo or in vitro show that MENK treatment either in vivo or in vitro could up-regulate the percentages of CD8+T cells, induce markers of activated T cells, increased cytotoxic activity against mouse S180 tumor cells and increase secretion of IFNγ. In addition, the adoptively transferred CD8+T cells, after either in vitro or in vivo treatment with MENK, result in significantly increased survival of S180 tumor-bearing mice and significant shrinkage in tumor growth. Opioid receptors are detected on normal CD8+T cells and exposure to MENK leads to increased expression of opioid receptors. Interaction between MENK and the opioid receptors on CD8+T cells appears to be essential for the activation of CTL, since the addition of naltrexone (NTX), an opioid receptor antagonist, significantly inhibits all of the effects of MENK. The evidence obtained indicates that the MENK-induced T cell signaling is associated with a significant up-regulation of Ca2+ influx into the cytoplasm and the translocation of NFAT2 into nucleus, and these signaling effects are also inhibited by naltrexone.

  10. Protection from Ebola Virus Mediated by Cytotoxic T Lymphocytes Specific for the Viral Nucleoprotein

    DTIC Science & Technology

    2001-03-01

    be required for optimal protection from Ebola virus. Ebola viruses are associated with outbreaks of highly lethal hemorrhagic fever in humans and...nonhuman primates. The Ebola Zaire viruses responsible for outbreaks of human dis- ease in 1976 and 1995 had case-fatality rates of greater than 80...encoding the Ebola virus NP protein (12, 13) or with a control replicon encoding Lassa virus N (14). For booster vaccinations, animals 2660 VOL

  11. Identification and Characterization of Ovarian Carcinoma Peptide Epitopes Recognized by Cytotoxic T Lymphocytes

    DTIC Science & Technology

    2007-11-01

    class II MHC molecules as determined by their ability to bind the class II MHC -specific mAb, L243 (Fig. 2 ). Most lines do not...express class II MHC molecules, although low expression was detected on CAOV-3, CAOV-4, OVCAR-3, SW626, and a subpopulation of ES- 2 . This indicates that...representative of a minimum of two independent experiments for each cell line. 22 Fig. 2 Class I and class II MHC

  12. Cytotoxic T lymphocyte antigen-4 (CTLA-4) A49G polymorphism and autoimmune blood diseases.

    PubMed

    Aktürk, Faruk; Hançer, Veysel Sabri; Küçükkaya, Reyhan

    2010-06-05

    AMAÇ: Sitotoksik T lenfosit antijen-4 (CTLA-4) ifadesi T lenfositlerde gerçekleşir ve T hücre cevabını engeller. Hayvan modellerinde CTLA-4 yokluğunun, dokuların poliklonal çoğalan lenfositler tarafından yoğun infiltrasyonu nedeni ile, ölümcül olduğu gösterilmiştir. Farklı otoimmün hastalıklar ile ilişkilendirilmiş CTLA-4 A49G polimorfizminin, CTLA-4 molekülünün inhibitör fonksiyonunu azalttığı düşünülmektedir. YÖNTEMLER: Bu çalışmada otoimmun hemolitik anemi (OIHA) hastası 46 kişi, immun trombositopenik purpura (ITP) hastası 62 kişi ve 150 sağlıklı kontrol bireyinde CTLA-4 A49G polimorfizmi çalışılmıştır.

  13. Activation of antitumor cytotoxic T lymphocytes by fusions of human dendritic cells and breast carcinoma cells

    PubMed Central

    Gong, Jianlin; Avigan, David; Chen, Dongshu; Wu, Zekui; Koido, Shigeo; Kashiwaba, Masahiro; Kufe, Donald

    2000-01-01

    We have reported that fusions of murine dendritic cells (DCs) and murine carcinoma cells reverse unresponsiveness to tumor-associated antigens and induce the rejection of established metastases. In the present study, fusions were generated with primary human breast carcinoma cells and autologous DCs. Fusion cells coexpressed tumor-associated antigens and DC-derived costimulatory molecules. The fusion cells also retained the functional potency of DCs and stimulated autologous T cell proliferation. Significantly, the results show that autologous T cells are primed by the fusion cells to induce MHC class I-dependent lysis of autologous breast tumor cells. These findings demonstrate that fusions of human breast cancer cells and DCs activate T cell responses against autologous tumors. PMID:10688917

  14. A Well-Controlled Experimental System to Study Interactions of Cytotoxic T Lymphocytes with Tumor Cells.

    PubMed

    Neubert, Natalie J; Soneson, Charlotte; Barras, David; Baumgaertner, Petra; Rimoldi, Donata; Delorenzi, Mauro; Fuertes Marraco, Silvia A; Speiser, Daniel E

    2016-01-01

    While T cell-based immunotherapies are steadily improving, there are still many patients who progress, despite T cell-infiltrated tumors. Emerging evidence suggests that T cells themselves may provoke immune escape of cancer cells. Here, we describe a well-controlled co-culture system for studying the dynamic T cell - cancer cell interplay, using human melanoma as a model. We explain starting material, controls, and culture parameters to establish reproducible and comparable cultures with highly heterogeneous tumor cells. Low passage melanoma cell lines and melanoma-specific CD8+ T cell clones generated from patient blood were cultured together for up to 3 days. Living melanoma cells were isolated from the co-culture system by fluorescence-activated cell sorting. We demonstrate that the characterization of isolated melanoma cells is feasible using flow cytometry for protein expression analysis as well as an Agilent whole human genome microarray and the NanoString technology for differential gene expression analysis. In addition, we identify five genes (ALG12, GUSB, RPLP0, KRBA2, and ADAT2) that are stably expressed in melanoma cells independent of the presence of T cells or the T cell-derived cytokines IFNγ and TNFα. These genes are essential for correct normalization of gene expression data by NanoString. Further to the characterization of melanoma cells after exposure to CTLs, this experimental system might be suitable to answer a series of questions, including how the affinity of CTLs for their target antigen influences the melanoma cell response and whether CTL-induced gene expression changes in melanoma cells are reversible. Taken together, our human T cell - melanoma cell culture system is well suited to characterize immune-related mechanisms in cancer cells.

  15. Recognition of cloned vesicular stomatitis virus internal and external gene products by cytotoxic T lymphocytes

    PubMed Central

    1986-01-01

    It has generally been assumed that most if not all CTL specific for vesicular stomatitis virus (VSV)-infected cells recognize the viral glycoprotein (G), an integral membrane protein abundantly expressed on infected cell surfaces. Using recombinant vaccinia viruses containing copies of cloned VSV genes to examine CTL recognition of VSV, we have confirmed that G is recognized by VSV-specific CTL. More interestingly, however, we have also found that nucleocapsid protein (N), an internal virion protein, can be detected on infected cell surfaces using mAb, and serves as a major target antigen for VSV-specific CTL. In contrast to the highly serotype-specific recognition of G, N is recognized by a major population of CTL able to lyse cells infected with either the Indiana or New Jersey VSV serotypes. Using target cells expressing a cloned MHC class I gene, we could directly show that CTL recognition of N occurs in the context of the MHC Ld molecule. PMID:3011949

  16. Cytotoxic T Lymphocytes Induced by Liposomal Antigens: Mechanisms of Immunological Presentation

    DTIC Science & Technology

    1994-01-01

    CLASSIFICATION OF THIS PAGE C AIS RESEARCH AND HUMAN RETROVIRUSES Vobme 10, Supplement 2, 194 Mary Am Usbew laný Puirtsen Novel Vaccines and Adjuvants...incorporated into phospholipid vesicles 38. White WI. Cassatt DR. Madsen J, Burke Si, Woods RM. Wassef elicit specific allogeneic cytotoxic T

  17. Prediction and identification of mouse cytotoxic T lymphocyte epitopes in Ebola virus glycoproteins

    PubMed Central

    2012-01-01

    Background Ebola viruses (EBOVs) cause severe hemorrhagic fever with a high mortality rate. At present, there are no licensed vaccines or efficient therapies to combat EBOV infection. Previous studies have shown that both humoral and cellular immune responses are crucial for controlling Ebola infection. CD8+ T cells play an important role in mediating vaccine-induced protective immunity. The objective of this study was to identify H-2d-specific T cell epitopes in EBOV glycoproteins (GPs). Results Computer-assisted algorithms were used to predict H-2d-specific T cell epitopes in two species of EBOV (Sudan and Zaire) GP. The predicted peptides were synthesized and identified in BALB/c mice immunized with replication-deficient adenovirus vectors expressing the EBOV GP. Enzyme-linked immunospot assays and intracellular cytokine staining showed that the peptides RPHTPQFLF (Sudan EBOV), GPCAGDFAF and LYDRLASTV (Zaire EBOV) could stimulate splenoctyes in immunized mice to produce large amounts of interferon-gamma. Conclusion Three peptides within the GPs of two EBOV strains were identified as T cell epitopes. The identification of these epitopes should facilitate the evaluation of vaccines based on the Ebola virus glycoprotein in a BALB/c mouse model. PMID:22695180

  18. Marking hypoxic cells for complement and cytotoxic T lymphocyte-mediated lysis: using pimonidazole.

    PubMed Central

    Chou, S. C.; Flood, P. M.; Raleigh, J. A.

    1996-01-01

    Artificial antigens are created when 2-nitroimidazoles bind to hypoxic cells. These antigens have been used in the immunodetection of tumour hypoxia but they might also serve to stimulate immune lysis of hypoxic tumour cells by complement- and cell-mediated processes. In order to test this hypothesis, lymphocytes isolated from the spleens of C3H/HeN mice that had been immunised with pimonidazole-labelled 3152-PRO cells were subcultured and tested for their ability to lyse chromium-51 loaded, pimonidazole-labelled 3152-PRO cells in an in vitro assay. In a parallel study, commercially available, rabbit complement was tested for its ability to lyse pimonidazole-labelled V79-4 cells in the presence of monoclonal antibodies which recognise protein adducts of reductively activated pimonidazole. Complement-mediated cell lysis was measured by means of an MTT assay. Complement-mediated and cell-mediated lysis was observed at pimonidazole concentrations which, in themselves, do not produce cell killing. PMID:8763883

  19. A validated model for induction heating of shape memory alloy actuators

    NASA Astrophysics Data System (ADS)

    Saunders, Robert N.; Boyd, James G.; Hartl, Darren J.; Brown, Jonathan K.; Calkins, Frederick T.; Lagoudas, Dimitris C.

    2016-04-01

    Shape memory alloy (SMA) actuators deliver high forces while being compact and reliable, making them ideal for consideration in aerospace applications. One disadvantage of these thermally driven actuators is their slow cyclic time response compared to conventional actuators. Induction heating has recently been proposed to quickly heat SMA components. However efforts to date have been purely empirical. The present work approachs this problem in a computational manner by developing a finite element model of induction heating in which the time-harmonic electromagnetic equations are solved for the Joule heat power field, the energy equation is solved for the temperature field, and the linear momentum equations are solved to find the stress, displacement, and internal state variable fields. The combined model was implemented in Abaqus using a Python script approach and applied to SMA torque tube and beam actuators. The model has also been used to examine magnetic flux concentrators to improve the induction systems performance. Induction heating experiments were performed using the SMA torque tube, and the model agreed well with the experiments.

  20. Reward improves long-term retention of a motor memory through induction of offline memory gains

    PubMed Central

    Abe, Mitsunari; Schambra, Heidi; Wassermann, Eric M; Luckenbaugh, Dave; Schweighofer, Nicolas; Cohen, Leonardo G

    2011-01-01

    Summary In humans, training in which good performance is rewarded or bad performance punished results in transient behavioral improvements [1–3]. Their relative effects on consolidation and long-term retention, critical behavioral stages for successful learning [4, 5], are not known. Here, we investigated the effects of reward and punishment on these different stages of human motor skill learning. We studied healthy subjects who trained on a motor task under rewarded, punished, or neutral control conditions. Performance was tested before, and immediately, 6 hs, 24 hs and 30 days after training in the absence of reward or punishment. Performance improvements immediately after training were comparable in the three groups. At 6 hs, the rewarded group maintained performance gains while the other two groups experienced significant forgetting. At 24 hs, the reward group showed significant offline (posttraining) improvements while the other two groups did not. At 30 days, the rewarded group retained the gains identified at 24 hs, while the other two groups experienced significant forgetting. We conclude that training under rewarded conditions is more effective than training under punished or neutral conditions in eliciting lasting motor learning, an advantage driven by offline memory gains that persist over time. PMID:21419628

  1. The phosphatase SHP2 regulates the spacing effect for long-term memory induction.

    PubMed

    Pagani, Mario R; Oishi, Kimihiko; Gelb, Bruce D; Zhong, Yi

    2009-10-02

    A property of long-term memory (LTM) induction is the requirement for repeated training sessions spaced over time. This augmentation of memory formation with spaced resting intervals is called the spacing effect. We now show that in Drosophila, the duration of resting intervals required for inducing LTM is regulated by activity levels of the protein tyrosine phosphatase corkscrew (CSW). Overexpression of wild-type CSW in mushroom body neurons shortens the inter-trial interval required for LTM induction, whereas overexpression of constitutively active CSW proteins prolongs these resting intervals. These gain-of-function csw mutations are associated with a clinical condition of mental retardation. Biochemical analysis reveals that LTM-inducing training regimens generate repetitive waves of CSW-dependent MAPK activation, the length of which appears to define the duration of the resting interval. Constitutively active CSW proteins prolong the resting interval by altering the MAPK inactivation cycle. We thus provide insight into the molecular basis of the spacing effect.

  2. Inductively Heated Shape Memory Polymer for the Magnetic Actuation of Medical Devices

    SciTech Connect

    Buckley, P; Mckinley, G; Wilson, T; Small, W; Benett, W; Bearinger, J; McElfresh, M; Maitland, D

    2005-09-06

    Presently there is interest in making medical devices such as expandable stents and intravascular microactuators from shape memory polymer (SMP). One of the key challenges in realizing SMP medical devices is the implementation of a safe and effective method of thermally actuating various device geometries in vivo. A novel scheme of actuation by Curie-thermoregulated inductive heating is presented. Prototype medical devices made from SMP loaded with Nickel Zinc ferrite ferromagnetic particles were actuated in air by applying an alternating magnetic field to induce heating. Dynamic mechanical thermal analysis was performed on both the particle-loaded and neat SMP materials to assess the impact of the ferrite particles on the mechanical properties of the samples. Calorimetry was used to quantify the rate of heat generation as a function of particle size and volumetric loading of ferrite particles in the SMP. These tests demonstrated the feasibility of SMP actuation by inductive heating. Rapid and uniform heating was achieved in complex device geometries and particle loading up to 10% volume content did not interfere with the shape recovery of the SMP.

  3. Inductively heated shape memory polymer for the magnetic actuation of medical devices.

    PubMed

    Buckley, Patrick R; McKinley, Gareth H; Wilson, Thomas S; Small, Ward; Benett, William J; Bearinger, Jane P; McElfresh, Michael W; Maitland, Duncan J

    2006-10-01

    Presently, there is interest in making medical devices such as expandable stents and intravascular microactuators from shape memory polymer (SMP). One of the key challenges in realizing SMP medical devices is the implementation of a safe and effective method of thermally actuating various device geometries in vivo. A novel scheme of actuation by Curie-thermoregulated inductive heating is presented. Prototype medical devices made from SMP loaded with nickel zinc ferrite ferromagnetic particles were actuated in air by applying an alternating magnetic field to induce heating. Dynamic mechanical thermal analysis was performed on both the particle-loaded and neat SMP materials to assess the impact of the ferrite particles on the mechanical properties of the samples. Calorimetry was used to quantify the rate of heat generation as a function of particle size and volumetric loading of ferrite particles in the SMP. These tests demonstrated the feasibility of SMP actuation by inductive heating. Rapid and uniform heating was achieved in complex device geometries and particle loading up to 10% volume content did not interfere with the shape recovery of the SMP.

  4. Induction of latent memory for conditioned food aversion and its transformation into "active" state depend on translation and transcription processes.

    PubMed

    Solntseva, S V; Nikitin, V P

    2014-05-01

    Mechanisms of induction and retrieval of latent (hidden) memory for conditioned food aversion were investigated in snails. After initial training (single combination of a food stimulus with electric shock), aversive reactions to presentation of the conditioned food stimulus were not revealed. Repeated presentation of the stimuli in 12 days after the first combination was followed by the appearance of aversive food reactions that persisted for at least 14 days. Injections of inhibitors of protein (cycloheximide) or RNA (α-amanitin) synthesis immediately after the first or second combined presentation of the stimuli disturbed skill performance. We hypothesized that single combination of food and reinforcing stimuli led to translation- and transcription-dependent induction of latent conditioned food aversion memory. Transformation of this memory into an active state after repeated presentation of the stimulus combination also depends on the synthesis of new proteins and RNA.

  5. Cancer-reactive memory T cells from bone marrow: Spontaneous induction and therapeutic potential (Review).

    PubMed

    Schirrmacher, Volker

    2015-12-01

    Cognate interactions between naïve tumor antigen (TA)-specific T cells and TA-presenting dendritic cells (DCs) are facilitated by secondary lymphoid organs such as lymph nodes or the spleen. These can result either in TA-specific tolerance or, depending on environmental costimulatory signals, in TA-specific immune responses. In the present review, we describe such events for the bone marrow (BM) when blood-borne TA, released from the primary tumor or expressed by blood circulating tumor cells or DCs enters the BM stroma and parenchyma. We argue that cognate T-DC interactions in the BM result in immune responses and generation of memory T cells (MTCs) rather than tolerance because T cells in the BM show an increased level of pre-activation. The review starts with the spontaneous induction of cancer-reactive MTCs in the BM and the involvement of such MTCs in the control of tumor dormancy. The main part deals with the therapeutic potency of BM MTCs. This is a new area of research in which the authors research group has performed pioneering studies which are summarized. These include studies in animal tumor models, studies with human cells in tumor xenotransplant models and clinical studies. Based on observations of an enormous expansion capacity, longevity and therapeutic capacity of BM MTCs, a hypothesis is presented which suggests the involvement of stem-like MTCs.

  6. ECM components guide IL-10 producing regulatory T-cell (TR1) induction from effector memory T-cell precursors.

    PubMed

    Bollyky, Paul L; Wu, Rebecca P; Falk, Ben A; Lord, James D; Long, S Alice; Preisinger, Anton; Teng, Brandon; Holt, Gregory E; Standifer, Nathan E; Braun, Kathleen R; Xie, Cindy Fang; Samuels, Peter L; Vernon, Robert B; Gebe, John A; Wight, Thomas N; Nepom, Gerald T

    2011-05-10

    We describe a role for ECM as a biosensor for inflammatory microenvironments that plays a critical role in peripheral immune tolerance. We show that hyaluronan (HA) promotes induction of Foxp3- IL-10-producing regulatory T cells (TR1) from conventional T-cell precursors in both murine and human systems. This is, to our knowledge, the first description of an ECM component inducing regulatory T cells. Intact HA, characteristic of healing tissues, promotes induction of TR1 capable of abrogating disease in an IL-10-dependent mouse colitis model whereas fragmentary HA, typical of inflamed tissues, does not, indicating a decisive role for tissue integrity in this system. The TR1 precursor cells in this system are CD4(+)CD62L(-)FoxP3(-), suggesting that effector memory cells assume a regulatory phenotype when they encounter their cognate antigen in the context of intact HA. Matrix integrity cues might thereby play a central role in maintaining peripheral tolerance. This TR1 induction is mediated by CD44 cross-linking and signaling through p38 and ERK1/2. This induction is suppressed, also in a CD44-dependent manner, by osteopontin, a component of chronically inflamed ECM, indicating that CD44 signaling serves as a nexus for fate decisions regarding TR1 induction. Finally, we demonstrate that TR1 induction signals can be recapitulated using synthetic matrices. These results reveal important roles for the matrix microenvironment in immune regulation and suggest unique strategies for immunomodulation.

  7. HLA-DPB1*05: 01-restricted WT1332-specific TCR-transduced CD4+ T lymphocytes display a helper activity for WT1-specific CTL induction and a cytotoxicity against leukemia cells.

    PubMed

    Lin, Yuhung; Fujiki, Fumihiro; Katsuhara, Akiko; Oka, Yoshihiro; Tsuboi, Akihiro; Aoyama, Nao; Tanii, Satoe; Nakajima, Hiroko; Tatsumi, Naoya; Morimoto, Soyoko; Tamanaka, Taichi; Tachino, Sho; Hosen, Naoki; Nishida, Sumiyuki; Oji, Yusuke; Kumanogoh, Atsushi; Sugiyama, Haruo

    2013-04-01

    Wilms tumor gene 1 (WT1) is overexpressed in various malignant neoplasms, and has been demonstrated as an attractive target for cancer immunotherapy. We previously reported the identification of a WT1 protein-derived, 16-mer helper peptide WT1332 that could elicit Th1-type CD4+ T-cell response and bind to multiple HLA class II molecules. In this study, we examined the feasibility of adoptive therapy using CD4+ T cells that were transduced an HLA-DPB1*05:01-restricted, WT1332-specific T-cell receptor (TCR). HLA-DPB1*05:01-restricted, WT1332-specific TCR-transduced CD4+ T cells were successfully generated using lentiviral vector and exhibited strong proliferative response and Th1-type cytokine production in response to WT1332 peptide, WT1 protein, or WT1-expressing tumor cell lysate. Furthermore, the WT1332-specific TCR-transduced CD4+ T cells lysed HLA-DPB1*05:01-positive, WT1-expressing human leukemia cells through granzyme B/perforin pathway. Furthermore, stimulation of peripheral blood mononuclear cells with both HLA-A*24:02-restricted cytotoxic T lymphocytes-epitope peptide (modified 9-mer WT1235 peptide, WT1235m) and WT1332 helper peptide in the presence of WT1332-specific TCR-transduced CD4+ T cells strikingly enhanced the induction of WT1235m-specific cytotoxic T lymphocytes. Thus, these results demonstrated the feasibility of immunotherapy based on adoptive transfer of WT1332-specific TCR-transduced CD4+ T cells for the treatment of leukemia.

  8. The induction of antigen-specific CTL by in situ Ad-REIC gene therapy.

    PubMed

    Ariyoshi, Y; Watanabe, M; Eikawa, S; Yamazaki, C; Sadahira, T; Hirata, T; Araki, M; Ebara, S; Nasu, Y; Udono, H; Kumon, H

    2016-05-01

    An adenovirus vector carrying the human Reduced Expression in Immortalized Cell (REIC)/Dkk-3 gene (Ad-REIC) mediates simultaneous induction of cancer-selective apoptosis and augmentation of anticancer immunity. In our preclinical and clinical studies, in situ Ad-REIC gene therapy showed remarkable direct and indirect antitumor effects to realize therapeutic cancer vaccines. We herein aimed to confirm the induction of tumor-associated antigen-specific cytotoxic T lymphocytes (CTLs) by Ad-REIC. Using an ovalbumin (OVA), a tumor-associated antigen, expressing E.G7 tumor-bearing mouse model, we investigated the induction and expansion of OVA-specific CTLs responsible for indirect, systemic effects of Ad-REIC. The intratumoral administration of Ad-REIC mediated clear antitumor effects with the accumulation of OVA-specific CTLs in the tumor tissues and spleen. The CD86-positive dendritic cells (DCs) were upregulated in the tumor draining lymph nodes of Ad-REIC-treated mice. In a dual tumor-bearing mouse model in the left and right back, Ad-REIC injection in one side significantly suppressed the tumor growth on both sides and significant infiltration of OVA-specific CTLs into non-injected tumor was also detected. Consequently, in situ Ad-REIC gene therapy is expected to realize a new-generation cancer vaccine via anticancer immune activation with DC and tumor antigen-specific CTL expansion.

  9. Quiescence of Memory CD8(+) T Cells Is Mediated by Regulatory T Cells through Inhibitory Receptor CTLA-4.

    PubMed

    Kalia, Vandana; Penny, Laura Anne; Yuzefpolskiy, Yevgeniy; Baumann, Florian Martin; Sarkar, Surojit

    2015-06-16

    Immune memory cells are poised to rapidly expand and elaborate effector functions upon reinfection yet exist in a functionally quiescent state. The paradigm is that memory T cells remain inactive due to lack of T cell receptor (TCR) stimuli. Here, we report that regulatory T (Treg) cells orchestrate memory T cell quiescence by suppressing effector and proliferation programs through inhibitory receptor, cytotoxic-T-lymphocyte-associated protein-4 (CTLA-4). Loss of Treg cells resulted in activation of genome-wide transcriptional programs characteristic of effector T cells and drove transitioning as well as established memory CD8(+) T cells toward terminally differentiated KLRG-1(hi)IL-7Rα(lo)GzmB(hi) phenotype, with compromised metabolic fitness, longevity, polyfunctionality, and protective efficacy. CTLA-4 functionally replaced Treg cells in trans to rescue memory T cell defects and restore homeostasis. These studies present the CTLA-4-CD28-CD80/CD86 axis as a potential target to accelerate vaccine-induced immunity and improve T cell memory quality in current cancer immunotherapies proposing transient Treg cell ablation.

  10. Processes of DNA methylation are involved in the mechanisms of amnesia induction and conditioned food aversion memory reconsolidation.

    PubMed

    Solntseva, S V; Filatova, T S; Nikitin, P V; Bredov, D V; Kozyrev, S A; Nikitin, V P

    2014-02-01

    We studied the role of DNA methylation in the mechanisms of amnesia in edible snails, which was induced by impairment of conditioned food aversion memory reconsolidation with NMDA glutamate receptor antagonist. The effects of DNA methyltransferase inhibitors were shown to depend on the stage of amnesia. At the early stage of amnesia (day 3 after induction), injections of methyltransferase inhibitors in combination with conditioned food stimulus (reminder) were followed by memory recovery. Application of inhibitors in the absence of the reminder was ineffective. Methyltransferase inhibitors were ineffective at the late stage of amnesia (day 10). Our results suggest that the presentation of reminding conditioned stimuli is followed by reactivation of amnesia. Methylation or demethylation of DNA in nerve cells serves as one of the key mechanisms for amnesia.

  11. ECM components guide IL-10 producing regulatory T-cell (TR1) induction from effector memory T-cell precursors

    PubMed Central

    Bollyky, Paul L.; Wu, Rebecca P.; Falk, Ben A.; Lord, James D.; Long, S. Alice; Preisinger, Anton; Teng, Brandon; Holt, Gregory E.; Standifer, Nathan E.; Braun, Kathleen R.; Xie, Cindy Fang; Samuels, Peter L.; Vernon, Robert B.; Gebe, John A.; Wight, Thomas N.; Nepom, Gerald T.

    2011-01-01

    We describe a role for ECM as a biosensor for inflammatory microenvironments that plays a critical role in peripheral immune tolerance. We show that hyaluronan (HA) promotes induction of Foxp3- IL-10–producing regulatory T cells (TR1) from conventional T-cell precursors in both murine and human systems. This is, to our knowledge, the first description of an ECM component inducing regulatory T cells. Intact HA, characteristic of healing tissues, promotes induction of TR1 capable of abrogating disease in an IL-10–dependent mouse colitis model whereas fragmentary HA, typical of inflamed tissues, does not, indicating a decisive role for tissue integrity in this system. The TR1 precursor cells in this system are CD4+CD62L−FoxP3−, suggesting that effector memory cells assume a regulatory phenotype when they encounter their cognate antigen in the context of intact HA. Matrix integrity cues might thereby play a central role in maintaining peripheral tolerance. This TR1 induction is mediated by CD44 cross-linking and signaling through p38 and ERK1/2. This induction is suppressed, also in a CD44-dependent manner, by osteopontin, a component of chronically inflamed ECM, indicating that CD44 signaling serves as a nexus for fate decisions regarding TR1 induction. Finally, we demonstrate that TR1 induction signals can be recapitulated using synthetic matrices. These results reveal important roles for the matrix microenvironment in immune regulation and suggest unique strategies for immunomodulation. PMID:21518860

  12. Induction of an Olfactory Memory by the Activation of a Metabotropic Glutamate Receptor

    NASA Astrophysics Data System (ADS)

    Kaba, Hideto; Hayashi, Yasunori; Higuchi, Takashi; Nakanishi, Shigetada

    1994-07-01

    Female mice form an olfactory memory of male pheromones at mating; exposure to the pheromones of a strange male after that mating will block pregnancy. The formation of this memory is mediated by the accessory olfactory system, in which an increase in norepinephrine after mating reduces inhibitory transmission of γ-aminobutyric acid from the granule cells to the mitral cells. This study shows that the activation of mGluR2, a metabotropic glutamate receptor that suppresses the γ-aminobutyric acid inhibition of the mitral cells, permits the formation of a specific olfactory memory without the occurrence of mating by infusion of mGluR2 agonists into the female's accessory olfactory bulb. This memory faithfully reflects the memory formed at mating.

  13. Memory

    MedlinePlus

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  14. Chronic stress-induced memory deficits are reversed by regular exercise via AMPK-mediated BDNF induction.

    PubMed

    Kim, D-M; Leem, Y-H

    2016-06-02

    Chronic stress has a detrimental effect on neurological insults, psychiatric deficits, and cognitive impairment. In the current study, chronic stress was shown to impair learning and memory functions, in addition to reducing in hippocampal Adenosine monophosphate-activated protein kinase (AMPK) activity. Similar reductions were also observed for brain-derived neurotrophic factor (BDNF), synaptophysin, and post-synaptic density-95 (PSD-95) levels, all of which was counter-regulated by a regime of regular and prolonged exercise. A 21-day restraint stress regimen (6 h/day) produced learning and memory deficits, including reduced alternation in the Y-maze and decreased memory retention in the water maze test. These effects were reversed post-administration by a 3-week regime of treadmill running (19 m/min, 1 h/day, 6 days/week). In hippocampal primary culture, phosphorylated-AMPK (phospho-AMPK) and BDNF levels were enhanced in a dose-dependent manner by 5-amimoimidazole-4-carboxamide riboside (AICAR) treatment, and AICAR-treated increase was blocked by Compound C. A 7-day period of AICAR intraperitoneal injections enhanced alternation in the Y-maze test and reduced escape latency in water maze test, along with enhanced phospho-AMPK and BDNF levels in the hippocampus. The intraperitoneal injection of Compound C every 4 days during exercise intervention diminished exercise-induced enhancement of memory improvement during the water maze test in chronically stressed mice. Also, chronic stress reduced hippocampal neurogenesis (lower Ki-67- and doublecortin-positive cells) and mRNA levels of BDNF, synaptophysin, and PSD-95. Our results suggest that regular and prolonged exercise can alleviate chronic stress-induced hippocampal-dependent memory deficits. Hippocampal AMPK-engaged BDNF induction is at least in part required for exercise-induced protection against chronic stress.

  15. Memory.

    ERIC Educational Resources Information Center

    McKean, Kevin

    1983-01-01

    Discusses current research (including that involving amnesiacs and snails) into the nature of the memory process, differentiating between and providing examples of "fact" memory and "skill" memory. Suggests that three brain parts (thalamus, fornix, mammilary body) are involved in the memory process. (JN)

  16. Fetal liver T cell receptor gamma/delta+ T cells as cytotoxic T lymphocytes specific for maternal alloantigens

    PubMed Central

    1992-01-01

    We have established fetal liver-derived T cell receptor (TCR) gamma/delta+, CD3+ T cell lines that are cytotoxic for maternal T cells. Fetal liver-derived lymphoid progenitors yielded predominantly TCR-gamma/delta+ cell clusters when cultured on fetal bone marrow- derived stromal cells in the presence of a cytokine cocktail under magnetic force. These tightly adherent clusters were cloned by limiting dilution and the resulting cell lines analyzed for phenotype and function. Six of eight TCR-gamma/delta lines from 8-9.5-wk gestation fetuses were V delta 2+ as compared with zero of eight lines from later stages of gestation (10 and 15 wk), where all the lines were V delta 1+. In cytotoxicity assays, these TCR-gamma/delta+, CD3+, CD4-, and CD8+ or CD8- long-term cultured lymphoid cells (LLC) were killer cells active against the class I antigens on maternal T cells. Of the cell lines, the CD8+ TCR-gamma/delta+ LLC had the highest levels of killer activity. Thus fetal liver TCR-gamma/delta+ T cells may play a crucial role in protection against invading maternal T cells generated in the feto-maternal interaction. PMID:1535364

  17. The prognostic value of cytotoxic T-lymphocyte antigen 4 in cancers: a systematic review and meta-analysis

    PubMed Central

    Hu, Pingping; Liu, Qiqi; Deng, Guodong; Zhang, Jingxin; Liang, Ning; Xie, Jian; Zhang, Jiandong

    2017-01-01

    The outcomes of studies analyzing the prognostic role of CTLA-4 in cancers are controversial. Therefore, the aim of our meta-analysis was to clarify the correlation between CTLA-4 expression and OS in different cancer cases. Relevant literature was searched using PubMed, EMBASE, Web of Science, and the Cochrane Library. The clinicopathological features, hazard ratio (HR) and 95% confidence intervals (CI) were collected from these studies and were analyzed using Stata version 12.0 software. The pooled HR values showed no significant correlation between CTLA-4 expression levels and OS in relation to tumors (HR: 1.24, 95% CI: 0.98–1.56, I2 = 71.7%, P = 0.000). Further subgroup analyses were conducted and categorized by experimental methods, CTLA-4 sources and cancer types. The survey showed a significant correlation (HR: 1.47, 95% CI: 1.14–1.89) between high expression of CTLA-4 and OS in the SNP subgroup, and subgroups analyzing by PCR (HR: 1.50, 95% CI: 1.20–1.86) and flow cytometry (HR: 2.76, 95% CI: 1.49–5.14). In addition, our analysis observed significant differences between patients and controls in inCTLA-4+CD4+ lymphocytes, surCTLA-4+CD4+ lymphocytes, inCTLA-4+CD8+ lymphocytes, and surCTLA-4+CD8+ lymphocytes. Knowledge of the effects of CTLA-4 could potentially be used to effectively guide appropriate prognosis and therapeutic strategies in cancer patients. PMID:28211499

  18. Role of germinal centers for the induction of broadly-reactive memory B cells.

    PubMed

    Takahashi, Yoshimasa; Kelsoe, Garnett

    2017-03-27

    Virus-specific memory B cells (Bmem) play a crucial role in protecting against variant viruses. The ability to recognize these variant viruses, defined as antibody breadth, is achieved in Bmem populations by two very different pathways, germline-encoded cross-reactivity and affinity-driven, somatic evolution in germinal centers (GCs) for conserved viral epitopes. The latter class of broadly-reactive Bmem cells are not cross-reactive per se, but bind epitopes crucial for viral fitness. Although these conserved epitopes are often weakly immunogenic, the GC reaction is surprisingly permissive for the continued survival/proliferation of B cells that bind with low affinity or react to cryptic epitopes, increasing their chance of memory recruitment. In this review, we discuss the adaptive strategies of B-cell memory to viral antigenic variations.

  19. Aging-associated B7-DC+ B cells enhance anti-tumor immunity via Th1 and Th17 induction.

    PubMed

    Tomihara, Kei; Shin, Takako; Hurez, Vincent J; Yagita, Hideo; Pardoll, Drew M; Zhang, Bin; Curiel, Tyler J; Shin, Tahiro

    2012-02-01

    Because most patients with cancer are aged and because immunological functions are altered during aging, it is important to account for aging-associated immunological alterations in the design of new cancer immunotherapies. We thus compared immune populations in young and aged mice and found that B7-DC(+) (PD-L2/CD273) B cells, a minor population in young mice, were significantly increased in aged mice. Induction of both Th1 and Th17 cells was significantly augmented by B7-DC(+) B cells from aged mice, and this effect was blocked with anti-B7-DC antibodies in vitro and in vivo. Moreover, retardation of tumor growth in aged mice was largely B7-DC dependent. Tumor growth in young mice was significantly inhibited by immunization with B7-DC(+) B cells from aged mice owing to increased induction of tumor antigen-specific cytotoxic T lymphocytes. These data indicate that B7-DC(+) B cells could play an important role in aging-associated cancer immunopathology as well as in other aging-associated diseases and further suggest that B7-DC(+) B cells have potential for future cancer immunotherapy.

  20. Memory-enhancing effect of Mori Fructus via induction of nerve growth factor.

    PubMed

    Kim, Hyo Geun; Oh, Myung Sook

    2013-07-14

    Fruits rich in phytochemicals have been shown to improve memory by protecting or enhancing neuronal functions mediated by neurotrophic factors, such as nerve growth factor (NGF), in the hippocampus. Mori Fructus (Morus alba L., Moraceae), also called mulberry, is used as a food, dietary supplement and an anti-ageing agent in traditional Oriental medicine. It is also known to contain abundant flavonoid compounds and to exhibit various pharmacological effects. The present study was performed to evaluate the memory-enhancing effect of Mori Fructus extract (ME) in mice, with a focus on NGF regulation. ME (20, 100 and 500 mg/kg per d for 7 d, per os) dose-dependently promoted NGF release in the mouse hippocampus, leading to phosphorylation of extracellular signal-regulated kinases and cyclic AMP response element-binding protein. ME significantly increased pre- and post-synapse formation, acetylcholine synthesisation, neuronal cell differentiation, neurite outgrowth and neuronal cell proliferation in the mouse hippocampus. Furthermore, ME significantly increased latency time in the passive avoidance task (P< 0·001) and recognition time of novel objects in the object recognition test (P< 0·05), indicating improvements in learning and memory. Taken together, these data suggest that ME exhibits a memory-enhancing effect via up-regulation of NGF.

  1. Pharmacologically regulated induction of silent mutations (PRISM): combined pharmacological and genetic approaches for learning and memory.

    PubMed

    Frankland, Paul W; Ohno, Masuo; Takahashi, Eiki; Chen, Adele R; Costa, Rui M; Kushner, Steven A; Silva, Alcino J

    2003-04-01

    Mouse transgenic and knock-out approaches have made fundamental contributions to our understanding of the molecular and cellular bases of learning and memory. These approaches have successfully identified a large number of molecules with either a central or modulatory role in learning and memory. However, there are limitations associated with first-generation mutant mice, which include, for example, the lack of temporal control over the mutation. Recent technical developments have started to address some of these shortcomings. Here, the authors review a newly developed inducible approach that takes advantage of synergistic interactions between subthreshold genetic and pharmacological manipulations. This approach is easily set up and can be used to study the functional interactions between molecules in signaling pathways.

  2. Immune activation and induction of memory: lessons learned from controlled human malaria infection with Plasmodium falciparum.

    PubMed

    Scholzen, Anja; Sauerwein, Robert W

    2016-02-01

    Controlled human malaria infections (CHMIs) are a powerful tool to assess the efficacy of drugs and/or vaccine candidates, but also to study anti-malarial immune responses at well-defined time points after infection. In this review, we discuss the insights that CHMI trials have provided into early immune activation and regulation during acute infection, and the capacity to induce and maintain immunological memory. Importantly, these studies show that a single infection is sufficient to induce long-lasting parasite-specific T- and B-cell memory responses, and suggest that blood-stage induced regulatory responses can limit inflammation both in ongoing and potentially future infections. As future perspective of investigation in CHMIs, we discuss the role of innate cell subsets, the interplay between innate and adaptive immune activation and the potential modulation of these responses after natural pre-exposure.

  3. Induction of a physiological memory in the cerebral cortex by stimulation of the nucleus basalis.

    PubMed

    Bakin, J S; Weinberger, N M

    1996-10-01

    Auditory cortical receptive field plasticity produced during behavioral learning may be considered to constitute "physiological memory" because it has major characteristics of behavioral memory: associativity, specificity, rapid acquisition, and long-term retention. To investigate basal forebrain mechanisms in receptive field plasticity, we paired a tone with stimulation of the nucleus basalis, the main subcortical source of cortical acetylcholine, in the adult guinea pig. Nucleus basalis stimulation produced electroencephalogram desynchronization that was blocked by systemic and cortical atropine. Paired tone/nucleus basalis stimulation, but not unpaired stimulation, induced receptive field plasticity similar to that produced by behavioral learning. Thus paired activation of the nucleus basalis is sufficient to induce receptive field plasticity, possibly via cholinergic actions in the cortex.

  4. Roles of testosterone and amygdaloid LTP induction in determining sex differences in fear memory magnitude.

    PubMed

    Chen, Li-Shen; Tzeng, Wen-Yu; Chuang, Jia-Ying; Cherng, Chianfang G; Gean, Po-Wu; Yu, Lung

    2014-08-01

    Women are thought to form fear memory more robust than men do and testosterone is suspected to play a role in determining such a sex difference. Mouse cued fear freezing was used to study the sex-related susceptibility and the role of testosterone in fear memory in humans. A 75-dB tone was found to provoke weak freezing, while 0.15-mA and 0.20-mA footshock caused strong freezing responses. No sex differences were noticed in the tone- or footshock-induced (naïve fear) freezing. Following the conditionings, female mice exhibited greater tone (cued fear)-induced freezing than did male mice. Nonetheless, female mice demonstrated indistinctive cued fear freezing across the estrous phases and ovariectomy did not affect such freezing in female mice. Orchidectomy enhanced the cued fear freezing in male mice. Systemic testosterone administrations and an intra-lateral nucleus of amygdala (LA) testosterone infusion diminished the cued fear freezing in orchidectomized male mice, while pretreatment with flutamide (Flu) eradicated these effects. Long-term potentiation (LTP) magnitude in LA has been known to correlate with the strength of the cued fear conditioning. We found that LA LTP magnitude was indeed greater in female than male mice. Orchidectomy enhanced LTP magnitude in males' LA, while ovariectomy decreased LTP magnitude in females' LA. Testosterone decreased LTP magnitude in orchidectomized males' LA and estradiol enhanced LTP magnitude in ovariectomized females' LA. Finally, male mice had lower LA GluR1 expression than female mice and orchidectomy enhanced the GluR1 expression in male mice. These findings, taken together, suggest that testosterone plays a critical role in rendering the sex differences in the cued fear freezing and LA LTP. Testosterone is negatively associated with LA LTP and the cued fear memory in male mice. However, ovarian hormones and LA LTP are loosely associated with the cued fear memory in female mice.

  5. Improving potato drought tolerance through the induction of long-term water stress memory.

    PubMed

    Ramírez, D A; Rolando, J L; Yactayo, W; Monneveux, P; Mares, V; Quiroz, R

    2015-09-01

    Knowledge of drought tolerance in potato is limited and very little is known about stress memory in this crop. In the present study, long-term stress memory was tested on tuber yield and drought tolerance related traits in three potato varieties (Unica, Désirée and Sarnav) with contrasted yields under water restriction. Seed tubers produced by plants grown under non-restricted (non-primed tubers) and restricted (primed tubers) water conditions were sown and exposed to similar watering treatments. Tuber yield and leaf greenness of plants from primed and non-primed seeds as well as tuber carbon isotope discrimination (Δ(13)C) and antioxidant activity (AA) responses to watering treatments were compared. Higher tuber yield, both under non-restricted and restricted water regimes, was produced by primed Sarnav plants. The decrease of tuber yield and Δ(13)C with water restriction was lower in primed Unica plants. Long-term stress memory consequently appears to be highly genotype-dependent in potato. Its expression in plants originated from primed tubers and facing water restriction seems to be positively associated to the degree of inherent capability of the cultivar to yield under water restriction. However, other effects of priming appear to be genotype-independent as priming enhanced the tuber AA in response to water restriction in the three varieties.

  6. Recombinant poxvirus boosting of DNA-primed rhesus monkeys augments peak but not memory T lymphocyte responses.

    PubMed

    Santra, Sampa; Barouch, Dan H; Korioth-Schmitz, Birgit; Lord, Carol I; Krivulka, Georgia R; Yu, Faye; Beddall, Margaret H; Gorgone, Darci A; Lifton, Michelle A; Miura, Ayako; Philippon, Valerie; Manson, Kelledy; Markham, Phillip D; Parrish, John; Kuroda, Marcelo J; Schmitz, Jörn E; Gelman, Rebecca S; Shiver, John W; Montefiori, David C; Panicali, Dennis; Letvin, Norman L

    2004-07-27

    Although a consensus has emerged that an HIV vaccine should elicit a cytotoxic T lymphocyte (CTL) response, the characteristics of an effective vaccine-induced T lymphocyte response remain unclear. We explored this issue in the simian human immunodeficiency virus/rhesus monkey model in the course of assessing the relative immunogenicity of vaccine regimens that included a cytokine-augmented plasmid DNA prime and a boost with DNA or recombinant pox vectors. Recombinant vaccinia virus, recombinant modified vaccinia Ankara (MVA), and recombinant fowlpox were comparable in their immunogenicity. Moreover, whereas the magnitude of the peak vaccine-elicited T lymphocyte responses in the recombinant pox virus-boosted monkeys was substantially greater than that seen in the monkeys immunized with plasmid DNA alone, the magnitudes of recombinant pox boosted CTL responses decayed rapidly and were comparable to those of the DNA-alone-vaccinated monkeys by the time of viral challenge. Consistent with these comparable memory T cell responses, the clinical protection seen in all groups of experimentally vaccinated monkeys was similar. This study, therefore, indicates that the steady-state memory, rather than the peak effector vaccine-elicited T lymphocyte responses, may be the critical immune correlate of protection for a CTL-based HIV vaccine.

  7. Intradermal gene immunization: the possible role of DNA uptake in the induction of cellular immunity to viruses.

    PubMed Central

    Raz, E; Carson, D A; Parker, S E; Parr, T B; Abai, A M; Aichinger, G; Gromkowski, S H; Singh, M; Lew, D; Yankauckas, M A

    1994-01-01

    The skin and mucous membranes are the anatomical sites were most viruses are first encountered by the immune system. Previous experiments have suggested that striated muscle cells are unique among mammalian cell types in their capacity to take up and express free DNA in the absence of a viral vector or physical carrier. However, we have found that mice injected into the superficial skin with free (naked) plasmid DNA encoding the influenza nucleoprotein gene had discrete foci of epidermal and dermal cells, including cells with dendritic morphology, that contained immunoreactive nucleoprotein antigen. A single intradermal administration of 0.3-15 micrograms of free plasmid DNA induced anti-nucleoprotein-specific antibody and cytotoxic T lymphocytes that persisted for at least 68-70 weeks after vaccination. Intradermal gene administration induced higher antibody titers than did direct gene injection into skeletal muscle and did not cause local inflammation or necrosis. Compared with control animals, the gene-injected mice were resistant to challenge with a heterologous strain of influenza virus. These results indicate that the cells of the skin can take up and express free foreign DNA and induce cellular and humoral immune responses against the encoded protein. We suggest that DNA uptake by the skin-associated lymphoid tissues may play a role in the induction of cytotoxic T cells against viruses and other intracellular pathogens. Images PMID:7937799

  8. A strategy for efficient cross-presentation of CTL-epitope peptides leading to enhanced induction of in vivo tumor immunity.

    PubMed

    Hayashi, Akira; Wakita, Hisashi; Yoshikawa, Tomoaki; Nakanishi, Tsuyoshi; Tsutsumi, Yasuo; Mayumi, Tadanori; Mukai, Yohei; Yoshioka, Yasuo; Okada, Naoki; Nakagawa, Shinsaku

    2007-01-22

    The activation of antitumor cytotoxic T-lymphocytes (CTLs) depends on how efficiently the relevant tumor antigen peptides are delivered into the major histocompatibility complex (MHC) class I presentation pathway in antigen presenting cells (APCs). An elegant approach to promote the peptide-MHC class I association has been described for enhanced peptide transportation into the endoplasmic reticulum (ER) by adding an ER insertion signal sequence (Eriss). Nevertheless, this approach does not appear potent enough to induce in vivo tumor protective immunity. Herein, we present a novel peptide-vaccine strategy based on the combined utilization of Eriss and fusogenic liposomes (FLs) capable of directly introducing encapsulated CTL-epitope peptides into the MHC class I pathway of APCs. APCs pulsed with free peptides, FL-encapsulated peptides, or FL-encapsulated Eriss-conjugated peptides exhibited comparable levels of antigen-presenting activity at early phases after pulsing. Interestingly, whereas in the first two methods the APC ability began to decline 40 to 60 h after pulsing, FL-encapsulated Eriss(+) peptides allowed APCs to retain peptide-presentation activity for at least 140 h. This advantage of FL-encapsulated Eriss(+) peptides correlated with the induction of more potent antitumor immunity compared with soluble Eriss(+) or Eriss(-) peptides or FL-encapsulated Eriss(-) peptides when they were administered in vivo. Thus, Eriss-conjugated CTL-epitope peptides encapsulated in FLs provide a highly efficient tumor-vaccine to enhance the induction of in vivo tumor immunity.

  9. On the Validity of the Autobiographical Emotional Memory Task for Emotion Induction

    PubMed Central

    Mills, Caitlin; D'Mello, Sidney

    2014-01-01

    The Autobiographical Emotional Memory Task (AEMT), which involves recalling and writing about intense emotional experiences, is a widely used method to experimentally induce emotions. The validity of this method depends upon the extent to which it can induce specific desired emotions (intended emotions), while not inducing any other (incidental) emotions at different levels across one (or more) conditions. A review of recent studies that used this method indicated that most studies exclusively monitor post-writing ratings of the intended emotions, without assessing the possibility that the method may have differentially induced other incidental emotions as well. We investigated the extent of this issue by collecting both pre- and post-writing ratings of incidental emotions in addition to the intended emotions. Using methods largely adapted from previous studies, participants were assigned to write about a profound experience of anger or fear (Experiment 1) or happiness or sadness (Experiment 2). In line with previous research, results indicated that intended emotions (anger and fear) were successfully induced in the respective conditions in Experiment 1. However, disgust and sadness were also induced while writing about an angry experience compared to a fearful experience. Similarly, although happiness and sadness were induced in the appropriate conditions, Experiment 2 indicated that writing about a sad experience also induced disgust, fear, and anger, compared to writing about a happy experience. Possible resolutions to avoid the limitations of the AEMT to induce specific discrete emotions are discussed. PMID:24776697

  10. In vitro induction of memory-driven responses against Neisseria meningitidis by priming with Neisseria lactamica.

    PubMed

    Sánchez, S; Troncoso, G; Criado, M T; Ferreirós, C

    2002-07-26

    Natural immunity against Neisseria meningitidis is acquired during childhood and youth through successive colonizations by commensal Neisseria, carrier N. meningitidis, and other bacterial genera sharing cross-reactive antigens with the meningococci. We have analyzed in mice the ability of Neisseria lactamica strains to induce immunological memory so that, upon a later contact with N. meningitidis, quickly raise protective responses against antigens that show cross-reactivity with meningococcal surface proteins. Sera obtained from mice immunized with N. lactamica and boosted with N. meningitidis were able to kill meningococci, with bactericidal activities variable depending on the immunizing strains used in the assays. Different mixtures of those sera resulted in higher killing activities, which agrees with the idea that successive colonizations by N. lactamica enhance the anti-meningococcal response. The existence of such outer membrane cross-reactive antigens has to be kept in mind when using outer membrane vesicle (OMV)-based anti-meningococcal vaccines because their use can affect colonization by N. lactamica and other species, hampering the natural mechanisms of acquisition of immunity to the meningococci, and leaving its ecological niche free for colonization by undesirable microorganisms.

  11. Artificial Induction of Associative Olfactory Memory by Optogenetic and Thermogenetic Activation of Olfactory Sensory Neurons and Octopaminergic Neurons in Drosophila Larvae

    PubMed Central

    Honda, Takato; Lee, Chi-Yu; Honjo, Ken; Furukubo-Tokunaga, Katsuo

    2016-01-01

    The larval brain of Drosophila melanogaster provides an excellent system for the study of the neurocircuitry mechanism of memory. Recent development of neurogenetic techniques in fruit flies enables manipulations of neuronal activities in freely behaving animals. This protocol describes detailed steps for artificial induction of olfactory associative memory in Drosophila larvae. In this protocol, the natural reward signal is substituted by thermogenetic activation of octopaminergic neurons in the brain. In parallel, the odor signal is substituted by optogenetic activation of a specific class of olfactory receptor neurons. Association of reward and odor stimuli is achieved with the concomitant application of blue light and heat that leads to activation of both sets of neurons in living transgenic larvae. Given its operational simplicity and robustness, this method could be utilized to further our knowledge on the neurocircuitry mechanism of memory in the fly brain. PMID:27445732

  12. Lenalidomide Polarizes Th1-specific Anti-tumor Immune Response and Expands XBP1 Antigen-Specific Central Memory CD3+CD8+ T cells against Various Solid Tumors

    PubMed Central

    Bae, Jooeun; Keskin, Derin B; Cowens, Kristen; Lee, Ann-Hwee; Dranoff, Glen; Munshi, Nikhil C; Anderson, Kenneth C

    2016-01-01

    Introduction Effective combination immunotherapeutic strategies may be required to enhance effector cells’ anti-tumor activities and improve clinical outcomes. Methods XBP1 antigen-specific cytotoxic T lymphocytes (XBP1-CTL) generated using immunogenic heteroclitic XBP1 US184-192 (YISPWILAV) and XBP1 SP367-375 (YLFPQLISV) peptides or various solid tumor cells over-expressing XBP1 target antigen were evaluated, either alone or in combination with lenalidomide, for phenotype and immune functional activity. Results Lenalidomide treatment of XBP1-CTL increased the proportion of CD45RO+ memory CD3+CD8+ T cells, but not the total CD3+CD8+ T cells. Lenalidomide upregulated critical T cell activation markers and costimulatory molecules (CD28, CD38, CD40L, CD69, ICOS), especially within the central memory CTL subset of XBP1-CTL, while decreasing TCRαβ and T cell checkpoint blockade (CTLA-4, PD-1). Lenalidomide increased the anti-tumor activities of XBP1-CTL memory subsets, which were associated with expression of Th1 transcriptional regulators (T-bet, Eomes) and Akt activation, thereby resulting in enhanced IFN-γ production, granzyme B upregulation and specific CD28/CD38-positive and CTLA-4/PD-1-negative cell proliferation. Conclusions These studies suggest the potential benefit of lenalidomide treatment to boost anti-tumor activities of XBP1-specific CTL against a variety of solid tumors and enhance response to an XBP1-directing cancer vaccine regime. PMID:27668268

  13. Dicer Regulates the Balance of Short-Lived Effector and Long-Lived Memory CD8 T Cell Lineages

    PubMed Central

    Baumann, Florian M.; Yuzefpolskiy, Yevgeniy; Sarkar, Surojit; Kalia, Vandana

    2016-01-01

    MicroRNAs constitute a major post-transcriptional mechanism for controlling protein expression, and are emerging as key regulators during T cell development and function. Recent reports of augmented CD8 T cell activation and effector differentiation, and aberrant migratory properties upon ablation of Dicer/miRNAs in naïve cells have established a regulatory role of miRNAs during priming. Whether miRNAs continue to exert similar functions or are dispensable during later stages of CD8 T cell expansion and memory differentiation remains unclear. Here, we report a critical role of Dicer/miRNAs in regulating the balance of long-lived memory and short-lived terminal effector fates during the post-priming stages when CD8 T cells undergo clonal expansion to generate a large cytotoxic T lymphocyte (CTL) pool and subsequently differentiate into a quiescent memory state. Conditional ablation of Dicer/miRNAs in early effector CD8 T cells following optimal activation and expression of granzyme B, using unique dicerfl/fl gzmb-cre mice, led to a strikingly diminished peak effector size relative to wild-type antigen-specific cells in the same infectious milieu. Diminished expansion of Dicer-ablated CD8 T cells was associated with lack of sustained antigen-driven proliferation and reduced accumulation of short-lived effector cells. Additionally, Dicer-ablated CD8 T cells exhibited more pronounced contraction after pathogen clearance and comprised a significantly smaller proportion of the memory pool, despite significantly higher proportions of CD127Hi memory precursors at the effector peak. Combined with previous reports of dynamic changes in miRNA expression as CD8 T cells differentiate from naïve to effector and memory states, these findings support distinct stage-specific roles of miRNA-dependent gene regulation during CD8 T cell differentiation. PMID:27627450

  14. Memories.

    ERIC Educational Resources Information Center

    Brand, Judith, Ed.

    1998-01-01

    This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

  15. Sample Preparation Problem Solving for Inductively Coupled Plasma-Mass Spectrometry with Liquid Introduction Systems I. Solubility, Chelation, and Memory Effects

    PubMed Central

    Pappas, R. Steven

    2015-01-01

    This tutorial was adapted from the first half of a course presented at the 7th International Conference on Sector Field Inductively Coupled Plasma Mass Spectrometry in 2008 and the 2012 Winter Conference on Plasma Spectrochemistry on sample preparation for liquid introduction systems. Liquid introduction in general and flow injection specifically are the most widely used sample introduction methods for inductively coupled plasma-mass spectrometry. Nevertheless, problems persist in determination of analytes that are commonly investigated, as well as in specialty applications for those seldom considered by most analysts. Understanding the chemistry that is common to different groups of analytes permits the development of successful approaches to rinse-out and elimination of memory effects. This understanding also equips the analyst for development of successful elemental analytical approaches in the face of a broad spectrum of matrices and other analytical challenges, whether the sample is solid or liquid. PMID:26321788

  16. Tolerance of CD8+ T cells developing in parent-->F1 chimeras prepared with supralethal irradiation: step-wise induction of tolerance in the intrathymic and extrathymic environments.

    PubMed

    Kosaka, H; Sprent, J

    1993-02-01

    Tolerance of CD8+ cells was examined in parent-->F1 bone marrow chimeras (BMC) prepared with supralethal irradiation; host class I expression in the chimeras was limited to non-BM-derived cells. In terms of helper-independent proliferative responses in vitro and induction of graft-vs.-host disease on adoptive transfer, CD8+ cells from long-term chimeras showed profound tolerance to host antigens irrespective of whether the cells were prepared from the thymus or from spleen or lymph nodes. By limiting dilution analysis, cytotoxic T lymphocyte (CTL) precursors specific for host antigens were rare in the extrathymic lymphoid tissues. In the thymus, by contrast, host-specific CTL precursors were only slightly less frequent than in normal parental strain mice. These host-specific CD8+ cells survived when BMC thymocytes were transferred intravenously to a neutral environment, i.e., to donor strain mice. When transferred to further BMC hosts, however, most of the host-reactive cells disappeared. Collectively, the data suggest that tolerance of CD8+ cells in BMC hosts occurs in both the intrathymic and extrathymic environments. In the thymus, contact with host antigens on thymic epithelial cells deletes CD8+ cells controlling helper-independent proliferative responses and in vivo effector functions but spares typical helper-dependent CTL precursors. After export from the thymus, most of the CTL precursors are eliminated after contacting host antigens on stromal cells in the extrathymic environment.

  17. Induction of the rainbow trout MHC class I pathway during acute IHNV infection.

    PubMed

    Hansen, John D; La Patra, Scott

    2002-12-01

    Interferons are essential for establishing cytotoxic T-lymphocyte immunity against viral pathogens through different mechanisms including the modulation of antigen presentation to T-cell subsets. At the present time, interferons have yet to be isolated from teleost fish. We have developed a salmonid model to examine whether MHC gene regulation is modulated during acute viral infection in trout, an event attributable to interferons in mammals. During peak infection with infectious hematopoietic necrosis virus, induction of STAT-1, PSMB9A and ABCB2 mRNA was evident in all tissues within infected fish, as compared with controls. In addition, MHC class Ia and beta(2) microglobulin (beta(2)m) transcript levels were enhanced within the experimental group but surprisingly, splenic and pronephric class IIB mRNA expression was virtually absent. A time-course study looking at 24, 72 and 192 h post-infection was then performed to determine the overall kinetics of this response. STAT-1 and PSMB9A message levels increased early during the immune response and remain at relatively high levels until the final time point. MHC class Ia expression is not consistently upregulated until midway in the response. MHC class IIB transcripts are downregulated by 72 h in the spleen and pronephros and then partially restored by 192 h. Finally, analysis of the putative promoter regions for PSMB9A and ABCB2 identified interferon (IFN) regulatory factory (IRF-1) and INF-gamma (GAS) activation sites that may be involved in the regulation of these genes during viral infection.

  18. CD28 is required for induction and maintenance of immunological memory in toxin-reactive CD4+ T cells in vivo.

    PubMed

    Fukada, Kenji; Koyanagi, Madoka; Arimura, Yutaka; Ogiuchi, Hideki; Uchiyama, Takehiko; Yagi, Junji

    2005-12-01

    We previously reported that Vbeta3+ CD4+ T cells maintained a protracted expansion, with the phenotypes of memory Th2 cells, for 30 days in C57BL/6 (B6) mice implanted with SEA-containing mini-osmotic pumps. In the present study, we followed the fate of Vbeta3+ CD4+ T cells in CD28-/- mice. Vbeta3+ CD4+ T cells increased to a degree similar to that of B6 Vbeta3+ CD4+ T cells until day 10 after implantation, then declined rapidly reaching the control level by 28 days. Remaining Vbeta3+ CD4+ T cells at that time did not exhibit memory phenotypes nor Th2-deviated responses. The rapid drop in Vbeta3+ CD4+ T cells in CD28-/- mice was attributable to upregulated induction of apoptosis owing to marginal inductions of Bcl-2 and Bcl-xL. Collectively, these data indicate CD28 to play critical roles in the generation and maintenance of SEA-reactive CD4+ T cells in vivo.

  19. Cross-dressed dendritic cells drive memory CD8+ T-cell activation after viral infection.

    PubMed

    Wakim, Linda M; Bevan, Michael J

    2011-03-31

    After an infection, cytotoxic T lymphocyte precursors proliferate and become effector cells by recognizing foreign peptides in the groove of major histocompatibility complex (MHC) class I molecules expressed by antigen-presenting cells (APCs). Professional APCs specialized for T-cell activation acquire viral antigen either by becoming infected themselves (direct presentation) or by phagocytosis of infected cells, followed by transfer of antigen to the cytosol, processing and MHC class I loading in a process referred to as cross-presentation. An alternative way, referred to as 'cross-dressing', by which an uninfected APC could present antigen was postulated to be by the transfer of preformed peptide-MHC complexes from the surface of an infected cell to the APC without the need of further processing. Here we show that this mechanism exists and boosts the antiviral response of mouse memory CD8(+) T cells. A number of publications have demonstrated sharing of peptide-loaded MHC molecules in vitro. Our in vitro experiments demonstrate that cross-dressing APCs do not acquire peptide-MHC complexes in the form of exosomes released by donor cells. Rather, the APCs and donor cells have to contact each other for the transfer to occur. After a viral infection, we could isolate cross-dressed APCs able to present viral antigen in vitro. Furthermore, using the diphtheria toxin system to selectively eliminate APCs that could only acquire viral peptide-MHC complexes by cross-dressing, we show that such presentation can promote the expansion of resting memory T cells. Notably, naive T cells were excluded from taking part in the response. Cross-dressing is a mechanism of antigen presentation used by dendritic cells that may have a significant role in activating previously primed CD8(+) T cells.

  20. Social Isolation During Adolescence Strengthens Retention of Fear Memories and Facilitates Induction of Late-Phase Long-Term Potentiation.

    PubMed

    Liu, Ji-Hong; You, Qiang-Long; Wei, Mei-Dan; Wang, Qian; Luo, Zheng-Yi; Lin, Song; Huang, Lang; Li, Shu-Ji; Li, Xiao-Wen; Gao, Tian-Ming

    2015-12-01

    Social isolation during the vulnerable period of adolescence produces emotional dysregulation that often manifests as abnormal behavior in adulthood. The enduring consequence of isolation might be caused by a weakened ability to forget unpleasant memories. However, it remains unclear whether isolation affects unpleasant memories. To address this, we used a model of associative learning to induce the fear memories and evaluated the influence of isolation mice during adolescence on the subsequent retention of fear memories and its underlying cellular mechanisms. Following adolescent social isolation, we found that mice decreased their social interaction time and had an increase in anxiety-related behavior. Interestingly, when we assessed memory retention, we found that isolated mice were unable to forget aversive memories when tested 4 weeks after the original event. Consistent with this, we observed that a single train of high-frequency stimulation (HFS) enabled a late-phase long-term potentiation (L-LTP) in the hippocampal CA1 region of isolated mice, whereas only an early-phase LTP was observed with the same stimulation in the control mice. Social isolation during adolescence also increased brain-derived neurotrophic factor (BDNF) expression in the hippocampus, and application of a tropomyosin-related kinase B (TrkB) receptor inhibitor ameliorated the facilitated L-LTP seen after isolation. Together, our results suggest that adolescent isolation may result in mental disorders during adulthood and that this may stem from an inability to forget the unpleasant memories via BDNF-mediated synaptic plasticity. These findings may give us a new strategy to prevent mental disorders caused by persistent unpleasant memories.

  1. Microneedle Array Design Determines the Induction of Protective Memory CD8+ T Cell Responses Induced by a Recombinant Live Malaria Vaccine in Mice

    PubMed Central

    Carey, John B.; Pearson, Frances E.; Vrdoljak, Anto; McGrath, Marie G.; Crean, Abina M.; Walsh, Patrick T.; Doody, Timothy; O'Mahony, Conor; Hill, Adrian V. S.; Moore, Anne C.

    2011-01-01

    Background Vaccine delivery into the skin has received renewed interest due to ease of access to the immune system and microvasculature, however the stratum corneum (SC), must be breached for successful vaccination. This has been achieved by removing the SC by abrasion or scarification or by delivering the vaccine intradermally (ID) with traditional needle-and-syringes or with long microneedle devices. Microneedle patch-based transdermal vaccine studies have predominantly focused on antibody induction by inactivated or subunit vaccines. Here, our principal aim is to determine if the design of a microneedle patch affects the CD8+ T cell responses to a malaria antigen induced by a live vaccine. Methodology and Findings Recombinant modified vaccinia virus Ankara (MVA) expressing a malaria antigen was percutaneously administered to mice using a range of silicon microneedle patches, termed ImmuPatch, that differed in microneedle height, density, patch area and total pore volume. We demonstrate that microneedle arrays that have small total pore volumes induce a significantly greater proportion of central memory T cells that vigorously expand to secondary immunization. Microneedle-mediated vaccine priming induced significantly greater T cell immunity post-boost and equivalent protection against malaria challenge compared to ID vaccination. Notably, unlike ID administration, ImmuPatch-mediated vaccination did not induce inflammatory responses at the site of immunization or in draining lymph nodes. Conclusions/Significance This study demonstrates that the design of microneedle patches significantly influences the magnitude and memory of vaccine-induced CD8+ T cell responses and can be optimised for the induction of desired immune responses. Furthermore, ImmuPatch-mediated delivery may be of benefit to reducing unwanted vaccine reactogenicity. In addition to the advantages of low cost and lack of pain, the development of optimised microneedle array designs for the induction

  2. Induction of memory cytotoxic T cells to influenza A virus and subsequent viral clearance is not modulated by PB1-F2-dependent inflammasome activation

    PubMed Central

    Lee, Patricia (Hoi Yee); Bird, Nicola; MacKenzie-Kludas, Charley; Mansell, Ashley; Kedzierska, Katherine; Brown, Lorena; McAuley, Julie

    2016-01-01

    Expression of the viral virulence protein PB1-F2 during infection has been linked to NLRP3 inflammasome complex activation in macrophages and induction of early inflammatory events enhancing immunopathology during influenza disease. We sought to determine whether PB1-F2-specific NLRP3 inflammasome activation influenced the magnitude and/or robustness of the CD8+ T-cell responses specific for conserved viral antigens and subsequent virus elimination. Using murine heterosubtypic viral infection models, we showed that mice infected with virus unable to produce PB1-F2 protein showed no deficit in the overall magnitude and functional memory responses of CD8+ T cells established during the effector phase compared with those infected with wild-type PB1-F2-expressing virus and were equally capable of mounting robust recall responses. These data indicate that while expression of PB1-F2 protein can induce inflammatory events, the capacity to generate memory CD8+ T cells specific for immunodominant viral epitopes remains uncompromised. PMID:26667784

  3. AIM2 co-immunization favors specific multifunctional CD8(+) T cell induction and ameliorates coxsackievirus B3-induced chronic myocarditis.

    PubMed

    Chai, Dafei; Yue, Yan; Xu, Wei; Dong, Chunsheng; Xiong, Sidong

    2015-07-01

    Coxsackievirus B3 (CVB3) infection can cause acute myocarditis and chronic myocarditis, leading to dilated cardiomyopathy (DCM) with no effective therapeutic strategy. Therefore, we investigated the potential of absent in melanoma 2 (AIM2) to enhance the therapeutic efficacy of DNA vaccine against CVB3-induced chronic myocarditis. Mice were infected with CVB3 and then intranasally immunized with chitosan-pcDNA3.1 (mock), chitosan-pAIM2 (CS-pAIM2), chitosan-pVP1 (CS-pVP1), or chitosan-pAIM2 plus chitosan-pVP1 (CS-pAIM2/CS-pVP1) at 7, 21, and 35d. Therapeutic efficacies of various vaccines were evaluated at day 56d. Compared with CS-pVP1 immunization, CS-pAIM2/CS-pVP1 co-immunization significantly increased survival rate, improved cardiac function, as well as decreased myocardial injury and fibrosis, this result indicated that CVB3-induced chronic myocarditis was alleviated. CVB3-specific T lymphocyte proliferation and cytotoxic T lymphocyte responses of the CS-pAIM2/CS-pVP1 co-immunization group were also increased. More interestingly, CS-pAIM2/CS-pVP1 co-immunization could facilitate CVB3-specific multifunctional CD8(+) T cell induction in the intestinal mucosa, and this induction was closely correlated with myocardial scores, this result indicated that CS-pAIM2/CS-pVP1 vaccine exhibits therapeutic efficacy by enhancing multifunctional CD8(+) T cells. This study may represent a novel therapy for CVB3-induced chronic myocarditis.

  4. Induction of effective and antigen-specific antitumour immunity by a liposomal ErbB2/HER2 peptide-based vaccination construct

    PubMed Central

    Roth, A; Rohrbach, F; Weth, R; Frisch, B; Schuber, F; Wels, W S

    2005-01-01

    Efficient delivery of tumour-associated antigens to appropriate cellular compartments of antigen-presenting cells is of prime importance for the induction of potent, cell-mediated antitumour immune responses. We have designed novel multivalent liposomal constructs that co-deliver the p63–71 cytotoxic T Lymphocyte epitope derived from human ErbB2 (HER2), and HA307–319, a T-helper (Th) epitope derived from influenza haemagglutinin. Both peptides were conjugated to the surface of liposomes via a Pam3CSS anchor, a synthetic lipopeptide with potent adjuvant activity. In a murine model system, vaccination with these constructs completely protected BALB/c mice from subsequent s.c. challenge with ErbB2-expressing, but not ErbB2-negative, murine renal carcinoma (Renca) cells, indicating the induction of potent, antigen-specific immune responses. I.v. re-challenge of tumour-free animals 2 months after the first tumour cell inoculation did not result in the formation of lung tumour nodules, suggesting that long-lasting, systemic immunity had been induced. While still protecting the majority of vaccinated mice, a liposomal construct lacking the Th epitope was less effective than the diepitope construct, also correlating with a lower number of CD8+ IFN-γ+ T-cells identified upon ex vivo peptide restimulation of splenocytes from vaccinated animals. Importantly, in a therapeutic setting treatment with the liposomal vaccines resulted in cures in the majority of tumour-bearing mice and delayed tumour growth in the remaining ones. Our results demonstrate that liposomal constructs which combine Tc and Th peptide antigens and lipopeptide adjuvants can induce efficient, antigen-specific antitumour immunity, and represent promising synthetic delivery systems for the design of specific antitumour vaccines. PMID:15812545

  5. Induction of Memory Deficit in Mice with Chronic Exposure to Cerebrospinal Fluid from Patients with Anti-N-Methyl-D-Aspartate Receptor Encephalitis.

    PubMed

    Li, Yongzhi; Tanaka, Keiko; Wang, Li; Ishigaki, Yasuhito; Kato, Nobuo

    2015-01-01

    Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is now widely recognized and the patients with this disease show prominent psychiatric symptoms followed by seizures, respiratory failure, involuntary movement, autonomic instability, and amnesia. The anti-NMDAR antibody titer coincides with disease activity, and antibody-deprivation treatment ameliorates neurological symptoms. Previous studies have shown that clusters of NMDARs on the neuronal surface decrease in density upon incubation with the cerebrospinal fluid from patients (NMDAR-CSF), and that the induction of long-term potentiation, a cellular mechanism underlie learning and memory processes, was suppressed with NMDAR-CSF. In this study, we exposed mice to NMDAR-CSF in an attempt to reproduce the human symptoms in mice. CSF was continuously administered via a cannula placed in the lateral ventricle of the mouse that connected to an osmotic pump transplanted in the back of the mouse. From day 8-18, we evaluated the behavior of the mice using standardized tests that were performed serially. Mice exposed to NMDAR-CSF showed impaired spatial memory, as detected with the Morris water maze test. Brain tissue from mice with memory disturbances had decreased content of NMDAR protein in the hippocampal area shown by immunohistochemistry, which is consistent with the anti-NMDAR antibodies affect the expression and function of NMDARs, resulting in anti-NMDAR encephalitis-like symptoms. Also, the mice treated with the NMDAR-CSF did not show inflammatory cell infiltration or neuron loss in their brain tissue and this lack of nervous tissue destruction is encouraging as it is consistent with the idea that this disease can be treated through immunotherapy.

  6. Mechanism of helix induction in poly(4-carboxyphenyl isocyanide) with chiral amines and memory of the macromolecular helicity and its helical structures.

    PubMed

    Hase, Yoko; Nagai, Kanji; Iida, Hiroki; Maeda, Katsuhiro; Ochi, Noriaki; Sawabe, Kyoichi; Sakajiri, Koichi; Okoshi, Kento; Yashima, Eiji

    2009-08-05

    An optically inactive poly(4-carboxyphenyl isocyanide) (poly-1-H) changed its structure into the prevailing, one-handed helical structure upon complexation with optically active amines in dimethylsulfoxide (DMSO) and water, and the complexes show a characteristic induced circular dichroism in the polymer backbone region. Moreover, the macromolecular helicity induced in water and aqueous organic solutions containing more than 50 vol % water could be "memorized" even after complete removal of the chiral amines (h-poly-1b-H), while that induced in DMSO and DMSO-water mixtures containing less than 30 vol % water could not maintain the optical activity after removal of the chiral amines (poly-1a-H). We now report fully detailed studies of the helix induction mechanism with chiral amines and the memory of the macromolecular helicity in water and a DMSO-water mixture by various spectroscopic measurements, theoretical calculations, and persistence length measurements together with X-ray diffraction (XRD) measurements. From the spectroscopic results, such as circular dichroism (CD), absorption, IR, vibrational CD, and NMR of poly-1a-H, h-poly-1b-H, and original poly-1-H, we concluded that the specific configurational isomerization around the C horizontal lineN double bonds occurs during the helicity induction process in each solvent. In order to obtain the structural information, XRD measurements were done on the uniaxially oriented films of the corresponding methyl esters (poly-1-Me, poly-1a-Me, and h-poly-1b-Me) prepared from their liquid crystalline polymer solutions. On the basis of the XRD analyses, the most plausible helical structure of poly-1a-Me was proposed to be a 9-unit/5-turn helix with two monomer units as a repeating unit, and that of h-poly-1b-Me was proposed to be a 10-unit/3-turn helix consisting of one repeating monomer unit. The density functional theory calculations of poly(phenyl isocyanide), a model polymer of h-poly-1b-Me, afforded a 7-unit/2-turn

  7. Apoptosis in an interleukin-2-dependent cytotoxic T lymphocyte cell line is associated with intracellular acidification. Role of the Na(+)/H(+)-antiport.

    PubMed

    Li, J; Eastman, A

    1995-02-17

    Apoptosis is a form of cell death associated with DNA fragmentation and chromatin condensation. We recently established that intracellular acidification occurred during apoptosis following cytotoxic insult. The current studies were designed to determine whether intracellular acidification was more generally associated with apoptosis, specifically in a model of growth factor withdrawal. Upon withdrawal of interleukin-2, CTLL-2 cells accumulated in the G1 phase of the cell cycle and started to fragment their DNA around 12 h concurrent with both decreased pH and increased Ca2. Chelation of Ca2+ did not inhibit DNA digestion, whereas incubation with a calcium ionophore prevented both acidification and DNA digestion. Hence, acidification rather than increased Ca2+ was associated with apoptosis. The acidified cells represented a discrete population up to 0.7 pH units below normal. The extent of acidification depended upon the extracellular pH; above pH 6.3, intracellular pH was significantly below extracellular pH, whereas below pH 6.3, the cells still regulated their pH. Inhibition of the Na+/H(+)-antiport prevented the apoptotic cells from regulating their intracellular pH under these acidic conditions. These intracellular pH under these acidic conditions. These results demonstrate that apoptotic cells retain a functional antiport but that its set-point has changed. Many survival factors are known to phosphorylate and activate the antiport, hence apoptosis is likely to be associated with dephosphorylation. Although acidification always occurred during apoptosis, maintaining intracellular pH above 7.2 did not prevent apoptosis, suggesting that an acid pH is not essential for apoptosis. We hypothesize that other critical regulators of apoptosis must be subject to dephosphorylation.

  8. Personalized Kampo Medicine Facilitated Both Cytotoxic T Lymphocyte Response and Clinical Benefits Induced by Personalized Peptide Vaccination for Advanced Esophageal Cancer

    PubMed Central

    Yutani, Shigeru; Shichijo, Shigeki; Sakamoto, Shinjiro; Naito, Masayasu; Okuda, Koji; Morita, Michi; Yamaguchi, Rin; Itoh, Kyogo

    2016-01-01

    We retrospectively evaluated if personalized Kampo medicine (PKM) could facilitate CTL responses and clinical benefits induced by personalized peptide vaccination (PPV), in which HLA-matched vaccines were selected and administered based on the preexisting host immunity, for advanced esophageal cancer (aEC) patients. Among 34 aEC patients entered in the clinical study, 23 patients received PKM and PPV without (n = 12) or with chemotherapy (n = 11), while the remaining 11 patients did not receive PKM but received PPV without (n = 6) or with chemotherapy (n = 5), respectively. Incidence of adverse events was significantly lower or higher in PKM and PPV arm (n = 23) or PPV and chemotherapy arm (n = 16) as compared to that of the counter arm (n = 11 or 18), respectively. Postvaccination PBMCs from the patients undergoing PKM and PPV showed significantly higher CTL responses as compared to the counter arm. The median progression-free survival (PFS) or median survival time (MST) of 34 patients was 2.9 or 7.6 months, respectively. The combination therapy in PPV and PKM arm, but not that in PPV and chemotherapy arm, significantly (P = 0.02) prolonged MST. These results could warrant a next step of prospective clinical study of PKM and PPV for aEC patients. PMID:27703488

  9. Generation of T-cell receptors targeting a genetically stable and immunodominant cytotoxic T-lymphocyte epitope within hepatitis C virus non-structural protein 3.

    PubMed

    Pasetto, Anna; Frelin, Lars; Brass, Anette; Yasmeen, Anila; Koh, Sarene; Lohmann, Volker; Bartenschlager, Ralf; Magalhaes, Isabelle; Maeurer, Markus; Sällberg, Matti; Chen, Margaret

    2012-02-01

    Hepatitis C virus (HCV) is a major cause of severe liver disease, and one major contributing factor is thought to involve a dysfunction of virus-specific T-cells. T-cell receptor (TCR) gene therapy with HCV-specific TCRs would increase the number of effector T-cells to promote virus clearance. We therefore took advantage of HLA-A2 transgenic mice to generate multiple TCR candidates against HCV using DNA vaccination followed by generation of stable T-cell-BW (T-BW) tumour hybrid cells. Using this approach, large numbers of non-structural protein 3 (NS3)-specific functional T-BW hybrids can be generated efficiently. These predominantly target the genetically stable HCV genotype 1 NS3(1073-1081) CTL epitope, frequently associated with clearance of HCV in humans. These T-BW hybrid clones recognized the NS3(1073) peptide with a high avidity. The hybridoma effectively recognized virus variants and targeted cells with low HLA-A2 expression, which has not been reported previously. Importantly, high-avidity murine TCRs effectively redirected human non-HCV-specific T-lymphocytes to recognize human hepatoma cells with HCV RNA replication driven by a subgenomic HCV replicon. Taken together, TCR candidates with a range of functional avidities, which can be used to study immune recognition of HCV-positive targets, have been generated. This has implications for TCR-related immunotherapy against HCV.

  10. Molecular cloning and DNA sequence analysis of genes encoding cytotoxic T lymphocyte-defined HLA-A3 subtypes: the E1 subtype.

    PubMed

    Cowan, E P; Jordan, B R; Coligan, J E

    1985-10-01

    Influenza-specific cytotoxic T cells restricted by HLA-A3 and allogeneic CTL specific for HLA-A3 recognize differences between serologically indistinguishable HLA-A3 antigens. Previous biochemical studies have indicated that such differential recognition can be explained by alterations in the primary structure of class I heavy chains. Characterization of these sequence differences may therefore identify portions of the class I molecule that form determinants recognized by CTL. In this study, we describe the cloning and sequencing of an HLA-A3 subtype from donor E1 (E1-A3). Cloning of the gene encoding E1-A3 was simplified by determining that a 15.5-kb BamHI fragment contains the complete gene and is characteristic of HLA-A3 and only one other class I gene (HLA-A11). Comparison of the E1-A3 sequence to that of a previously sequenced HLA-A3 gene for exons encoding extracellular class I domains revealed three nucleotide differences. All of these differences were located within a discrete region of exon 3 (encoding the alpha 2 domain) and result in a change of two amino acids, at positions 152 (Glu----Val) and 156 (Leu----Gln). This finding suggests that these amino acids are crucial for the information of a determinant recognized by CTL. Furthermore, the altered nucleotide sequence of E1-A3 is identical to the sequence of the HLA-Aw24 gene for codons 128 to 161. These observations of multiple clustered changes in the E1-A3 subtype (relative to the prototype sequence) and identity of the altered sequence with the sequence of another class I gene support the concept that gene conversion is a primary mechanism for the generation of class I polymorphism.

  11. Natural CD8{sup +}25{sup +} regulatory T cell-secreted exosomes capable of suppressing cytotoxic T lymphocyte-mediated immunity against B16 melanoma

    SciTech Connect

    Xie, Yufeng; Zhang, Xueshu; Zhao, Tuo; Li, Wei; Xiang, Jim

    2013-08-16

    Highlights: •CD8{sup +}25{sup +} regulatory T cells secrete tolerogenic exosomes. •CD8{sup +}25{sup +} regulatory T cell-derived exosomes exhibit immunosuppressive effect. •CD8{sup +}25{sup +} regulatory T cell-derived exosomes inhibit antitumor immunity. -- Abstract: Natural CD4{sup +}25{sup +} and CD8{sup +}25{sup +} regulatory T (Tr) cells have been shown to inhibit autoimmune diseases. Immune cells secrete exosomes (EXOs), which are crucial for immune regulation. However, immunomodulatory effect of natural Tr cell-secreted EXOs is unknown. In this study, we purified natural CD8{sup +}25{sup +} Tr cells from C57BL/6 mouse naive CD8{sup +} T cells, and in vitro amplified them with CD3/CD28 beads. EXOs (EXO{sub Tr}) were purified from Tr cell’s culture supernatants by differential ultracentrifugation and analyzed by electron microscopy, Western blot and flow cytometry. Our data showed that EXO{sub Tr} had a “saucer” or round shape with 50–100 nm in diameter, contained EXO-associated markers LAMP-1 and CD9, and expressed natural Tr cell markers CD25 and GITR. To assess immunomodulatory effect, we i.v. immunized C57BL/6 mice with ovalbumin (OVA)-pulsed DCs (DC{sub OVA}) plus Tr cells or EXO{sub Tr}, and then assessed OVA-specific CD8{sup +} T cell responses using PE-H-2K{sup b}/OVA tetramer and FITC-anti-CD8 antibody staining by flow cytometry and antitumor immunity in immunized mice with challenge of OVA-expressing BL6–10{sub OVA} melanoma cells. We demonstrated that DC{sub OVA}-stimulated CD8{sup +} T cell responses and protective antitumor immunity significantly dropped from 2.52% to 1.08% and 1.81% (p < 0.05), and from 8/8 to 2/8 and 5/8 mice DC{sub OVA} (p < 0.05) in immunized mice with co-injection of Tr cells and EXO{sub Tr}, respectively. Our results indicate that natural CD8{sup +}25{sup +} Tr cell-released EXOs, alike CD8{sup +}25{sup +} Tr cells, can inhibit CD8{sup +} T cell responses and antitumor immunity. Therefore, EXOs derived from natural CD4{sup +}25{sup +} and CD8{sup +}25{sup +} Tr cells may become an alternative for immunotherapy of autoimmune diseases.

  12. Enhanced cytotoxicity and decreased CD8 dependence of human cancer-specific cytotoxic T lymphocytes after vaccination with low peptide dose.

    PubMed

    Lövgren, Tanja; Baumgaertner, Petra; Wieckowski, Sébastien; Devêvre, Estelle; Guillaume, Philippe; Luescher, Immanuel; Rufer, Nathalie; Speiser, Daniel E

    2012-06-01

    In mice, vaccination with high peptide doses generates higher frequencies of specific CD8+ T cells, but with lower avidity compared to vaccination with lower peptide doses. To investigate the impact of peptide dose on CD8+ T cell responses in humans, melanoma patients were vaccinated with 0.1 or 0.5 mg Melan-A/MART-1 peptide, mixed with CpG 7909 and Incomplete Freund's adjuvant. Neither the kinetics nor the amplitude of the Melan-A-specific CD8+ T cell responses differed between the two vaccination groups. Also, CD8+ T cell differentiation and cytokine production ex vivo were similar in the two groups. Interestingly, after low peptide dose vaccination, Melan-A-specific CD8+ T cells showed enhanced degranulation upon peptide stimulation, as assessed by CD107a upregulation and perforin release ex vivo. In accordance, CD8+ T cell clones derived from low peptide dose-vaccinated patients showed significantly increased degranulation and stronger cytotoxicity. In parallel, Melan-A-specific CD8+ T cells and clones from low peptide dose-vaccinated patients expressed lower CD8 levels, despite similar or even stronger binding to tetramers. Furthermore, CD8+ T cell clones from low peptide dose-vaccinated patients bound CD8 binding-deficient tetramers more efficiently, suggesting that they may express higher affinity TCRs. We conclude that low peptide dose vaccination generated CD8+ T cell responses with stronger cytotoxicity and lower CD8 dependence.

  13. Transfer of Maternal Immune Cells by Breastfeeding: Maternal Cytotoxic T Lymphocytes Present in Breast Milk Localize in the Peyer’s Patches of the Nursed Infant

    PubMed Central

    Tang, May; Zumba, Osvaldo; Mehta, Hetali; Toma, Annmarie; Sant’Angelo, Derek; Laouar, Yasmina

    2016-01-01

    Despite our knowledge of the protective role of antibodies passed to infants through breast milk, our understanding of immunity transfer via maternal leukocytes is still limited. To emulate the immunological interface between the mother and her infant while breast-feeding, we used murine pups fostered after birth onto MHC-matched and MHC-mismatched dams. Overall, data revealed that: 1) Survival of breast milk leukocytes in suckling infants is possible, but not significant after the foster-nursing ceases; 2) Most breast milk lymphocytes establish themselves in specific areas of the intestine termed Peyer’s patches (PPs); 3) While most leukocytes in the milk bolus were myeloid cells, the majority of breast milk leukocytes localized to PPs were T lymphocytes, and cytotoxic T cells (CTLs) in particular; 4) These CTLs exhibit high levels of the gut-homing molecules α4β7 and CCR9, but a reduced expression of the systemic homing marker CD62L; 5) Under the same activation conditions, transferred CD8 T cells through breast milk have a superior capacity to produce potent cytolytic and inflammatory mediators when compared to those generated by the breastfed infant. It is therefore possible that maternal CTLs found in breast milk are directed to the PPs to compensate for the immature adaptive immune system of the infant in order to protect it against constant oral infectious risks during the postnatal phase. PMID:27285085

  14. The PD-1/PD-L1 (B7-H1) Pathway in Chronic Infection-Induced Cytotoxic T Lymphocyte Exhaustion

    PubMed Central

    Hofmeyer, Kimberly A.; Jeon, Hyungjun; Zang, Xingxing

    2011-01-01

    Cytotoxic CD8 T lymphocytes (CTLs) play a pivotal role in the control of infection. Activated CTLs, however, often lose effector function during chronic infection. PD-1 receptor and its ligand PD-L1 of the B7/CD28 family function as a T cell coinhibitory pathway and are emerging as major regulators converting effector CTLs into exhausted CTLs during chronic infection with human immunodeficiency virus, hepatitis B virus, hepatitis C virus, and other pathogens capable of establishing chronic infections. Importantly, blockade of the PD-1/PD-L1 pathway is able to restore functional capabilities to exhausted CTLs and early clinical trials have shown promise. Further research will reveal how chronic infection induces upregulation of PD-1 on CTLs and PD-L1 on antigen-presenting cells and other tissue cells and how the PD-1/PD-L1 interaction promotes CTLs exhaustion, which is crucial for developing effective prophylactic and therapeutic vaccination against chronic infections. PMID:21960736

  15. Spatial memory consolidation is associated with induction of several lysine-acetyltransferase (histone acetyltransferase) expression levels and H2B/H4 acetylation-dependent transcriptional events in the rat hippocampus.

    PubMed

    Bousiges, Olivier; Vasconcelos, Anne Pereira de; Neidl, Romain; Cosquer, Brigitte; Herbeaux, Karine; Panteleeva, Irina; Loeffler, Jean-Philippe; Cassel, Jean-Christophe; Boutillier, Anne-Laurence

    2010-12-01

    Numerous genetic studies have shown that the CREB-binding protein (CBP) is an essential component of long-term memory formation, through its histone acetyltransferase (HAT) function. E1A-binding protein p300 and p300/CBP-associated factor (PCAF) have also recently been involved in memory formation. By contrast, only a few studies have reported on acetylation modifications during memory formation, and it remains unclear as to how the system is regulated during this dynamic phase. We investigated acetylation-dependent events and the expression profiles of these HATs during a hippocampus-dependent task taxing spatial reference memory in the Morris water maze. We found a specific increase in H2B and H4 acetylation in the rat dorsal hippocampus, while spatial memory was being consolidated. This increase correlated with the degree of specific acetylated histones enrichment on some memory/plasticity-related gene promoters. Overall, a global increase in HAT activity was measured during this memory consolidation phase, together with a global increase of CBP, p300, and PCAF expression. Interestingly, these regulations were altered in a model of hippocampal denervation disrupting spatial memory consolidation, making it impossible for the hippocampus to recruit the CBP pathway (CBP regulation and acetylated-H2B-dependent transcription). CBP has long been thought to be present in limited concentrations in the cells. These results show, for the first time, that CBP, p300, and PCAF are dynamically modulated during the establishment of a spatial memory and are likely to contribute to the induction of a specific epigenetic tagging of the genome for hippocampus-dependent (spatial) memory consolidation. These findings suggest the use of HAT-activating molecules in new therapeutic strategies of pathological aging, Alzheimer's disease, and other neurodegenerative disorders.

  16. Experimental induction of type 2 diabetes in aging-accelerated mice triggered Alzheimer-like pathology and memory deficits.

    PubMed

    Mehla, Jogender; Chauhan, Balwantsinh C; Chauhan, Neelima B

    2014-01-01

    Alzheimer's disease (AD) is an age-dependent neurodegenerative disease constituting ~95% of late-onset non-familial/sporadic AD, and only ~5% accounting for early-onset familial AD. Availability of a pertinent model representing sporadic AD is essential for testing candidate therapies. Emerging evidence indicates a causal link between diabetes and AD. People with diabetes are >1.5-fold more likely to develop AD. Senescence-accelerated mouse model (SAMP8) of accelerated aging displays many features occurring early in AD. Given the role played by diabetes in the pre-disposition of AD, and the utility of SAMP8 non-transgenic mouse model of accelerated aging, we examined if high fat diet-induced experimental type 2 diabetes in SAMP8 mice will trigger pathological aging of the brain. Results showed that compared to non-diabetic SAMP8 mice, diabetic SAMP8 mice exhibited increased cerebral amyloid-β, dysregulated tau-phosphorylating glycogen synthase kinase 3β, reduced synaptophysin immunoreactivity, and displayed memory deficits, indicating Alzheimer-like changes. High fat diet-induced type 2 diabetic SAMP8 mice may represent the metabolic model of AD.

  17. Therapeutic effect of ergotope peptides on CIA by down-regulation of inflammatory and Th1/Th17 responses and induction of regulatory T cells.

    PubMed

    Niu, Xiaoyin; Deng, Shaohua; Li, Shan; Xi, Yebin; Li, Chengzhen; Wang, Li; He, Dongyi; Wang, Zhaojun; Chen, Guangjie

    2016-08-30

    Rheumatoid arthritis (RA) is a systemic autoimmune disease that results in a chronic and inflammatory disorder. Dynamic balance of helper T cells (Th)1, Th17 and regulatory T cells (Treg) is broken in RA. Since there is no cure for RA at present, it's necessary to find a truly effective and convenient treatment. Several studies intended to induce ergotopic regulation to treat autoimmune diseases. This study was undertaken to find the potential ergotope peptides and investigate its effect in treating the animal model of RA and their underlying regulatory mechanisms. Firstly, we selected the functional ergotope peptides from 25 overlapping peptides derived from interlukin(IL)-2 receptor (IL-2R) α chain, and then used these peptides to treat collagen-induced arthritis (CIA). The study showed ergotope peptides as immunomodulatory factors with great benefits at the clinical and pathologic levels. This effect was associated with the inhibition of type II collagen (CII)-specific proliferation and autoantibody production as well as the induction of anti-ergotypic immune response, the down-regulation of both Th1 and Th17 cells and their related components, and the emergence of Treg cells that had suppressive actions on autoreactive T cells. We also proved that cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and IL-10 are two important mediators which are critical to Treg suppressive function. The inhibition of Th1 and Th17 in established CIA could be attributed to ergotope induced Treg cells. Our findings reveal that ergotope peptides induce regulatory immune responses and restore immune tolerance, suggesting ergotope peptides treatment appears to be a novel approach to the therapy of RA patients and has a good application prospect with cheap, effective, convenient, wide-spectrum features.

  18. A novel dendritic cell-based immunization approach for the induction of durable Th1-polarized anti-HER-2/neu responses in women with early breast cancer.

    PubMed

    Koski, Gary K; Koldovsky, Ursula; Xu, Shuwen; Mick, Rosemarie; Sharma, Anupama; Fitzpatrick, Elizabeth; Weinstein, Susan; Nisenbaum, Harvey; Levine, Bruce L; Fox, Kevin; Zhang, Paul; Czerniecki, Brian J

    2012-01-01

    Twenty-seven patients with HER-2/neu overexpressing ductal carcinoma in situ of the breast were enrolled in a neoadjuvant immunization trial for safety and immunogenicity of DC1-polarized dendritic cells (DC1) pulsed with 6 HER-2/neu promiscuous major histocompatibility complex class II-binding peptides and 2 additional human leukocyte antigen (HLA)-A2.1 class I-binding peptides. DC1 were generated with interferon-γ and a special clinical-grade bacterial endotoxin (lipopolysaccharide) and administered directly into groin lymph nodes 4 times at weekly intervals before scheduled surgical resection of ductal carcinoma in situ. Patients were monitored for the induction of new or enhanced antipeptide reactivity by interferon-γ ELISPOT and enzyme-linked immunosorbentassays performed on Th cells obtained from peripheral blood or excised sentinel lymph nodes. Responses by cytotoxic T lymphocyte against HLA-A2.1-binding peptides were measured using peptide-pulsed T2 target cells or HER-2/neu-expressing or nonexpressing tumor cell lines. DC1 showed surface phenotype indistinct from "gold standard" inflammatory cocktail-activated DC, but displayed a number of distinguishing functional characteristics including the secretion of soluble factors and enhanced "killer DC" capacity against tumor cells in vitro. Postimmunization, we observed sensitization of Th cells to at least 1 class II peptide in 22 of 25 (88%; 95% exact confidence interval, 68.8%-97.5%) evaluable patients, whereas 11 of 13 (84.6%; 95% exact confidence interval, 64%-99.8%) HLA-A2.1 patients were successfully sensitized to class I peptides. Perhaps most importantly, anti-HER-2/neu peptide responses were observed up to 52-month postimmunization. These data show that even in the presence of early breast cancer such DC1 are potent inducers of durable type I-polarized immunity, suggesting potential clinical value for development of cancer immunotherapy.

  19. A tumor lysate is an effective vaccine antigen for the stimulation of CD4(+) T-cell function and subsequent induction of antitumor immunity mediated by CD8(+) T cells.

    PubMed

    Kawahara, Mamoru; Takaku, Hiroshi

    2015-01-01

    To develop a potent cancer vaccine, it is important to study how to prepare highly immunogenic antigens and to identify the most appropriate adjuvants for the antigens. Here we show that a tumor lysate works as an effective antigen to prime CD4(+) T-cell help when baculovirus is employed as an adjuvant. When immunized intradermally with the combination (BLP) of baculovirus, a CT26 tumor lysate, and a cytotoxic T-cell epitope peptide before a tumor challenge, 60% of mice rejected tumors. In contrast, all mice vaccinated with baculovirus plus a tumor lysate (BL) developed tumors. In addition, flow cytometry showed that tumor-specific, interferon γ-producing CD8(+) cytotoxic T lymphocytes (CTLs) were robustly activated by intradermal immunization with BLP. When BLP was administered therapeutically to tumor-bearing mice, antitumor efficacy was better compared to BL. The established tumor was completely eradicated in 50-60% of BLP-treated mice, and induction of tumor-specific CTLs was observed, suggesting that the antitumor efficacy of BLP is mediated by CD8(+) T cells. Numerous CD4(+) T cells infiltrated the tumors of BLP-treated mice, whereas the antitumor effect of BLP almost disappeared after removal of the tumor lysate from BLP or after depletion of BLP-immunized mice of CD4(+) T cells. Thus, the combination of a peptide, lysate, and baculovirus provides stronger antitumor immunity than does a peptide plus baculovirus or a lysate plus baculovirus; effectiveness of BLP is determined by functioning of CD4(+) T cells stimulated with a tumor lysate.

  20. Induction of methotrexate resistance by retroviral-mediated transfer of a mutant dihydrofolate reductase gene

    SciTech Connect

    Ricciardone, M.D.

    1986-01-01

    Methotrexate (MTX), a folate analog which inhibits the enzyme dihydrofolate reductase (DHFR), is an effective antineoplastic drug. However, MTX-induced myelosuppression limits the effectiveness of this agent. Selective induction of MTX resistance in bone marrow stem cells, prior to treatment with MTX, might prevent this toxicity and improve the therapeutic index of the drug. In these studies drug resistance was transferred to mouse and human bone marrow stem cells by retroviral expression vectors containing coding sequences of a mutant DHFR with a decreased affinity for MTX. Three retroviral expression vectors were analyzed. The CIS DR vector contained the mutant DHFR gene inserted into the replication-defective amphotropic 4070 virus, Cistor. The other vectors contained the mutant DHFR inserted into either the env region (SDHT1) or gag-pol region (SDHT2) of a replication-defective spleen focus-forming virus. All three constructs induced approximately a 200-fold resistance to MTX when transfected into NIH3T3 cells. Amphotropic infectious retroviruses were obtained by transfecting the mutant DHFR vectors into a packaging cell line, which supplied the gag, pol, and env proteins for virus production. Virus titers of 4.5 x 10/sup 3/ colony-forming units (CFU)/ml (CIS DR), 1.5 x 10/sup 4/ CFU/ml (SDHT2), and 5 x 10/sup 5/ CFU/ml (SDHT1) were measured by the transfer of MTX resistance to NIH3T3 cells. The amphotropic SDHT1 virus efficiently induced MTX resistance in cells of several species, including mouse NIH3T3 cells (5 x 10/sup 5/ CFU/ml), monkey CV1 cells (4 x 10/sup 3/ CFU/ml), and human MCF-7 cells (6 x 10/sup 4/ CFU/ml). When cocultured with SDHT1 virus-producing cells, both mouse and human bone marrow cells could be infected and rendered resistant to MTX. Mouse cytotoxic T lymphocytes and mouse helper T lymphocytes can also be made resistant to MTX.

  1. Predicting Reasoning from Memory

    ERIC Educational Resources Information Center

    Heit, Evan; Hayes, Brett K.

    2011-01-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the…

  2. Invariant NKT cells induce plasmacytoid dendritic cell (DC) cross-talk with conventional DCs for efficient memory CD8+ T cell induction.

    PubMed

    Shimizu, Kanako; Asakura, Miki; Shinga, Jun; Sato, Yusuke; Kitahara, Shuji; Hoshino, Katsuaki; Kaisho, Tsuneyasu; Schoenberger, Stephen P; Ezaki, Taichi; Fujii, Shin-ichiro

    2013-06-01

    A key goal of vaccine immunotherapy is the generation of long-term memory CD8(+) T cells capable of mediating immune surveillance. We discovered a novel intercellular pathway governing the development of potent memory CD8(+) T cell responses against cell-associated Ags that is mediated through cross-presentation by XCR1(+) dendritic cells (DCs). Generation of CD8(+) memory T cells against tumor cells pulsed with an invariant NKT cell ligand depended on cross-talk between XCR1(+) and plasmacytoid DCs that was regulated by IFN-α/IFN-αR signals. IFN-α production by plasmacytoid DCs was stimulated by an OX40 signal from the invariant NKT cells, as well as an HMGB1 signal from the dying tumor cells. These findings reveal a previously unknown pathway of intercellular collaboration for the generation of tumor-specific CD8(+) memory T cells that can be exploited for strategic vaccination in the setting of tumor immunotherapy.

  3. The Role of Lymphocytes in the Development and Treatment of Alopecia Areata

    PubMed Central

    Guo, Hongwei; Cheng, Yabin; Shapiro, Jerry; McElwee, Kevin

    2016-01-01

    Summary Alopecia areata (AA) development is associated with both innate and adaptive immune cell activation, migration to peri-and intra-follicular regions, and hair follicle disruption. Both CD4+ and CD8+ lymphocytes are abundant in AA lesions; however, CD8+ cytotoxic T lymphocytes are more likely to enter inside hair follicles, circumstantially suggesting that they have a significant role to play in AA development. Several rodent models recapitulate important features of the human autoimmune disease and demonstrate that CD8+ cytotoxic T lymphocytes are fundamentally required for AA induction and perpetuation. However, the initiating events, the self-antigens involved, and the molecular signaling pathways, all need further exploration. Studying CD8+ cytotoxic T lymphocytes and their fate decisions in AA development may reveal new and improved treatment approaches. PMID:26548356

  4. Induction of cAMP response element-binding protein-dependent medium-term memory by appetitive gustatory reinforcement in Drosophila larvae.

    PubMed

    Honjo, Ken; Furukubo-Tokunaga, Katsuo

    2005-08-31

    The fruit fly Drosophila melanogaster has been successfully used as a model animal for the study of the genetic and molecular mechanisms of learning and memory. Although most of the Drosophila learning studies have used the adult fly, the relative complexity of its neural network hinders cellular and molecular studies at high resolution. In contrast, the Drosophila larva has a simple brain with uniquely identifiable neural networks, providing an opportunity of an attractive alternative system for elucidation of underlying mechanisms involved in learning and memory. In this paper, we describe a novel paradigm of larval associative learning with a single odor and a positive gustatory reinforcer, sucrose. Mutant analyses have suggested importance of cAMP signaling and potassium channel activities in larval learning as has been demonstrated with the adult fly. Intriguingly, larval memory produced by the appetitive conditioning lasts medium term and depends on both amnesiac and cAMP response element-binding protein (CREB). A significant part of memory was disrupted at very early phase by CREB blockade without affecting immediate learning performance. Moreover, we also show that synaptic output of larval mushroom body neurons is required for retrieval but not for acquisition and retention of the larval memory, including the CREB-dependent component.

  5. CTLA4-Ig suppresses development of experimental autoimmune uveitis in the induction and effector phases: Comparison with blockade of interleukin-6.

    PubMed

    Iwahashi, Chiharu; Fujimoto, Minoru; Nomura, Shintaro; Serada, Satoshi; Nakai, Kei; Ohguro, Nobuyuki; Nishida, Kohji; Naka, Tetsuji

    2015-11-01

    Recently, a number of biologics have been used in the treatment of autoimmune diseases. However, in the treatment of severe autoimmune uveitis, only TNF-alpha inhibitors are preferably used and the effect of other biologics such as interleukin-6 (IL-6) signaling blockade or cytotoxic T-lymphocyte antigen-4-immunoglobulin fusion protein (CTLA4-Ig) has not been well studied. Previously, we reported that IL-6 blockade effectively suppresses the development of experimental autoimmune uveitis (EAU), a mouse model for uveitis, by inhibiting Th17 cell development. In this study, we investigated the effect of CTLA4-Ig on EAU development and compared it with the effect of anti-IL-6 receptor monoclonal antibody (MR16-1). C57BL/6J mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) and treated once with CTLA4-Ig or MR16-1. Both CTLA4-Ig and MR16-1 administered in the induction phase (the same day as immunization) significantly reduced the clinical and histopathological scores of EAU. Fluorescence-activated cell sorting studies using draining lymph node (LN) cells from EAU mice 10 days after immunization showed that CTLA4-Ig can suppress early T-helper cell activation. CTLA4-Ig administered in the effector phase of the disease (one week after immunization), when IRBP-reactive T cells have been primed, also significantly reduced the clinical and histopathological scores of EAU. In contrast, MR16-1 administered in the effector phase did not ameliorate EAU. To investigate the differences between these biologics in the effector phase, in vitro restimulation analysis of LN cells obtained from EAU mice one week after immunization was performed and revealed that CTLA4-Ig, but not MR16-1, added to culture media could inhibit the proliferation of IRBP-specific CD4(+) T cells which possessed capacities of producing IFN-gamma and/or IL-17. Collectively, CTLA4-Ig ameliorated EAU through preventing initial T-cell activation in the induction phase and suppressing

  6. Predicting reasoning from memory.

    PubMed

    Heit, Evan; Hayes, Brett K

    2011-02-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the presence of stimuli from other categories, there was a high correlation between reasoning and memory responses (average r = .87), and these manipulations showed similar effects on the 2 tasks. The results point to common mechanisms underlying inductive reasoning and recognition memory abilities. A mathematical model, GEN-EX (generalization from examples), derived from exemplar models of categorization, is presented, which predicts both reasoning and memory responses from pairwise similarities among the stimuli, allowing for additional influences of subtyping and deterministic responding.

  7. The Contribution of Spatial and Temporal Molecular Networks in the Induction of Long-term Memory and Its Underlying Synaptic Plasticity

    PubMed Central

    Mirisis, Anastasios A.; Alexandrescu, Anamaria; Carew, Thomas J.; Kopec, Ashley M.

    2016-01-01

    The ability to form long-lasting memories is critical to survival and thus is highly conserved across the animal kingdom. By virtue of its complexity, this same ability is vulnerable to disruption by a wide variety of neuronal traumas and pathologies. To identify effective therapies with which to treat memory disorders, it is critical to have a clear understanding of the cellular and molecular mechanisms which subserve normal learning and memory. A significant challenge to achieving this level of understanding is posed by the wide range of distinct temporal and spatial profiles of molecular signaling induced by learning-related stimuli. In this review we propose that a useful framework within which to address this challenge is to view the molecular foundation of long-lasting plasticity as composed of unique spatial and temporal molecular networks that mediate signaling both within neurons (such as via kinase signaling) as well as between neurons (such as via growth factor signaling). We propose that evaluating how cells integrate and interpret these concurrent and interacting molecular networks has the potential to significantly advance our understanding of the mechanisms underlying learning and memory formation. PMID:27819030

  8. Evaluation of the Induction of Immune Memory following Infant Immunisation with Serogroup C Neisseria meningitidis Conjugate Vaccines – Exploratory Analyses within a Randomised Controlled Trial

    PubMed Central

    Khatami, Ameneh; Clutterbuck, Elizabeth A.; Thompson, Amber J.; McKenna, Jennifer A.; Pace, David; Birks, Jacqueline; Snape, Matthew D.; Pollard, Andrew J.

    2014-01-01

    Aim We measured meningococcal serogroup C (MenC)-specific memory B-cell responses in infants by Enzyme-Linked Immunospot (ELISpot) following different MenC conjugate vaccine schedules to investigate the impact of priming on immune memory. Methods Infants aged 2 months were randomised to receive 1 or 2 doses of MenC-CRM197 at 3 or 3 and 4 months, 1 dose of MenC-TT at 3 months, or no primary MenC doses. All children received a Haemophilus influenzae type b (Hib)-MenC booster at 12 months. Blood was drawn at 5, 12, 12 months +6 days and 13 months of age. Results Results were available for 110, 103, 76 and 44 children from each group respectively. Following primary immunisations, and prior to the 12-month booster, there were no significant differences between 1- or 2-dose primed children in the number of MenC memory B-cells detected. One month following the booster, children primed with 1 dose MenC-TT had more memory B-cells than children primed with either 1-dose (p = 0.001) or 2-dose (p<0.0001) MenC-CRM197. There were no differences in MenC memory B-cells detected in children who received 1 or 2 doses of MenC-CRM197 in infancy and un-primed children. Conclusions MenC-specific memory B-cell production may be more dependent on the type of primary vaccine used than the number of doses administered. Although the mechanistic differences between MenC-CRM197 and MenC-TT priming are unclear, it is possible that structural differences, including the carrier proteins, may underlie differential interactions with B- and T-cell populations, and thus different effects on various memory B-cell subsets. A MenC-TT/Hib-MenC-TT combination for priming/boosting may offer an advantage in inducing more persistent antibody. Trial Registration EU Clinical Trials Register 2009-016579-31 ClinicalTrials.gov NCT01129518 PMID:25020050

  9. Prostaglandin E2 EP2 activation reduces memory decline in R6/1 mouse model of Huntington's disease by the induction of BDNF-dependent synaptic plasticity.

    PubMed

    Anglada-Huguet, Marta; Vidal-Sancho, Laura; Giralt, Albert; García-Díaz Barriga, Gerardo; Xifró, Xavier; Alberch, Jordi

    2016-11-01

    Huntington's disease (HD) patients and mouse models show learning and memory impairment even before the onset of motor symptoms. Deficits in hippocampal synaptic plasticity have been involved in the HD memory impairment. Several studies show that prostaglandin E2 (PGE2) EP2 receptor stimulates synaptic plasticity and memory formation. However, this role was not explored in neurodegenerative diseases. Here, we investigated the capacity of PGE2 EP2 receptor to promote synaptic plasticity and memory improvements in a model of HD, the R6/1 mice, by administration of the agonist misoprostol. We found that misoprostol increases dendritic branching in cultured hippocampal neurons in a brain-derived neurotrophic factor (BDNF)-dependent manner. Then, we implanted an osmotic mini-pump system to chronically administrate misoprostol to R6/1 mice from 14 to 18weeks of age. We observed that misoprostol treatment ameliorates the R6/1 long-term memory deficits as analyzed by the T-maze spontaneous alternation task and the novel object recognition test. Importantly, administration of misoprostol promoted the expression of hippocampal BDNF. Moreover, the treatment with misoprostol in R6/1 mice blocked the reduction in the number of PSD-95 and VGluT-1 positive particles observed in hippocampus of vehicle-R6/1 mice. In addition, we observed an increase of cAMP levels in the dentate ` of WT and R6/1 mice treated with misoprostol. Accordingly, we showed a reduction in the number of mutant huntingtin nuclear inclusions in the dentate gyrus of R6/1 mice. Altogether, these results suggest a putative therapeutic effect of PGE2 EP2 receptor in reducing cognitive deficits in HD.

  10. Induction of Plasmodium falciparum-Specific CD4+ T Cells and Memory B Cells in Gabonese Children Vaccinated with RTS,S/AS01E and RTS,S/AS02D

    PubMed Central

    Agnandji, Selidji T.; Fendel, Rolf; Mestré, Michaël; Janssens, Michel; Vekemans, Johan; Held, Jana; Gnansounou, Ferdinand; Haertle, Sonja; von Glasenapp, Isabel; Oyakhirome, Sunny; Mewono, Ludovic; Moris, Philippe; Lievens, Marc; Demoitie, Marie-Ange; Dubois, Patrice M.; Villafana, Tonya; Jongert, Erik; Olivier, Aurelie; Cohen, Joe; Esen, Meral; Kremsner, Peter G.; Lell, Bertrand; Mordmüller, Benjamin

    2011-01-01

    The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01E and RTS,S/AS02D. Our data show that a CS-specific memory B cell response is induced one month after the second and third vaccine dose and that CS-specific antibodies and memory B cells persist up to 12 months after the last vaccine injection. Both formulations also induced low but significant amounts of CS-specific IL-2+ CD4+ T cells one month after the second and third vaccine dose, upon short-term in vitro stimulation of whole blood cells with peptides covering the entire CS derived sequence in RTS,S. These results provide evidence that both RTS,S/AS01E and RTS,S/AS02D induced adaptive immune responses including antibodies, circulating memory B cells and CD4+ T cells directed against P. falciparum CS protein. Trial Registration ClinicalTrials.gov NCT00307021 PMID:21494604

  11. Expression of chicken interleukin-2 by a highly virulent strain of Newcastle disease virus leads to decreased systemic viral load but does not significantly affect mortality in chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In mammals, interleukin 2 (IL-2) has been shown to decrease replication or attenuate pathogenicity of numerous viral pathogens by activating natural killer cells (NK), cytotoxic T lymphocytes, and expanding subsets of memory cells. In chickens, IL-2 has been shown to activate T cells, and as such i...

  12. Induction of eEF2-specific antitumor CTL responses in vivo by vaccination with eEF2-derived 9mer-peptides.

    PubMed

    Nakajima, Hiroko; Murakami, Yui; Morii, Eiichi; Akao, Toshiki; Tatsumi, Naoya; Odajima, Satoko; Fukuda, Mari; Machitani, Takao; Iwai, Miki; Kawata, Sayo; Hojo, Nozomi; Oka, Yoshihiro; Sugiyama, Haruo; Oji, Yusuke

    2016-04-01

    Eukaryotic elongation factor 2 (eEF2) is an essential factor for protein synthesis. Previous studies have shown that the eEF2 gene was overexpressed and plays an oncogenic role in various types of cancers and that eEF2 gene product elicited both humoral immune responses to produce eEF2-specific IgG autoantibody in cancer-bearing individuals and cellular immune responses to induce eEF2 peptide-specific cytotoxic T lymphocytes (CTLs) in vitro. The purpose of the present study was to induce eEF2-specific, antitumor CTL responses in vivo by vaccination with MHC class I-binding eEF2-derived peptide. First, two mouse MHC class I-restricted eEF2‑derived, 9-mer peptides, EF17 (17-25 aa, ANIRNMSVI) and EF180 (180-188 aa, RIVENVNVI) were identified as eEF2-specific CTL peptides, and mice were vaccinated intradermally eight times with either EF17 or EF180 peptide emulsified with Montanide ISA51 adjuvant. Cytotoxicity assay showed that eEF2-specific CTLs were induced in both EF17‑and EF180‑vaccinated mice, and histological study showed no detectable damage in the organs of these mice. Next, to examine in vivo antitumor effects of eEF2 peptide vaccination in a therapeutic model, mice were vaccinated four times with one each of the two eEF2 peptides at weekly intervals after implantation of eEF2-expressing leukemia cells. The vaccination with eEF2 peptides induced eEF2-specific CTLs and suppressed tumor growth, and disease-free survival was significantly longer in EF180-vaccinated mice compared to control mice. The survival was associated with the robustness of eEF2-specific CTL induction. These results indicate that vaccination with MHC class I-binding eEF2 peptide induced eEF2-targeting, antitumor CTL responses in vivo without damage to normal organs, which provided us a rationale for eEF2 peptide-based cancer immunotherapy.

  13. Applying a dual process model of self-regulation: The association between executive working memory capacity, negative urgency, and negative mood induction on pre-potent response inhibition.

    PubMed

    Gunn, Rachel L; Finn, Peter R

    2015-03-01

    This study tested a dual-process model of self-control where the combination of high impulsivity (negative urgency - NU), weak reflective / control processes (low executive working memory capacity - E-WMC), and a cognitive load is associated with increased failures to inhibit pre-potent responses on a cued go/no-go task. Using a within-subjects design, a cognitive load with and without negative emotional load was implemented to consider situational factors. Results suggested that: (1) high NU was associated with low E-WMC; (2) low E-WMC significantly predicted more inhibitory control failures across tasks; and (3) there was a significant interaction of E-WMC and NU, revealing those with low E-WMC and high NU had the highest rates of inhibitory control failures on all conditions of the task. In conclusion, results suggest that while E-WMC is a strong independent predictor of inhibitory control, NU provides additional information for vulnerability to problems associated with self-regulation.

  14. Applying a dual process model of self-regulation: The association between executive working memory capacity, negative urgency, and negative mood induction on pre-potent response inhibition

    PubMed Central

    Gunn, Rachel L.; Finn, Peter R.

    2014-01-01

    This study tested a dual-process model of self-control where the combination of high impulsivity (negative urgency – NU), weak reflective / control processes (low executive working memory capacity - E-WMC), and a cognitive load is associated with increased failures to inhibit pre-potent responses on a cued go/no-go task. Using a within-subjects design, a cognitive load with and without negative emotional load was implemented to consider situational factors. Results suggested that: (1) high NU was associated with low E-WMC; (2) low E-WMC significantly predicted more inhibitory control failures across tasks; and (3) there was a significant interaction of E-WMC and NU, revealing those with low E-WMC and high NU had the highest rates of inhibitory control failures on all conditions of the task. In conclusion, results suggest that while E-WMC is a strong independent predictor of inhibitory control, NU provides additional information for vulnerability to problems associated with self-regulation. PMID:25530648

  15. Gravitational induction

    NASA Astrophysics Data System (ADS)

    Bini, Donato; Cherubini, Christian; Chicone, Carmen; Mashhoon, Bahram

    2008-11-01

    We study the linear post-Newtonian approximation to general relativity known as gravitoelectromagnetism (GEM); in particular, we examine the similarities and differences between GEM and electrodynamics. Notwithstanding some significant differences between them, we find that a special nonstationary metric in GEM can be employed to show explicitly that it is possible to introduce gravitational induction within GEM in close analogy with Faraday's law of induction and Lenz's law in electrodynamics. Some of the physical implications of gravitational induction are briefly discussed.

  16. Induction of cytotoxic T cell precursors in vivo. Role of T helper cells

    PubMed Central

    1983-01-01

    Strain AS rats respond with two populations of cytotoxic T lymphocytes to stimulation in vitro by the major histocompatibility complex (MHC)- incompatible strain HL rat tumor (HL-A2T2). One is specific for MHC alloantigens present on both HL-A2T2 and normal HL targets, the other is tumor specific. The activation of these killer cells requires helper T lymphocytes. The tumor-specific helper cells depend on syngeneic radioresistant accessory cells to present the tumor antigens in an immunogenic form. The appropriate helper-accessory cell interaction results in the production of soluble factors which then induce the maturation of precursor cells into effective killer cells. Studies with a procedure for inducing negative selection of T cells in vivo showed that short-term exposure to HL-A2T2 tumor induced selection only for TH but not cytotoxic T lymphocyte precursors (CTLp). Simultaneous injection of supernatants from concanavalin A-activated spleen cell cultures, however, did produce selection of CTLp. These and other findings suggest that under normal circumstances in vivo, both signals (recognition of antigen and acceptance of maturation factors) are provided in the vicinity of an antigen presenting macrophage-like accessory cell. PMID:6222131

  17. Inductive reasoning.

    PubMed

    Hayes, Brett K; Heit, Evan; Swendsen, Haruka

    2010-03-01

    Inductive reasoning entails using existing knowledge or observations to make predictions about novel cases. We review recent findings in research on category-based induction as well as theoretical models of these results, including similarity-based models, connectionist networks, an account based on relevance theory, Bayesian models, and other mathematical models. A number of touchstone empirical phenomena that involve taxonomic similarity are described. We also examine phenomena involving more complex background knowledge about premises and conclusions of inductive arguments and the properties referenced. Earlier models are shown to give a good account of similarity-based phenomena but not knowledge-based phenomena. Recent models that aim to account for both similarity-based and knowledge-based phenomena are reviewed and evaluated. Among the most important new directions in induction research are a focus on induction with uncertain premise categories, the modeling of the relationship between inductive and deductive reasoning, and examination of the neural substrates of induction. A common theme in both the well-established and emerging lines of induction research is the need to develop well-articulated and empirically testable formal models of induction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

  18. Electrical stimulation during skill training with a therapeutic glove enhances the induction of cortical plasticity and has a positive effect on motor memory.

    PubMed

    Christova, Monica; Rafolt, Dietmar; Golaszewski, Stefan; Nardone, Raffaele; Gallasch, Eugen

    2014-08-15

    To examine whether afferent stimulation of hand muscles has a facilitating effect on motor performance, learning and cortical excitability, healthy subjects were trained on the grooved pegboard test (GTP) while wearing a mesh glove (MG) with incorporated electrical stimulation. Three study groups (n=12) were compared in a between subjects design, the bare handed (BH), gloved (MG) and gloved with electrical stimulation (MGS) groups. Motor performance was assessed by the GPT completion time across 4 training blocks, and further one block was retested 7 days later to determine the off-line effects. On-line learning was obtained by normalizing the completion time values to the first training block, and off-line learning was obtained by normalizing the retest values to the last training block. Cortical excitability was assessed via single and paired-pulse transcranial magnetic stimulation (TMS) at pre-training, post-training and 30 min post-training. Motor evoked potential recruitment curve, short-latency intracortical inhibition and intracortical facilitation were estimated from the TMS assessments. Motor performance across all 4 training blocks was poor in the MG and MGS groups, while on-line learning was not affected by wearing the glove or by afferent stimulation. However, off-line learning, tested 7 days after training, was improved in the MGS group compared to the MG group. In addition, post-training corticospinal excitability was increased in the MGS group. It can be concluded that afferent stimulation improves off-line learning and thus has a positive effect on motor memory, likely due to LTP-like cortical plasticity in the consolidation phase.

  19. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-08-15

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  20. Mechanical memory

    DOEpatents

    Gilkey, Jeffrey C.; Duesterhaus, Michelle A.; Peter, Frank J.; Renn, Rosemarie A.; Baker, Michael S.

    2006-05-16

    A first-in-first-out (FIFO) microelectromechanical memory apparatus (also termed a mechanical memory) is disclosed. The mechanical memory utilizes a plurality of memory cells, with each memory cell having a beam which can be bowed in either of two directions of curvature to indicate two different logic states for that memory cell. The memory cells can be arranged around a wheel which operates as a clocking actuator to serially shift data from one memory cell to the next. The mechanical memory can be formed using conventional surface micromachining, and can be formed as either a nonvolatile memory or as a volatile memory.

  1. Abatacept (cytotoxic T lymphocyte antigen 4-immunoglobulin) improves B cell function and regulatory T cell inhibitory capacity in rheumatoid arthritis patients non-responding to anti-tumour necrosis factor-α agents.

    PubMed

    Picchianti Diamanti, A; Rosado, M M; Scarsella, M; Germano, V; Giorda, E; Cascioli, S; Laganà, B; D'Amelio, R; Carsetti, R

    2014-09-01

    The use of biological agents combined with methotrexate (MTX) in rheumatoid arthritis (RA) patients has strongly improved disease outcome. In this study, the effects of abatacept on the size and function of circulating B and T cells in RA patients not responding to anti-tumour necrosis factor (TNF)-α have been analysed, with the aim of identifying immunological parameters helpful to choosing suitable tailored therapies. We analysed the frequency of peripheral B and T cell subsets, B cell function and T regulatory cell (Treg ) inhibitory function in 20 moderate/severe RA patients, according to the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) criteria, primary non-responders to one TNF-α blocking agent, who received abatacept + MTX. Patients were studied before and 6 months after therapy. We found that abatacept therapy significantly reduced disease activity score on 44 joints (DAS)/erythrocyte sedimentation rate (ESR) values without causing severe side effects. The size of the circulating B and T cell compartments in RA patients was not significantly different from healthy donors, but B cell proliferation and plasma cell differentiation was impaired before therapy and restored by abatacept. While Treg cell frequency was normal, its inhibitory function was absent before therapy and was partially recovered 6 months after abatacept. B and Treg cell function is impaired in RA patients not responding to the first anti-TNF-α agent. Abatacept therapy was able to rescue immune function and led to an effective and safe clinical outcome, suggesting that RA patients, in whom anti-TNF-α failed, are immunologically prone to benefit from an agent targeting a different pathway.

  2. Analysis of the T-cell receptor repertoire of human T-cell leukemia virus type 1 (HTLV-1) Tax-specific CD8+ cytotoxic T lymphocytes from patients with HTLV-1-associated disease: evidence for oligoclonal expansion.

    PubMed

    Utz, U; Banks, D; Jacobson, S; Biddison, W E

    1996-02-01

    Human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic, progressive neurological disease characterized by marked degeneration of the spinal cord and the presence of antibodies against HTLV-1. Patients with HAM/TSP, but not asymptomatic carriers, show very high precursor frequencies of HTLV-1-specific CD8+ T cells in peripheral blood and cerebrospinal fluid, suggestive of a role of these T cells in the pathogenesis of the disease. In HLA-A2+ HAM/TSP patients, HTLV-1-specific T cells were demonstrated to be directed predominantly against one HTLV-1 epitope, namely, Tax11-19. In the present study, we analyzed HLA-A2-restricted HTLV-1 Tax11-19-specific cytotoxic T cells from three patients with HAM/TSP. An analysis of the T-cell receptor (TCR) repertoire of these cells revealed an absence of restricted variable (V) region usage. Different combinations of TCR V alpha and V beta genes were utilized between, but also within, the individual patients for the recognition of Tax11-19. Sequence analysis of the TCR showed evidence for an oligoclonal expansion of few founder T cells in each patient. Apparent structural motifs were identified for the CDR3 regions of the TCR beta chains. One T-cell clone could be detected within the same patient over a period of 3 years. We suggest that these in vivo clonally expanded T cells might play a role in the pathogenesis of HAM/TSP and provide information on HTLV-1-specific TCR which may elucidate the nature of the T cells that infiltrate the central nervous system in HAM/TSP patients.

  3. Neurotransmitter Suppression of the In Vitro Generation of the Cytotoxic T-Lymphocyte Response Against Syngeneic MOPC-315 Plasmacytomas by Spleen Cells from Melphalan-Cured MOPC-315 Tumor Bearers (Catecholamine Inhibition of Tumor Immunity Following Chemotherapy)

    DTIC Science & Technology

    1991-01-01

    chosen because it is the lowest dose of melphalan which is curative for at least 90% of mice 8 bearing a large (>20 mm) MOPC-315 tumor (22). Spleen...2+ T-ce!ls in the curative effectiveness of a low dose of melphalin for mice bearing a large MOPC-315 tumor. Cancer Res., 49:4597-4606, 1989. 35

  4. Intradermal vaccination of adults with three low doses (2 micrograms) of recombinant hepatitis B vaccine. II. Persistence of immunity and induction of immunologic memory.

    PubMed

    Elisbão, Maria do Carmo M; Baldy, José Luís da S; Bonametti, Ana Maria; Reiche, Edna Maria V; Morimoto, Helena K; Pontello, Rubens; Matsuo, Tiemi; Ferelle, Antônio; Neves, Jayme

    2003-12-01

    Of the 110 dentists who had presented seroconversion 50 days after the intradermal application of three 2 micrograms doses of the Belgian recombinant vaccine against hepatitis B (HB), administered eight years before at an interval of one month between the 1st and 2nd doses and of five months between the 2nd and 3rd doses, 51 were included for the assessment of the persistence of immunity. None of the dentists had hepatitis or had received HB vaccine during this period. All subjects were submitted to serological tests for the detection of the following markers of hepatitis B virus (HBV) infection: HBsAg, anti-HBc, HBeAg, anti-HBe, and anti-HBs, with no HBsAg, anti-HBc, HBeAg or anti-HBe being detected. A microparticle enzyme immunoassay (MEIA) revealed the presence of anti-HBs at protective titers (> or = 10 mIU/ml) in 42 dentists (82.4%), with the anti-HBs titer being higher than 100 mIU/ml in 36 of them (70.6%) (good responders), between 10 and 100 mIU/ml in 6 (11.8%) (poor responders), and lower than 10 mIU/ml in 9 (17.6%) (non-responders). According to clinical data and serological tests, none of the dentists had presented disease or latent HBV infection during the eight years following the first vaccination. A 2 micrograms booster dose was administered intradermally to eight dentists with anti-HBs titers lower than 10 mIU/ml (non-responders) and to six dentists with titers ranging from 10 to 100 mIU/ml (poor responders); the determination of anti-HBs one month later demonstrated the occurrence of seroconversion in the eight non-responders and an increase in anti-HBs titer in the six poor responders. In summary, the present results demonstrated the prolonged persistence of protection against HBV infection and the development of immunologic memory provided by vaccination against HB--with intradermal application of three 2 micrograms doses of the Belgian recombinant vaccine at 0, 1, and 6 months--carried out eight years before in 51 dentists.

  5. Induction voidmeter

    DOEpatents

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Brewer, John

    1986-01-01

    An induction voidmeter for detecting voids in a conductive fluid may comprise: a four arm bridge circuit having two adjustable circuit elements connected as opposite arms of said bridge circuit, an input branch, and an output branch; two induction coils, bifilarly wound together, connected as the remaining two opposing arms of said bridge circuit and positioned such that the conductive fluid passes through said coils; applying an AC excitation signal to said input branch; and detecting the output signal generated in response to said excitation signal across said output branch. The induction coils may be located outside or inside a non-magnetic pipe containing the conductive fluid.

  6. Induction voidmeter

    DOEpatents

    Anderson, T.T.; Roop, C.J.; Schmidt, K.J.; Brewer, J.

    1983-12-21

    An induction voidmeter for detecting voids in a conductive fluid may comprise: a four arm bridge circuit having two adjustable circuit elements connected as opposite arms of said bridge, an input branch, and an output branch; two induction coils, bifilarly wound together, connected as the remaining two opposing arms of said bridge circuit and positioned such that the conductive fluid passes through said coils; means for applying an AC excitation signal to said input branch; and means for detecting the output signal generated in response to said excitation signal across said output branch. The induction coils may be located outside or inside a non-magnetic pipe containing the conductive fluid.

  7. The Evolving Roles of Memory Immune Cells in Transplantation.

    PubMed

    Chen, Wenhao; Ghobrial, Rafik M; Li, Xian C

    2015-10-01

    Memory cells are the products of immune responses but also exert significant impact on subsequent immunity and immune tolerance, thus placing them in a unique position in transplant research. Memory cells are heterogeneous, including not only memory T cells but also memory B cells and innate memory cells. Memory cells are a critical component of protective immunity against invading pathogens, especially in immunosuppressed patients, but they also mediate graft loss and tolerance resistance. Recent studies suggest that some memory cells unexpectedly act as regulatory cells, promoting rather than hindering transplant survival. This functional diversity makes therapeutic targeting of memory cells a challenging task in transplantation. In this article, we highlight recent advances in our understanding of memory cells, focusing on diversity of memory cells and mechanisms involved in their induction and functions. We also provide a broad overview on the challenges and opportunities in targeting memory cells in the induction of transplant tolerance.

  8. The role of stress during memory reactivation on intrusive memories.

    PubMed

    Cheung, Jessica; Garber, Benjamin; Bryant, Richard A

    2015-09-01

    Intrusive memories are unwanted recollections that maintain distress in psychological disorders. Increasing evidence suggests that memories that are reactivated through retrieval become temporarily vulnerable to environmental or pharmacological manipulation, including changes in levels of circulating stress hormones. This study investigated the influence of stress during memory reactivation of an emotionally arousing trauma film on subsequent intrusive memories. Three groups of participants (N=63) viewed a trauma film depicting a serious car accident at baseline. Two days later (Time 2), one group received a reactivation induction following a socially evaluated cold pressor test (SECPT; Stress/Reactivation condition), whilst the second group reactivated the memory after a control procedure (Reactivation condition). A third group underwent the SECPT but was not asked to reactivate memory of the trauma film (Stress condition). Two days later (Time 3), all participants received a surprise cued memory recall test and intrusions questionnaire which they completed online. Results showed that those in the Stress/Reactivation group had higher intrusions scores than the other two groups, suggesting that acute stress promotes intrusive memories only when the memory trace is reactivated shortly afterwards. Increased cortisol predicted enhanced intrusive experiences in the Stress/Reactivation condition but not in the other conditions. This pattern of results suggests that acute stress during the reactivation of emotional material impacts on involuntary emotional memories. These findings suggest a possible explanation for the mechanism underlying the maintenance of intrusive memories in clinical disorders.

  9. Memory Matters

    MedlinePlus

    ... different parts. Some of them are important for memory. The hippocampus (say: hih-puh-KAM-pus) is one of the more important parts of the brain that processes memories. Old information and new information, or memories, are ...

  10. Induction synchrotron

    NASA Astrophysics Data System (ADS)

    Takayama, Ken; Kishiro, Junichi

    2000-08-01

    A novel proton synchrotron employing induction cells instead of radio frequency cavities is proposed. The major feature of the barrier bucket acceleration, where acceleration and longitudinal focusing are independently achieved is theoretically discussed with the help of multi-particle simulations. It is proved that barrier bucket acceleration allows ultimate use of longitudinal phase-space and is quite effective to substantially increase the beam intensity in synchrotrons. Engineering aspects of key devices to realize the novel synchrotron, a ferri/ferro-magnetic material loaded induction cell and a modulator being rapidly switched in synchronization with beam acceleration are described in detail. The idea is applied to an existing machine (the KEK 12 GeV-PS) and high-intensity proton rings such as JHF, ESS, and SNS and their predicted improvement in machine performance is given with numerical values for each case.

  11. Induction machine

    DOEpatents

    Owen, Whitney H.

    1980-01-01

    A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

  12. Boosting Tumor-Specific Immunity Using PDT

    PubMed Central

    Maeding, Nicole; Verwanger, Thomas; Krammer, Barbara

    2016-01-01

    Photodynamic therapy (PDT) is a cancer treatment with a long-standing history. It employs the application of nontoxic components, namely a light-sensitive photosensitizer and visible light, to generate reactive oxygen species (ROS). These ROS lead to tumor cell destruction, which is accompanied by the induction of an acute inflammatory response. This inflammatory process sends a danger signal to the innate immune system, which results in activation of specific cell types and release of additional inflammatory mediators. Activation of the innate immune response is necessary for subsequent induction of the adaptive arm of the immune system. This includes the priming of tumor-specific cytotoxic T lymphocytes (CTL) that have the capability to directly recognize and kill cells which display an altered self. The past decades have brought increasing appreciation for the importance of the generation of an adaptive immune response for long-term tumor control and induction of immune memory to combat recurrent disease. This has led to considerable effort to elucidate the immune effects PDT treatment elicits. In this review we deal with the progress which has been made during the past 20 years in uncovering the role of PDT in the induction of the tumor-specific immune response, with special emphasis on adaptive immunity. PMID:27782066

  13. Memory Matters

    MedlinePlus

    ... blood vessel (which carries the blood) bursts. continue Brain Injuries Affect Memory At any age, an injury to ... with somebody's memory. Some people who recover from brain injuries need to learn old things all over again, ...

  14. Relations between Inductive Reasoning and Deductive Reasoning

    ERIC Educational Resources Information Center

    Heit, Evan; Rotello, Caren M.

    2010-01-01

    One of the most important open questions in reasoning research is how inductive reasoning and deductive reasoning are related. In an effort to address this question, we applied methods and concepts from memory research. We used 2 experiments to examine the effects of logical validity and premise-conclusion similarity on evaluation of arguments.…

  15. LTP Induction Modifies Functional Relationship among Hippocampal Neurons

    ERIC Educational Resources Information Center

    Yun, Sung H.; Lee, Deok S.; Lee, Hyunjung; Baeg, Eun H.; Kim, Yun B.; Jung, Min W.

    2007-01-01

    To obtain evidence linking long-term potentiation (LTP) and memory, we examined whether LTP induction modifies functional relationship among neurons in the rat hippocampus. In contrast to neurons in low-frequency stimulated or AP5-treated slices, LTP induction altered "functional connectivity," as defined by the degree of synchronous firing, among…

  16. Unities in Inductive Reasoning. Technical Report No. 18.

    ERIC Educational Resources Information Center

    Sternberg, Robert J.; Gardner, Michael K.

    Two experiments were performed to study inductive reasoning as a set of thought processes that operates on the structure, as opposed to the content, of organized memory. The content of the reasoning consisted of inductions concerning the names of mammals, assumed to occupy a Euclidean space of three dimensions (size, ferocity, and humanness) in…

  17. Memory Dysfunction

    PubMed Central

    Matthews, Brandy R.

    2015-01-01

    Purpose of Review: This article highlights the dissociable human memory systems of episodic, semantic, and procedural memory in the context of neurologic illnesses known to adversely affect specific neuroanatomic structures relevant to each memory system. Recent Findings: Advances in functional neuroimaging and refinement of neuropsychological and bedside assessment tools continue to support a model of multiple memory systems that are distinct yet complementary and to support the potential for one system to be engaged as a compensatory strategy when a counterpart system fails. Summary: Episodic memory, the ability to recall personal episodes, is the subtype of memory most often perceived as dysfunctional by patients and informants. Medial temporal lobe structures, especially the hippocampal formation and associated cortical and subcortical structures, are most often associated with episodic memory loss. Episodic memory dysfunction may present acutely, as in concussion; transiently, as in transient global amnesia (TGA); subacutely, as in thiamine deficiency; or chronically, as in Alzheimer disease. Semantic memory refers to acquired knowledge about the world. Anterior and inferior temporal lobe structures are most often associated with semantic memory loss. The semantic variant of primary progressive aphasia (svPPA) is the paradigmatic disorder resulting in predominant semantic memory dysfunction. Working memory, associated with frontal lobe function, is the active maintenance of information in the mind that can be potentially manipulated to complete goal-directed tasks. Procedural memory, the ability to learn skills that become automatic, involves the basal ganglia, cerebellum, and supplementary motor cortex. Parkinson disease and related disorders result in procedural memory deficits. Most memory concerns warrant bedside cognitive or neuropsychological evaluation and neuroimaging to assess for specific neuropathologies and guide treatment. PMID:26039844

  18. Memory protection

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    Accidental overwriting of files or of memory regions belonging to other programs, browsing of personal files by superusers, Trojan horses, and viruses are examples of breakdowns in workstations and personal computers that would be significantly reduced by memory protection. Memory protection is the capability of an operating system and supporting hardware to delimit segments of memory, to control whether segments can be read from or written into, and to confine accesses of a program to its segments alone. The absence of memory protection in many operating systems today is the result of a bias toward a narrow definition of performance as maximum instruction-execution rate. A broader definition, including the time to get the job done, makes clear that cost of recovery from memory interference errors reduces expected performance. The mechanisms of memory protection are well understood, powerful, efficient, and elegant. They add to performance in the broad sense without reducing instruction execution rate.

  19. Memory B cells contribute to rapid Bcl6 expression by memory follicular helper T cells.

    PubMed

    Ise, Wataru; Inoue, Takeshi; McLachlan, James B; Kometani, Kohei; Kubo, Masato; Okada, Takaharu; Kurosaki, Tomohiro

    2014-08-12

    In primary humoral responses, B-cell lymphoma 6 (Bcl6) is a master regulator of follicular helper T (TFH) cell differentiation; however, its activation mechanisms and role in memory responses remain unclear. Here we demonstrate that survival of CXCR5(+) TFH memory cells, and thus subsequent recall antibody response, require Bcl6 expression. Furthermore, we show that, upon rechallenge with soluble antigen Bcl6 in memory TFH cells is rapidly induced in a dendritic cell-independent manner and that peptide:class II complexes (pMHC) on cognate memory B cells significantly contribute to this induction. Given the previous evidence that antigen-specific B cells residing in the follicles acquire antigens within minutes of injection, our results suggest that memory B cells present antigens to the cognate TFH memory cells, thereby contributing to rapid Bcl6 reexpression and differentiation of the TFH memory cells during humoral memory responses.

  20. Flashbulb Memories

    PubMed Central

    Hirst, William; Phelps, Elizabeth A.

    2015-01-01

    We review and analyze the key theories, debates, findings, and omissions of the existing literature on flashbulb memories (FBMs), including what factors affect their formation, retention, and degree of confidence. We argue that FBMs do not require special memory mechanisms and are best characterized as involving both forgetting and mnemonic distortions, despite a high level of confidence. Factual memories for FBM-inducing events generally follow a similar pattern. Although no necessary and sufficient factors straightforwardly account for FBM retention, media attention particularly shapes memory for the events themselves. FBMs are best characterized in term of repetitions, even of mnemonic distortions, whereas event memories evidence corrections. The bearing of this literature on social identity and traumatic memories is also discussed. PMID:26997762

  1. Virtual memory

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Virtual memory was conceived as a way to automate overlaying of program segments. Modern computers have very large main memories, but need automatic solutions to the relocation and protection problems. Virtual memory serves this need as well and is thus useful in computers of all sizes. The history of the idea is traced, showing how it has become a widespread, little noticed feature of computers today.

  2. Skilled Memory.

    DTIC Science & Technology

    1980-11-06

    Morse code (Bryan & Harter , 1899). In every case, memory performance of the expert seems to violate the established limits of short- term memory. How is...of immediate memory. Quarterly Journal of Experimental psychology, 1958, 10, 12-21. Bryan, W. L., & Harter N. psychological Review, 1899, 6, 345-375...16, 1980 Page 5 Civil Govt Non Govt Dr. Susan Chipman 1 Dr. John R. Anderson Learning and Development Department of Psychology National Institute of

  3. A dynamic model of reasoning and memory.

    PubMed

    Hawkins, Guy E; Hayes, Brett K; Heit, Evan

    2016-02-01

    Previous models of category-based induction have neglected how the process of induction unfolds over time. We conceive of induction as a dynamic process and provide the first fine-grained examination of the distribution of response times observed in inductive reasoning. We used these data to develop and empirically test the first major quantitative modeling scheme that simultaneously accounts for inductive decisions and their time course. The model assumes that knowledge of similarity relations among novel test probes and items stored in memory drive an accumulation-to-bound sequential sampling process: Test probes with high similarity to studied exemplars are more likely to trigger a generalization response, and more rapidly, than items with low exemplar similarity. We contrast data and model predictions for inductive decisions with a recognition memory task using a common stimulus set. Hierarchical Bayesian analyses across 2 experiments demonstrated that inductive reasoning and recognition memory primarily differ in the threshold to trigger a decision: Observers required less evidence to make a property generalization judgment (induction) than an identity statement about a previously studied item (recognition). Experiment 1 and a condition emphasizing decision speed in Experiment 2 also found evidence that inductive decisions use lower quality similarity-based information than recognition. The findings suggest that induction might represent a less cautious form of recognition. We conclude that sequential sampling models grounded in exemplar-based similarity, combined with hierarchical Bayesian analysis, provide a more fine-grained and informative analysis of the processes involved in inductive reasoning than is possible solely through examination of choice data.

  4. Sleep unbinds memories from their emotional context.

    PubMed

    Deliens, Gaétane; Gilson, Médhi; Schmitz, Rémy; Peigneux, Philippe

    2013-09-01

    Consistent evidence nowadays indicates that sleep protects declarative memory from lexical interference. However, little is known about its effect against emotional interference. In a within-subject counterbalanced design, participants learned a list of word pairs after a mood induction procedure (MIP), then slept or stayed awake during the post-learning night. After two recovery nights, half of the list was recalled after a similar mood induction than at the encoding session (no interference condition) and the other half after a different mood induction (interference condition). Amongst participants for whom the MIP was effective, an emotional interference effect appeared only in the sleep-deprived condition, with a lower recall of word pairs subjected to contextual interference than of the other pairs. These findings support the hypothesis of a decoupling between memories and their "affective blanket" during post-learning sleep, protecting recent memories against emotional contextual interference.

  5. Episodic Memories

    ERIC Educational Resources Information Center

    Conway, Martin A.

    2009-01-01

    An account of episodic memories is developed that focuses on the types of knowledge they represent, their properties, and the functions they might serve. It is proposed that episodic memories consist of "episodic elements," summary records of experience often in the form of visual images, associated to a "conceptual frame" that provides a…

  6. Collaging Memories

    ERIC Educational Resources Information Center

    Wallach, Michele

    2011-01-01

    Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

  7. Memory conformity affects inaccurate memories more than accurate memories.

    PubMed

    Wright, Daniel B; Villalba, Daniella K

    2012-01-01

    After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

  8. Memory loss

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003257.htm Memory loss To use the sharing features on this ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  9. Repetitive peptide boosting progressively enhances functional memory CTLs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Induction of functional memory CTLs holds promise for fighting critical infectious diseases through vaccination, but so far, no effective regime has been identified. We show here that memory CTLs can be enhanced progressively to high levels by repetitive intravenous boosting with peptide and adjuvan...

  10. Feelings Without Memory in Alzheimer Disease

    PubMed Central

    Guzmán-Vélez, Edmarie; Feinstein, Justin S.

    2014-01-01

    Background: Patients with Alzheimer disease (AD) typically have impaired declarative memory as a result of hippocampal damage early in the disease. Far less is understood about AD’s effect on emotion. Objective: We investigated whether feelings of emotion can persist in patients with AD, even after their declarative memory for what caused the feelings has faded. Methods: A sample of 17 patients with probable AD and 17 healthy comparison participants (case-matched for age, sex, and education) underwent 2 separate emotion induction procedures in which they watched film clips intended to induce feelings of sadness or happiness. We collected real-time emotion ratings at baseline and at 3 post-induction time points, and we administered a test of declarative memory shortly after each induction. Results: As expected, the patients with AD had severely impaired declarative memory for both the sad and happy films. Despite their memory impairment, the patients continued to report elevated levels of sadness and happiness that persisted well beyond their memory for the films. This outcome was especially prominent after the sadness induction, with sustained elevations in sadness lasting for more than 30 minutes, even in patients with no conscious recollection for the films. Conclusions: These findings indicate that patients with AD can experience prolonged states of emotion that persist well beyond the patients’ memory for the events that originally caused the emotion. The preserved emotional life evident in patients with AD has important implications for their management and care, and highlights the need for caretakers to foster positive emotional experiences. PMID:25237742

  11. Effective Respiratory CD8 T-Cell Immunity to Influenza Virus Induced by Intranasal Carbomer-Lecithin-Adjuvanted Non-replicating Vaccines

    PubMed Central

    Gasper, David J.; Neldner, Brandon; Plisch, Erin H.; Rustom, Hani; Imai, Hirotaka; Kawaoka, Yoshihiro; Suresh, M.

    2016-01-01

    CD8+ cytotoxic T lymphocytes (CTLs) are critical for clearing many viral infections, and protective CTL memory can be induced by vaccination with attenuated viruses and vectors. Non-replicating vaccines are typically potentiated by the addition of adjuvants that enhance humoral responses, however few are capable of generating CTL responses. Adjuplex is a carbomer-lecithin-based adjuvant demonstrated to elicit robust humoral immunity to non-replicating antigens. We report that mice immunized with non-replicating Adjuplex-adjuvanted vaccines generated robust antigen-specific CTL responses. Vaccination by the subcutaneous or the intranasal route stimulated systemic and mucosal CTL memory respectively. However, only CTL memory induced by intranasal vaccination was protective against influenza viral challenge, and correlated with an enhancement of memory CTLs in the airways and CD103+ CD69+ CXCR3+ resident memory-like CTLs in the lungs. Mechanistically, Myd88-deficient mice mounted primary CTL responses to Adjuplex vaccines that were similar in magnitude to wild-type mice, but exhibited altered differentiation of effector cell subsets. Immune potentiating effects of Adjuplex entailed alterations in the frequency of antigen-presenting-cell subsets in vaccine draining lymph nodes, and in the lungs and airways following intranasal vaccination. Further, Adjuplex enhanced the ability of dendritic cells to promote antigen-induced proliferation of naïve CD8 T cells by modulating antigen uptake, its intracellular localization, and rate of processing. Taken together, we have identified an adjuvant that elicits both systemic and mucosal CTL memory to non-replicating antigens, and engenders protective CTL-based heterosubtypic immunity to influenza A virus in the respiratory tract. Further, findings presented in this manuscript have provided key insights into the mechanisms and factors that govern the induction and programming of systemic and protective memory CTLs in the

  12. Electromagnetic induction methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electromagnetic induction geophysical methods are finding greater and greater use for agricultural purposes. Electromagnetic induction methods measure the electrical conductivity (or resistivity) for a bulk volume of soil directly beneath the surface. An instrument called a ground conductivity meter...

  13. Relations between inductive reasoning and deductive reasoning.

    PubMed

    Heit, Evan; Rotello, Caren M

    2010-05-01

    One of the most important open questions in reasoning research is how inductive reasoning and deductive reasoning are related. In an effort to address this question, we applied methods and concepts from memory research. We used 2 experiments to examine the effects of logical validity and premise-conclusion similarity on evaluation of arguments. Experiment 1 showed 2 dissociations: For a common set of arguments, deduction judgments were more affected by validity, and induction judgments were more affected by similarity. Moreover, Experiment 2 showed that fast deduction judgments were like induction judgments-in terms of being more influenced by similarity and less influenced by validity, compared with slow deduction judgments. These novel results pose challenges for a 1-process account of reasoning and are interpreted in terms of a 2-process account of reasoning, which was implemented as a multidimensional signal detection model and applied to receiver operating characteristic data.

  14. "El pasado refleja el futuro": Pre-Service Teachers' Memories of Growing up Bilingual

    ERIC Educational Resources Information Center

    Miller, Kyle

    2017-01-01

    This study examined the school memories of a cohort of bilingual pre-service teachers who experienced school as English Learners. As part of a course assignment, participants described a memory from elementary school and later used that memory to reflect on its future impact on their teaching. Data were inductively analyzed, and themes were…

  15. Fear Memory.

    PubMed

    Izquierdo, Ivan; Furini, Cristiane R G; Myskiw, Jociane C

    2016-04-01

    Fear memory is the best-studied form of memory. It was thoroughly investigated in the past 60 years mostly using two classical conditioning procedures (contextual fear conditioning and fear conditioning to a tone) and one instrumental procedure (one-trial inhibitory avoidance). Fear memory is formed in the hippocampus (contextual conditioning and inhibitory avoidance), in the basolateral amygdala (inhibitory avoidance), and in the lateral amygdala (conditioning to a tone). The circuitry involves, in addition, the pre- and infralimbic ventromedial prefrontal cortex, the central amygdala subnuclei, and the dentate gyrus. Fear learning models, notably inhibitory avoidance, have also been very useful for the analysis of the biochemical mechanisms of memory consolidation as a whole. These studies have capitalized on in vitro observations on long-term potentiation and other kinds of plasticity. The effect of a very large number of drugs on fear learning has been intensively studied, often as a prelude to the investigation of effects on anxiety. The extinction of fear learning involves to an extent a reversal of the flow of information in the mentioned structures and is used in the therapy of posttraumatic stress disorder and fear memories in general.

  16. Inductive Reasoning and Writing

    ERIC Educational Resources Information Center

    Rooks, Clay; Boyd, Robert

    2003-01-01

    Induction, properly understood, is not merely a game, nor is it a gimmick, nor is it an artificial way of explaining an element of reasoning. Proper understanding of inductive reasoning--and the various types of reasoning that the authors term inductive--enables the student to evaluate critically other people's writing and enhances the composition…

  17. Teaching Arrangement Inductively.

    ERIC Educational Resources Information Center

    Mendelson, Michael

    1988-01-01

    Argues that teaching arrangement inductively offers an alternative to the standard imitation of business communication text models. Asserts that the inductive method stimulates individual rather than formulaic responses to the problems of organization, and that inductively-trained writers see arrangements as a powerful element in persuasive…

  18. Pulsed IR inductive lasers

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.

    2014-07-01

    Pulsed inductive discharge is a new alternative method of pumping active gas laser media. The work presents results of experimental investigations of near, mid, and far IR inductive gas lasers (H2, HF, and CO2) operating at different transitions of atoms and molecules with different mechanisms of formation of inversion population. The excitation systems of a pulsed inductive cylindrical discharge (pulsed inductively coupled plasma) and pulsed RF inductive discharge in the gases are developed. Various gas mixtures including H2, N2, He, Ne, F2, NF3, and SF6 are used. Characteristics of near IR H2 laser radiation are investigated. Maximal pulse peak power of 7 kW is achieved. The possibility of using a pulsed inductive discharge as a new method of pumping HF laser active medium is demonstrated. The pulsed RF inductive CO2 laser is created and a total efficiency of 17% is achieved.

  19. Fueling Memories

    PubMed Central

    Powell, Jonathan D.; Pollizzi, Kristen

    2012-01-01

    A hallmark of the adaptive immune response is rapid and robust activation upon rechallenge. In the current issue of Immunity van der Windt et al. (2012) provide an important link between mitochondrial respiratory capacity and the development of CD8+ T cell memory. PMID:22284413

  20. Childhood Memories.

    ERIC Educational Resources Information Center

    Soto, Lourdes Diaz

    2001-01-01

    Describes how artwork can be a valuable catalyst for discussions in preservice education classes, allowing students to explore how their work as educators relates to their childhood memories and can be shaped by childhood experiences. Examines an art exhibition in which diverse artists depicted autobiographical text in their paintings. Discusses…

  1. Retracing Memories

    ERIC Educational Resources Information Center

    Harrison, David L.

    2005-01-01

    There are plenty of paths to poetry but few are as accessible as retracing ones own memories. When students are asked to write about something they remember, they are given them the gift of choosing from events that are important enough to recall. They remember because what happened was funny or scary or embarrassing or heartbreaking or silly.…

  2. Hollow memories

    NASA Astrophysics Data System (ADS)

    2014-04-01

    A hollow-core optical fibre filled with warm caesium atoms can temporarily store the properties of photons. Michael Sprague from the University of Oxford, UK, explains to Nature Photonics how this optical memory could be a useful building block for fibre-based quantum optics.

  3. Affect influences false memories at encoding: evidence from recognition data.

    PubMed

    Storbeck, Justin; Clore, Gerald L

    2011-08-01

    Memory is susceptible to illusions in the form of false memories. Prior research found, however, that sad moods reduce false memories. The current experiment had two goals: (1) to determine whether affect influences retrieval processes, and (2) to determine whether affect influences the strength and the persistence of false memories. Happy or sad moods were induced either before or after learning word lists designed to produce false memories. Control groups did not experience a mood induction. We found that sad moods reduced false memories only when induced before learning. Signal detection analyses confirmed that sad moods induced prior to learning reduced activation of nonpresented critical lures suggesting that they came to mind less often. Affective states, however, did not influence retrieval effects. We conclude that negative affective states promote item-specific processing, which reduces false memories in a similar way as using an explicitly guided cognitive control strategy.

  4. [Genes and the modulation of learning and memory].

    PubMed

    Xiong, Y; Zhang, C C

    1995-10-01

    Recently, progress in the study of the relationship between gene and the modulation of learning and memory was noticeable. The studies showed that: (1) The expression of immediate early genes (IEGs), especially the c-fos, is a necessary prerequisite for the formation of memory; the induction of long term potentiation (LTP) is accompanied by an increase of IEGs expression; (2) Mice with deficiency of alpha-Calcium-Calmodulin Kinase II (alpha-CaMK II), or neural-cell adhesion molecules (N-CAM) or tyrosine kinase gene (fyn) generated by gene targeting appear deficits in spatial learning and memory, mutation of alpha-CaMK II and N-CAM gene can also interfere with the induction and maintenance of LTP; (3) The single-gene mutants of Drosophilia (dnc, rut) showed significant decrease of the ability of memory. The mechanism is related to the altered synaptic plasticity, and the mushroom body may be the memory center of Drosophila.

  5. Wnt signaling inhibits CTL memory programming.

    PubMed

    Xiao, Zhengguo; Sun, Zhifeng; Smyth, Kendra; Li, Lei

    2013-12-01

    Induction of functional CTLs is one of the major goals for vaccine development and cancer therapy. Inflammatory cytokines are critical for memory CTL generation. Wnt signaling is important for CTL priming and memory formation, but its role in cytokine-driven memory CTL programming is unclear. We found that wnt signaling inhibited IL-12-driven CTL activation and memory programming. This impaired memory CTL programming was attributed to up-regulation of eomes and down-regulation of T-bet. Wnt signaling suppressed the mTOR pathway during CTL activation, which was different to its effects on other cell types. Interestingly, the impaired memory CTL programming by wnt was partially rescued by mTOR inhibitor rapamycin. In conclusion, we found that crosstalk between wnt and the IL-12 signaling inhibits T-bet and mTOR pathways and impairs memory programming which can be recovered in part by rapamycin. In addition, direct inhibition of wnt signaling during CTL activation does not affect CTL memory programming. Therefore, wnt signaling may serve as a new tool for CTL manipulation in autoimmune diseases and immune therapy for certain cancers.

  6. Sequential inductive learning

    SciTech Connect

    Gratch, J.

    1996-12-31

    This article advocates a new model for inductive learning. Called sequential induction, it helps bridge classical fixed-sample learning techniques (which are efficient but difficult to formally characterize), and worst-case approaches (which provide strong statistical guarantees but are too inefficient for practical use). Learning proceeds as a sequence of decisions which are informed by training data. By analyzing induction at the level of these decisions, and by utilizing the only enough data to make each decision, sequential induction provides statistical guarantees but with substantially less data than worst-case methods require. The sequential inductive model is also useful as a method for determining a sufficient sample size for inductive learning and as such, is relevant to learning problems where the preponderance of data or the cost of gathering data precludes the use of traditional methods.

  7. Spacing and Induction: Application to Exemplars Presented as Auditory and Visual Text

    ERIC Educational Resources Information Center

    Zulkiply, Norehan; McLean, John; Burt, Jennifer S.; Bath, Debra

    2012-01-01

    It is an established finding that spacing repetitions generally facilitates memory for the repeated events. However, the effect of spacing of exemplars on inductive learning is not really known. Two experiments using textual material were conducted to investigate the effect of spacing on induction. Experiment 1 and 2 extended the generality of…

  8. Explaining prompts children to privilege inductively rich properties.

    PubMed

    Walker, Caren M; Lombrozo, Tania; Legare, Cristine H; Gopnik, Alison

    2014-11-01

    Four experiments with preschool-aged children test the hypothesis that engaging in explanation promotes inductive reasoning on the basis of shared causal properties as opposed to salient (but superficial) perceptual properties. In Experiments 1a and 1b, 3- to 5-year-old children prompted to explain during a causal learning task were more likely to override a tendency to generalize according to perceptual similarity and instead extend an internal feature to an object that shared a causal property. Experiment 2 replicated this effect of explanation in a case of label extension (i.e., categorization). Experiment 3 demonstrated that explanation improves memory for clusters of causally relevant (non-perceptual) features, but impairs memory for superficial (perceptual) features, providing evidence that effects of explanation are selective in scope and apply to memory as well as inference. In sum, our data support the proposal that engaging in explanation influences children's reasoning by privileging inductively rich, causal properties.

  9. [Neural correlates of memory].

    PubMed

    Fujii, Toshikatsu

    2013-01-01

    Memory can be divided into several types, although all of them involve three successive processes: encoding, storage, and retrieval. In terms of the duration of retention, neurologists classify memory into immediate, recent, and remote memories, whereas psychologists classify memory into short-term and long-term memories. In terms of the content, episodic, semantic, and procedural memories are considered to be different types of memory. Furthermore, researchers on memory have proposed relatively new concepts of memory, i.e., working memory and prospective memory. This article first provides explanations for these several types of memory. Next, neuropsychological characteristics of amnesic syndrome are briefly outlined. Finally, how several different types of memory are affected (or preserved) in patients with amnesic syndrome is described.

  10. Heterogeneity within T Cell Memory: Implications for Transplant Tolerance

    PubMed Central

    Krummey, Scott M.; Ford, Mandy L.

    2012-01-01

    Adaptive immunity in both mouse and man results in the generation of immunological memory. Memory T cells are both friend and foe to transplant recipients, as they are intimately involved and in many cases absolutely required for the maintenance of protective immunity in the face immunosuppression, yet from the evidence presented herein they clearly constitute a formidable barrier for the successful implementation of tolerance induction strategies in transplantation. This review describes the experimental evidence demonstrating the increased resistance of memory T cells to many distinct tolerance induction strategies, and outlines recent advances in our knowledge of the ways in which alloreactive memory T cells arise in previously untransplanted individuals. Understanding the impact of alloreactive memory T cell specificity, frequency, and quality might allow for better donor selection in order to minimize the donor-reactive memory T cell barrier in an individual transplant recipient, thus allowing stratification of relative risk of alloreactive memory T cell mediated rejection, and conversely increase the likelihood of successful establishment of tolerance. However, further research into the molecular and cellular pathways involved in alloreactive memory T cell-mediated rejection is required in order to design new strategies to overcome the memory T cell barrier, without critically impairing protective immunity. PMID:22566919

  11. Progress in Induction Linacs

    SciTech Connect

    Caporaso, G J

    2000-09-27

    This presentation will be a broad survey of progress in induction technology over the past four years. Much work has been done on accelerators for hydrodynamic test radiography and other applications. Solid-state pulsers have been developed which can provide unprecedented flexibility and precision in pulse format and accelerating voltage for both ion and electron induction machines. Induction linacs can now be built which can operate with MHz repetition rates. Solid-state technology has also made possible the development of fast kickers for precision control of high current beams. New insulator technology has been developed which will improve conventional induction linacs in addition to enabling a new class of high gradient induction linacs.

  12. Principles of Induction Accelerators

    NASA Astrophysics Data System (ADS)

    Briggs*, Richard J.

    The basic concepts involved in induction accelerators are introduced in this chapter. The objective is to provide a foundation for the more detailed coverage of key technology elements and specific applications in the following chapters. A wide variety of induction accelerators are discussed in the following chapters, from the high current linear electron accelerator configurations that have been the main focus of the original developments, to circular configurations like the ion synchrotrons that are the subject of more recent research. The main focus in the present chapter is on the induction module containing the magnetic core that plays the role of a transformer in coupling the pulsed power from the modulator to the charged particle beam. This is the essential common element in all these induction accelerators, and an understanding of the basic processes involved in its operation is the main objective of this chapter. (See [1] for a useful and complementary presentation of the basic principles in induction linacs.)

  13. Properties of inductive reasoning.

    PubMed

    Heit, E

    2000-12-01

    This paper reviews the main psychological phenomena of inductive reasoning, covering 25 years of experimental and model-based research, in particular addressing four questions. First, what makes a case or event generalizable to other cases? Second, what makes a set of cases generalizable? Third, what makes a property or predicate projectable? Fourth, how do psychological models of induction address these results? The key results in inductive reasoning are outlined, and several recent models, including a new Bayesian account, are evaluated with respect to these results. In addition, future directions for experimental and model-based work are proposed.

  14. Direct reading inductance meter

    NASA Technical Reports Server (NTRS)

    Kolby, R. B. (Inventor)

    1977-01-01

    A direct reading inductance meter comprised of a crystal oscillator and an LC tuned oscillator is presented. The oscillators function respectively to generate a reference frequency, f(r), and to generate an initial frequency, f(0), which when mixed produce a difference equal to zero. Upon connecting an inductor of small unknown value in the LC circuit to change its resonant frequency to f(x), a difference frequency (f(r)-f(x)) is produced that is very nearly a linear function of the inductance of the inductor. The difference frequency is measured and displayed on a linear scale in units of inductance.

  15. How induction generators work

    SciTech Connect

    Nailen, R.L.

    1980-06-01

    The operating principles of the induction generator, which is a standard squirrel cage motor in which the shaft is coupled to and driven by an engine or turbine at a rate above its synchronous speed and which, under these conditions, produces electrical power, are described. The advantages of induction generators, e.g., low cost, simplicity, frequency and voltage controlled by the utility system, no synchronizing controls needed, and the advantages of using small induction generators run by wind turbines, small gas turbines and in low head hydro plants are discussed. (LCL)

  16. A Beginner's Guide to Memory.

    ERIC Educational Resources Information Center

    Hughes, Elizabeth M.

    1981-01-01

    This article is designed to equip the reader with the information needed to deal with questions of computer memory. Discussed are core memory; semiconductor memory; size of memory; expanding memory; charge-coupled device memories; magnetic bubble memory; and read-only and read-mostly memories. (KC)

  17. Induction of broad cytotoxic T cells by protective DNA vaccination against Marburg and Ebola.

    PubMed

    Shedlock, Devon J; Aviles, Jenna; Talbott, Kendra T; Wong, Gary; Wu, Stephan J; Villarreal, Daniel O; Myles, Devin Jf; Croyle, Maria A; Yan, Jian; Kobinger, Gary P; Weiner, David B

    2013-07-01

    Marburg and Ebola hemorrhagic fevers have been described as the most virulent viral diseases known to man due to associative lethality rates of up to 90%. Death can occur within days to weeks of exposure and there is currently no licensed vaccine or therapeutic. Recent evidence suggests an important role for antiviral T cells in conferring protection, but little detailed analysis of this response as driven by a protective vaccine has been reported. We developed a synthetic polyvalent-filovirus DNA vaccine against Marburg marburgvirus (MARV), Zaire ebolavirus (ZEBOV), and Sudan ebolavirus (SUDV). Preclinical efficacy studies were performed in guinea pigs and mice using rodent-adapted viruses, whereas murine T-cell responses were extensively analyzed using a novel modified assay described herein. Vaccination was highly potent, elicited robust neutralizing antibodies, and completely protected against MARV and ZEBOV challenge. Comprehensive T-cell analysis revealed cytotoxic T lymphocytes (CTLs) of great magnitude, epitopic breadth, and Th1-type marker expression. This model provides an important preclinical tool for studying protective immune correlates that could be applied to existing platforms. Data herein support further evaluation of this enhanced gene-based approach in nonhuman primate studies for in depth analyses of T-cell epitopes in understanding protective efficacy.

  18. Memory Retrieval and Interference: Working Memory Issues

    ERIC Educational Resources Information Center

    Radvansky, Gabriel A.; Copeland, David E.

    2006-01-01

    Working memory capacity has been suggested as a factor that is involved in long-term memory retrieval, particularly when that retrieval involves a need to overcome some sort of interference (Bunting, Conway, & Heitz, 2004; Cantor & Engle, 1993). Previous work has suggested that working memory is related to the acquisition of information during…

  19. Induction heating coupler

    NASA Technical Reports Server (NTRS)

    Fox, Robert L. (Inventor); Copeland, Carl E. (Inventor); Swaim, Robert J. (Inventor); Coultrip, Robert H. (Inventor); Johnston, David F. (Inventor); Phillips, W. Morris (Inventor); Johnson, Samuel D. (Inventor); Dinkins, James R. (Inventor); Buckley, John D. (Inventor)

    1994-01-01

    An induction heating device includes a handle having a hollow interior and two opposite ends, a wrist connected to one end of the handle, a U-shaped pole piece having two spaced apart ends, a tank circuit including an induction coil wrapped around the pole piece and a capacitor connected to the induction coil, a head connected to the wrist and including a housing for receiving the U-shaped pole piece, the two spaced apart ends of the pole piece extending outwardely beyond the housing, and a power source connected to the tank circuit. When the tank circuit is energized and a susceptor is placed in juxtaposition to the ends of the U-shaped pole piece, the susceptor is heated by induction heating due to magnetic flux passing between the two ends of the pole piece.

  20. Induction melter apparatus

    DOEpatents

    Roach, Jay A [Idaho Falls, ID; Richardson, John G [Idaho Falls, ID; Raivo, Brian D [Idaho Falls, ID; Soelberg, Nicholas R [Idaho Falls, ID

    2008-06-17

    Apparatus and methods of operation are provided for a cold-crucible-induction melter for vitrifying waste wherein a single induction power supply may be used to effect a selected thermal distribution by independently energizing at least two inductors. Also, a bottom drain assembly may be heated by an inductor and may include an electrically resistive heater. The bottom drain assembly may be cooled to solidify molten material passing therethrough to prevent discharge of molten material therefrom. Configurations are provided wherein the induction flux skin depth substantially corresponds with the central longitudinal axis of the crucible. Further, the drain tube may be positioned within the induction flux skin depth in relation to material within the crucible or may be substantially aligned with a direction of flow of molten material within the crucible. An improved head design including four shells forming thermal radiation shields and at least two gas-cooled plenums is also disclosed.

  1. Thermal kinetic inductance detector

    DOEpatents

    Cecil, Thomas; Gades, Lisa; Miceli, Antonio; Quaranta, Orlando

    2016-12-20

    A microcalorimeter for radiation detection that uses superconducting kinetic inductance resonators as the thermometers. The detector is frequency-multiplexed which enables detector systems with a large number of pixels.

  2. Enhancing Induction Coil Reliability

    NASA Astrophysics Data System (ADS)

    Kreter, K.; Goldstein, R.; Yakey, C.; Nemkov, V.

    2014-12-01

    In induction hardening, thermal fatigue is one of the main copper failure modes of induction heat treating coils. There have been papers published that describe this failure mode and others that describe some good design practices. The variables previously identified as the sources of thermal fatigue include radiation from the part surface, frequency, current, concentrator losses, water pressure and coil wall thickness. However, there is very little quantitative data on the factors that influence thermal fatigue in induction coils is available in the public domain. By using finite element analysis software this study analyzes the effect of common design variables of inductor cooling, and quantifies the relative importance of these variables. A comprehensive case study for a single shot induction coil with Fluxtrol A concentrator applied is used for the analysis.

  3. Doubly fed induction machine

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2005-10-11

    An electro-mechanical energy conversion system coupled between an energy source and an energy load including an energy converter device having a doubly fed induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer coupled to the energy converter device to control the flow of power or energy through the doubly fed induction machine.

  4. Induction launcher design considerations

    NASA Technical Reports Server (NTRS)

    Driga, M. D.; Weldon, W. F.

    1989-01-01

    New concepts in the design of induction accelerators and their power supplies for space and military applications are discussed. Particular attention is given to a piecewise-rising-frequency power supply in which each elementary generator (normal compulsator or rising frequency generator) has a different base frequency. A preliminary design of a coaxial induction accelerator for a hypersonic real gas facility is discussed to illustrate the concepts described.

  5. Induction of the Proepicardium.

    PubMed

    Maya-Ramos, Lisandro; Cleland, James; Bressan, Michael; Mikawa, Takashi

    2013-09-01

    The proepicardium is a transient extracardiac embryonic tissue that gives rise to the epicardium and a number of coronary vascular cell lineages. This important extracardiac tissue develops through multiple steps of inductive events, from specification of multiple cell lineages to morphogenesis. This article will review our current understanding of inductive events involved in patterning of the proepicardium precursor field, specification of cell types within the proepicardium, and their extension and attachment to the heart.

  6. Induction Heating Systems

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Induction heating technology, a magnetic non-deforming process, was developed by Langley researchers to join plastic and composite components in space. Under NASA license, Inductron Corporation uses the process to produce induction heating systems and equipment for numerous applications. The Torobonder, a portable system, comes with a number of interchangeable heads for aircraft repair. Other developments are the E Heating Head, the Toroid Joining Gun, and the Torobrazer. These products perform bonding applications more quickly, safely and efficiently than previous methods.

  7. Linear induction accelerator

    DOEpatents

    Buttram, M.T.; Ginn, J.W.

    1988-06-21

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

  8. Optical memory

    DOEpatents

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  9. Simultaneous approach using systemic, mucosal and transcutaneous routes of immunization for development of protective HIV-1 vaccines.

    PubMed

    Belyakov, I M; Ahlers, J D

    2011-01-01

    Mucosal tissues are major sites of HIV entry and initial infection. Induction of a local mucosal cytotoxic T lymphocyte response is considered an important goal in developing an effective HIV vaccine. In addition, activation and recruitment of memory CD4(+) and CD8(+) T cells in systemic lymphoid circulation to mucosal effector sites might provide the firewall needed to prevent virus spread. Therefore a vaccine that generates CD4(+) and CD8(+) responses in both mucosal and systemic tissues might be required for protection against HIV. However, optimal routes and number of vaccinations required for the generation of long lasting CD4(+) and CD8(+) CTL effector and memory responses are not well understood especially for mucosal T cells. A number of studies looking at protective immune responses against diverse mucosal pathogens have shown that mucosal vaccination is necessary to induce a compartmentalized immune response including maximum levels of mucosal high-avidity CD8(+) CTL, antigen specific mucosal antibodies titers (especially sIgA), as well as induction of innate anti-viral factors in mucosa tissue. Immune responses are detectable at mucosal sites after systemic delivery of vaccine, and prime boost regimens can amplify the magnitude of immune responses in mucosal sites and in systemic lymphoid tissues. We believe that the most optimal mucosal and systemic HIV/SIV specific protective immune responses and innate factors might best be achieved by simultaneous mucosal and systemic prime and boost vaccinations. Similar principals of vaccination may be applied for vaccine development against cancer and highly invasive pathogens that lead to chronic infection.

  10. Order-memory and association-memory.

    PubMed

    Caplan, Jeremy B

    2015-09-01

    Two highly studied memory functions are memory for associations (items presented in pairs, such as SALT-PEPPER) and memory for order (a list of items whose order matters, such as a telephone number). Order- and association-memory are at the root of many forms of behaviour, from wayfinding, to language, to remembering people's names. Most researchers have investigated memory for order separately from memory for associations. Exceptions to this, associative-chaining models build an ordered list from associations between pairs of items, quite literally understanding association- and order-memory together. Alternatively, positional-coding models have been used to explain order-memory as a completely distinct function from association-memory. Both classes of model have found empirical support and both have faced serious challenges. I argue that models that combine both associative chaining and positional coding are needed. One such hybrid model, which relies on brain-activity rhythms, is promising, but remains to be tested rigourously. I consider two relatively understudied memory behaviours that demand a combination of order- and association-information: memory for the order of items within associations (is it William James or James William?) and judgments of relative order (who left the party earlier, Hermann or William?). Findings from these underexplored procedures are already difficult to reconcile with existing association-memory and order-memory models. Further work with such intermediate experimental paradigms has the potential to provide powerful findings to constrain and guide models into the future, with the aim of explaining a large range of memory functions, encompassing both association- and order-memory.

  11. Emotional memory persists longer than event memory.

    PubMed

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-03-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition performance for event memory differs from that for emotional memory. Although event recognition deteriorated equally for episodes that were or were not emotionally salient, emotional recognition remained high for only stimuli related to emotional episodes. Recognition performance pertaining to delayed emotional memory is an accurate predictor of the context of past episodes.

  12. Sleep, Torpor and Memory Impairment

    NASA Astrophysics Data System (ADS)

    Palchykova, S.; Tobler, I.

    It is now well known that daily torpor induces a sleep deficit. Djungarian hamsters emerging from this hypometabolic state spend most of the time in sleep. This sleep is characterized by high initial values of EEG slow-wave activity (SWA) that monotonically decline during recovery sleep. These features resemble the changes seen in numerous species during recovery after prolonged wakefulness or sleep deprivation (SD). When hamsters are totally or partially sleep deprived immediately after emerging from torpor, an additional increase in SWA can be induced. It has been therefore postulated, that these slow- waves are homeostatically regulated, as predicted by the two-process model of sleep regulation, and that during daily torpor a sleep deficit is accumulated as it is during prolonged waking. The predominance of SWA in the frontal EEG observed both after SD and daily torpor provides further evidence for the similarity of these conditions. It has been shown in several animal and human studies that sleep can enhance memory consolidation, and that SD leads to memory impairment. Preliminary data obtained in the Djungarian hamster showed that both SD and daily torpor result in object recognition deficits. Thus, animals subjected to SD immediately after learning, or if they underwent an episode of daily torpor between learning and retention, displayed impaired recognition memory for complex object scenes. The investigation of daily torpor can reveal mechanisms that could have important implications for hypometabolic state induction in other mammalian species, including humans.

  13. Recombinant measles viruses expressing respiratory syncytial virus proteins induced virus-specific CTL responses in cotton rats.

    PubMed

    Yamaji, Yoshiaki; Nakayama, Tetsuo

    2014-07-31

    Respiratory syncytial virus (RSV) is a common cause of serious lower respiratory tract illnesses in infants. Natural infections with RSV provide limited protection against reinfection because of inefficient immunological responses that do not induce long-term memory. RSV natural infection has been shown to induce unbalanced immune response. The effective clearance of RSV is known to require the induction of a balanced Th1/Th2 immune response, which involves the induction of cytotoxic T lymphocytes (CTL). In our previous study, recombinant AIK-C measles vaccine strains MVAIK/RSV/F and MVAIK/RSV/G were developed, which expressed the RSV fusion (F) protein or glycoprotein (G). These recombinant viruses elicited antibody responses against RSV in cotton rats, and no infectious virus was recovered, but small amounts of infiltration of inflammatory cells were observed in the lungs following RSV challenge. In the present study, recombinant AIK-C measles vaccine strains MVAIK/RSV/M2-1 and MVAIK/RSV/NP were developed, expressing RSV M2-1 or Nucleoprotein (NP), respectively. These viruses exhibited temperature-sensitivity (ts), which was derived from AIK-C, and expressed respective RSV antigens. The intramuscular inoculation of cotton rats with the recombinant measles virus led to the induction of CD8(+) IFN-γ(+) cells. No infectious virus was recovered from a lung homogenate following the challenge. A Histological examination of the lungs revealed a significant reduction in inflammatory reactions without alveolar damage. These results support the recombinant measles viruses being effective vaccine candidates against RSV that induce RSV-specific CTL responses with or without the development of an antibody response.

  14. Using Implicit Instructional Cues to Influence False Memory Induction

    ERIC Educational Resources Information Center

    Cirelli, Laura K.; Dickinson, Joël; Poirier, Marie

    2015-01-01

    Previous research has shown that explicit cues specific to the encoding process (endogenous) or characteristic of the stimuli themselves (exogenous) can be used to direct a reader's attentional resources towards either relational or item-specific information. By directing attention to relational information (and therefore away from item-specific…

  15. Induction of potent cellular immune response in mice by hepatitis C virus NS3 protein with double-stranded RNA

    PubMed Central

    Jin, Bo; Wang, Richard Y; Qiu, Qi; Sugauchi, Fuminaka; Grandinetti, Teresa; Alter, Harvey J; Shih, J Wai-Kuo

    2007-01-01

    Double-stranded RNA is produced during virus replication and, together with the viral antigen, is responsible for inducing host antivirus immunity. The hepatitis C virus (HCV) non-structural protein-3 (NS3) has been implicated in the immune evasion of HCV, and is one of the prime targets for inducing immunity against HCV infection. Mice were immunized with recombinant NS3 protein (rNS3) and poly (I:C) emulsified in Montanide ISA 720 (M720). Cytokine production was assayed by enzyme-linked immunospot assay, and CD4+ IFN-γ+ T helper (Th) cells or CD8+ IFN-γ+ cytotoxic T lymphocytes were detected by flow cytometry. Anti-NS3 titre and immunoglobulin G2a (IgG2a) and IgG1 levels were monitored by enzyme-linked immunosorbent assay. Administration of rNS3 formulated in poly (I:C) and M720 induced anti-NS3 titres with a predominantly IgG2a isotype comparable to those induced by rNS3 in CpG-ODN and M720. The cytokine profiles showed that this formulation induced a Th1-biased immune response with several-fold more interferon-γ (IFN-γ)-producing cells than interleukin-4-producing cells. In contrast, rNS3 in M720 induced a Th2-biased immune response. The frequency of IFN-γ-producing CD4+ and CD8+ cells induced by rNS3 in poly (I:C) and M720 was significantly higher than that induced by rNS3, rNS3 in M720, or rNS3 in poly (I:C), and was comparable to that induced by rNS3 in CpG-ODN with M720. The antigen-specific CD8+ T-cell immune response persisted for up to 7 months after immunization. In conclusion, poly (I:C) with rNS3 in M720 can elicit a strong and persistent Th1-biased immune response and a cytotoxic T-lymphocyte response through cross-priming in mice. This study highlighted a promising formulation for inducing an efficient cellular immune response against HCV that has potential for HCV vaccine development. PMID:17451465

  16. An episodic specificity induction enhances means-end problem solving in young and older adults.

    PubMed

    Madore, Kevin P; Schacter, Daniel L

    2014-12-01

    Episodic memory plays an important role not only in remembering past experiences, but also in constructing simulations of future experiences and solving means-end social problems. We recently found that an episodic specificity induction-brief training in recollecting details of past experiences-enhances performance of young and older adults on memory and imagination tasks. Here we tested the hypothesis that this specificity induction would also positively impact a means-end problem-solving task on which age-related changes have been linked to impaired episodic memory. Young and older adults received the specificity induction or a control induction before completing a means-end problem-solving task, as well as memory and imagination tasks. Consistent with previous findings, older adults provided fewer relevant steps on problem solving than did young adults, and their responses also contained fewer internal (i.e., episodic) details across the 3 tasks. There was no difference in the number of other (e.g., irrelevant) steps on problem solving or external (i.e., semantic) details generated on the 3 tasks as a function of age. Critically, the specificity induction increased the number of relevant steps and internal details (but not other steps or external details) that both young and older adults generated in problem solving compared with the control induction, as well as the number of internal details (but not external details) generated for memory and imagination. Our findings support the idea that episodic retrieval processes are involved in means-end problem solving, extend the range of tasks on which a specificity induction targets these processes, and show that the problem-solving performance of older adults can benefit from a specificity induction as much as that of young adults.

  17. An episodic specificity induction enhances means-end problem solving in young and older adults

    PubMed Central

    Madore, Kevin P.; Schacter, Daniel L.

    2014-01-01

    Episodic memory plays an important role not only in remembering past experiences, but also in constructing simulations of future experiences and solving means-end social problems. We recently found that an episodic specificity induction- brief training in recollecting details of past experiences- enhances performance of young and older adults on memory and imagination tasks. Here we tested the hypothesis that this specificity induction would also positively impact a means-end problem solving task on which age-related changes have been linked to impaired episodic memory. Young and older adults received the specificity induction or a control induction before completing a means-end problem solving task as well as memory and imagination tasks. Consistent with previous findings, older adults provided fewer relevant steps on problem solving than did young adults, and their responses also contained fewer internal (i.e., episodic) details across the three tasks. There was no difference in the number of other (e.g., irrelevant) steps on problem solving or external (i.e., semantic) details generated on the three tasks as a function of age. Critically, the specificity induction increased the number of relevant steps and internal details (but not other steps or external details) that both young and older adults generated in problem solving compared with the control induction, as well as the number of internal details (but not external details) generated for memory and imagination. Our findings support the idea that episodic retrieval processes are involved in means-end problem solving, extend the range of tasks on which a specificity induction targets these processes, and show that the problem solving performance of older adults can benefit from a specificity induction as much as that of young adults. PMID:25365688

  18. Memory Metals

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Under contract to NASA during preparations for the space station, Memry Technologies Inc. investigated shape memory effect (SME). SME is a characteristic of certain metal alloys that can change shape in response to temperature variations. In the late 1980s and early 1990s, Memry used its NASA-acquired expertise to produce a line of home and industrial safety products, and refined the technology in the mid-1990s. Among the new products they developed are three MemrySafe units which prevent scalding from faucets. Each system contains a small valve that reacts to temperature, not pressure. When the water reaches dangerous temperatures, the unit reduces the flow to a trickle; when the scalding temperature subsides, the unit restores normal flow. Other products are the FIRECHEK 2 and 4, heat-activated shutoff valves for industrial process lines, which sense excessive heat and cut off pneumatic pressure. The newest of these products is Memry's Demand Management Water Heater which shifts the electricity requirement from peak to off-peak demands, conserving energy and money.

  19. Wrapper Induction Software

    SciTech Connect

    2011-08-18

    Wrapper Induction is a software package that allows for unsupervised, semi-supervised, and manual extraction of social media data independent of language or site architecture. A large range of blog formats is available to individuals as means of publishing data to the internet. Blogs are a source of rich information for analysts. With a growing volume of information and blog engines, there is an increased need for automatic or semi-automatic extraction of that data for processing to help deliver results to analysts. Wrapper Induction is designed to automatically or semi-automatically create a template that can be used to harvest blog data from websites. Blogs are in a variety of formats and languages. Wrapper Induction creates a template and extracts blog data in a way that is independent of a specified blog format or language.

  20. Drink, drugs and disruption: memory manipulation for the treatment of addiction.

    PubMed

    Milton, A L

    2013-08-01

    Addiction is a complex disorder, and one characterised by the acquisition of maladaptive instrumental (drug-seeking and drug-taking) and pavlovian (cue-drug associations) memories. These memories markedly contribute to the long-term risk of relapse, so reduction of the impact of these memories on behaviour could potentially be an important addition to current therapies for addiction. Memory reconsolidation may provide such a target for disrupting well-consolidated pavlovian cue-drug memories following an extensive drug history. Reconsolidation can be disrupted either by administering amnestic drugs in conjunction with a memory reactivation session, or by updating the memory adaptively through the induction of 'superextinction'. More work is needed before these therapies are ready for translation to the clinic, but if found clinically effective memory manipulation promises a radical new way of treating addiction.

  1. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  2. Inductive dielectric analyzer

    NASA Astrophysics Data System (ADS)

    Agranovich, Daniel; Polygalov, Eugene; Popov, Ivan; Ben Ishai, Paul; Feldman, Yuri

    2017-03-01

    One of the approaches to bypass the problem of electrode polarization in dielectric measurements is the free electrode method. The advantage of this technique is that, the probing electric field in the material is not supplied by contact electrodes, but rather by electromagnetic induction. We have designed an inductive dielectric analyzer based on a sensor comprising two concentric toroidal coils. In this work, we present an analytic derivation of the relationship between the impedance measured by the sensor and the complex dielectric permittivity of the sample. The obtained relationship was successfully employed to measure the dielectric permittivity and conductivity of various alcohols and aqueous salt solutions.

  3. Induction powered biological radiosonde

    NASA Technical Reports Server (NTRS)

    Fryer, T. B. (Inventor)

    1980-01-01

    An induction powered implanted monitor for epidurally measuring intracranial pressure and telemetering the pressure information to a remote readout is disclosed. The monitor utilizes an inductance-capacitance (L-C) oscillator in which the C comprises a variable capacitance transducer, one electrode of which is a small stiff pressure responsive diaphragm. The oscillator is isolated from a transmitting tank circuit by a buffer circuit and all electric components in the implanted unit except an input and an output coil are shielded by a metal housing.

  4. Memory cell operation based on small Josephson junctions arrays

    NASA Astrophysics Data System (ADS)

    Braiman, Y.; Nair, N.; Rezac, J.; Imam, N.

    2016-12-01

    In this paper we analyze a cryogenic memory cell circuit based on a small coupled array of Josephson junctions. All the basic memory operations (e.g., write, read, and reset) are implemented on the same circuit and different junctions in the array can in principle be utilized for these operations. The presented memory operation paradigm is fundamentally different from conventional single quantum flux operation logics (SFQ). As an example, we demonstrate memory operation driven by a SFQ pulse employing an inductively coupled array of three Josephson junctions. We have chosen realistic Josephson junction parameters based on state-of-the-art fabrication capabilities and have calculated access times and access energies for basic memory cell operations. We also implemented an optimization procedure based on the simulated annealing algorithm to calculate the optimized and typical values of access times and access energies.

  5. Memory beyond expression.

    PubMed

    Delorenzi, A; Maza, F J; Suárez, L D; Barreiro, K; Molina, V A; Stehberg, J

    2014-01-01

    The idea that memories are not invariable after the consolidation process has led to new perspectives about several mnemonic processes. In this framework, we review our studies on the modulation of memory expression during reconsolidation. We propose that during both memory consolidation and reconsolidation, neuromodulators can determine the probability of the memory trace to guide behavior, i.e. they can either increase or decrease its behavioral expressibility without affecting the potential of persistent memories to be activated and become labile. Our hypothesis is based on the findings that positive modulation of memory expression during reconsolidation occurs even if memories are behaviorally unexpressed. This review discusses the original approach taken in the studies of the crab Neohelice (Chasmagnathus) granulata, which was then successfully applied to test the hypothesis in rodent fear memory. Data presented offers a new way of thinking about both weak trainings and experimental amnesia: memory retrieval can be dissociated from memory expression. Furthermore, the strategy presented here allowed us to show in human declarative memory that the periods in which long-term memory can be activated and become labile during reconsolidation exceeds the periods in which that memory is expressed, providing direct evidence that conscious access to memory is not needed for reconsolidation. Specific controls based on the constraints of reminders to trigger reconsolidation allow us to distinguish between obliterated and unexpressed but activated long-term memories after amnesic treatments, weak trainings and forgetting. In the hypothesis discussed, memory expressibility--the outcome of experience-dependent changes in the potential to behave--is considered as a flexible and modulable attribute of long-term memories. Expression seems to be just one of the possible fates of re-activated memories.

  6. Latent memory facilitates relearning through molecular signaling mechanisms that are distinct from original learning.

    PubMed

    Menges, Steven A; Riepe, Joshua R; Philips, Gary T

    2015-09-01

    A highly conserved feature of memory is that it can exist in a latent, non-expressed state which is revealed during subsequent learning by its ability to significantly facilitate (savings) or inhibit (latent inhibition) subsequent memory formation. Despite the ubiquitous nature of latent memory, the mechanistic nature of the latent memory trace and its ability to influence subsequent learning remains unclear. The model organism Aplysia californica provides the unique opportunity to make strong links between behavior and underlying cellular and molecular mechanisms. Using Aplysia, we have studied the mechanisms of savings due to latent memory for a prior, forgotten experience. We previously reported savings in the induction of three distinct temporal domains of memory: short-term (10min), intermediate-term (2h) and long-term (24h). Here we report that savings memory formation utilizes molecular signaling pathways that are distinct from original learning: whereas the induction of both original intermediate- and long-term memory in naïve animals requires mitogen activated protein kinase (MAPK) activation and ongoing protein synthesis, 2h savings memory is not disrupted by inhibitors of MAPK or protein synthesis, and 24h savings memory is not dependent on MAPK activation. Collectively, these findings reveal that during forgetting, latent memory for the original experience can facilitate relearning through molecular signaling mechanisms that are distinct from original learning.

  7. Benzodiazepines and memory

    PubMed Central

    Roth, T.; Roehrs, T.; Wittig, R.; Zorick, F.

    1984-01-01

    1 Benzodiazepines possess anterograde amnesic properties, disrupting both short-term and long-term memory function. 2 The amount of amnesia is systematically related to dose effects and half-life differences among the benzodiazepines. 3 Memory deficits are found for episodic, semantic, and iconic memory function. 4 The deficits in long-term memory are probably the result of a disruption of consolidation of information in memory and not retrieval from memory. The disruption is produced by rapid sleep onset. 5 Thus the long-term amnesia is really a retrograde effect of sleep and not the anterograde effect of the drug. PMID:6151849

  8. Problems of neural memory

    NASA Astrophysics Data System (ADS)

    Mikaelian, Andrei L.

    2005-01-01

    The paper considers the neural memory of the human brain from the viewpoint of visual information processing. A model that explains the principle of data recording and storing, memory relaxation, associative remembering and other memory functions is offered. The model of associative memory is based on the methods of holography, "wave biochemistry" and autowaves. Brief consideration is given to the associative properties of holographic neural structures and the memory architecture using running chemical reactions. The paper also outlines the problem of developing artificial memory elements for restoring the brain functions and possible interface devices for coupling neurons to electronic systems.

  9. Iteration, Not Induction

    ERIC Educational Resources Information Center

    Dobbs, David E.

    2009-01-01

    The main purpose of this note is to present and justify proof via iteration as an intuitive, creative and empowering method that is often available and preferable as an alternative to proofs via either mathematical induction or the well-ordering principle. The method of iteration depends only on the fact that any strictly decreasing sequence of…

  10. Using Continuity Induction

    ERIC Educational Resources Information Center

    Hathaway, Dan

    2011-01-01

    Here is a technique for proving the fundamental theorems of analysis that provides a unified way to pass from local properties to global properties on the real line, just as ordinary induction passes from local implication (if true for "k", the theorem is true for "k" + 1) to a global conclusion in the natural numbers.

  11. Learning and Inductive Inference

    DTIC Science & Technology

    1982-07-01

    is also a paradigm example of induction as discussed by philosophers ( Carnap , 1950). Data compression is of practical value for storage and...IBelser, A. 0. Hlolzman, and A. Kent (Eds.., Eneyclopedia of computer science and technology (Vol. II). New York: Marcel Dekker, 24 51. " Carnap , R. 1950

  12. Educational Inductive Gravimeter

    ERIC Educational Resources Information Center

    Nunn, John

    2014-01-01

    A simple inductive gravimeter constructed from a rigid plastic pipe and insulated copper wire is described. When a magnet is dropped through the vertically mounted pipe it induces small alternating voltages. These small signals are fed to the microphone input of a typical computer and sampled at a typical rate of 44.1 kHz using a custom computer…

  13. Training in Inductive Reasoning.

    ERIC Educational Resources Information Center

    Tomic, Welko

    This study investigated the effects of K. J. Klauer's (1989) inductive reasoning training program of teaching children. Effects of training and the range of transfer of the training were assessed. The subjects were 34 third-grade Dutch children of average ability, matched on age, sex, and IQ. Children from the training condition (N=17) received…

  14. Chimeric SV40 virus-like particles induce specific cytotoxicity and protective immunity against influenza A virus without the need of adjuvants

    SciTech Connect

    Kawano, Masaaki; Morikawa, Katsuma; Suda, Tatsuya; Ohno, Naohito; Matsushita, Sho; Akatsuka, Toshitaka; Handa, Hiroshi; Matsui, Masanori

    2014-01-05

    Virus-like particles (VLPs) are a promising vaccine platform due to the safety and efficiency. However, it is still unclear whether polyomavirus-based VLPs are useful for this purpose. Here, we attempted to evaluate the potential of polyomavirus VLPs for the antiviral vaccine using simian virus 40 (SV40). We constructed chimeric SV40-VLPs carrying an HLA-A{sup ⁎}02:01-restricted, cytotoxic T lymphocyte (CTL) epitope derived from influenza A virus. HLA-A{sup ⁎}02:01-transgenic mice were then immunized with the chimeric SV40-VLPs. The chimeric SV40-VLPs effectively induced influenza-specific CTLs and heterosubtypic protection against influenza A viruses without the need of adjuvants. Because DNase I treatment of the chimeric SV40-VLPs did not disrupt CTL induction, the intrinsic adjuvant property may not result from DNA contaminants in the VLP preparation. In addition, immunization with the chimeric SV40-VLPs generated long-lasting memory CTLs. We here propose that the chimeric SV40-VLPs harboring an epitope may be a promising CTL-based vaccine platform with self-adjuvant properties. - Highlights: • We constructed chimeric SV40-VLPs carrying an influenza virus-derived CTL epitope. • Chimeric SV40-VLPs induce influenza-specific CTLs in mice without adjuvants. • Chimeric SV40-VLPs induce heterosubtypic protection against influenza A viruses. • Chimeric SV40-VLPs induce long-lasting memory CTLs. • Chimeric SV40-VLPs is a promising vaccine platform with self-adjuvant properties.

  15. Searching for repressed memory.

    PubMed

    McNally, Richard J

    2012-01-01

    This chapter summarizes the work of my research group on adults who report either repressed, recovered, or continuous memories of childhood sexual abuse (CSA) or who report no history of CSA. Adapting paradigms from cognitive psychology, we tested hypotheses inspired by both the "repressed memory" and "false memory" perspectives on recovered memories of CSA. We found some evidence for the false memory perspective, but no evidence for the repressed memory perspective. However, our work also suggests a third perspective on recovered memories that does not require the concept of repression. Some children do not understand their CSA when it occurs, and do not experience terror. Years later, they recall the experience, and understanding it as abuse, suffer intense distress. The memory failed to come to mind for years, partly because the child did not encode it as terrifying (i.e., traumatic), not because the person was unable to recall it.

  16. Emotional Memory Persists Longer than Event Memory

    ERIC Educational Resources Information Center

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-01-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition…

  17. Memory and the Self

    ERIC Educational Resources Information Center

    Conway, Martin A.

    2005-01-01

    The Self-Memory System (SMS) is a conceptual framework that emphasizes the interconnectedness of self and memory. Within this framework memory is viewed as the data base of the self. The self is conceived as a complex set of active goals and associated self-images, collectively referred to as the "working self." The relationship between the…

  18. Music, memory and emotion.

    PubMed

    Jäncke, Lutz

    2008-08-08

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory.

  19. Inductive Reasoning: A Training Approach

    ERIC Educational Resources Information Center

    Klauer, Karl Josef; Phye, Gary D.

    2008-01-01

    Researchers have examined inductive reasoning to identify different cognitive processes when participants deal with inductive problems. This article presents a prescriptive theory of inductive reasoning that identifies cognitive processing using a procedural strategy for making comparisons. It is hypothesized that training in the use of the…

  20. Inductive Position Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Simmons, Stephen M. (Inventor)

    2015-01-01

    An inductive position sensor uses three independent inductors inductively coupled by a common medium such as air. First and second inductors are separated by a fixed distance with the first inductor's axial core and second inductor's axial core maintained parallel to one another. A third inductor is disposed between the first and second inductors with the third inductor's axial core being maintained parallel to those of the first and second inductors. The combination of the first and second inductors are configured for relative movement with the third inductor's axial core remaining parallel to those of the first and second inductors as distance changes from the third inductor to each of the first inductor and second inductor. An oscillating current can be supplied to at least one of the three inductors, while voltage induced in at least one of the three inductors not supplied with the oscillating current is measured.

  1. Induction motor control

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  2. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly utilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilizes induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  3. Induction motor control

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.

    1990-01-01

    Electromechanical actuators developed to date have commonly ultilized permanent magnet (PM) synchronous motors. More recently switched reluctance (SR) motors have been advocated due to their robust characteristics. Implications of work which utilized induction motors and advanced control techniques are discussed. When induction motors are operated from an energy source capable of controlling voltages and frequencies independently, drive characteristics are obtained which are superior to either PM or SR motors. By synthesizing the machine frequency from a high-frequency carrier (nominally 20 kHz), high efficiencies, low distortion, and rapid torque response are available. At this time multiple horsepower machine drives were demonstrated, and work is on-going to develop a 20 hp average, 40 hp peak class of aerospace actuators. This effort is based upon high-frequency power distribution and management techniques developed by NASA for Space Station Freedom.

  4. Induction plasma tube

    DOEpatents

    Hull, D.E.

    1982-07-02

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  5. Pulsed inductive HF laser

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.; Demchuk, S. V.

    2016-03-01

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H2 - F2(NF3 or SF66) and He(Ne) - H2 - F2(NF3 or SF6) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% - 6%.

  6. Induction plasma tube

    DOEpatents

    Hull, Donald E.

    1984-01-01

    An induction plasma tube having a segmented, fluid-cooled internal radiation shield is disclosed. The individual segments are thick in cross-section such that the shield occupies a substantial fraction of the internal volume of the plasma enclosure, resulting in improved performance and higher sustainable plasma temperatures. The individual segments of the shield are preferably cooled by means of a counterflow fluid cooling system wherein each segment includes a central bore and a fluid supply tube extending into the bore. The counterflow cooling system results in improved cooling of the individual segments and also permits use of relatively larger shield segments which permit improved electromagnetic coupling between the induction coil and a plasma located inside the shield. Four embodiments of the invention, each having particular advantages, are disclosed.

  7. Inductively commutated coilguns

    SciTech Connect

    Mongeau, P.P. )

    1991-01-01

    In this paper the concept and relevance of power factor is presented in regards to high performance launchers. As the scale of launchers grows and as efforts to improve efficiency continue power factor considerations will become crucial in engineering design and ultimate launcher performance limits. The use of motion induced commutation to improve the power factor are discussed. Various approaches to inductive commutation are presented, including: the brush-commutated 9 MJ Coilgun, the solid state-switched coilgun and the quenchgun.

  8. High Gradient Induction Cell

    SciTech Connect

    Caporaso, G J

    2004-11-29

    A concept being developed for high current electron beams may have application to HEDP and is described here. It involves the use of planar Blumlein stacks placed inside an induction cell. The output end of the Blumlein stack is applied across a high gradient insulator (HGI). These insulators have been used successfully in the presence of kilo Ampere-level electron beam currents for tens of nanoseconds at gradients of 20 MV/meter.

  9. Diagnostics for induction accelerators

    SciTech Connect

    Fessenden, T.J.

    1996-04-01

    The induction accelerator was conceived by N. C. Christofilos and first realized as the Astron accelerator that operated at LLNL from the early 1960`s to the end of 1975. This accelerator generated electron beams at energies near 6 MeV with typical currents of 600 Amperes in 400 ns pulses. The Advanced Test Accelerator (ATA) built at Livermore`s Site 300 produced 10,000 Ampere beams with pulse widths of 70 ns at energies approaching 50 MeV. Several other electron and ion induction accelerators have been fabricated at LLNL and LBNL. This paper reviews the principal diagnostics developed through efforts by scientists at both laboratories for measuring the current, position, energy, and emittance of beams generated by these high current, short pulse accelerators. Many of these diagnostics are closely related to those developed for other accelerators. However, the very fast and intense current pulses often require special diagnostic techniques and considerations. The physics and design of the more unique diagnostics developed for electron induction accelerators are presented and discussed in detail.

  10. CTLA-4 genotype and relapse incidence in patients with acute myeloid leukemia in first complete remission after induction chemotherapy.

    PubMed

    Pérez-García, A; Brunet, S; Berlanga, J J; Tormo, M; Nomdedeu, J; Guardia, R; Ribera, J M; Heras, I; Llorente, A; Hoyos, M; Esteve, J; Besalduch, J; Bueno, J; Sierra, J; Gallardo, D

    2009-03-01

    The recently described single-nucleotide polymorphism CT60, located in the 3'-untranslated region of the CTLA4 (cytotoxic T-lymphocyte antigen 4 ) gene, has been associated with susceptibility to several autoimmune diseases and has also been shown to be involved in immune responses following allogeneic stem cell transplantation (SCT). However, the contribution of the CTLA4 genotype to the control of minimal residual disease in patients with acute myeloid leukemia (AML) has yet to be explored. We investigated the association between the CTLA4 CT60 A/G genotype and the incidence of leukemic relapse in 143 adult patients with AML in first complete remission after the same chemotherapy protocol (CETLAM LAM'03). The CT60 AA genotype was associated with a higher rate of leukemic relapse (56.4 vs 35.6%, P=0.004; hazard ratio (HR)=2.64, 95% confidence interval (CI)=1.36-5.14) and lower overall survival at 3 years (39.4 vs 68.4%, P=0.004; HR=2.80, 95% CI=1.39-5.64). This is the first study to report an association between polymorphisms at CTLA-4 and AML relapse.

  11. Development of replication-defective lymphocytic choriomeningitis virus vectors for the induction of potent CD8+ T cell immunity

    PubMed Central

    Flatz, Lukas; Hegazy, Ahmed N; Bergthaler, Andreas; Verschoor, Admar; Claus, Christina; Fernandez, Marylise; Gattinoni, Luca; Johnson, Susan; Kreppel, Florian; Kochanek, Stefan; van den Broek, Maries; Radbruch, Andreas; Lévy, Frédéric; Lambert, Paul-Henri; Siegrist, Claire-Anne; Restifo, Nicholas P; Löhning, Max; Ochsenbein, Adrian F; Nabel, Gary J; Pinschewer, Daniel D

    2011-01-01

    Lymphocytic choriomeningitis virus (LCMV) exhibits natural tropism for dendritic cells and represents the prototypic infection that elicits protective CD8+ T cell (cytotoxic T lymphocyte (CTL)) immunity. Here we have harnessed the immunobiology of this arenavirus for vaccine delivery. By using producer cells constitutively synthesizing the viral glycoprotein (GP), it was possible to replace the gene encoding LCMV GP with vaccine antigens to create replication-defective vaccine vectors. These rLCMV vaccines elicited CTL responses that were equivalent to or greater than those elicited by recombinant adenovirus 5 or recombinant vaccinia virus in their magnitude and cytokine profiles, and they exhibited more effective protection in several models. In contrast to recombinant adenovirus 5, rLCMV failed to elicit vector-specific antibody immunity, which facilitated re-administration of the same vector for booster vaccination. In addition, rLCMV elicited T helper type 1 CD4+ T cell responses and protective neutralizing antibodies to vaccine antigens. These features, together with low seroprevalence in humans, suggest that rLCMV may show utility as a vaccine platform against infectious diseases and cancer. PMID:20139992

  12. Role of Memory T Cells in Allograft Rejection and Tolerance

    PubMed Central

    Benichou, Gilles; Gonzalez, Bruno; Marino, Jose; Ayasoufi, Katayoun; Valujskikh, Anna

    2017-01-01

    Memory T cells are characterized by their low activation threshold, robust effector functions, and resistance to conventional immunosuppression and costimulation blockade. Unlike their naïve counterparts, memory T cells reside in and recirculate through peripheral non-lymphoid tissues. Alloreactive memory T cells are subdivided into different categories based on their origins, phenotypes, and functions. Recipients whose immune systems have been directly exposed to allogeneic major histocompatibility complex (MHC) molecules display high affinity alloreactive memory T cells. In the absence of any prior exposure to allogeneic MHC molecules, endogenous alloreactive memory T cells are regularly generated through microbial infections (heterologous immunity). Regardless of their origin, alloreactive memory T cells represent an essential element of the allograft rejection process and a major barrier to tolerance induction in clinical transplantation. This article describes the different subsets of alloreactive memory T cells involved in transplant rejection and examine their generation, functional properties, and mechanisms of action. In addition, we discuss strategies developed to target deleterious allospecific memory T cells in experimental animal models and clinical settings. PMID:28293238

  13. Immunological memory is associative

    SciTech Connect

    Smith, D.J.; Forrest, S.; Perelson, A.S.

    1996-12-31

    The purpose of this paper is to show that immunological memory is an associative and robust memory that belongs to the class of sparse distributed memories. This class of memories derives its associative and robust nature by sparsely sampling the input space and distributing the data among many independent agents. Other members of this class include a model of the cerebellar cortex and Sparse Distributed Memory (SDM). First we present a simplified account of the immune response and immunological memory. Next we present SDM, and then we show the correlations between immunological memory and SDM. Finally, we show how associative recall in the immune response can be both beneficial and detrimental to the fitness of an individual.

  14. Flexible Kernel Memory

    PubMed Central

    Nowicki, Dimitri; Siegelmann, Hava

    2010-01-01

    This paper introduces a new model of associative memory, capable of both binary and continuous-valued inputs. Based on kernel theory, the memory model is on one hand a generalization of Radial Basis Function networks and, on the other, is in feature space, analogous to a Hopfield network. Attractors can be added, deleted, and updated on-line simply, without harming existing memories, and the number of attractors is independent of input dimension. Input vectors do not have to adhere to a fixed or bounded dimensionality; they can increase and decrease it without relearning previous memories. A memory consolidation process enables the network to generalize concepts and form clusters of input data, which outperforms many unsupervised clustering techniques; this process is demonstrated on handwritten digits from MNIST. Another process, reminiscent of memory reconsolidation is introduced, in which existing memories are refreshed and tuned with new inputs; this process is demonstrated on series of morphed faces. PMID:20552013

  15. A taxonomy of inductive problems.

    PubMed

    Kemp, Charles; Jern, Alan

    2014-02-01

    Inductive inferences about objects, features, categories, and relations have been studied for many years, but there are few attempts to chart the range of inductive problems that humans are able to solve. We present a taxonomy of inductive problems that helps to clarify the relationships between familiar inductive problems such as generalization, categorization, and identification, and that introduces new inductive problems for psychological investigation. Our taxonomy is founded on the idea that semantic knowledge is organized into systems of objects, features, categories, and relations, and we attempt to characterize all of the inductive problems that can arise when these systems are partially observed. Recent studies have begun to address some of the new problems in our taxonomy, and future work should aim to develop unified theories of inductive reasoning that explain how people solve all of the problems in the taxonomy.

  16. Memory access in shared virtual memory

    SciTech Connect

    Berrendorf, R. )

    1992-01-01

    Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

  17. Memory access in shared virtual memory

    SciTech Connect

    Berrendorf, R.

    1992-09-01

    Shared virtual memory (SVM) is a virtual memory layer with a single address space on top of a distributed real memory on parallel computers. We examine the behavior and performance of SVM running a parallel program with medium-grained, loop-level parallelism on top of it. A simulator for the underlying parallel architecture can be used to examine the behavior of SVM more deeply. The influence of several parameters, such as the number of processors, page size, cold or warm start, and restricted page replication, is studied.

  18. Stochastic memory: memory enhancement due to noise.

    PubMed

    Stotland, Alexander; Di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO(2) thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  19. Stochastic memory: Memory enhancement due to noise

    NASA Astrophysics Data System (ADS)

    Stotland, Alexander; di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO2 thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  20. Cognitive activity and physiological arousal: processes that mediate mood-congruent memory.

    PubMed

    Varner, L J; Ellis, H C

    1998-09-01

    This research proposes that the cognitive activity associated with the experience of an emotional state mediates the occurrence of mood-congruent processing. Two experiments examined the role of cognitive activity in selective processing of words in a mood congruence paradigm. Four induction procedures were used: a depressed-mood induction, a schema induction organized around the theme of writing a paper, an arousal induction, and a control neutral-mood induction. The memory task consisted of recalling a word list composed of negatively associated and thematically organized words. Selective processing was demonstrated in conjunction with the depressed-mood and organizational-schema induction procedures. In contrast, the arousal and neutral induction procedures did not produce selective processing of words from the list. The findings support the thesis that cognitive activity mediates the selective processing typical of mood congruence as distinct from arousal processes per se. The findings are discussed with respect to the resource allocation model and semantic network theory.

  1. Memory bistable mechanisms of organic memory devices

    NASA Astrophysics Data System (ADS)

    Lee, Ching-Ting; Yu, Li-Zhen; Chen, Hung-Chun

    2010-07-01

    To investigate the memory bistable mechanisms of organic memory devices, the structure of [top Au anode/9,10-di(2-naphthyl)anthracene (ADN) active layer/bottom Au cathode] was deposited using a thermal deposition system. The Au atoms migrated into the ADN active layer was observed from the secondary ion mass spectrometry. The density of 9.6×1016 cm-3 and energy level of 0.553 eV of the induced trapping centers caused by the migrated Au atoms in the ADN active layer were calculated. The induced trapping centers did not influence the carrier injection barrier height between Au and ADN active layer. Therefore, the memory bistable behaviors of the organic memory devices were attributed to the induced trapping centers. The energy diagram was established to verify the mechanisms.

  2. Psychophysiology of prospective memory.

    PubMed

    Rothen, Nicolas; Meier, Beat

    2014-01-01

    Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.

  3. Low inductance gas switching.

    SciTech Connect

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  4. Working Memory and Dynamic Measures of Analogical Reasoning as Predictors of Children's Math and Reading Achievement

    ERIC Educational Resources Information Center

    Stevenson, Claire E.; Bergwerff, Catharina E.; Heiser, Willem J.; Resing, Wilma C. M.

    2014-01-01

    Working memory and inductive reasoning ability each appear related to children's achievement in math and reading. Dynamic measures of reasoning, based on an assessment procedure including feedback, may provide additional predictive value. The aim of this study was to investigate whether working memory and dynamic measures of analogical…

  5. Human learning and memory.

    PubMed

    Johnson, M K; Hasher, L

    1987-01-01

    There have been several notable recent trends in the area of learning and memory. Problems with the episodic/semantic distinction have become more apparent, and new efforts have been made (exemplar models, distributed-memory models) to represent general knowledge without assuming a separate semantic system. Less emphasis is being placed on stable, prestored prototypes and more emphasis on a flexible memory system that provides the basis for a multitude of categories or frames of reference, derived on the spot as tasks demand. There is increasing acceptance of the idea that mental models are constructed and stored in memory in addition to, rather than instead of, memorial representations that are more closely tied to perceptions. This gives rise to questions concerning the conditions that permit inferences to be drawn and mental models to be constructed, and to questions concerning the similarities and differences in the nature of the representations in memory of perceived and generated information and in their functions. There has also been a swing from interest in deliberate strategies to interest in automatic, unconscious (even mechanistic!) processes, reflecting an appreciation that certain situations (e.g. recognition, frequency judgements, savings in indirect tasks, aspects of skill acquisition, etc) seem not to depend much on the products of strategic, effortful or reflective processes. There is a lively interest in relations among memory measures and attempts to characterize memory representations and/or processes that could give rise to dissociations among measures. Whether the pattern of results reflects the operation of functional subsystems of memory and, if so, what the "modules" are is far from clear. This issue has been fueled by work with amnesics and has contributed to a revival of interaction between researchers studying learning and memory in humans and those studying learning and memory in animals. Thus, neuroscience rivals computer science as a

  6. Induction linear accelerators

    NASA Astrophysics Data System (ADS)

    Birx, Daniel

    1992-03-01

    Among the family of particle accelerators, the Induction Linear Accelerator is the best suited for the acceleration of high current electron beams. Because the electromagnetic radiation used to accelerate the electron beam is not stored in the cavities but is supplied by transmission lines during the beam pulse it is possible to utilize very low Q (typically<10) structures and very large beam pipes. This combination increases the beam breakup limited maximum currents to of order kiloamperes. The micropulse lengths of these machines are measured in 10's of nanoseconds and duty factors as high as 10-4 have been achieved. Until recently the major problem with these machines has been associated with the pulse power drive. Beam currents of kiloamperes and accelerating potentials of megavolts require peak power drives of gigawatts since no energy is stored in the structure. The marriage of liner accelerator technology and nonlinear magnetic compressors has produced some unique capabilities. It now appears possible to produce electron beams with average currents measured in amperes, peak currents in kiloamperes and gradients exceeding 1 MeV/meter, with power efficiencies approaching 50%. The nonlinear magnetic compression technology has replaced the spark gap drivers used on earlier accelerators with state-of-the-art all-solid-state SCR commutated compression chains. The reliability of these machines is now approaching 1010 shot MTBF. In the following paper we will briefly review the historical development of induction linear accelerators and then discuss the design considerations.

  7. Pulsed inductive HF laser

    SciTech Connect

    Razhev, A M; Kargapol'tsev, E S; Churkin, D S; Demchuk, S V

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  8. "Menstrual induction" with Sulproston.

    PubMed

    Csapo, A I; Peskin, E G; Pulkkinen, M; Laajoki, V; Kivikoski, A; Lampe, L; Godeny, S; Szeverenyi, M; Herczeg, J; Resch, B; Bacos, L

    1982-11-01

    The PGE2-analogue Sulproston (16-phenoxy-omega-17,18,19,20-tetranor-PGE2-mythylsulfonylamide) was administered to 200 medically and gynecologically normal women who were 17 +/- 0.4 days beyond their expected menstrual period and who had a positive pregnancy test. The intramuscular impact dose (500 micrograms repeated after 4 hours) caused an immediate tonic uterine contraction which compromised the estradiol 17 beta, progesterone and chorionic gonadotropin production within the fetoplacental unit, and thereby allowed the evolution of cyclic uterine activity, cervical dilatation and tissue expulsion. Pregnancy termination was complete in 92% of women, 5.5% required surgical curettage and 2.5% were given a second Sulproston treatment 2-3 weeks after the first to remove retained tissue from the uterus. The medical induction of menstruation was preferred by 83% of the women who had previously experienced surgical termination of pregnancy. Normal menstruation resumed in all women after 36 +/- 0.9 days. The majority of 42 women questioned found Sulproston a satisfactory, safe, simple and effective drug regimen for "menstrual induction".

  9. Conscious and Unconscious Memory Systems

    PubMed Central

    Squire, Larry R.; Dede, Adam J.O.

    2015-01-01

    The idea that memory is not a single mental faculty has a long and interesting history but became a topic of experimental and biologic inquiry only in the mid-20th century. It is now clear that there are different kinds of memory, which are supported by different brain systems. One major distinction can be drawn between working memory and long-term memory. Long-term memory can be separated into declarative (explicit) memory and a collection of nondeclarative (implicit) forms of memory that include habits, skills, priming, and simple forms of conditioning. These memory systems depend variously on the hippocampus and related structures in the parahippocampal gyrus, as well as on the amygdala, the striatum, cerebellum, and the neocortex. This work recounts the discovery of declarative and nondeclarative memory and then describes the nature of declarative memory, working memory, nondeclarative memory, and the relationship between memory systems. PMID:25731765

  10. A generalized memory test algorithm

    NASA Technical Reports Server (NTRS)

    Milner, E. J.

    1982-01-01

    A general algorithm for testing digital computer memory is presented. The test checks that (1) every bit can be cleared and set in each memory work, and (2) bits are not erroneously cleared and/or set elsewhere in memory at the same time. The algorithm can be applied to any size memory block and any size memory word. It is concise and efficient, requiring the very few cycles through memory. For example, a test of 16-bit-word-size memory requries only 384 cycles through memory. Approximately 15 seconds were required to test a 32K block of such memory, using a microcomputer having a cycle time of 133 nanoseconds.

  11. Regulatory T cell memory

    PubMed Central

    Rosenblum, Michael D.; Way, Sing Sing; Abbas, Abul K.

    2016-01-01

    Memory for antigen is a defining feature of adaptive immunity. Antigen-specific lymphocyte populations show an increase in number and function after antigen encounter and more rapidly re-expand upon subsequent antigen exposure. Studies of immune memory have primarily focused on effector B cells and T cells with microbial specificity, using prime challenge models of infection. However, recent work has also identified persistently expanded populations of antigen-specific regulatory T cells that protect against aberrant immune responses. In this Review, we consider the parallels between memory effector T cells and memory regulatory T cells, along with the functional implications of regulatory memory in autoimmunity, antimicrobial host defence and maternal fetal tolerance. In addition, we discuss emerging evidence for regulatory T cell memory in humans and key unanswered questions in this rapidly evolving field. PMID:26688349

  12. Shape memory polymers

    DOEpatents

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  13. Complexity of Geometric Inductive Reasoning Tasks: Contribution to the Understanding of Fluid Intelligence.

    ERIC Educational Resources Information Center

    Primi, Ricardo

    2002-01-01

    Created two geometric inductive reasoning matrix tests by manipulating four sources of complexity orthogonally. Results for 313 undergraduates show that fluid intelligence is most strongly associated with the part of the central executive component of working memory that is related to controlled attention processing and selective encoding. (SLD)

  14. Divergent creative thinking in young and older adults: Extending the effects of an episodic specificity induction.

    PubMed

    Madore, Kevin P; Jing, Helen G; Schacter, Daniel L

    2016-08-01

    Recent research has suggested that an episodic specificity induction-brief training in recollecting the details of a past experience-enhances divergent creative thinking on the alternate uses task (AUT) in young adults, without affecting performance on tasks thought to involve little divergent thinking; however, the generalizability of these results to other populations and tasks is unknown. In the present experiments, we examined whether the effects of an episodic specificity induction would extend to older adults and a different index of divergent thinking, the consequences task. In Experiment 1, the specificity induction significantly enhanced divergent thinking on the AUT in both young and older adults, as compared with a control induction not requiring specific episodic retrieval; performance on a task involving little divergent thinking (generating associates for common objects) did not vary as a function of induction. No overall age-related differences were observed on either task. In Experiment 2, the specificity induction significantly enhanced divergent thinking (in terms of generating consequences of novel scenarios) in young adults, relative to another control induction not requiring episodic retrieval. To examine the types of creative ideas affected by the induction, the participants in both experiments also labeled each of their divergent-thinking responses as an "old idea" from memory or a "new idea" from imagination. New, and to some extent old, ideas were significantly boosted following the specificity induction relative to the control. These experiments provide novel evidence that an episodic specificity induction can boost divergent thinking in young and older adults, and indicate that episodic memory is involved in multiple divergent-thinking tasks.

  15. Content Addressable Memory Project

    DTIC Science & Technology

    1990-11-01

    The Content Addressable M1-emory Project consists of the development of several experimental software systems on an AMT Distributed Array Processor...searching (database) compiler algorithms memory management other systems software) Linear C is an unlovely hybrid language which imports the CAM...memory from AMT’s operating system for the DAP; how- ever, other than this limitation, the memory management routines work exactly as their C counterparts

  16. Sparse distributed memory

    NASA Technical Reports Server (NTRS)

    Kanerva, Pentti

    1988-01-01

    Theoretical models of the human brain and proposed neural-network computers are developed analytically. Chapters are devoted to the mathematical foundations, background material from computer science, the theory of idealized neurons, neurons as address decoders, and the search of memory for the best match. Consideration is given to sparse memory, distributed storage, the storage and retrieval of sequences, the construction of distributed memory, and the organization of an autonomous learning system.

  17. Memory Load and Dump

    NASA Astrophysics Data System (ADS)

    Welty, Alan

    2009-07-01

    This proposal is a test and verification of the STIS dump of memory capability.Areas of Control Section {CS} to dump include: EDAC RAM, EEPROM, and CS PROM {with the CS in Operate}. Areas of MIE memory to dump include: MIE RAM and MIE PROM {with the MIE in Operate}. Note that the MIE memory must first be copied to CS buffer RAM as images, which are then dumped.Supports Activity STIS-02

  18. Myrmics Memory Allocator

    SciTech Connect

    Lymperis, S.

    2011-09-23

    MMA is a stand-alone memory management system for MPI clusters. It implements a shared Partitioned Global Address Space, where multiple MPI processes request objects from the allocator and the latter provides them with system-wide unique memory addresses for each object. It provides applications with an intuitive way of managing the memory system in a unified way, thus enabling easier writing of irregular application code.

  19. Memory Golf Clubs

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Memory Corporation's investigation of shape memory effect, stemming from Marshall Space Flight Center contracts to study materials for the space station, has aided in the development of Zeemet, a proprietary, high-damping shape memory alloy for the golf industry. The Nicklaus Golf Company has created a new line of golf clubs using Zeemet inserts. Its superelastic and high damping attributes translate into more spin on the ball, greater control, and a solid feel.

  20. Induction of anaesthesia in children.

    PubMed

    Boezaart, A P; van Hasselt, C H

    1987-05-16

    Induction of anaesthesia in children in the age group 2-6 years is a special challenge. In order to minimise emotional and physical stress during induction of anaesthesia by gas inhalation, a toy telephone has been modified to deliver induction gases to the mouthpiece while taped nursery stories can be heard from a small speaker placed in the earpiece. The child holds the hand set and listens to a suitable story, while appropriate concentrations of inhalation agents are adjusted inconspicuously.

  1. Networks of Memories

    DTIC Science & Technology

    2013-03-01

    2000). The construction of  autobiographical   memories in the self­memory system. Psychological Review, 107(2), 261­288. Dennis, S., & Chapman, A. (2010...AFRL-OSR-VA-TR-2013-0131 Networks of Memories Simon Dennis, Mikhail Belkin Ohio State University March 2013 Final...Back (Rev. 8/98) 1 Networks of  Memories FA9550­09­1­0614 Professor Jay Myung PI: Simon Dennis Ohio State University February 15, 2013 2 Introduction

  2. Hypnosis, memory and amnesia.

    PubMed Central

    Kihlstrom, J F

    1997-01-01

    Hypnotized subjects respond to suggestions from the hypnotist for imaginative experiences involving alterations in perception and memory. Individual differences in hypnotizability are only weakly related to other forms of suggestibility. Neuropsychological speculations about hypnosis focus on the right hemisphere and/or the frontal lobes. Posthypnotic amnesia refers to subjects' difficulty in remembering, after hypnosis, the events and experiences that transpired while they were hypnotized. Posthypnotic amnesia is not an instance of state-dependent memory, but it does seem to involve a disruption of retrieval processes similar to the functional amnesias observed in clinical dissociative disorders. Implicit memory, however, is largely spared, and may underlie subjects' ability to recognize events that they cannot recall. Hypnotic hypermnesia refers to improved memory for past events. However, such improvements are illusory: hypermnesia suggestions increase false recollection, as well as subjects' confidence in both true and false memories. Hypnotic age regression can be subjectively compelling, but does not involve the ablation of adult memory, or the reinstatement of childlike modes of mental functioning, or the revivification of memory. The clinical and forensic use of hypermnesia and age regression to enhance memory in patients, victims and witnesses (e.g. recovered memory therapy for child sexual abuse) should be discouraged. PMID:9415925

  3. New gravitational memories

    NASA Astrophysics Data System (ADS)

    Pasterski, Sabrina; Strominger, Andrew; Zhiboedov, Alexander

    2016-12-01

    The conventional gravitational memory effect is a relative displacement in the position of two detectors induced by radiative energy flux. We find a new type of gravitational `spin memory' in which beams on clockwise and counterclockwise orbits acquire a relative delay induced by radiative angular momentum flux. It has recently been shown that the displacement memory formula is a Fourier transform in time of Weinberg's soft graviton theorem. Here we see that the spin memory formula is a Fourier transform in time of the recently-discovered subleading soft graviton theorem.

  4. Sparse distributed memory overview

    NASA Technical Reports Server (NTRS)

    Raugh, Mike

    1990-01-01

    The Sparse Distributed Memory (SDM) project is investigating the theory and applications of massively parallel computing architecture, called sparse distributed memory, that will support the storage and retrieval of sensory and motor patterns characteristic of autonomous systems. The immediate objectives of the project are centered in studies of the memory itself and in the use of the memory to solve problems in speech, vision, and robotics. Investigation of methods for encoding sensory data is an important part of the research. Examples of NASA missions that may benefit from this work are Space Station, planetary rovers, and solar exploration. Sparse distributed memory offers promising technology for systems that must learn through experience and be capable of adapting to new circumstances, and for operating any large complex system requiring automatic monitoring and control. Sparse distributed memory is a massively parallel architecture motivated by efforts to understand how the human brain works. Sparse distributed memory is an associative memory, able to retrieve information from cues that only partially match patterns stored in the memory. It is able to store long temporal sequences derived from the behavior of a complex system, such as progressive records of the system's sensory data and correlated records of the system's motor controls.

  5. The future of memory

    NASA Astrophysics Data System (ADS)

    Marinella, M.

    In the not too distant future, the traditional memory and storage hierarchy of may be replaced by a single Storage Class Memory (SCM) device integrated on or near the logic processor. Traditional magnetic hard drives, NAND flash, DRAM, and higher level caches (L2 and up) will be replaced with a single high performance memory device. The Storage Class Memory paradigm will require high speed (< 100 ns read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (< 10 pJ per switch). The International Technology Roadmap for Semiconductors (ITRS) has recently evaluated several potential candidates SCM technologies, including Resistive (or Redox) RAM, Spin Torque Transfer RAM (STT-MRAM), and phase change memory (PCM). All of these devices show potential well beyond that of current flash technologies and research efforts are underway to improve the endurance, write speeds, and scalabilities to be on-par with DRAM. This progress has interesting implications for space electronics: each of these emerging device technologies show excellent resistance to the types of radiation typically found in space applications. Commercially developed, high density storage class memory-based systems may include a memory that is physically radiation hard, and suitable for space applications without major shielding efforts. This paper reviews the Storage Class Memory concept, emerging memory devices, and possible applicability to radiation hardened electronics for space.

  6. STAT1 negatively regulates spatial memory formation and mediates the memory-impairing effect of Aβ.

    PubMed

    Hsu, Wei-Lun; Ma, Yun-Li; Hsieh, Ding-You; Liu, Yen-Chen; Lee, Eminy Hy

    2014-02-01

    Signal transducer and activator of transcription-1 (STAT1) has an important role in inflammation and the innate immune response, but its role in the central nervous system is less well understood. Here, we examined the role of STAT1 in spatial learning and memory, and assessed the involvement of STAT1 in mediating the memory-impairing effect of amyloid-beta (Aβ). We found that water maze training downregulated STAT1 expression in the rat hippocampal CA1 area, and spatial learning and memory function was enhanced in Stat1-knockout mice. Conversely, overexpression of STAT1 impaired water maze performance. STAT1 strongly upregulated the expression of the extracellular matrix protein laminin β1 (LB1), which also impaired water maze performance in rats. Furthermore, Aβ impaired spatial learning and memory in association with a dose-dependent increase in STAT1 and LB1 expression, but knockdown of STAT1 and LB1 both reversed this effect of Aβ. This Aβ-induced increase in STAT1 and LB1 expression was also associated with a decrease in the expression of the N-methyl-D-aspartate receptor (NMDAR) subunits, NR1, and NR2B. Overexpression of NR1 or NR2B or exogenous application of NMDA reversed Aβ-induced learning and memory deficits as well as Aβ-induced STAT1 and LB1 expression. Our results demonstrate that STAT1 negatively regulates spatial learning and memory through transcriptional regulation of LB1 expression. We also identified a novel mechanism for Aβ pathogenesis through STAT1 induction. Notably, impairment of spatial learning and memory by this STAT1-mediated mechanism is independent of cAMP responsive element-binding protein signaling.

  7. Induction Linac Pulsers

    SciTech Connect

    Faltens, Andris

    2011-01-07

    The pulsers used in most of the induction linacs evolved from the very large body of work that was done in the U.S. and Great Britain during the development of the pulsed magnetron for radar. The radar modulators started at {approx}100 kW and reached >10 MW by 1945. A typical pulse length was 1 {mu}s at a repetition rate of 1,000 pps. A very comprehensive account of the modulator development is Pulse Generators by Lebacqz and Glasoe, one of the Radiation Laboratory Series. There are many permutations of possible modulators, two of the choices being tube type and line type. In earlier notes I wrote that technically the vacuum tube pulser met all of our induction linac needs, in the sense that a number of tubes, in series and parallel if required, could produce our pulses, regulate their voltage, be useable in feed-forward correctors, and provide a low source impedance. At a lower speed, an FET array is similar, and we have obtained and tested a large array capable of >10 MW switching. A modulator with an electronically controlled output only needs a capacitor for energy storage and in a switched mode can transfer the energy from the capacitor to the load at high efficiency. Driving a full size Astron induction core and a simulated resistive 'beam load' we achieved >50% efficiency. These electronically controlled output pulses can produce the pulses we desire but are not used because of their high cost. The second choice, the line type pulser, visually comprises a closing switch and a distributed or a lumped element transmission line. The typical switch cannot open or stop conducting after the desired pulse has been produced, and consequently all of the initially stored energy is dissipated. This approximately halves the efficiency, and the original cost estimating program LIACEP used this factor of two, even though our circuits are usually worse, and even though our inveterate optimists often omit it. The 'missing' energy is that which is reflected back into the

  8. Memory, reasoning, and categorization: parallels and common mechanisms

    PubMed Central

    Hayes, Brett K.; Heit, Evan; Rotello, Caren M.

    2014-01-01

    Traditionally, memory, reasoning, and categorization have been treated as separate components of human cognition. We challenge this distinction, arguing that there is broad scope for crossover between the methods and theories developed for each task. The links between memory and reasoning are illustrated in a review of two lines of research. The first takes theoretical ideas (two-process accounts) and methodological tools (signal detection analysis, receiver operating characteristic curves) from memory research and applies them to important issues in reasoning research: relations between induction and deduction, and the belief bias effect. The second line of research introduces a task in which subjects make either memory or reasoning judgments for the same set of stimuli. Other than broader generalization for reasoning than memory, the results were similar for the two tasks, across a variety of experimental stimuli and manipulations. It was possible to simultaneously explain performance on both tasks within a single cognitive architecture, based on exemplar-based comparisons of similarity. The final sections explore evidence for empirical and processing links between inductive reasoning and categorization and between categorization and recognition. An important implication is that progress in all three of these fields will be expedited by further investigation of the many commonalities between these tasks. PMID:24987380

  9. Memory, reasoning, and categorization: parallels and common mechanisms.

    PubMed

    Hayes, Brett K; Heit, Evan; Rotello, Caren M

    2014-01-01

    Traditionally, memory, reasoning, and categorization have been treated as separate components of human cognition. We challenge this distinction, arguing that there is broad scope for crossover between the methods and theories developed for each task. The links between memory and reasoning are illustrated in a review of two lines of research. The first takes theoretical ideas (two-process accounts) and methodological tools (signal detection analysis, receiver operating characteristic curves) from memory research and applies them to important issues in reasoning research: relations between induction and deduction, and the belief bias effect. The second line of research introduces a task in which subjects make either memory or reasoning judgments for the same set of stimuli. Other than broader generalization for reasoning than memory, the results were similar for the two tasks, across a variety of experimental stimuli and manipulations. It was possible to simultaneously explain performance on both tasks within a single cognitive architecture, based on exemplar-based comparisons of similarity. The final sections explore evidence for empirical and processing links between inductive reasoning and categorization and between categorization and recognition. An important implication is that progress in all three of these fields will be expedited by further investigation of the many commonalities between these tasks.

  10. Comprehensive Teacher Induction: Linking Teacher Induction to Theory

    ERIC Educational Resources Information Center

    Keilwitz, Heather A.

    2014-01-01

    Teacher retention is a wide concern in education and in response school districts throughout the United States are developing more comprehensive teacher induction programs. Components of teacher induction programs that have assisted with successful teacher development include release time for teacher observation, assignment of a knowledgeable…

  11. Cooling by Thermodynamic Induction

    NASA Astrophysics Data System (ADS)

    Patitsas, S. N.

    2017-03-01

    A method is described for cooling conductive channels to below ambient temperature. The thermodynamic induction principle dictates that the electrically biased channel will cool if the electrical conductance decreases with temperature. The extent of this cooling is calculated in detail for both cases of ballistic and conventional transport with specific calculations for carbon nanotubes and conventional metals, followed by discussions for semiconductors, graphene, and metal-insulator transition systems. A theorem is established for ballistic transport stating that net cooling is not possible. For conventional transport, net cooling is possible over a broad temperature range, with the range being size-dependent. A temperature clamping scheme for establishing a metastable nonequilibrium stationary state is detailed and followed with discussion of possible applications to on-chip thermoelectric cooling in integrated circuitry and quantum computer systems.

  12. Borehole induction coil transmitter

    DOEpatents

    Holladay, Gale; Wilt, Michael J.

    2002-01-01

    A borehole induction coil transmitter which is a part of a cross-borehole electromagnetic field system that is used for underground imaging applications. The transmitter consists of four major parts: 1) a wound ferrite or mu-metal core, 2) an array of tuning capacitors, 3) a current driver circuit board, and 4) a flux monitor. The core is wound with several hundred turns of wire and connected in series with the capacitor array, to produce a tuned coil. This tuned coil uses internal circuitry to generate sinusoidal signals that are transmitted through the earth to a receiver coil in another borehole. The transmitter can operate at frequencies from 1-200 kHz and supplies sufficient power to permit the field system to operate in boreholes separated by up to 400 meters.

  13. Kinetic inductance magnetometer.

    PubMed

    Luomahaara, Juho; Vesterinen, Visa; Grönberg, Leif; Hassel, Juha

    2014-09-10

    Sensing ultra-low magnetic fields has various applications in the fields of science, medicine and industry. There is a growing need for a sensor that can be operated in ambient environments where magnetic shielding is limited or magnetic field manipulation is involved. To this end, here we demonstrate a new magnetometer with high sensitivity and wide dynamic range. The device is based on the current nonlinearity of superconducting material stemming from kinetic inductance. A further benefit of our approach is of extreme simplicity: the device is fabricated from a single layer of niobium nitride. Moreover, radio frequency multiplexing techniques can be applied, enabling the simultaneous readout of multiple sensors, for example, in biomagnetic measurements requiring data from large sensor arrays.

  14. Cooling by Thermodynamic Induction

    NASA Astrophysics Data System (ADS)

    Patitsas, S. N.

    2016-11-01

    A method is described for cooling conductive channels to below ambient temperature. The thermodynamic induction principle dictates that the electrically biased channel will cool if the electrical conductance decreases with temperature. The extent of this cooling is calculated in detail for both cases of ballistic and conventional transport with specific calculations for carbon nanotubes and conventional metals, followed by discussions for semiconductors, graphene, and metal-insulator transition systems. A theorem is established for ballistic transport stating that net cooling is not possible. For conventional transport, net cooling is possible over a broad temperature range, with the range being size-dependent. A temperature clamping scheme for establishing a metastable nonequilibrium stationary state is detailed and followed with discussion of possible applications to on-chip thermoelectric cooling in integrated circuitry and quantum computer systems.

  15. Inductive System Health Monitoring

    NASA Technical Reports Server (NTRS)

    Iverson, David L.

    2004-01-01

    The Inductive Monitoring System (IMS) software was developed to provide a technique to automatically produce health monitoring knowledge bases for systems that are either difficult to model (simulate) with a computer or which require computer models that are too complex to use for real time monitoring. IMS uses nominal data sets collected either directly from the system or from simulations to build a knowledge base that can be used to detect anomalous behavior in the system. Machine learning and data mining techniques are used to characterize typical system behavior by extracting general classes of nominal data from archived data sets. IMS is able to monitor the system by comparing real time operational data with these classes. We present a description of learning and monitoring method used by IMS and summarize some recent IMS results.

  16. Inductive Position Sensor

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Simmons, Stephen M. (Inventor)

    2015-01-01

    An inductive position sensor uses three parallel inductors, each of which has an axial core that is an independent magnetic structure. A first support couples first and second inductors and separate them by a fixed distance. A second support coupled to a third inductor disposed between the first and second inductors. The first support and second support are configured for relative movement as distance changes from the third inductor to each of the first and second inductors. An oscillating current is supplied to the first and second inductors. A device measures a phase component of a source voltage generating the oscillating current and a phase component of voltage induced in the third inductor when the oscillating current is supplied to the first and second inductors such that the phase component of the voltage induced overlaps the phase component of the source voltage.

  17. [Memory disorders in schizophrenia].

    PubMed

    Danion, J M; Peretti, S; Gras-Vincendon, A; Singer, L

    1992-01-01

    The current interest in memory disorders in schizophrenia results from the way perceptions of schizophrenia--whose organic origin is becoming increasingly evident--and memory--according to which there exist not one, but several memories--have developed. Memory disorders in the schizophrenic cannot be considered in isolation from knowledge accumulated in other areas of the cognitive and neuro-sciences; a more detailed understanding of these disorders requires a comparison of the different cognitive approaches, both with each other and with the neurobiological and clinical approaches, so that they can be integrated. Despite numerous methodological and conceptual difficulties, it now appears to have been established that the schizophrenic's memory deficit should be seen in the context of a wider cognitive deficit, that the memory tasks are not all disturbed and that the memory deficit cannot be identified with one specific form of memory. Thus, iconic formation, short-term memory in the traditionally accepted sense and implicit memory are hardly, if at all, affected; in contrast, the early processing of information, working memory and explicit memory are disturbed, probably to the extent that they require the implementation of strategies to organise the information to be memorized. Finally, in certain tasks, such as those evaluating latent inhibition or negative priming, schizophrenics perform better than normal subjects, suggesting that schizophrenics' cognitive deficit is localised. This profile of memory disorders is compatible with a dysfunction predominating in the frontal and temporo-hippocampal regions. Neuroleptics and anticholinergics have opposite effects on cognitive and mnesic performance, which is improved by the former and aggravated by the latter. The influence of clinical symptoms, positive or negative, institutionalisation of patients and chronic tardive dyskinesia is unclear. Among the theoretical proposals put forward to account for the observed

  18. Amygdala Dopamine Receptors Are Required for the Destabilization of a Reconsolidating Appetitive Memory(1,2).

    PubMed

    Merlo, Emiliano; Ratano, Patrizia; Ilioi, Elena C; Robbins, Miranda A L S; Everitt, Barry J; Milton, Amy L

    2015-01-01

    Disrupting maladaptive memories may provide a novel form of treatment for neuropsychiatric disorders, but little is known about the neurochemical mechanisms underlying the induction of lability, or destabilization, of a retrieved consolidated memory. Destabilization has been theoretically linked to the violation of expectations during memory retrieval, which, in turn, has been suggested to correlate with prediction error (PE). It is well-established that PE correlates with dopaminergic signaling in limbic forebrain structures that are critical for emotional learning. The basolateral amygdala is a key neural substrate for the reconsolidation of pavlovian reward-related memories, but the involvement of dopaminergic mechanisms in inducing lability of amygdala-dependent memories has not been investigated. Therefore, we tested the hypothesis that dopaminergic signaling within the basolateral amygdala is required for the destabilization of appetitive pavlovian memories by investigating the effects dopaminergic and protein synthesis manipulations on appetitive memory reconsolidation in rats. Intra-amygdala administration of either the D1-selective dopamine receptor antagonist SCH23390 or the D2-selective dopamine receptor antagonist raclopride prevented memory destabilization at retrieval, thereby protecting the memory from the effects of an amnestic agent, the protein synthesis inhibitor anisomycin. These data show that dopaminergic transmission within the basolateral amygdala is required for memory labilization during appetitive memory reconsolidation.

  19. Distributed multiport memory architecture

    NASA Technical Reports Server (NTRS)

    Kohl, W. H. (Inventor)

    1983-01-01

    A multiport memory architecture is diclosed for each of a plurality of task centers connected to a command and data bus. Each task center, includes a memory and a plurality of devices which request direct memory access as needed. The memory includes an internal data bus and an internal address bus to which the devices are connected, and direct timing and control logic comprised of a 10-state ring counter for allocating memory devices by enabling AND gates connected to the request signal lines of the devices. The outputs of AND gates connected to the same device are combined by OR gates to form an acknowledgement signal that enables the devices to address the memory during the next clock period. The length of the ring counter may be effectively lengthened to any multiple of ten to allow for more direct memory access intervals in one repetitive sequence. One device is a network bus adapter which serially shifts onto the command and data bus, a data word (8 bits plus control and parity bits) during the next ten direct memory access intervals after it has been granted access. The NBA is therefore allocated only one access in every ten intervals, which is a predetermined interval for all centers. The ring counters of all centers are periodically synchronized by DMA SYNC signal to assure that all NBAs be able to function in synchronism for data transfer from one center to another.

  20. [Learning and memory].

    PubMed

    Lombroso, Paul

    2004-09-01

    Memory is broadly divided into declarative and nondeclarative forms of memory. The hippocampus is required for the formation of declarative memories, while a number of other brain regions including the striatum, amygdala and nucleus accumbens are involved in the formation of nondeclarative memories. The formation of all memories require morphological changes of synapses: new ones must be formed or old ones strengthened. These changes are thought to reflect the underlying cellular basis for persistent memories. Considerable advances have occurred over the last decade in our understanding of the molecular bases of how these memories are formed. A key regulator of synaptic plasticity is a signaling pathway that includes the mitogen activated protein (MAP) kinase. As this pathway is required for normal memory and learning, it is not surprising that mutations in members of this pathway lead to disruptions in learning. Neurofibromatosis, Coffin-Lowry syndrome and Rubinstein-Taybi syndrome are three examples of developmental disorders that have mutations in key components of the MAP kinase signaling pathway.

  1. Memory and Aging

    MedlinePlus

    ... or home environment and you’re not paying attention when your friend gives you directions to her new home, you will not be able to recall how to get there. Memory and Aging Memory Aids Keep “to do” lists Keep “to do” lists and ...

  2. Regret as Autobiographical Memory

    ERIC Educational Resources Information Center

    Davison, Ian M.; Feeney, Aidan

    2008-01-01

    We apply an autobiographical memory framework to the study of regret. Focusing on the distinction between regrets for specific and general events we argue that the temporal profile of regret, usually explained in terms of the action-inaction distinction, is predicted by models of autobiographical memory. In two studies involving participants in…

  3. Memories of Physical Education

    ERIC Educational Resources Information Center

    Sidwell, Amy M.; Walls, Richard T.

    2014-01-01

    The purpose of this investigation was to explore college students' autobiographical memories of physical education (PE). Questionnaires were distributed to students enrolled in undergraduate Introduction to PE and Introduction to Communications courses. The 261 participants wrote about memories of PE. These students recalled events from Grades…

  4. Experimental Optoelectronic Associative Memory

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin

    1992-01-01

    Optoelectronic associative memory responds to input image by displaying one of M remembered images. Which image to display determined by optoelectronic analog computation of resemblance between input image and each remembered image. Does not rely on precomputation and storage of outer-product synapse matrix. Size of memory needed to store and process images reduced.

  5. Memorial symptom assessment scale.

    PubMed

    Chang, Victor T; Hwang, Shirley S; Thaler, Howard T; Kasimis, Basil S; Portenoy, Russell K

    2004-04-01

    Patients with advanced illnesses often have multiple symptoms. As interest in palliative care and interventions for symptom control increase, the ability to assess multiple symptoms has become more important. A number of instruments have been developed to meet this need in cancer patients. This article reviews the development and applications of a multidimensional instrument, the Memorial Symptom Assessment Scale. The Memorial Symptom Assessment Scale has 32 symptoms and three dimensions of frequency, severity, and distress. Shorter versions - The Memorial Symptom Assessment Scale Short Form (32 symptoms with one dimension) and the Condensed Memorial Symptom Assessment Scale (14 symptoms with one dimension), and a version for children aged 7-12 years, have also been developed. A distinctive feature is the summary subscales for physical distress, psychological distress, and The Global Distress Index. The Memorial Symptom Assessment Scale has proven useful in description of symptom epidemiology, the role of symptoms in pain, fatigue, and spirituality; as a predictor of survival, and in proxy assessments of pain. The Memorial Symptom Assessment Scale has been used in studies of cancer and AIDS patients, and patients with advanced medical illnesses. Possible future roles of instruments such as the Memorial Symptom Assessment Scale include use in clinical trials, for pharmacoeconomic analyses, definition of symptom clusters and symptom burden, the development of symptom outcome measures, symptom monitoring, and improving care for patients. Continued research is needed for the versions of the Memorial Symptom Assessment Scale and other symptom instruments in different populations and applications.

  6. Visual Memory at Birth.

    ERIC Educational Resources Information Center

    Slater, Alan; And Others

    1982-01-01

    Explored new-born babys' capacity for forming visual memories. Used an habituation procedure that accommodated individual differences by allowing each infant to control the time course of habituation trials. Found significant novelty preference, providing strong evidence that recognition memory can be reliably demonstrated from birth. (Author/JAC)

  7. Human Learning and Memory

    ERIC Educational Resources Information Center

    Lieberman, David A.

    2012-01-01

    This innovative textbook is the first to integrate learning and memory, behaviour, and cognition. It focuses on fascinating human research in both memory and learning (while also bringing in important animal studies) and brings the reader up to date with the latest developments in the subject. Students are encouraged to think critically: key…

  8. Human Memory: The Basics

    ERIC Educational Resources Information Center

    Martinez, Michael E.

    2010-01-01

    The human mind has two types of memory: short-term and long-term. In all types of learning, it is best to use that structure rather than to fight against it. One way to do that is to ensure that learners can fit new information into patterns that can be stored in and more easily retrieved from long-term memory.

  9. Memory Efficient Ranking.

    ERIC Educational Resources Information Center

    Moffat, Alistair; And Others

    1994-01-01

    Describes an approximate document ranking process that uses a compact array of in-memory, low-precision approximations for document length. Combined with another rule for reducing the memory required by partial similarity accumulators, the approximation heuristic allows the ranking of large document collections using less than one byte of memory…

  10. Memory technology survey

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The current status of semiconductor, magnetic, and optical memory technologies is described. Projections based on these research activities planned for the shot term are presented. Conceptual designs of specific memory buffer pplications employing bipola, CMOS, GaAs, and Magnetic Bubble devices are discussed.

  11. An Exceptional Memory

    ERIC Educational Resources Information Center

    Hunter, Ian M. L.

    1977-01-01

    An account is given of the exceptional memory of the late Professor A. C. Aitken who was also a distinguished mathematician and mental calculator. Compared with Shereshevskii, another man with exceptional memory, he shows the scholar's reliance on conceptual mapping rather than the mnemonist's reliance on perceptual chaining. (Editor)

  12. Memory Metals (Marchon Eyewear)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Another commercial application of memory metal technology is found in a "smart" eyeglass frame that remembers its shape and its wearer's fit. A patented "memory encoding process" makes this possible. Heat is not required to return the glasses to shape. A large commercial market is anticipated.

  13. A Space for Memory

    ERIC Educational Resources Information Center

    Charman, Karen

    2015-01-01

    In this article I examine the possibilities of reparation in an era of privatisation and de-industrialisation. I examine the effect of a recent project Sunshine Memory Space, a space, designed to evoke memories of a de-industrialised urban Melbourne suburb Sunshine. This project offered the opportunity for the effects of industrial change to be…

  14. From Inductive Reasoning to Proof

    ERIC Educational Resources Information Center

    Yopp, David A.

    2009-01-01

    Mathematical proof is an expression of deductive reasoning (drawing conclusions from previous assertions). However, it is often inductive reasoning (conclusions drawn on the basis of examples) that helps learners form their deductive arguments, or proof. In addition, not all inductive arguments generate more formal arguments. This article draws a…

  15. The Rapid Induction Susceptibility Scale.

    ERIC Educational Resources Information Center

    Page, Roger A.; Handley, George W.

    1989-01-01

    Developed Rapid Induction Susceptibility Scale using Chiasson induction to produce hypnotic susceptibility scale which is quickly administered and yields scores comparable to the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C). Found that validation study with college students (N=100) produced a correlation of .88 with the SHSS:C and…

  16. Sampling Assumptions in Inductive Generalization

    ERIC Educational Resources Information Center

    Navarro, Daniel J.; Dry, Matthew J.; Lee, Michael D.

    2012-01-01

    Inductive generalization, where people go beyond the data provided, is a basic cognitive capability, and it underpins theoretical accounts of learning, categorization, and decision making. To complete the inductive leap needed for generalization, people must make a key "sampling" assumption about how the available data were generated.…

  17. A Student Teamwork Induction Protocol

    ERIC Educational Resources Information Center

    Kamau, Caroline; Spong, Abigail

    2015-01-01

    Faulty group processes have harmful effects on performance but there is little research about intervention protocols to pre-empt them in higher education. This naturalistic experiment compared a control cohort with an inducted cohort. The inducted cohort attended a workshop, consultations, elected a leader and used tools (a group log and group…

  18. Animal models of source memory.

    PubMed

    Crystal, Jonathon D

    2016-01-01

    Source memory is the aspect of episodic memory that encodes the origin (i.e., source) of information acquired in the past. Episodic memory (i.e., our memories for unique personal past events) typically involves source memory because those memories focus on the origin of previous events. Source memory is at work when, for example, someone tells a favorite joke to a person while avoiding retelling the joke to the friend who originally shared the joke. Importantly, source memory permits differentiation of one episodic memory from another because source memory includes features that were present when the different memories were formed. This article reviews recent efforts to develop an animal model of source memory using rats. Experiments are reviewed which suggest that source memory is dissociated from other forms of memory. The review highlights strengths and weaknesses of a number of animal models of episodic memory. Animal models of source memory may be used to probe the biological bases of memory. Moreover, these models can be combined with genetic models of Alzheimer's disease to evaluate pharmacotherapies that ultimately have the potential to improve memory.

  19. Is random access memory random?

    NASA Technical Reports Server (NTRS)

    Denning, P. J.

    1986-01-01

    Most software is contructed on the assumption that the programs and data are stored in random access memory (RAM). Physical limitations on the relative speeds of processor and memory elements lead to a variety of memory organizations that match processor addressing rate with memory service rate. These include interleaved and cached memory. A very high fraction of a processor's address requests can be satified from the cache without reference to the main memory. The cache requests information from main memory in blocks that can be transferred at the full memory speed. Programmers who organize algorithms for locality can realize the highest performance from these computers.

  20. Induction: The Early Years of Teaching.

    ERIC Educational Resources Information Center

    Guyton, Edi; Davis, Douglas; Colarusso, Ron; Grainger, Barbara

    2002-01-01

    Addresses the need for induction programs for beginning teachers and discusses the theoretical and research support for them. Develops the notion of induction as a community responsibility and describes a university-school induction consortium, a university induction program, an induction program at a middle school, and the role of the principal…

  1. Computer memory management system

    DOEpatents

    Kirk, III, Whitson John

    2002-01-01

    A computer memory management system utilizing a memory structure system of "intelligent" pointers in which information related to the use status of the memory structure is designed into the pointer. Through this pointer system, The present invention provides essentially automatic memory management (often referred to as garbage collection) by allowing relationships between objects to have definite memory management behavior by use of coding protocol which describes when relationships should be maintained and when the relationships should be broken. In one aspect, the present invention system allows automatic breaking of strong links to facilitate object garbage collection, coupled with relationship adjectives which define deletion of associated objects. In another aspect, The present invention includes simple-to-use infinite undo/redo functionality in that it has the capability, through a simple function call, to undo all of the changes made to a data model since the previous `valid state` was noted.

  2. Memory B cells.

    PubMed

    Kurosaki, Tomohiro; Kometani, Kohei; Ise, Wataru

    2015-03-01

    The immune system can remember a previously experienced pathogen and can evoke an enhanced response to reinfection that depends on memory lymphocyte populations. Recent advances in tracking antigen-experienced memory B cells have revealed the existence of distinct classes of cells that have considerable functional differences. Some of these differences seem to be determined by the stimulation history during memory cell formation. To induce rapid recall antibody responses, the contributions of other types of cells, such as memory T follicular helper cells, have also now begun to be appreciated. In this Review, we discuss these and other recent advances in our understanding of memory B cells, focusing on the underlying mechanisms that are required for rapid and effective recall antibody responses.

  3. Serotonin transporter and memory.

    PubMed

    Meneses, Alfredo; Perez-Garcia, Georgina; Ponce-Lopez, Teresa; Tellez, Ruth; Castillo, Carlos

    2011-09-01

    The serotonin transporter (SERT) has been associated to diverse functions and diseases, though seldom to memory. Therefore, we made an attempt to summarize and discuss the available publications implicating the involvement of the SERT in memory, amnesia and anti-amnesic effects. Evidence indicates that Alzheimer's disease and drugs of abuse like d-methamphetamine (METH) and (+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") have been associated to decrements in the SERT expression and memory deficits. Several reports have indicated that memory formation and amnesia affected the SERT expression. The SERT expression seems to be a reliable neural marker related to memory mechanisms, its alterations and potential treatment. The pharmacological, neural and molecular mechanisms associated to these changes are of great importance for investigation.

  4. Cosmological memory effect

    NASA Astrophysics Data System (ADS)

    Tolish, Alexander; Wald, Robert M.

    2016-08-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to memory depends only on the cosmological scale factor at the source and observation events, not on the detailed expansion history of the universe. In particular, for sources at the same luminosity distance, the memory effect in a spatially flat FLRW spacetime is enhanced over the Minkowski case by a factor of (1 +z ).

  5. Imaging autobiographical memory.

    PubMed

    Fossati, Philippe

    2013-12-01

    Autobiographical memory (AM) defines the memory systems that encode, consolidate, and retrieve personal events and facts, AM is strongly related to self-perception and self representation. We review here the neural correlates of AM retrieval. AM retrieval encompasses a large neural network including the prefrontal, temporal, and parietal cortex, and limbic structures. All these regions subserve the cognitive processes (episodic remembering, cognitive control, self-processing, and scene construction) at play during memory retrieval. We emphasize the specific role of medial prefrontal cortex and precuneus in self-processing during autobiographical memory retrieval. Overall, these data call for further studies in psychiatric patients, to investigate the neural underpinnings of autobiographical memory and self-representation in mental disorders.

  6. Innate Memory T cells

    PubMed Central

    Jameson, Stephen C.; Lee, You Jeong; Hogquist, Kristin A.

    2015-01-01

    Memory T cells are usually considered to be a feature of a successful immune response against a foreign antigen, and such cells can mediate potent immunity. However, in mice, alternative pathways have been described, through which naïve T cells can acquire the characteristics and functions of memory T cells without encountering specific foreign antigen or the typical signals required for conventional T cell differentiation. Such cells reflect a response to the internal rather the external environment, and hence such cells are called innate memory T cells. In this review, we describe how innate memory subsets were identified, the signals that induce their generation and their functional properties and potential role in the normal immune response. The existence of innate memory T cells in mice raises questions about whether parallel populations exist in humans, and we discuss the evidence for such populations during human T cell development and differentiation. PMID:25727290

  7. Inductance due to spin current

    SciTech Connect

    Chen, Wei

    2014-03-21

    The inductance of spintronic devices that transport charge neutral spin currents is discussed. It is known that in a media that contains charge neutral spins, a time-varying electric field induces a spin current. We show that since the spin current itself produces an electric field, this implies existence of inductance and electromotive force when the spin current changes with time. The relations between the electromotive force and the corresponding flux, which is a vector calculated by the cross product of electric field and the trajectory of the device, are clarified. The relativistic origin generally renders an extremely small inductance, which indicates the advantage of spin current in building low inductance devices. The same argument also explains the inductance due to electric dipole current and applies to physical dipoles consist of polarized bound charges.

  8. Induction of models under uncertainty

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter

    1986-01-01

    This paper outlines a procedure for performing induction under uncertainty. This procedure uses a probabilistic representation and uses Bayes' theorem to decide between alternative hypotheses (theories). This procedure is illustrated by a robot with no prior world experience performing induction on data it has gathered about the world. The particular inductive problem is the formation of class descriptions both for the tutored and untutored cases. The resulting class definitions are inherently probabilistic and so do not have any sharply defined membership criterion. This robot example raises some fundamental problems about induction; particularly, it is shown that inductively formed theories are not the best way to make predictions. Another difficulty is the need to provide prior probabilities for the set of possible theories. The main criterion for such priors is a pragmatic one aimed at keeping the theory structure as simple as possible, while still reflecting any structure discovered in the data.

  9. Misoprostol for induction of labor.

    PubMed

    Stephenson, Megan L; Wing, Deborah A

    2015-10-01

    Labor-induction rates have increased considerably in the United States as well as around the world. With up to half of all induced labors requiring cervical ripening, prostaglandins have been utilized to increase induction success and achieve vaginal delivery. Misoprostol, a synthetic prostaglandin E1 analog has the ability to mimic the changes of spontaneous labor and has been used off label for over 30 years as a labor-induction agent. In the following article, cervical ripening and induction of labor with misoprostol will be discussed. The risks and benefits of misoprostol for ripening and induction and routes of administration will be reviewed, as well as future directions and new developments for its use.

  10. Sustained experience of emotion after loss of memory in patients with amnesia

    PubMed Central

    Feinstein, Justin S.; Duff, Melissa C.; Tranel, Daniel

    2010-01-01

    Can the experience of an emotion persist once the memory for what induced the emotion has been forgotten? We capitalized on a rare opportunity to study this question directly using a select group of patients with severe amnesia following circumscribed bilateral damage to the hippocampus. The amnesic patients underwent a sadness induction procedure (using affectively-laden film clips) to ascertain whether their experience of sadness would persist beyond their memory for the sadness-inducing films. The experiment showed that the patients continued to experience elevated levels of sadness well beyond the point in time at which they had lost factual memory for the film clips. A second experiment using a happiness induction procedure yielded similar results, suggesting that both positive and negative emotional experiences can persist independent of explicit memory for the inducing event. These findings provide direct evidence that a feeling of emotion can endure beyond the conscious recollection for the events that initially triggered the emotion. PMID:20385824

  11. Streamlined approach to mapping the magnetic induction of skyrmionic materials.

    PubMed

    Chess, Jordan J; Montoya, Sergio A; Harvey, Tyler R; Ophus, Colin; Couture, Simon; Lomakin, Vitaliy; Fullerton, Eric E; McMorran, Benjamin J

    2017-02-28

    Recently, Lorentz transmission electron microscopy (LTEM) has helped researchers advance the emerging field of magnetic skyrmions. These magnetic quasi-particles, composed of topologically non-trivial magnetization textures, have a large potential for application as information carriers in low-power memory and logic devices. LTEM is one of a very few techniques for direct, real-space imaging of magnetic features at the nanoscale. For Fresnel-contrast LTEM, the transport of intensity equation (TIE) is the tool of choice for quantitative reconstruction of the local magnetic induction through the sample thickness. Typically, this analysis requires collection of at least three images. Here, we show that for uniform, thin, magnetic films, which includes many skyrmionic samples, the magnetic induction can be quantitatively determined from a single defocused image using a simplified TIE approach.

  12. The effect of a musical mood induction procedure on mood state-dependent word retrieval.

    PubMed

    De L'Etoile, Shannon K

    2002-01-01

    The purpose of this experiment was to replicate and expand upon an earlier study by Thaut and de l'Etoile (1993) by examining the effect of a musical mood induction procedure on mood state-dependent word retrieval. Participants (N = 45) completed a 2-day testing procedure. On day one, participants read a list of adjectives and wrote down an antonym for each one. On day two, participants recalled as many of the antonyms as possible. During the testing procedure, participants were placed in 1 of 4 conditions: (a) mood induction at encoding, (b) mood induction at recall, (c) no mood induction, and (d) mood induction at both encoding and recall. The mood induction procedure included 3 steps. Participants first assessed their current mood state using a visual analog scale. They then listened to music for 5 minutes, determined the mood of the piece while listening, and tried to match their mood to the music. Finally, participants again used the visual analog scale to indicate their mood. Results indicated that participants who received mood induction prior to both encoding and recall were able to retrieve significantly more words than participants who did not undergo any mood induction. The results are discussed in light of the associative network theory of memory and emotions and the treatment of mood disorders.

  13. Linear induction pump

    DOEpatents

    Meisner, John W.; Moore, Robert M.; Bienvenue, Louis L.

    1985-03-19

    Electromagnetic linear induction pump for liquid metal which includes a unitary pump duct. The duct comprises two substantially flat parallel spaced-apart wall members, one being located above the other and two parallel opposing side members interconnecting the wall members. Located within the duct are a plurality of web members interconnecting the wall members and extending parallel to the side members whereby the wall members, side members and web members define a plurality of fluid passageways, each of the fluid passageways having substantially the same cross-sectional flow area. Attached to an outer surface of each side member is an electrically conductive end bar for the passage of an induced current therethrough. A multi-phase, electrical stator is located adjacent each of the wall members. The duct, stators, and end bars are enclosed in a housing which is provided with an inlet and outlet in fluid communication with opposite ends of the fluid passageways in the pump duct. In accordance with a preferred embodiment, the inlet and outlet includes a transition means which provides for a transition from a round cross-sectional flow path to a substantially rectangular cross-sectional flow path defined by the pump duct.

  14. Inductively generating Euler diagrams.

    PubMed

    Stapleton, Gem; Rodgers, Peter; Howse, John; Zhang, Leishi

    2011-01-01

    Euler diagrams have a wide variety of uses, from information visualization to logical reasoning. In all of their application areas, the ability to automatically layout Euler diagrams brings considerable benefits. In this paper, we present a novel approach to Euler diagram generation. We develop certain graphs associated with Euler diagrams in order to allow curves to be added by finding cycles in these graphs. This permits us to build Euler diagrams inductively, adding one curve at a time. Our technique is adaptable, allowing the easy specification, and enforcement, of sets of well-formedness conditions; we present a series of results that identify properties of cycles that correspond to the well-formedness conditions. This improves upon other contributions toward the automated generation of Euler diagrams which implicitly assume some fixed set of well-formedness conditions must hold. In addition, unlike most of these other generation methods, our technique allows any abstract description to be drawn as an Euler diagram. To establish the utility of the approach, a prototype implementation has been developed.

  15. Inductive source induced polarization

    NASA Astrophysics Data System (ADS)

    Marchant, David; Haber, Eldad; Oldenburg, Douglas W.

    2013-02-01

    Induced polarization (IP) surveys are commonly performed to map the distribution of electrical chargeability that is a diagnostic physical property in mineral exploration and in many environmental problems. Although these surveys have been successful in the past, the galvanic sources required for traditional IP and magnetic IP (MIP) surveys prevent them from being applied in some geological settings. We develop a new methodology for processing frequency domain EM data to identify the presence of IP effects in observations of the magnetic fields arising from an inductive source. The method makes use of the asymptotic behaviour of the secondary magnetic fields at low frequency. A new quantity, referred to as the ISIP datum, is defined so that it equals zero at low frequencies for any frequency-independent (non-chargeable) conductivity distribution. Thus, any non-zero response in the ISIP data indicates the presence of chargeable material. Numerical simulations demonstrate that the method can be applied even in complicated geological situations. A 3-D inversion algorithm is developed to recover the chargeability from the ISIP data and the inversion is demonstrated on synthetic examples.

  16. Aging Memories: Differential Decay of Episodic Memory Components

    ERIC Educational Resources Information Center

    Talamini, Lucia M.; Gorree, Eva

    2012-01-01

    Some memories about events can persist for decades, even a lifetime. However, recent memories incorporate rich sensory information, including knowledge on the spatial and temporal ordering of event features, while old memories typically lack this "filmic" quality. We suggest that this apparent change in the nature of memories may reflect a…

  17. Single-Item Memory, Associative Memory, and the Human Hippocampus

    ERIC Educational Resources Information Center

    Squire, Larry R.; Gold, Jeffrey J.; Hopkins, Ramona O.

    2006-01-01

    We tested recognition memory for items and associations in memory-impaired patients with bilateral lesions thought to be limited to the hippocampal region. In Experiment 1 (Combined memory test), participants studied words and then took a memory test in which studied words, new words, studied word pairs, and recombined word pairs were presented in…

  18. Specific Therapy Regimes Could Lead to Long-Term Immunological Control of HIV

    NASA Astrophysics Data System (ADS)

    Wodarz, Dominik; Nowak, Martin A.

    1999-12-01

    We use mathematical models to study the relationship between HIV and the immune system during the natural course of infection and in the context of different antiviral treatment regimes. The models suggest that an efficient cytotoxic T lymphocyte (CTL) memory response is required to control the virus. We define CTL memory as long-term persistence of CTL precursors in the absence of antigen. Infection and depletion of CD4+ T helper cells interfere with CTL memory generation, resulting in persistent viral replication and disease progression. We find that antiviral drug therapy during primary infection can enable the development of CTL memory. In chronically infected patients, specific treatment schedules, either including deliberate drug holidays or antigenic boosts of the immune system, can lead to a re-establishment of CTL memory. Whether such treatment regimes would lead to long-term immunologic control deserves investigation under carefully controlled conditions.

  19. Memory, language, and ageing.

    PubMed Central

    Burke, D M; Mackay, D G

    1997-01-01

    This overview provides both theoretical and empirical reasons for emphasizing practice and familiar skills as a practical strategy for enhancing cognitive functioning in old age. Our review of empirical research on age-related changes in memory and language reveals a consistent pattern of spared and impaired abilities in normal old age. Relatively preserved in old age is memory performance involving highly practised skills and familiar information, including factual, semantic and autobiographical information. Relatively impaired in old age is memory performance that requires the formation of new connections, for example, recall of recent autobiographical experiences, new facts or the source of newly acquired facts. This pattern of impaired new learning versus preserved old learning cuts across distinctions between semantic memory, episodic memory, explicit memory and perhaps also implicit memory. However, familiar verbal information is not completely preserved when accessed on the output side rather than the input side: aspects of language production, namely word finding and spelling, exhibit significant age-related declines. This emerging pattern of preserved and impaired abilities presents a fundamental challenge for theories of cognitive ageing, which must explain why some aspects of language and memory are more vulnerable to the effects of ageing than others. Information-universal theories, involving mechanisms such as general slowing that are independent of the type or structure of the information being processed, require additional mechanisms to account for this pattern of cognitive aging. Information-specific theories, where the type or structure of the postulated memory units can influence the effects of cognitive ageing, are able to account for this emerging pattern, but in some cases require further development to account for comprehensive cognitive changes such as general slowing. PMID:9460069

  20. Sleep and memory.

    PubMed

    Roth, T; Roehrs, T; Zwyghuizen-Doorenbos, A; Stepanski, E; Wittig, R

    1988-01-01

    Generally sleep is considered a time of amnesia. It is not uncommon for an individual to experience 8 h of sleep and have no memory for events during that time. Similarly, a substantial proportion of the population has no memory for dreams that occurred during the night, despite the fact that the literature on awakening during rapid eye movement (REM) sleep clearly shows that individuals normally have four to six "dream experiences" a night. Research on this issue seems to indicate that the lack of memory cannot be explained by the organisms' inability to perceive stimuli. The data indicate that although perceptual thresholds are elevated, organisms can clearly perceive stimuli, and, in fact, can discriminate between them during sleep. The amnesia also cannot be explained by a defect in long-term memory, as studies have indicated that stimuli put into the memory during wakefulness are more efficiently retrieved after a sleep period than after a comparable period of wakefulness. The most likely explanation for the amnestic property of sleep seems to be the inability of organisms to transfer information from short-term memory to long-term memory during sleep. There are several sources of evidence to support this hypothesis. First, the probability of remembering a stimulus given during wakefulness is related to the proximity of sleep onset to the stimulus. Generally, information put into the system within 5 min of sleep onset is lost from memory. Secondly, disorders of excessive daytime somnolence which cause individuals to have frequent microsleeps are often associated with complains of memory problems.(ABSTRACT TRUNCATED AT 250 WORDS)