scholarly journals DETERMINATION OF ANTIBODY CLASS IN A SYSTEM OF COOPERATING ANTIGENIC DETERMINANTS

1970 ◽  
Vol 132 (5) ◽  
pp. 1019-1034 ◽  
Author(s):  
Volker Schirrmacher ◽  
Klaus Rajewsky

19S and 7S memory is analyzed in a system of cooperating antigenic determinants. Cooperation occurs in the induction of both 19S and 7S secondary antibodies, and for both responses carrier specificity can be entirely accounted for by presensitization of the animal to carrier determinants. The class distribution of secondary anti-hapten antibody depends on the dose of the hapten primary-carrier conjugate used for priming, and on the time interval between priming with the hapten primary-carrier conjugate and secondary injection. The conditions of priming with the secondary carrier influence the extent of the secondary response but not the class distribution of secondary antibody. The data confirm the cooperation hypothesis of antibody induction. Specifically, we interpret them to mean that in hapten-carrier cooperation, the hapten-specific memory cells are predetermined for the class of the emerging antibodies. Together with the hapten-specific memory cells, the carrier-specific helpers are responsible for the extent of the secondary response.

1974 ◽  
Vol 140 (6) ◽  
pp. 1571-1578 ◽  
Author(s):  
Jean-Louis Virelizier ◽  
Anthony C. Allison ◽  
Geoffrey C. Schild

Mice immunized sequentially with two related influenza virus hemagglutinins (HA) produced a secondary antibody response with two different specificities. Some antibodies were specific for determinants common to both HA's. Paradoxically, some antibodies were directed to determinants existing only in the HA first encountered. Primed spleen cells treated with anti-θ serum and complement were transferred from animals immunized with the first HA to either normal, irradiated, or thymus-deprived recipients. These memory cells were boosted in the recipients with either the homologous or the heterologous cross-reacting HA. B-memory lymphocytes were shown to be directly triggered by both HA's and to be able to secrete, independently of T lymphocytes, antibodies to both kinds of determinants. However, T cells were shown to modulate this secondary response by either enhancing or suppressing antibody secretion by B-memory cells, depending on experimental conditions. These results are discussed in terms of antigen recognition by B cells and of kinetics of development of immunological memory.


Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4273-4280 ◽  
Author(s):  
Su Jeong Ryu ◽  
Kyung Min Jung ◽  
Hyun Seung Yoo ◽  
Tae Woo Kim ◽  
Sol Kim ◽  
...  

AbstractIn contrast to previous notions of the help-independency of memory CD8 T cells during secondary expansion, here we show that CD4 help is indispensable for the re-expansion of once-helped memory CD8 T cells, using a hematopoietic cell–specific dominant minor histocompatibility (H) antigen, H60, as a model antigen. H60-specific memory CD8 T cells generated during a helped primary response vigorously expanded only when rechallenged under helped conditions. The help requirement for an optimal secondary response was confirmed by a reduction in peak size by CD4 depletion, and was reproduced after skin transplantation. Helpless conditions or noncognate separate help during the secondary response resulted in a significant reduction in the peak size and different response kinetics. Providing CD4 help again during a tertiary challenge restored robust memory expansion; however, the repeated deprivation of help further reduced clonal expansion. Adoptively transferred memory CD8 T cells did not proliferate in CD40L−/− hosts. In the CD40−/− hosts, marginal memory expansion was detected after priming with male H60 cells but was completely abolished by priming with peptide-loaded CD40−/− cells, suggesting the essential role of CD40 and CD40L in memory responses. These results provide insight into the control of minor H antigen-specific CD8 T-cell responses, to maximize the graft-versus-leukemia response.


2003 ◽  
Vol 198 (12) ◽  
pp. 1909-1922 ◽  
Author(s):  
Souheil-Antoine Younes ◽  
Bader Yassine-Diab ◽  
Alain R. Dumont ◽  
Mohamed-Rachid Boulassel ◽  
Zvi Grossman ◽  
...  

CD4+ T cell responses are associated with disease control in chronic viral infections. We analyzed human immunodeficiency virus (HIV)-specific responses in ten aviremic and eight viremic patients treated during primary HIV-1 infection and for up to 6 yr thereafter. Using a highly sensitive 5-(and-6)-carboxyfluorescein diacetate-succinimidyl ester–based proliferation assay, we observed that proliferative Gag and Nef peptide-specific CD4+ T cell responses were 30-fold higher in the aviremic patients. Two subsets of HIV-specific memory CD4+ T cells were identified in aviremic patients, CD45RA− CCR7+ central memory cells (Tcm) producing exclusively interleukin (IL)-2, and CD45RA− CCR7− effector memory cells (Tem) that produced both IL-2 and interferon (IFN)-γ. In contrast, in viremic, therapy-failing patients, we found significant frequencies of Tem that unexpectedly produced exclusively IFN-γ. Longitudinal analysis of HIV epitope–specific CD4+ T cells revealed that only cells that had the capacity to produce IL-2 persisted as long-term memory cells. In viremic patients the presence of IFN-γ–producing cells was restricted to periods of elevated viremia. These findings suggest that long-term CD4+ T cell memory depends on IL-2–producing CD4+ T cells and that IFN-γ only–producing cells are short lived. Our data favor a model whereby competent HIV-specific Tcm continuously arise in small numbers but under persistent antigenemia are rapidly induced to differentiate into IFN-γ only–producing cells that lack self-renewal capacity.


1981 ◽  
Vol 154 (5) ◽  
pp. 1525-1538 ◽  
Author(s):  
Y N Liu ◽  
C A Bona ◽  
J L Schulman

Anti-idiotype antisera were raised in syngeneic (BALB/c mice) and homologous (A/J mice) systems to study the cross-reactive idiotypes among monoclonal antibodies to PR8 and B/Lee virus HA and the expression of these idiotypes during primary and secondary antiviral responses of BALB/c mice. Extensive idiotypic cross-reactivity was demonstrated among monoclonal antibodies specific for distinct antigenic determinants on PR8 hemagglutinin (HA). The study of idiotypy of monoclonal antibodies against the same or overlapping antigenic determinants on B/Lee HA showed that these monoclonal antibodies may bear (a) a true individual idiotype not shared by other monoclonal antibodies, (b) idiotypes shared by few monoclonal antibodies, and (c) true cross-reactive idiotypes shared by all of these monoclonal antibodies. In contrast, no cross-reactive idiotypes were detectable among monoclonal antibodies to B/Lee HA and monoclonal antibodies to PR8 HA. Furthermore, we have shown that the anti-idiotype antibodies we used recognize determinants on monoclonal antibodies closely associated with antigenic binding sites. Finally, studies of the idiotypes expressed during primary and secondary antiviral HA responses of mice immunized with B/Lee virus revealed persistence of some idiotypes during both primary and secondary responses, whereas others were only expressed in the primary or secondary response.


2006 ◽  
Vol 203 (4) ◽  
pp. 897-906 ◽  
Author(s):  
Megan MacLeod ◽  
Mark J. Kwakkenbos ◽  
Alison Crawford ◽  
Sheila Brown ◽  
Brigitta Stockinger ◽  
...  

Secondary T cell responses are enhanced because of an expansion in numbers of antigen-specific (memory) cells. Using major histocompatibility complex class II tetramers we have tracked peptide-specific endogenous (non–T cell receptor transgenic) CD4 memory T cells in normal and in costimulation-deficient mice. CD4 memory T cells were detectable after immunization for more than 200 days, although decay was apparent. Memory cells generated in CD40 knockout mice by immunization with peptide-pulsed wild-type dendritic cells survived in the absence of CD40 and proliferated when boosted with peptide (plus adjuvant) in a CD40-independent fashion. However, differentiation of the memory cells into cytokine-producing effector cells did not occur in the absence of CD40. The data indicate that memory cells can be generated without passing through the effector cell stage.


2020 ◽  
Vol 94 (23) ◽  
Author(s):  
Stephen A. Migueles ◽  
Daniel C. Rogan ◽  
Noah V. Gavil ◽  
Elizabeth P. Kelly ◽  
Sushila A. Toulmin ◽  
...  

ABSTRACT In various infections or vaccinations of mice or humans, reports of the persistence and the requirements for restimulation of the cytotoxic mediators granzyme B (GrB) and perforin (PRF) in CD8+ T cells have yielded disparate results. In this study, we examined the kinetics of PRF and GrB mRNA and protein expression after stimulation and associated changes in cytotoxic capacity in virus-specific memory cells in detail. In patients with controlled HIV or cleared respiratory syncytial virus (RSV) or influenza virus infections, all virus-specific CD8+ T cells expressed low PRF levels without restimulation. Following stimulation, they displayed similarly delayed kinetics for lytic protein expression, with significant increases occurring by days 1 to 3 before peaking on days 4 to 6. These increases were strongly correlated with, but were not dependent upon, proliferation. Incremental changes in PRF and GrB percent expression and mean fluorescence intensity (MFI) were highly correlated with increases in HIV-specific cytotoxicity. mRNA levels in HIV-specific CD8+ T-cells exhibited delayed kinetics after stimulation as with protein expression, peaking on day 5. In contrast to GrB, PRF mRNA transcripts were little changed over 5 days of stimulation (94-fold versus 2.8-fold, respectively), consistent with posttranscriptional regulation. Changes in expression of some microRNAs, including miR-17, miR-150, and miR-155, suggested that microRNAs might play a significant role in regulation of PRF expression. Therefore, under conditions of extremely low or absent antigen levels, memory virus-specific CD8+ T cells require prolonged stimulation over days to achieve maximal lytic protein expression and cytotoxic capacity. IMPORTANCE Antigen-specific CD8+ T cells play a major role in controlling most virus infections, primarily by perforin (PRF)- and granzyme B (GrB)-mediated apoptosis. There is considerable controversy regarding whether PRF is constitutively expressed, rapidly increased similarly to a cytokine, or delayed in its expression with more prolonged stimulation in virus-specific memory CD8+ T cells. In this study, the degree of cytotoxic capacity of virus-specific memory CD8+ T cells was directly proportional to the content of lytic molecules, which required antigenic stimulation over several days for maximal levels. This appeared to be modulated by increases in GrB transcription and microRNA-mediated posttranscriptional regulation of PRF expression. Clarifying the requirements for maximal cytotoxic capacity is critical to understanding how viral clearance might be mediated by memory cells and what functions should be induced by vaccines and immunotherapies.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3104-3104
Author(s):  
Mohamed-Rachid Boulassel ◽  
Souheil-Antoine Younes ◽  
Bader Yacine-Diab ◽  
Rafick-Pierre Sekaly ◽  
Jean Pierre Routy

Abstract Virus-specific CD4 T-cells are believed to play a critical role in determining the persistence of memory and effector CD8 T-cell responses during viral infections. However, the reasons for which human immunodeficiency virus (HIV)-specific CD4 cells fail to generate effective CD8 cell responses remain incompletely understood. In this study, we analyzed the HIV-specific CD4 cells in 10 aviremic (viral load < 50 copies/ml) and 8 viremic (mean viral load 45,295 copies/ml) patients treated during primary HIV infection and followed for up to 6 years. At the time of apheresis, median CD4 T cell counts for aviremic and viremic patients were 671 cells/μl and 485 cells/μl respectively. Using Gag and Nef overlapping HIV peptides, the highly sensitive CFSE-based proliferation assay and intracellular staining techniques, we observed that proliferative Gag and Nef peptide-specific CD4 cell responses were 30-fold higher in aviremic patients compared to viremic. Several subsets of HIV-specific memory CD4 cells endowed with different proliferative and functional capacities were identified. We observed two subsets of HIV-specific memory CD4 cells in aviremic patients, CD45RA− CCR7+ central memory cells (Tcm) producing exclusively IL-2 and CD45RA− CCR7− effector memory cells (Tem) that produced both IL-2 and IFN-γ. In contrast, in viremic patients, Tem were found to unexpectedly produce IFN-γ exclusively. Longitudinal data showed that only cells, which were capable of producing IL-2, persisted as long-term memory cells. In viremic patients, HIV-specific CD4 cells that produce INF-γ were found only during periods of elevated viral loads. To test if the presence of IL-2 could restore the proliferation of these cells, we stimulated CD4 cells from viremic patients with a pool of peptides, which gave strong IFN-γ responses in these patients in the presence of exogenous IL-2. The addition of IL-2 during the in vitro peptide stimulation dramatically increased the fraction of proliferating cells. This experiment strongly suggests that the impaired proliferation of CD4 cells from viremic patients is not caused by a virus-mediated destruction of proliferating cells but a lack of producing IL-2. Altogether, these results indicate that long-term memory HIV-specific CD4 cell produce mainly IL-2, while those producing IFN-γ are short-lived. These findings favor a model in which Tcm are continuously produced in limited numbers but under continuous viral stimulation are rapidly induced to differentiate into IFN-γ only-producing cells that lack the capacity for self-renewal.These findings also indicate that treatment strategies aimed to increase the long-term memory CD4 cells are needed for future HIV vaccine development.


1981 ◽  
Vol 11 (12) ◽  
pp. 990-996 ◽  
Author(s):  
Yaela Baine ◽  
Nicholas M. Ponzio ◽  
G. Jeanette Thorbecke

2005 ◽  
Vol 79 (7) ◽  
pp. 4510-4513 ◽  
Author(s):  
Heike Unsoeld ◽  
Hanspeter Pircher

ABSTRACT Antigen-experienced T cells have been divided into CD62L+ CCR7+ central memory (TCM) and CD62L− CCR7− effector memory (TEM) cells. Here, we examined coexpression of CD62L and CCR7 in lymphocytic choriomeningitis virus-specific memory CD8 T cells from both lymphoid and nonlymphoid tissues. Three main points emerged: firstly, memory cells frequently expressed a mixed CD62L− CCR7+ phenotype that differed from the phenotypes of classical TEM and TCM cells; secondly, TCM cells were not restricted to lymphoid organs but were also present in significant numbers in nonlymphoid tissues; and thirdly, a major shift from a TCM to TEM phenotype was found in memory cells that had been stimulated repetitively with antigen.


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