Prediction of MHC Class I-Restricted Immunogenic Epitopes of B-Cell Receptors Indicates T Cell-Mediated Immunosurveillance of Malignant B Cell Clones.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1949-1949
Author(s):  
Anna-Maria Strothmeyer ◽  
Marcus Duehren-von Minden ◽  
Marcelo A Navarrete ◽  
Kristina Heining-Mikesch ◽  
Hendrik Veelken
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Mhc Class I ◽  
Cell Activity ◽  
Class I ◽  
Cell Responses ◽  
Hla Haplotypes

Abstract Abstract 1949 Poster Board I-972 Tumor-specific immune responses can be induced in patients with indolent B cell lymphomas (iNHL) by active immunization against the individual B cell receptor (BCR) expressed by the malignant B cell clone, the so-called “idiotype” (Id). In subsequent trials of intradermal vaccination with recombinant lymphoma-derived Fab fragment in iNHL, we have studied the specificity of MHC class I-restricted anti-Id T cell responses by epitope mapping experiments with synthetic Id-derived peptides predicted to be presented by the respective patient's HLA complex. While such peptides exist in hypervariable and conserved Id regions, these assays have shown consistently that in vivo-induced T cell responses occur preferentially against individual Id epitopes located in complementarity-determining regions (CDR), whereas framework (FR) and constant region-derived epitopes are ignored (Bertinetti et al., Cancer Res. 2006; Navarrete et al., ASH 2008). These results contrast with in vitro studies showing that FR-derived peptides are excellent targets for cytotoxic T cells in iNHL patients (Trojan et al., Nat Med 2000). To gain further insight into the relative predominance and immunological role of MHC class I-restricted Id epitopes, we conducted a comprehensive reverse immunology study in follicular lymphoma (FL). Clonal and functional IgH chain transcript sequences were identified from tumor biopsies of 39 FL patients by A-PCR (Bertinetti et al., EJH 2006). The HLA-A and B haplotype of the patients was determined by conventional serological testing and high-resolution PCR genotyping. Potentially MHC-presentable peptides from all Id sequences and their corresponding germ-line (GL) VH genes were identified for the HLA haplotypes of all 39 patients by reverse immunology (bimas.cit.nih.gov). Identified peptides were ranked for each haplotype according to their predicted score, and the sum of the scores for the 20 highest ranking peptides was calculated. The sum score for any given Id was compared to the mean of the sum scores of the other 38 Ids on the respective patient's HLA haplotypes. Separate analyses were performed for CDR peptides (containing at least 2 AA in any CDR) versus non-CDR-peptides (allocated through imgt.cines.fr), Id versus GL sequences, and Id versus contaminating sporadic Ig sequences that represent bona fide normal B cells in the biopsies. 72% of all peptides with BIMAS scores of ≥50 and ≥10, respectively, were located in FR, expecially in FR3. The ranked sum Id scores were lower for the patients' own tumor Id than for the mean of the allogeneic Ids (Table; Wilcoxon's matched pair test). This difference was mostly attributable to CDR-derived epitopes throughout all CDRs despite overall lower immunogenicity compared to FR. There was no evidence for differential immunogenicity between a hypermutated FL Id and the corresponding GL (p=0.58). Finally, a preliminary survey of IgH sequences from non-clonal B cells indicated similar immunogenicity compared to FL Id (p=0.31). These bioinformatic findings indicate T cell-mediated immunosurveillance against the BCR of malignant and perhaps nonmalignant B cells. T cell activity appears to be directed predominantly against individual CDR peptides despite their lesser predicted HLA binding capacity compared to FR peptides. Existing CDR epitopes are not generated during the hypermutation process of BCRs, raising the possibility that randomly generated, more immunogenic hypervariable peptides are not permitted by the immune system. In conjunction with the T cell activity observed in in vivo and in vitro studies cited above, these findings are consistent with strong peripheral tolerance to shared Id structures. On the other hand, T cell control of individual Id peptides may play a role in immunosurveillance of malignant B cells and may be exploited for active immunotherapy of lymphoma. In contrast, generic or pan-B-cell epitopes are predicted to be less effective in inducing anti-lymphoma T cell responses.Median (range) BIMASPatient IdMean of allogeneic IdscomparisonAll peptides213 (40-5920)369 (56-5520)p=0.0012FR peptides157 (20-5415)239 (18-3891)p=0.045CDR peptides74 (7-648)175 (21-1760)p<0.0001- CDR1 peptides21 (0.7-144)52 (1.9-630)p=0.0007- CDR2 peptides7.6 (0.2-345)30 (2.2-212)p=0.0089- CDR3 peptides16 (1.3-506)37 (6-980)p=0.0008 Disclosures: No relevant conflicts of interest to declare.

scholarly journals Defective T cell-mediated, isotype-specific immunoglobulin regulation in B cell chronic lymphocytic leukemia

Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 1012-1020 ◽  
Author(s):  
JS Moore ◽  
MB Prystowsky ◽  
RG Hoover ◽  
EC Besa ◽  
PC Nowell
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Cell Activity ◽  
Lymphocytic Leukemia ◽  
Specific Immunoglobulin ◽  
Cell Chronic Lymphocytic Leukemia

The consistent occurrence of T cell abnormalities in patients with B cell chronic lymphocytic leukemia (B-CLL) suggest that the non- neoplastic host T cells may be involved in the pathogenesis of this B cell neoplasm. Because potential defects of immunoglobulin regulation are evident in B-CLL patients, we investigated one aspect of this by studying the T cell-mediated immunoglobulin isotype-specific immunoregulatory circuit in B-CLL. The existence of class-specific immunoglobulin regulatory mechanisms mediated by Fc receptor-bearing T cells (FcR + T) through soluble immunoglobulin binding factors (IgBFs) has been well established in many experimental systems. IgBFs can both suppress and enhance B cell activity in an isotype-specific manner. We investigated the apparently abnormal IgA regulation in a B-CLL patient (CLL249) whose B cells secrete primarily IgA in vitro. Enumeration of FcR + T cells showed a disproportionate increase in IgA FcR + T cells in the peripheral blood of this patient. Our studies showed that the neoplastic B cells were not intrinsically unresponsive to the suppressing component of IgABF produced from normal T cells, but rather the IgABF produced by the CLL249 host T cells was defective. CLL249 IgABF was unable to suppress IgA secretion by host or normal B cells and enhanced the in vitro proliferation of the host B cells. Size fractionation of both normal and CLL249 IgABF by gel-filtration high- performance liquid chromatography (HPLC) demonstrated differences in the ultraviolet-absorbing components of IgABF obtained from normal T cells v that from our patient with defective IgA regulation. Such T cell dysfunction may not be restricted to IgA regulation, since we have found similar expansion of isotype-specific FcR + T cells associated with expansion of the corresponding B cell clone in other patients with B-CLL. These data suggest that this T cell-mediated regulatory circuit could be significantly involved in the pathogenesis of B-CLL.

scholarly journals In vitro regulation of immunoglobulin synthesis after marrow transplantation. I. T-cell and B-cell deficiencies in patients with and without chronic graft-versus-host disease

Blood ◽  
1981 ◽  
Vol 58 (3) ◽  
pp. 431-439 ◽  
Author(s):  
LG Lum ◽  
MC Seigneuret ◽  
RF Storb ◽  
RP Witherspoon ◽  
ED Thomas
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Graft Versus Host Disease ◽  
Marrow Transplantation ◽  
Cell Function ◽  
Cell Activity ◽  
Graft Versus Host ◽  
B Cell Function

Abstract Twenty-four patients with aplastic anemia or acute leukemia were treated by marrow grafts from HLA-identical donors after conditioning with high doses of cyclophosphamide and/or today body irradiation. They were studied between 4 and 63 mo (median 14.2) after transplantation. Seventeen patients had chronic graft-versus-host disease (C-GVHD) and 7 were healthy. They were studied for defects in their T- and B-cell function using and indirect hemolytic plaque assay for Ig production after 6 days of culture in the presence of pokeweek mitogen. T or B cells from the patients with or without C-GVHD were cocultured with T or B cells from their HLA-identical marrow donors or unrelated normal controls. Intrinsic B-cell defects, lack of helper T-cell activity, and suppressor T-cell activity were more frequently found in patients with C-GVHD than in healthy patients. Fifteen of the 17 patients with C-GVHD showed on or more defects in their T-and B-cell function compared to only 3 of the 7 patients without C-GVHD. None of the healthy controls, including the marrow donors, showed defects in their T- and B-cell functions. These in vitro findings may be helpful in assessing the process of immune reconstitution and the immunologic aberration found after human marrow transplantation.

scholarly journals Cd5 Maintains Tolerance in Anergic B Cells

2000 ◽  
Vol 191 (5) ◽  
pp. 883-890 ◽  
Author(s):  
Keli L. Hippen ◽  
Lina E. Tze ◽  
Timothy W. Behrens
Keyword(s):  
B Cells ◽  
B Cell ◽  
Cell Receptor ◽  
Immunoglobulin M ◽  
B Cell Tolerance ◽  
Cell Responses ◽  
B Cell Anergy ◽  
Clonal Anergy

Clonal anergy of autoreactive B cells is a key mechanism regulating tolerance. Here, we show that anergic B cells express significant surface levels of CD5, a molecule normally found on T cells and a subset of B-1 cells. Breeding of the hen egg lysozyme (HEL) transgenic model for B cell anergy onto the CD5 null background resulted in a spontaneous loss of B cell tolerance in vivo. Evidence for this included elevated levels of anti-HEL immunoglobulin M (IgM) antibodies in the serum of CD5−/− mice transgenic for both an HEL-specific B cell receptor (BCR) and soluble lysozyme. “Anergic” B cells lacking CD5 also showed enhanced proliferative responses in vitro and elevated intracellular Ca2+ levels at rest and after IgM cross-linking. These data support the hypothesis that CD5 negatively regulates Ig receptor signaling in anergic B cells and functions to inhibit autoimmune B cell responses.

Agonist for Toll-Like Receptor (TLR) 9 Amplifies as Well as Inhibits the Differentiation of FVIII-Specific Memory B Cells into Antibody-Producing Plasma Cells in Vitro and in Vivo.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3382-3382
Author(s):  
Peter Allacher ◽  
Christina Hausl ◽  
Aniko Ginta Pordes ◽  
Rafi Uddin Ahmad ◽  
Hartmut J Ehrlich ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Memory B Cells ◽  
Memory B Cell ◽  
Cpg Dna ◽  
Cell Responses ◽  
Specific Memory ◽  
B Cell Responses

Abstract Memory B cells are essential for maintaining long-term antibody responses. They can persist for years even in the absence of antigen and are rapidly re-stimulated to differentiate into antibody-producing plasma cells when they encounter their specific antigen. Previously we demonstrated that ligands for TLR 7 and 9 amplify the differentiation of FVIII-specific memory B cells into anti-FVIII antibody-producing plasma cells at low concentrations of FVIII and prevent the inhibition of memory-B-cell differentiation at high concentrations of FVIII. The modulation of FVIII-specific memory-B-cell responses by agonists for TLR is highly relevant for the design of new immunotherapeutic approaches in patients with FVIII inhibitors because TLR are activated by a range of different viral and bacterial components. Specifically, TLR 7 is triggered by single-stranded RNA derived from viruses and TLR 9 is triggered by bacterial DNA containing unmethylated CpG motifs. We further explored the modulation of FVIII-specific memory-B-cell responses by agonists for TLRs by studying a broad range of concentrations of CpG DNA, a ligand for TLR 9, both in vitro and in vivo using the murine E17 model of hemophilia A. We used CpG-DNA in concentrations ranging from 0.1 to 10,000 ng/ml to study the modulation of FVIII-specific memory-B-cell responses in vitro and verified the specificity of the effects observed by including a blocking agent for TLR 9 and GpC-DNA, a non-stimulating negative control for CpG DNA. Furthermore, we used doses of CpG DNA ranging from 10 to 50,000 ng per dose to study the modulation of FVIII-specific memory-B-cell responses in vivo. E17 hemophilic mice were treated with a single intravenous dose of 200 ng FVIII to stimulate the generation of FVIII-specific memory B cells and were subsequently treated with another dose of FVIII that was given together with CpG DNA. We analyzed titers of anti-FVIII antibodies in the circulation of these mice one week after the second dose of FVIII. Previously we had shown that a single dose of 200 ng FVIII, given intravenously to E17 hemophilic mice, stimulates the formation of FVIII-specific memory B cells but is not sufficient to induce anti-FVIII antibodies that would be detectable in the circulation. Our results demonstrate a biphasic effect of CpG DNA on the re-stimulation of FVIII-specific memory B cells and their differentiation into antibody-producing plasma cells. Both in vitro and in vivo studies show that CpG DNA at high doses inhibits the re-stimulation and differentiation of FVIII-specific memory B cells. However, CpG DNA at low doses amplifies these processes. Amplification and inhibition of memory-B-cell responses are due to specific interactions of CpG DNA with TLR 9. Both effects are blocked by addition of a blocking agent for TLR 9 in vitro. We conclude that triggering of TLR 9 by bacterial DNA has a substantial influence on FVIII-specific memory-B-cell responses. The consequence of TLR 9 triggering can be inhibitory or stimulatory, depending on the actual concentration of the bacterial DNA. Our findings demonstrate the potential modulatory effects of bacterial infections on the regulation of FVIII inhibitor development.

Non-Cognate Cytotoxic T Cells Can Be Retargeted Against CD20 Positive Tumour Cells Using [Fab' × MHC Class I/Peptide] Conjugates.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2838-2838
Author(s):  
Angela D Hamblin ◽  
Ben CR King ◽  
Ruth R French ◽  
Claude H Chan ◽  
Alison L Tutt ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
B Cell ◽  
Mhc Class I ◽  
Peripheral Blood ◽  
Class I ◽  
B Cell Depletion ◽  
Cytokine Release ◽  
Anti Cd20

Abstract Abstract 2838 To circumvent cytotoxic T lymphocyte (CTL) tolerance of tumour-associated antigens, the concept of redirecting CTLs against non-cognate targets has developed. One way of doing this is to use bispecific antibodies comprising anti-CD3 and anti-tumour antigen moieties. Unfortunately, this is frequently associated with unacceptable toxicity due to inflammatory cytokine release. As an alternative our approach has been to use a bivalent conjugate recognising a tumour antigen (through an antibody fragment) and a defined population of CTLs (specific for a single antigenic peptide e.g. viral epitope) through peptide presented in the context of recombinant MHC class I. We have produced a conjugate consisting of an anti-human CD20 Fab' fragment joined via a chemical crosslinker (succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate) to murine MHC class I/peptide (Kbα1-α3 domains/β2microglobulin presenting the ovalbumin-derived peptide SIINFEKL; expressed bacterially as a continuous polypeptide single chain trimer after Yu et al, J Immunol 2002). Size exclusion chromatography allowed purification of conjugates with [Fab':MHC class I/peptide] ratios of 1:1 and 2:1 (F2 and F3 respectively). In vitro both constructs were able to redirect the transgenic murine CTL line OT-1 (specific for KbSIINFEKL) to lyse human CD20+ tumour cells (lymphoblastoid Daudi cell line) at effector: target ratios of 10:1. This lysis could be blocked by the addition of 100 fold excess of either anti-CD20 F(ab')2 or the Kb/SIINFEKL-specific antibody 25D1. The constructs were also able to cause in vitro proliferation of naïve OT-1 cells (but not irrelevant CD8+ T cells) in the presence of human CD20+ cells in both thymidine incorporation and CFSE dilution assays. Using a human CD20 transgenic mouse model (Ahuja et al, J Immunol 2007) we have evaluated both constructs in vivo for their ability to redirect adoptively transferred OT-1 cells to deplete B cells from the peripheral blood. A single dose of 1 nmole F3 and 2 nmole F2 caused respectively up to 95% and 85% B cell depletion at day 7. The efficacy of lower doses suggested a dose: response relationship. As a marker of toxicity, we have measured cytokine levels at 2, 8 and 24 hours following a dose of 1 nmole F3 and compared them to those seen after administration of an [anti-CD3 × anti-CD20] bispecific F(ab')2 at a dose (0.5 nmole) which produced similar day 7 peripheral blood B cell depletion: phosphate-buffered saline was given as a negative control. Maximal cytokine release was seen at 2 hours with the levels of IL-4, IL-5, KC, IL-2 and IL-10 being lower after administration of the F3 than after the bispecific F(ab')2. However, interestingly, the F3 resulted in greater IL-12 release. Overall these data suggest that [Fab' × MHC class I/peptide] constructs have the potential to redirect non-cognate CTLs to deplete CD20+ malignant B cells from the peripheral blood and that this is associated with a lower level of cytokine release than a similarly efficacious dose of an anti-CD3-containing bispecific F(ab')2. Furthermore, the ability of [Fab' × MHC class I/peptide] constructs to cause proliferation of OT-1 cells in vitro suggests it may be possible to use a single molecule to both generate a secondary cytotoxic T cell response and subsequently to retarget it, increasing the viability of the approach if adopted in the clinic. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Enhanced B Cell Expansion, Survival, and Humoral Responses by Targeting Death Receptor 6

2002 ◽  
Vol 197 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Clint S. Schmidt ◽  
Jinqi Liu ◽  
Tonghai Zhang ◽  
Ho Yeong Song ◽  
George Sandusky ◽  
...  
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Expansion ◽  
Death Receptor ◽  
Immunoglobulin M ◽  
Type I ◽  
Factor C

Targeted disruption of death receptor (DR)6 results in enhanced CD4+ T cell expansion and T helper cell type 2 differentiation after stimulation. Similar to T cells, DR6 is expressed on resting B cells but is down-regulated upon activation. We examined DR6−/− B cell responses both in vitro and in vivo. In vitro, DR6−/− B cells undergo increased proliferation in response to anti–immunoglobulin M, anti-CD40, and lipopolysaccharide. This hyperproliferative response was due, at least in part, to both increased cell division and reduced cell apoptosis when compared with wild-type B cells. Consistent with these observations, increased nuclear levels and activity of nuclear factor κB transcription factor, c-Rel, and elevated Bcl-xl expression were observed in DR6−/− B cells upon stimulation. In addition, DR6−/− B cells exhibited higher surface levels of CD86 upon activation and were more effective as antigen-presenting cells in an allogeneic T cell proliferation response. DR6−/− mice exhibited enhanced germinal center formation and increased titers of immunoglobulins to T-dependent as well as T-independent type I and II antigens. This is the first demonstration of a regulatory role of DR6 in the activation and function of B cells.

scholarly journals Autoreactive marginal zone B cells are spontaneously activated but lymph node B cells require T cell help

2006 ◽  
Vol 203 (8) ◽  
pp. 1985-1998 ◽  
Author(s):  
Laura Mandik-Nayak ◽  
Jennifer Racz ◽  
Barry P. Sleckman ◽  
Paul M. Allen
Keyword(s):  
Lymph Node ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Marginal Zone ◽  
B Cell Tolerance ◽  
Marginal Zone B Cells ◽  
T Cell Help

In K/BxN mice, arthritis is induced by autoantibodies against glucose-6-phosphate-isomerase (GPI). To investigate B cell tolerance to GPI in nonautoimmune mice, we increased the GPI-reactive B cell frequency using a low affinity anti-GPI H chain transgene. Surprisingly, anti-GPI B cells were not tolerant to this ubiquitously expressed and circulating autoantigen. Instead, they were found in two functionally distinct compartments: an activated population in the splenic marginal zone (MZ) and an antigenically ignorant one in the recirculating follicular/lymph node (LN) pool. This difference in activation was due to increased autoantigen availability in the MZ. Importantly, the LN anti-GPI B cells remained functionally competent and could be induced to secrete autoantibodies in response to cognate T cell help in vitro and in vivo. Therefore, our study of low affinity autoreactive B cells reveals two distinct but potentially concurrent mechanisms for their activation, of which one is T cell dependent and the other is T cell independent.

scholarly journals In vitro regulation of immunoglobulin synthesis after marrow transplantation. I. T-cell and B-cell deficiencies in patients with and without chronic graft-versus-host disease

Blood ◽  
1981 ◽  
Vol 58 (3) ◽  
pp. 431-439 ◽  
Author(s):  
LG Lum ◽  
MC Seigneuret ◽  
RF Storb ◽  
RP Witherspoon ◽  
ED Thomas
Keyword(s):  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Graft Versus Host Disease ◽  
Marrow Transplantation ◽  
Cell Function ◽  
Cell Activity ◽  
Graft Versus Host ◽  
B Cell Function

Twenty-four patients with aplastic anemia or acute leukemia were treated by marrow grafts from HLA-identical donors after conditioning with high doses of cyclophosphamide and/or today body irradiation. They were studied between 4 and 63 mo (median 14.2) after transplantation. Seventeen patients had chronic graft-versus-host disease (C-GVHD) and 7 were healthy. They were studied for defects in their T- and B-cell function using and indirect hemolytic plaque assay for Ig production after 6 days of culture in the presence of pokeweek mitogen. T or B cells from the patients with or without C-GVHD were cocultured with T or B cells from their HLA-identical marrow donors or unrelated normal controls. Intrinsic B-cell defects, lack of helper T-cell activity, and suppressor T-cell activity were more frequently found in patients with C-GVHD than in healthy patients. Fifteen of the 17 patients with C-GVHD showed on or more defects in their T-and B-cell function compared to only 3 of the 7 patients without C-GVHD. None of the healthy controls, including the marrow donors, showed defects in their T- and B-cell functions. These in vitro findings may be helpful in assessing the process of immune reconstitution and the immunologic aberration found after human marrow transplantation.

Mature dendritic cells pulsed with freeze–thaw cell lysates define an effective in vitro vaccine designed to elicit EBV-specific CD4+ and CD8+ T lymphocyte responses

Blood ◽  
2000 ◽  
Vol 96 (5) ◽  
pp. 1857-1864 ◽  
Author(s):  
Wolfgang Herr ◽  
Elena Ranieri ◽  
Walter Olson ◽  
Hassane Zarour ◽  
Loreto Gesualdo ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Mhc Class I ◽  
T Cell Responses ◽  
Class Ii ◽  
Interferon Γ ◽  
Class I ◽  
Freeze Thaw ◽  
Cell Responses

Abstract Immunotherapy trials targeting the induction of tumor-reactive T-cell responses in cancer patients appear to hold significant promise. Because nonmutated lineage-specific antigens and mutated idiotypic antigens may be coexpressed by tumor cells, the use of autologous tumor material to promote the broadest range of antitumor T-cell specificities has significant clinical potential in cancer vaccination trials. As a model for vaccination in the cancer setting, we chose to analyze the promotion of T-cell responses against Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell line (B-LCL)–derived antigens in vitro. A series of bulk antigenic formats (freeze–thaw lysate, trifluoroacetic acid lysate, extracted membranes, affinity-purified MHC class I– and class II–presented peptides, acid-eluted peptides) prepared from EBV B-LCLs were tested for their ability to stimulate EBV B-LCL–reactive CD4+ and CD8+ T lymphocytes in vitro when pulsed onto autologous dendritic cells (DCs). DC presentation of freeze–thaw lysate material derived from (either autologous or allogeneic) EBV B-LCLs with an Mr of 10 kd or larger stimulated optimal anti-EBV B-LCL responsiveness from freshly isolated CD4+ and CD8+ peripheral blood T cells. These in vivo “memory” T-cell responses were observed only in EBV-seropositive donors. CD4+ T-cell responses to lysate-pulsed DCs were Th1 type (ie, strong interferon-γ and weak interleukin-5 responses). While CD8+ T-cell responses were also observed in interferon-γ Elispot assays and in cytotoxicity assays, these responses were of low frequency unless the DC stimulators were induced to “mature” after being fed with tumor lysates. Optimal-length, naturally processed, and MHC class I– or class II–presented tumor peptides were comparatively poorly immunogenic in this model system.

In Vitro and in Vivo Imaging of Initial T-B Cell Interactions in the Setting of B Cell-Based Cancer Immunotherapy

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2740-2740
Author(s):  
Kerstin Wennhold ◽  
Nela Klein-Gonzalez ◽  
Michael von Bergwelt-Baildon ◽  
Alexander Shimabukuro-Vornhagen
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cancer Immunotherapy ◽  
Cell Interactions ◽  
Migration Behavior ◽  
Cell Zone

Abstract In recent years, there has been a growing interest in the use of B cells for cellular immunotherapy, since B cell-based cancer vaccines have yielded promising results in preclinical animal models. Contrary to dendritic cells (DCs), we know little about the migration behavior of B cells in vivo. Therefore, we investigated the interactions between CD40-activated (CD40) B cells and cytotoxic T cells in vitro and the migration behavior of CD40B cells in vivo. The dynamic interactions of human antigen-presenting cells and antigen-specific T cells were observed by time-lapse videomicroscopy. The migratory and chemoattractant potential of CD40B cells was analyzed by flow cytometry and standard transwell migration assays. GFP+ CD40B cells or CD40B cells isolated from Luciferase+mice were used for subsequent in vivo studies. Murine CD40B cells show similar migratory and chemotactic characteristics compared to human CD40B cells. Upon CD40-activation, B cells upregulate the important molecules involved in lymh node homing (CD62L, CCR7/CDCR4), which are functional and induce chemotaxis of T cells in vitro. Striking differences were observed for interactions of human CD40B cells or DCs with T cells. Antigen-loaded CD40B cells differ from immature and mature DCs by displaying a rapid migratory pattern undergoing highly dynamic, short-lived (7.5 min) and sequential interactions with cognate T cells. In vivo, CD40B cells migrate to the spleen and the lymph nodes, where they enrich in the B cell zone before traveling to B cell/ T cell boundary close to the T cell zone. CD40B cell interactions with T cells are dynamic and short-lived and thereby differ from DCs. Taken together, the migration behavior of CD40B cells and their interaction with T cells underline their potential as cellular adjuvant for cancer immunotherapy. Disclosures No relevant conflicts of interest to declare.

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