scholarly journals Interaction of helper T cells and Lyb5+ B cells responding to phosphorylcholine is MHC-restricted.

1984 ◽  
Vol 160 (1) ◽  
pp. 329-334 ◽  
Author(s):  
D E Mosier ◽  
A J Feeney

The requirements for T cell/B cell interaction for the induction of primary in vitro antibody responses to phosphorylcholine (PC)-keyhole limpet hemocyanin (KLH) were examined. Long-term helper T cell lines derived from KLH-primed (CBA/N X BALB/c) F1 female mice (H-2k/d) were able to support a T15-idiotype dominant, IgM anti-PC response of BALB/c (H-2d) B cells and macrophages, but could not activate PC-specific responses by BALB.B (H-2b) B cells, even in the presence of irradiated H-2k/d antigen-presenting cells. Polyclonal IgM secretion in the same cultures did not appear to depend upon a major histocompatibility complex (MHC)-restricted T-B interaction. Since IgM anti-PC responses seem to be entirely derived from the Lyb5+ B cell subpopulation, we conclude that at least some Lyb5+ B cells can only be activated by MHC-restricted T-B interactions. We also found that xid B cells from (CBA/N X BALB/c) F1 male mice could be polyclonally activated by helper T cell lines by an apparently MHC-unrestricted interaction. Our data thus suggests that residence in the Lyb5- or Lyb5+ B cell subset does not determine the T:B interaction requirements for antibody synthesis.

1985 ◽  
Vol 161 (1) ◽  
pp. 223-241 ◽  
Author(s):  
H P Tony ◽  
D C Parker

Anti-Ig has been widely used as a model for antigen receptor-mediated B cell activation. B cells activated with mitogenic concentrations of anti-Ig (approximately 10 micrograms/ml) become responsive to a set of T cell-derived, antigen-nonspecific helper factors that enable the B cells to proliferate, and, in some cases, mature to Ig secretion. In the present experiments, we show that anti-Ig can also be used as a model for major histocompatibility complex (MHC)-restricted, antigen-specific T-B cell collaboration. We used murine helper T cell lines and T cell hybridomas specific for a protein antigen, the F(ab')2 fragment of normal rabbit IgG. Small B cells are very efficient at presenting rabbit anti-IgM or rabbit anti-IgD to these rabbit Ig-specific T cell lines and hybridomas, and the responding (initially) small B cells, appear to be the only antigen-presenting cells required. Efficient presentation depends upon binding of rabbit antibody to mIg on the B cell surface. MHC-restricted recognition of rabbit Ig determinants on the B cell surface results in a polyclonal B cell response. This response is qualitatively different from the well-studied response to blastogenic concentrations of anti-Ig plus stable, T cell-derived helper factors, since it (a) requires 1,000-fold lower concentrations of anti-Ig, (b) involves helper T cell functions other than, or in addition to, the local production of the same stable helper factors, and (c) is largely MHC-restricted at the T-B cell level.


2006 ◽  
Vol 80 (8) ◽  
pp. 3923-3934 ◽  
Author(s):  
Vito Racanelli ◽  
Maria Antonia Frassanito ◽  
Patrizia Leone ◽  
Maria Galiano ◽  
Valli De Re ◽  
...  

ABSTRACT There is growing interest in the tendency of B cells to change their functional program in response to overwhelming antigen loading, perhaps by regulating specific parameters, such as efficiency of activation, proliferation rate, differentiation to antibody-secreting cells (ASC), and rate of cell death in culture. We show that individuals persistently infected with hepatitis C virus (HCV) carry high levels of circulating immunoglobulin G (IgG) and IgG-secreting cells (IgG-ASC). Thus, generalized polyclonal activation of B-cell functions may be supposed. While IgGs include virus-related and unrelated antibodies, IgG-ASC do not include HCV-specific plasma cells. Despite signs of widespread activation, B cells do not accumulate and memory B cells seem to be reduced in the blood of HCV-infected individuals. This apparent discrepancy may reflect the unconventional activation kinetics and functional responsiveness of the CD27+ B-cell subset in vitro. Following stimulation with T-cell-derived signals in the absence of B-cell receptor (BCR) engagement, CD27+ B cells do not expand but rapidly differentiate to secrete Ig and then undergo apoptosis. We propose that their enhanced sensitivity to BCR-independent noncognate T-cell help maintains a constant level of nonspecific serum antibodies and ASC and serves as a backup mechanism of feedback inhibition to prevent exaggerated B-cell responses that could be the cause of significant immunopathology.


1983 ◽  
Vol 158 (6) ◽  
pp. 2024-2039 ◽  
Author(s):  
M Howard ◽  
L Matis ◽  
T R Malek ◽  
E Shevach ◽  
W Kell ◽  
...  

Antigen-activated T lymphocytes produce within 24 h of stimulation a factor that is indistinguishable biochemically and functionally from the B cell co-stimulating growth factor, BCGF-I, originally identified in induced EL4 supernatants: Supernatants from antigen-stimulated T cell lines are not directly mitogenic for resting B cells, but synergize in an H-2-unrestricted manner with anti-Ig activated B cells to produce polyclonal proliferation but not antibody-forming-cell development; biochemical studies reveal the B cell co-stimulating factor present in antigen-stimulated T cell line supernatants is identical by phenyl Sepharose chromatography and isoelectric focusing (IEF) to EL4 supernatant BCGF-I. We thus conclude that normal T cells produce BCGF-I in response to antigenic stimulation. Analysis of the mechanism of BCGF-I production by antigen-stimulated T cells showed that optimum amounts of BCGF-I were obtained as quickly as 24 h post-stimulation, and that the factor producing cells in the T cell line investigated bore the Lyt-1+2- phenotype. As few as 10(4) T cells produced sufficient BCGF-I to support the proliferation of 5 X 10(4) purified anti-Ig activated B cells. Finally, the activation of normal T cell lines to produce BCGF-I required either antigen presented in the context of syngeneic antigen-presenting cells (APC) or interleukin 2 (IL-2).


1983 ◽  
Vol 158 (1) ◽  
pp. 192-209 ◽  
Author(s):  
E Kraig ◽  
M Kronenberg ◽  
J A Kapp ◽  
C W Pierce ◽  
A F Abruzzini ◽  
...  

We have attempted to determine whether T cells and B cells that have the same antigenic specificity and whose receptors share idiotypic determinants in fact express similar VH gene segments. To do this, we have obtained and characterized a cDNA clone containing the entire coding sequence for the VH gene from a glutamic acid60/alanine30/tyrosine10 (GAT)-binding immunoglobulin that carries the CGAT idiotype. The GAT-VH clone was hybridized to Northern blots of GAT-specific T cell RNAs; there was no evidence of a T cell transcript that hybridized to the GAT-VH probe. The T cells analyzed included: (a) 10 GAT-binding suppressor T cell hybridomas, 6 of which secreted factors with CGAT idiotypic determinants, (b) one GAT-specific helper T cell hybridoma, and (c) two GAT-specific helper T cell lines grown in the absence of feeder cells. The detection limit of the Northern blot analysis was 1-2 copies of a particular mRNA species per cell for the hybridomas and 5-10 copies per cell for the T cell lines. Therefore, we conclude that T and B lymphocytes responding to GAT do not utilize similar VH gene segments. Furthermore, the presence of idiotypic determinants on T lymphocytes does not necessarily imply close structural similarity between T and B cell antigen receptors.


Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2164-2170
Author(s):  
N Bonnefoy-Berard ◽  
M Flacher ◽  
JP Revillard

Antithymocyte and antilymphocyte globulins (ALG) are currently used as immunosuppressive agents in organ transplantation and for the treatment of acute graft-versus-host disease and aplastic anemia. Since any type of immunosuppressive treatment is known to carry the risk of developing B-cell lymphoproliferative disorders, we investigated the in vitro effect of ALG on human B-cell activation and proliferation. The data demonstrate that whatever the source of lymphocytes used for ALG preparation (thymocytes, thoracic duct lymphocytes, B- or T-cell lines), (1) ALG react with both B- and T-cell lines, and (2) ALG contain antibodies specific for B cells (eg, CD21) or common to T and B cells (eg anti-beta 2-microglobulin, anti-HLA-DR, CD18, CD11a) in addition to T-cell-specific antibodies. Unlike all other T-cell mitogens tested (Concanavalin A [Con A], Pokeweek mitogen [PWM], CD3 and CD2 antibodies), ALG do not trigger B-cell differentiation into immunoglobulin-secreting cells at concentrations which induce maximum T- cell proliferation. This effect could be attributed to a direct interaction of ALG with B lymphocytes as shown by the capacity of ALG to block the response of purified B cells to a variety of activators. Furthermore, all the ALG tested were shown to inhibit the proliferation of six of the seven Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines and six of the seven Burkitt's lymphoma cell lines studied. This selective B-cell antiproliferative property of ALG was not reproduced with CD11a, CD18, CD21, CD24, or anti-HLA-DR monoclonal antibodies (MoAbs). These results suggest that, although suppressing T- cell responses, ALG treatment may directly control B cell proliferation to some extent, in keeping with the relatively low risk of posttransplant lymphoproliferative disorders reported with ALG.


1977 ◽  
Vol 146 (6) ◽  
pp. 1748-1764 ◽  
Author(s):  
JW Kappler ◽  
P Marrack

The ability of murine helper T cells primed to the antigen, sheep erythrocytes (SRBC) to cross-react with burro erythrocytes (BRBC) in the in vitro anti-trinitrophenol (TNP) response to TNP-RBC was shown to be under genetic control. Although non-H-2 genes were shown to influence the absolute level of helper activity assayed after SRBC priming, the extent of cross-reaction of SRBC-primed helpers with BRBC was shown to be controlled by an H-2-1inked Ir gene(s). H-2 haplotypes were identified which determined high, intermediate, or low response to the cross- reacting determinants and the gene(s) controlling the cross-reaction tentatively mapped to the K through I-E end of the H-2 complex. Helpers primed in F(1) mice of high x intermediate or high x low responder parents were tested for cross-reaction using B cells and macrophages (Mφ) of parental haplotypes. In each case the extent of cross-reaction was predicted by the H-2 haplotype of the B cells and Mφ, establishing the expression of the Ir gene(s) in B cells and/or Mφ a t least, but not ruling out its expression in T cells as well. The low cross-reaction seen when T cells from F(1) mice of high × low responder parents were tested on low responder B cells and Mφ was not increased by the presence of high responder Mφ, indicating the Ir gene(s) is expressed in the B cell a t least although it may be expressed in Mφ as well. These and our previously reported experiments are consistent with the hypothesis that helper T cells recognize antigen bound to the surface of B cells and Mφ in association with the product(s) of Ir gene(s) expressed on the B cell and Mφ.


Blood ◽  
1992 ◽  
Vol 79 (8) ◽  
pp. 2164-2170 ◽  
Author(s):  
N Bonnefoy-Berard ◽  
M Flacher ◽  
JP Revillard

Abstract Antithymocyte and antilymphocyte globulins (ALG) are currently used as immunosuppressive agents in organ transplantation and for the treatment of acute graft-versus-host disease and aplastic anemia. Since any type of immunosuppressive treatment is known to carry the risk of developing B-cell lymphoproliferative disorders, we investigated the in vitro effect of ALG on human B-cell activation and proliferation. The data demonstrate that whatever the source of lymphocytes used for ALG preparation (thymocytes, thoracic duct lymphocytes, B- or T-cell lines), (1) ALG react with both B- and T-cell lines, and (2) ALG contain antibodies specific for B cells (eg, CD21) or common to T and B cells (eg anti-beta 2-microglobulin, anti-HLA-DR, CD18, CD11a) in addition to T-cell-specific antibodies. Unlike all other T-cell mitogens tested (Concanavalin A [Con A], Pokeweek mitogen [PWM], CD3 and CD2 antibodies), ALG do not trigger B-cell differentiation into immunoglobulin-secreting cells at concentrations which induce maximum T- cell proliferation. This effect could be attributed to a direct interaction of ALG with B lymphocytes as shown by the capacity of ALG to block the response of purified B cells to a variety of activators. Furthermore, all the ALG tested were shown to inhibit the proliferation of six of the seven Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines and six of the seven Burkitt's lymphoma cell lines studied. This selective B-cell antiproliferative property of ALG was not reproduced with CD11a, CD18, CD21, CD24, or anti-HLA-DR monoclonal antibodies (MoAbs). These results suggest that, although suppressing T- cell responses, ALG treatment may directly control B cell proliferation to some extent, in keeping with the relatively low risk of posttransplant lymphoproliferative disorders reported with ALG.


2001 ◽  
Vol 75 (8) ◽  
pp. 3740-3752 ◽  
Author(s):  
Sarah Nikiforow ◽  
Kim Bottomly ◽  
George Miller

ABSTRACT In immunodeficient hosts, Epstein-Barr virus (EBV) often induces extensive B-cell lymphoproliferative disease and lymphoma. Without effective in vitro immune surveillance, B cells infected by the virus readily form immortalized cell lines. In the regression assay, memory T cells inhibit the formation of foci of EBV-transformed B cells that follows recent in vitro infection by EBV. No one has yet addressed which T cell regulates the early proliferative phase of B cells newly infected by EBV. Using new quantitative methods, we analyzed T-cell surveillance of EBV-mediated B-cell proliferation. We found that CD4+ T cells play a significant role in limiting proliferation of newly infected, activated CD23+ B cells. In the absence of T cells, EBV-infected CD23+ B cells divided rapidly during the first 3 weeks after infection. Removal of CD4+ but not CD8+ T cells also abrogated immune control. Purified CD4+ T cells eliminated outgrowth when added to EBV-infected B cells. Thus, unlike the killing of EBV-infected lymphoblastoid cell lines, in which CD8+ cytolytic T cells play an essential role, prevention of early-phase EBV-induced B-cell proliferation requires CD4+ effector T cells.


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