scholarly journals Specific T helper cells that activate B cells polyclonally. In vitro enrichment and cooperative function.

1980 ◽  
Vol 151 (3) ◽  
pp. 587-601 ◽  
Author(s):  
A A Augustin ◽  
A Coutinho

C3H/HeJ T cells which specifically recognize B cell-surface antigens of the related, major histocompatibility complex-compatible C3H/Tif strain, can be substantially enriched in vitro by long-term exposure (2--6 wk) of primed lymph node cells to the relevant cellular antigens. These enriched T cells contain functional helper cells as demonstrated by their capacity to induce large numbers of Ig-secreting plaque-forming cells (PFC) in cultures of antigenic B cells. The cooperative interaction results in activation of a large fraction of all splenic B cells, with consequent exponential growth and maturation to high rate secretion of IgM, IgG1, and IgG2, but not IgG3. The IgM PFC response includes antibody specificities to a number of different antigens and can be considered, therefore, as polyclonal. The T helper cell-dependent B-cell response is insensitive to inhibition by anti-delta antibodies, and in contrast with lipopolysaccharide-induced PFC responses, is only partially sensitive to the inhibitory effects of anti-mu antibodies. Finally, B-cell activation to growth and maturation by helper T cells strictly required direct T-cell recognition of antigens on the surface of responding B cells, leading us to the conclusions that if any soluble factors are generated in the collaborative process, they are either antigen specific or incompetent to initiate B-cell growth.

1983 ◽  
Vol 158 (2) ◽  
pp. 265-279 ◽  
Author(s):  
K Bottomly ◽  
B Jones ◽  
J Kaye ◽  
F Jones

We have investigated in vitro the induction of antibody responses to phosphorylcholine (PC) by cloned T helper (Th) cell lines. The cloned Th cells are antigen specific, in this case ovalbumin (OVA), self-Ia recognizing, and induce antibody secretion only if the hapten, PC, is physically linked to the carrier (OVA) molecule. The plaque-forming cell (PFC) response generated in the presence of cloned Th cells is idiotypically diverse with 5-40% of the secreting B cells bearing the TEPC-15 (T15) idiotype. The interaction of the cloned Th cells and unprimed B cells requires recognition of B cell surface Ia glycoproteins for all B cells activated to secrete anti-PC antibody, whether they be T15-bearing or not. More importantly, however, effective interaction between a cloned Th cell and a B cell is determined by the quantity of B cell surface Ia glycoproteins. Our results indicate that quantitative differences in B cell surface Ia antigens are directly related to B cell activation by the cloned Th cell. The high Ia density B cells are most easily activated by cloned Th cells, and these appear to be mainly non-T15-bearing. These data suggest that the failure of cloned Th cells to effectively activate T15-bearing B cells in vitro may be due to the lower relative Ia density of these B cells and therefore to their inability to interact effectively with cloned Ia-recognizing Th cells. These results imply that monoclonal T cells may distinguish between T15-bearing and non-T15-bearing B cells based on their Ia density.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4692-4692
Author(s):  
Mauro Di Ianni ◽  
Lorenzo Moretti ◽  
Beatrice Del Papa ◽  
Maria De Ioanni ◽  
Adelmo Terenzi ◽  
...  

Abstract As Chronic Lymphocytic Leukemia (CLL) is associated with several defects in the T cell compartment, the impact of tumour burden on the autologous immune system was studied. Gene expression profiles (using Applied Biosystem Human Genome Microarray) identified 237 genes with significantly increased expression and 221 genes with significantly decreased expression (p<0.05) in CD3+ cells from CLL patients compared with healthy donors. Panther software analysis identified 34/237 upregulated genes and 26/221 downregulated genes that were involved in specific pathways, mainly cell differentiation and proliferation, survival, apoptosis, cytoskeleton formation, vesicle trafficking and T cell activation. The 26 dowregulated genes included Zap70, a member of the syk family protein tyrosine kinase, which is involved in T-cell activation. Zap-70 results were validated by mRNA quantification by RT-PCR (−1.77 fold in comparison with healthy controls) and by flow-cytometric analysis (Mean Intensity Fluorescence=33±12 vs 80±23.62 in controls, p<0.05). To test the hypothesis that activation with OKT3 /IL-2 could bypass these T cell deficiencies, activated T cells from 20 patients with CLL were tested in vitro for cytotoxicity (using the 51chromium release assay) against mutated and unmutated (according to IgVH mutational status) autologous B cells, DAUDI, K562 and P815 cell lines. After 10 days’ culture, the T cell count remained unchanged; CD8 cells expanded more than CD4; TCR spectratyping analysis indicated no differences in TCR repertoires. Activation restored the ZAP-70 mRNA (+1.67 fold). The 51chromium release cytotoxicity assay showed an index > 30% in 5/20 patients. The other 15 were partially cytotoxic against P815, K562 and Daudi. Cell line analysis in all 20 confirmed prevalently T cell-mediated cytotoxicity and poor NK/LAK activity. Cytotoxicity did not correlate with B cell mutational status. We tested the cytotoxic activity of autologous activated T cells in NOD/SCID mice co-transplanted with leukaemic B cells. Only activated T cells exerting cytotoxicity vs autologous B-cell CLL prevent CLL in human-mouse chimera, as confirmed by PCR and FACS analysis which visualised only CD3+ cells. In conclusion, in patients with CLL, activating autologous T cells with OKT3 /IL-2 bypasses, at least in part, the T cell immunological deficiencies. These in vitro and in vivo findings might serve to throw light on new mechanisms that could be exploited in immunotherapy designed to exert disease control.


Blood ◽  
2005 ◽  
Vol 106 (6) ◽  
pp. 1924-1931 ◽  
Author(s):  
Svenja Hardtke ◽  
Lars Ohl ◽  
Reinhold Förster

Abstract The production of high-affinity antibodies to T-dependent antigens requires the interaction of B cells and T helper cells expressing receptors specific for the same antigen. Although several mechanisms have been elucidated that regulate B-cell trafficking within lymphoid organs, less is known about molecular cues that guide the small subpopulation of CD4+ follicular T helper cells to B-cell follicles. Using adoptive transfer of transgenic T cells in mice, we demonstrate that antigen-induced activation leads to a finely tuned positioning of T cells either to the T-cell area or the B-cell follicle. We show that expression of CXCR5 is indispensable for T cells to enter B-cell follicles, whereas expression of CCR7 provides a counteracting signal to retain activated T cells in the T-cell area. Although only few T cells transiently migrate from the T-cell area to the B-cell follicle of peripheral lymph nodes following antigenic challenge, this step is essential to provide the help B cells require to produce antibodies efficiently. Thus, we demonstrate that the balanced expression of CCR7 and CXCR5 determines the positioning and proper function of follicular T helper cells.


1975 ◽  
Vol 142 (4) ◽  
pp. 928-935 ◽  
Author(s):  
E Heber-Katz ◽  
D B Wilson

This study provides a direct quantitative comparison of the helper effects of allogeneic and syngeneic rat T cells in the production of direct SRBC plaque-forming cell (PFC) responses by B cells in culture. In syngeneic T-B combinations, log-log plots of the number of PFC generated after 5.5 days in culture vs. the number of T cells employed as helpers showed a linear response between 10(4) and 2.5 times 10(5) T cells added. Allogeneic T-B combinations, in which the T cells possess the capacity for reactivity to major alloantigens of the B-cell donor, showed a different dose/response relationship in which PFC responses were decreased at high T/B ratios and augmented at low T/B rations. In this system responses were detected with as few as 10(3) allogeneic T cells. Use of negatively selected allogeneic T populations, specifically depleted of mixed lymphocyte interaction (MLI) and graft-vs-host reactivity for B-cell alloantigens, as helpers gave dose/response curves quantitatively identical to responses with syngeneic T-B combinations and also with F1 T-cell parental B-cell combinations. These data indicate that rat T and B cells need not share a major histocompatibility complex haplotype in order to collaborate effectively in a primary direct PFC response to SRBC in culture. In addition, the PFC response required the combinaed presence of T and B cells as well as antigen in the cultures, a finding consistent with the two signal model of B-cell activation. Finally, the dose/response data obtained suggest the possibility that although SRBC antigen is required in the cultures helper activity with low numbers of normal allogeneic T cells may not depend on T cells having specificity for this antigen.


1982 ◽  
Vol 155 (5) ◽  
pp. 1267-1276 ◽  
Author(s):  
Y Asano ◽  
R J Hodes

The present studies have been carried out to characterize the regulatory influences acting upon defined pathways of T cell-dependent B cell activation. In these studies, it was demonstrated that high concentrations of free carrier strongly inhibited the MHC-restricted in vitro T cell-dependent antibody responses of primed Lyb-5- B cells to the corresponding carrier-hapten conjugate. In contrast, these same concentrations of free carrier failed to inhibit the T cell dependent responses of Lyb-5+ B cells to the same antigen. The inhibition of Lyb-5- B cell responses by free carrier was shown to result from active suppression mediated by carrier-specific primed Lyt-1+2- T cells and to require the additional participation of unprimed Lyt-1-2+ T cells. The activation of this suppression was antigen-specific, but suppression once activated was antigen nonspecific in its effect. These findings thus demonstrate that distinct pathways of B cell activation can be independently regulated by T suppressor network influences, and that these pathways therefore constitute potentially independent components of the immune response to a given antigenic stimulus.


1993 ◽  
Vol 178 (3) ◽  
pp. 1097-1102 ◽  
Author(s):  
S Nonoyama ◽  
D Hollenbaugh ◽  
A Aruffo ◽  
J A Ledbetter ◽  
H D Ochs

Costimulatory signals provided by T cells are required for B cells to produce specific antibody (Ab) to T-dependent antigen (Ag) bacteriophage phi x 174. In this study, we demonstrate that if cultured in the presence of anti-CD40, interleukin 10 (IL-10), and Ag, purified B cells can produce antiphage Ab in quantities comparable to those synthesized by B cells cocultured with Ag and T cells. Isotypes produced by B cells in this culture system correspond to those observed in sera of B cell donors. Culture of immunoglobulin (Ig)D- and IgD+ B cells reveals that Ag-induced production of antiphage Ab is restricted to IgD- subset of B cells. In the absence of Ag, anti-CD40/IL-10-stimulated B cells produce only minute amounts of antiphage Ab, indicating that Ag stimulation is indispensable and provides a signal that is synergistic with anti-CD40 and IL-10. Addition of a soluble form of the CD40 ligand (sgp39) to the culture system has a similar effect on specific Ab synthesis as anti-CD40; addition of the soluble construct, CD40 Ig, known to inhibit gp39/CD40 interaction, suppresses in vitro antiphage Ab production by Ag exposed peripheral blood mononuclear cells. Finally, in vivo requirement of gp39/CD40 interaction for specific Ab production was demonstrated by the finding that activated T cells from patients with x-linked hyper IgM syndrome express functionally defective gp39 and respond with depressed Ab titers and fail to switch from IgM to IgG after multiple phage immunizations. These observations illustrate that in vitro and possibly in vivo Ag-specific Ab synthesis requires the presence of Ag and IL-10, and activation signals via CD40.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1817-1817
Author(s):  
Frank Neumann ◽  
Boris Kubuschok ◽  
Klaus-Dieter Preuss ◽  
Claudia Schormann ◽  
Michael Pfreundschuh

Abstract Background: Paratarg-7 (P-7) is the antigenic target of paraproteins(Preuss et al. Int J Cancer 2009;125:656-61) from 15% of European and 37% of African-American MGUS/MM patients, stronlgy supporting a role of P-7 in the pathogenesis of MGUS/MM via chronic auto-antigenic stimulation. All patients with P-7 specific paraproteins are carriers of the hyperphosphorylated version of p-7 (pP-7). We recently identified pP-7 specific T-helper cells which were restricted by certain "permissive" HLA-DR haplotypes (Neumann et al., Int J Cancer 2015; 137:1076-1084). These HLA-DR subtypes are overrepresented among patients with P-7 specific paraproteins compared to the corresponding normal population indicating that there are two prerequisites for the development of MGUS/MM with a P-7 specific paraprotein: 1st carriership of pP-7 and 2nd a permissive HLA-DR subtype. We now investigated the functional role of the pP-7 specific T-helper cells and their interaction with peripheral B cells with cognate specificity. Methods: Three patients with MGUS or MM, respectively, with a P-7 specific paraprotein and pP-7 specific T-helper cells were included in this study so far. In addition, the B cells from one healthy pP-7 carrying son of one of the patients were also analyzed. In vitro stimulation of antigen-specific peripheral B cells by pP-7 specific T-helper cells followed a modified protocol previously described by Lanzavecchia et al. (Eur J Immunol. 1983; 13:733-738). To this end, CD19+ B cells and CD3+ T cells were magnetically isolated from the proband's PBMC. T cells were replaced by corresponding T-helper cell clones. Results: In all patients studied, the autologous pP-7 specific T-helper cells stimulated the peripheral B cells to produce P-7 specific antibodies. The P-7 specific B-cell responses were monoclonal and the immunoglobulin type was the same as the paraprotein of the corresponding patient. In contrast, B-cell stimulation with CMV-pp65 specific T-helper cells used as controls always induced an antigen-specific, yet polyclonal response. When the peripheral B cells of a pP-7 carrying patient's son were also stimulated with pP-7 specific T-helper cells, they induced - in contrast to the mother - a polyclonal P-7 specific antibody response in his B cells, even though mother and son shared a "permissive" HLA-DR haplotype (HLA-DRB1*1301). Conclusion: In patients with MGUS/MM monoclonal B cells are found in the peripheral blood that can be induced to produce monoclonal antibodies identical to the serum paraprotein by T-helper cells with specificity for the antigenic target of the paraprotein. This does not only support an indispensable role of these T-helper cells in the pathogenesis of MGUS/MM via chronic antigenic stimulation, it also proves that precursors of the malignant plasma cells can be found in the peripheral blood that might fuel the development of malignant plasma cells. Cytogenetic and molecular genetic analyses are underway to determine if these precursor B-cells share the malignant genotype of their malignant plasma cells. These B cells can now be targeted by PARs (p araprotein a ntigens for r everse targeting) conjugated to toxins, as parts of bispecific constructs (PAR/CD3 or PAR/CD16) and/or PAR/CAR T cells. Use of PARs can be envisaged prophylactically for carriers of modified autoantigens like pP-7 with a permissive HLA-DR haplotype and a monoclonal B-cell response in vitro or in MM patients achieving a VGPR or CR after treatment for the prevention of relapse. Disclosures No relevant conflicts of interest to declare.


2002 ◽  
Vol 9 (3) ◽  
pp. 169-172 ◽  
Author(s):  
Nobuo Sakaguchi ◽  
Satoru Fujimura ◽  
Kazuhiko Kuwahara

Adaptive immunity is dependent on proliferation of antigen-driven B cells for clonal expansion in germinal centers (GCs) against T cell-dependent antigens (TD-Ag), accompanied with somatic hypermutation of variable-region gene and class switching of B cell antigen receptors. To study molecular mechanisms for B cell differentiation in GCs, we have identified and studied a 210 kDa GANP protein expressed in GC-B cells. GANP has domains for MCM3-binding and RNA-primase activities and is selectively up-regulated in centrocytes surrounded with follicular dendritic cells (FDCs) upon immunization with TD-Agin vivoand in B cells stimulated with anti-CD40 monoclonal antibodyin vitro, which suggested that GANP plays a certain important role in the maturation of immunoglobulin or selection of B cells in GC during the immune response to TD-Ag. Since this up-regulation has not been detected in T cells in GCs and in Concanavalin A-stimulated T cellsin vitro, selective function of GANP molecule on B cell proliferation and differentiation might exist.


Blood ◽  
1997 ◽  
Vol 89 (8) ◽  
pp. 2901-2908 ◽  
Author(s):  
Asimah Rafi ◽  
Mitzi Nagarkatti ◽  
Prakash S. Nagarkatti

Abstract CD44 is a widely distributed cell surface glycoprotein whose principal ligand has been identified as hyaluronic acid (HA), a major component of the extracellular matrix (ECM). Recent studies have demonstrated that activation through CD44 leads to induction of effector function in T cells and macrophages. In the current study, we investigated whether HA or monoclonal antibodies (MoAbs) against CD44 would induce a proliferative response in mouse lymphocytes. Spleen cells from normal and nude, but not severe combined immunodeficient mice, exhibited strong proliferative responsiveness to stimulation with soluble HA or anti-CD44 MoAbs. Furthermore, purified B cells, but not T cells, were found to respond to HA. HA was unable to stimulate T cells even in the presence of antigen presenting cells (APC) and was unable to act as a costimulus in the presence of mitogenic or submitogenic concentrations of anti-CD3 MoAbs. In contrast, stimulation of B cells with HA in vitro, led to B-cell differentiation as measured by production of IgM antibodies in addition to increased expression of CD44 and decreased levels of CD45R. The fact that the B cells were responding directly to HA through its binding to CD44 and not to any contaminants or endotoxins was demonstrated by the fact that F(ab)2 fragments of anti-CD44 MoAbs or soluble CD44 fusion proteins could significantly inhibit the HA-induced proliferation of B cells. Also, HA-induced proliferation of B cells was not affected by the addition of polymixin B, and B cells from lipopolysaccharide (LPS)-unresponsive C3H/HeJ strain responded strongly to stimulation with HA. Furthermore, HA, but not chondroitin-sulfate, another major component of the ECM, induced B-cell activation. It was also noted that injection of HA intraperitoneally, triggered splenic B cell proliferation in vivo. Together, the current study demonstrates that interaction between HA and CD44 can regulate murine B-cell effector functions and that such interactions may play a critical role during normal or autoimmune responsiveness of B cells.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1046.1-1046
Author(s):  
L. Schlicher ◽  
P. Kulig ◽  
M. Murphy ◽  
M. Keller

Background:Cenerimod is a potent, selective, and orally active sphingosine 1-phosphate receptor 1 (S1P1) modulator that is currently being evaluated in a Phase 2b study in patients with systemic lupus erythematosus (SLE) (NCT03742037). S1P1 receptor modulators sequester circulating lymphocytes within lymph nodes, thereby reducing pathogenic autoimmune cells (including B lymphocytes) in the blood stream and in inflamed tissues. Extensive clinical experience has become available for the nonselective S1P receptor modulator fingolimod in relapsing forms of multiple sclerosis, supporting this therapeutic concept for the treatment of autoimmune disorders.Objectives:Although the effect of S1P-receptor modulators in reducing peripheral B cells is well documented1,2, the role of the S1P1 receptor on this cell type is only incompletely understood. In this study, the mode of action of cenerimod on primary human B cells was investigated in a series of in vitro experiments, including S1P1 receptor cell surface expression and chemotaxis towards S1P. Moreover, S1P1 expression following B cell activation in vitro was studied. As glucocorticoids (GC) are frequently used in the treatment of patients with autoimmune disorders including SLE, the potential influence of GC on the mode of action of cenerimod was evaluated.Methods:Primary human B lymphocytes from healthy donors were isolated from whole blood. In one set of experiments, cells were treated with different concentrations of cenerimod to measure S1P1 receptor internalization by flow cytometry. In a second set of experiments, isolated B cells were activated using different stimuli or left untreated. Cells were then analysed for S1P1 and CD69 cell surface expression and tested in a novel real-time S1P-mediated migration assay. In addition, the effect of physiological concentrations of GCs (prednisolone and prednisone) on cenerimod activity in preventing S1P mediated migration was tested.Results:In vitro, cenerimod led to a dose-dependent internalization of the S1P1 receptor on primary human B lymphocytes. Cenerimod also blocked migration of nonactivated and activated B lymphocytes towards S1P in a concentration-dependent manner, which is in line with the retention of lymphocytes in the lymph node and the reduction of circulating lymphocytes observed in the clinical setting. Upon B cell activation, which was monitored by CD69 upregulation, a simultaneous downregulation of S1P1 expression was detected, leading to less efficient S1P-directed cell migration. Importantly, physiological concentrations of GC did not affect the inhibitory activity of cenerimod on B cell migration.Conclusion:These results show that cenerimod, by modulating S1P1, blocks B lymphocyte migration towards its natural chemoattractant S1P and demonstrate compatibility of cenerimod with GC. These results are consistent with results of comparable experiments done previously using primary human T lymphocytes.References:[1]Nakamura M et al., Mult Scler. 2014 Sep; 20(10):1371-80.[2]Strasser DS et al., RMD Open 2020;6:e001261.Disclosure of Interests:None declared


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