CLL Cells Can Diversify, Switch, and Differentiate in Response to Autologous T Cell Stimuli Present in a Murine Adoptive Transfer Model

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 315-315
Author(s):  
Piers E.M. Patten ◽  
Shih-Shih Chen ◽  
Davide Bagnara ◽  
Rita Simone ◽  
Sonia Marsilio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Adoptive Transfer ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Transfer Model ◽  
B Cell Differentiation ◽  
Cell Numbers ◽  
Nsg Mice

Abstract Abstract 315 Adoptive transfer of primary patient CLL cells into NOD/SCID/γcnull(NSG) mice results in engraftment and proliferation of CLL cells if autologous T cells are present. Formation of splenic follicles consisting of B cells interspersed and surrounded by T cells indicates engraftment. However, ultimately these CD20+ cells are lost several weeks later. We describe one of the mechanisms for this apparent loss: differentiation to plasma cells. Peripheral blood cells from 9 IgM+ CLL patients (6 U-CLL and 3 M-CLL) were adoptively transferred into NSG mice with enriched autologous CD3+ cells pre-activated with anti-CD3/28 beads. B and T cell engraftment and subset distributions were analyzed for 47 mice by immunohistochemistry (IHC) and flow cytometry (FC) at the time of sacrifice. The earliest and latest times of assessment were 12 and 124 days, respectively, after CLL cell injection. In some cases, CLL cells were labeled with CFSE to track cell division. At sacrifice, 3 engraftment patterns were observed. Pattern 1 (observed up to day 56) showed small follicles of CD20+ cells with low-moderate numbers of surrounding T cells. Intensely positive CD38 cells were inconspicuous. FC showed CD19+CD5+ cells with no increase in CD38 and variable CFSE dilution indicating lower levels of proliferation. Pattern 2 (observed throughout the study period) showed much higher T and B cell numbers. CD20+ cells were interspersed with and surrounded by principally CD4+ cells which were activated and functional as indicated by expression of Ki-67, PD-1, CD57, and T cell derived cytokines IFNγ and IL5 in plasma. Follicles contained CD20 and cytoplasmic Ig+ (cIg+) cells that double stained for IRF-4 and Blimp-1, transcription factors required for B cell differentiation. While Bcl-6 staining in these cells was minimal or absent, follicles from all 9 patients contained activation-induced deaminase (AID)+ cells. Cells with dim IgM expression localized to follicles; however, cells with intense IgM, IgA, or IgG were present both within, surrounding, and outside follicles matched by similar CD38 staining. Smaller populations of CD138+ cells surrounded follicles and were interspersed throughout non-follicular splenic areas. FC showed a novel CD19+CD5-CFSE-CD38++ population containing a CD138+ subset. Pattern 3 (observed in a limited subset of cases not before day 63) had minimal CD20+ cells by IHC, but noticeable populations of cIg+CD38+ and CD138+ cells interspersed amongst plentiful T cells. Such cells corresponded with cells with plasma cell morphology. Confirmation that differentiated cells were from the patient clone was achieved in 3 ways. First, in FACS sorted CD19+CD5+ and CD19+CD5-38++ cells from a subset of pattern 2 cases, RT-PCR revealed that all fractions contained both IGHC unswitched and switched clones identical to those found in the patients. Second, cases with pattern 3 engraftment generated CLL clonal switched and unswitched cDNA sequences. Finally, adoptive transfer of highly purified CD5+CD19+ patient cells generated IRF-4+Blimp-1+CD138+ cells. The generation of switched cells from all 9 patients indicated functional AID. In one U- CLL case, ultra-deep sequencing on pre-transfer and post-transfer human cells taken from mouse spleen revealed a significant number of new IGHVDJ mutations in spleen-derived cells. Such mutations targeted nucleotides typical for AID's action. In conclusion, CLL cells can diversify, switch, and differentiate in NSG mice in response to autologous T cell signals. The extent of this maturation is a function of T cell numbers and activity and the duration of the experiment. Differentiation without significant Bcl-6 expression suggests that follicles in NSG mice are not recapitulating classic germinal center reactions, possibly giving clues to the origin of CLL. Several features of poor prognosis disease were demonstrated (e.g., increased CD38 and AID expression with the development of clonally related switched transcripts) that might mirror clinical disease features. AID expressed by CLL cells is fully functional as indicated by de novo somatic hypermutation and class switch recombination. Both U-CLL and M-CLL clones respond in a similar manner in this model, suggesting the importance of T– B cell interactions in all types of CLL. Finally, the demonstration that cells can differentiate when appropriately induced may lead to novel therapeutic options for CLL. Disclosures: No relevant conflicts of interest to declare.

scholarly journals B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner

2021 ◽  
pp. annrheumdis-2021-220435
Author(s):  
Theresa Graalmann ◽  
Katharina Borst ◽  
Himanshu Manchanda ◽  
Lea Vaas ◽  
Matthias Bruhn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Expansion ◽  
De Novo ◽  
T Cell Responses ◽  
Type I ◽  
Cell Responses ◽  
T Cell Expansion

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

scholarly journals Phenotypic and functional characterization of T-BAM (CD40 ligand)+ T- cell non-Hodgkin's lymphoma

Blood ◽  
1994 ◽  
Vol 84 (3) ◽  
pp. 866-872 ◽  
Author(s):  
G Inghirami ◽  
S Lederman ◽  
MJ Yellin ◽  
A Chadburn ◽  
L Chess ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Functional Characterization ◽  
Cd40 Ligand ◽  
B Cell Differentiation ◽  
Helper Function ◽  
Unique Distribution ◽  
Hodgkin's Lymphomas

Abstract The precise mechanisms regulating T-helper function have been intensively investigated. We and others have recently identified a new T-cell-B-cell-activating molecule called T-BAM that directs B-cell differentiation by interacting with the CD40 molecule on B cells. Using a specific monoclonal antibody against T-BAM (5C8), we have previously shown that T-BAM expressing T cells are predominantly CD4+CD8- and in normal lymphoid tissue have a unique distribution. However, no information has been obtained regarding the phenotype and functional properties of human neoplastic T cells. Therefore, we investigated T- BAM expression immunohistochemically in 87 well-characterized T-cell non-Hodgkin's lymphomas and lymphoid leukemias (LL). We found that 21/81 neoplasms expressed detectable T-BAM and these positive tumors belong almost exclusively to the CD4+CD8- subtype. In addition, to determine whether T-BAM expression could be induced on T-BAM-LL cells, we activated T-BAM-LLs in vitro and showed that T-BAM could be upregulated only in CD4+CD8- tumors. Our studies clearly show that T- BAM is constitutively expressed in a large number of T-cell neoplasms with a relative mature phenotype (CD4+CD8-) and that only CD4+ neoplastic T cells can be induced in vitro to express this molecule. Additional studies are necessary to identify the biologic significance of T-BAM expression and its potential and clinical implications.

scholarly journals IL-7 and IL-21 are superior to IL-2 and IL-15 in promoting human T cell–mediated rejection of systemic lymphoma in immunodeficient mice

Blood ◽  
2010 ◽  
Vol 115 (17) ◽  
pp. 3508-3519 ◽  
Author(s):  
John C. Markley ◽  
Michel Sadelain
Keyword(s):  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Memory T Cells ◽  
Tumor Rejection ◽  
Effector Memory ◽  
Transfer Model ◽  
Human T Cell

Abstract The γc-cytokines are critical regulators of immunity and possess both overlapping and distinctive functions. However, comparative studies of their pleiotropic effects on human T cell–mediated tumor rejection are lacking. In a xenogeneic adoptive transfer model, we have compared the therapeutic potency of CD19-specific human primary T cells that constitutively express interleukin-2 (IL-2), IL-7, IL-15, or IL-21. We demonstrate that each cytokine enhanced the eradication of systemic CD19+ B-cell malignancies in nonobese diabetic/severe combined immunodeficient (NOD/SCID)/γcnull mice with markedly different efficacies and through singularly distinct mechanisms. IL-7– and IL-21–transduced T cells were most efficacious in vivo, although their effector functions were not as enhanced as IL-2– and IL-15–transduced T cells. IL-7 best sustained in vitro T-cell accumulation in response to repeated antigenic stimulation, but did not promote long-term T-cell persistence in vivo. Both IL-15 and IL-21 overexpression supported long-term T-cell persistence in treated mice, however, the memory T cells found 100 days after adoptive transfer were phenotypically dissimilar, resembling central memory and effector memory T cells, respectively. These results support the use of γc-cytokines in cancer immunotherapy, and establish that there exists more than 1 human T-cell memory phenotype associated with long-term tumor immunity.

Establishing CD8+ T Cell Immunity by Adoptive Transfer of Autologous, IL-15 Expanded, Anti-Tumor CTL with a Central/Effector Memory Phenotype Can Induce Objective Clinical Responses.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 782-782 ◽  
Author(s):  
Marcus Butler ◽  
Philip Friedlander ◽  
Mary Mooney ◽  
Linda Drury ◽  
Martha Metzler ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Adoptive Transfer ◽  
De Novo ◽  
Effector Memory ◽  
Large Numbers ◽  
Central Effector

Abstract Abstract 782 The goal of cellular immunotherapy is to build long-lasting anti-tumor immunologic “memory” in patients and reject tumors for a lifetime. Previously, we and others demonstrated that IL-15 promotes the generation of T cells with a central memory (CM) phenotype which have the capacity to persist and establish effective anti-tumor memory in vivo. Furthermore, it has been shown that CD83 delivers a CD80-dependent T cell stimulatory signal that allows T cells to be long-lived. Based on these findings, we developed a system to generate large numbers of long-lived antigen-specific CD8+ T cells with a memory phenotype. This in vitro culture system utilizes IL-15 and a standardized, renewable artificial antigen presenting cell (aAPC) which was produced by transducing CD80, CD83, and HLA-A*0201 to the human cell line, K562. This aAPC can uniquely support the priming and prolonged expansion of large numbers of antigen-specific CD8+ CTL which display a central/effector memory (CM/EM) phenotype, possess potent effector function, and can be maintained in vitro for >1 year without any feeder cells or cloning. We hypothesized that adoptive transfer of these CTL with a CM/EM phenotype should result in anti-tumor memory in humans even without lymphodepletion or high dose IL-2. For our “first-in-human” clinical study, we chose the melanoma antigen MART1 as a target antigen, since MART1-specific HLA-A*0201+-restricted precursor CTL are detectable in some melanoma patients and can be immunophenotyped pre-infusion. Autologous CD8+ T cells were stimulated weekly with peptide-pulsed human cell-based aAPC and expanded with low dose IL-2 and IL-15. After three weeks, polyclonal MART1 CTL were reinfused without additional lymphodepletion, chemotherapy, IL-2, or vaccination. Eight study participants have enrolled and received a total of 15 MART1 CTL infusions (31% MART1 multimer positivity, median). All but one subject received two reinfusions where the 2nd graft was produced from CD8+ T cells harvested two weeks after the 1st reinfusion. To date, ≥2×109 CTL with potent effector function and a CM/EM phenotype were successfully generated for all subjects. No dose limiting toxicities were observed at either Dose Level 1 (2×108/m2) or Dose Level 2 (2×109/m2). Clinical activity was observed with a response by RECIST criteria in 1 subject, which was confirmed by a negative PET/CT 100 days following the last CTL infusion. In addition, 1 patient experienced a mixed response, 1 had stable disease, 3 had progression, and 2 are currently on active therapy. Multimer staining showed that, immediately post infusion, the percentage of CD8+ T cells specific for MART1 temporarily increased in all subjects, with the highest (6.5%) observed in subject #7. In 4 subjects, sustained increases in the frequency of MART1 specific T cells by more than two-fold (range 2.0-10x) for ≥21 days were observed despite the fact that no exogenous cytokines or vaccination was administered. Moreover, an increase of detectable MART1 specific T cells which display a CM phenotype was observed in all evaluable subjects and was observed for ≥35 days in 6 of 8 subjects. In subject #2, the conversion of MART1 CTL immunophenotype from a naïve to a mixture of naïve/memory phenotypes was observed for more than 6 months. We identified 10 individual MART1 T cell clonotypes from peripheral CD45RA- memory T cells on day 21. Clonotypic TCR Vbeta CDR3 analysis revealed that CTL grafts contained 7 out of 10 of these clonotypes. Furthermore, 6 clonotypes persisted in the peripheral CD45RA- memory fraction on days 39, 67 and/or 132. In Subject #3, who showed a mixed clinical response, 5 individual MART1 T cell clonotypes were isolated from lung metastases. 4 out of 5 clones were included in the CTL grafts. This finding supports the possibility that infused CTL can traffic and localize to sites of disease. Intriguingly, in both subjects, we were able to identify MART1 CTL clonotypes that were not detectable in the CTL grafts but possibly emerged after CTL infusion, indicating that adoptive transfer of MART1-specific CTL may provoke a de novo antitumor response. Taken together, these results suggest that CM/EM MART1 CTL generated ex vivo using our cell-based artificial APC in the presence of IL-15 may persist in vivo and induce de novo anti-tumor responses. Further enhancement of anti-tumor activity may be achieved through vaccination, cytokine administration, and/or removal of cytokine sinks and inhibitory factors following appropriate lymphodepletion. Disclosures: No relevant conflicts of interest to declare.

Inhibiting IL-2 Signaling and the Regulatory T-Cell Pathway Using Computationally Designed Novel Peptides

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3875-3875
Author(s):  
Tammy Price-Troska ◽  
David Diller ◽  
Alexander Bayden ◽  
Mark Jarosinski ◽  
Joseph Audies ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Function ◽  
Treg Cell ◽  
Immune Cell ◽  
Conflicts Of Interest ◽  
Interleukin 2 ◽  
Computational Design ◽  
Treg Cells ◽  
Cell Numbers

Abstract Regulatory T-cells (TREG) are the gateway to immune function and typically regulate immune cell activation. Cytokines, including interleukin-2 (IL-2), induce T-cell differentiation and promote a regulatory phenotype. Once activated via the IL-2 receptor (IL-2R), a cascade of events in T-cells initiate signal transducer and activator of transcription 5 (STAT5) and Forkhead box P3 (FOXP3) activation which appear to function as important regulators of this immunologic pathway and promote the development and function of TREG cells. In non-Hodgkin lymphoma (NHL), we have found that intratumoral TREG cells are increased in number and suppress immune function. In previous work, we have found that TREG cells inhibit T-cell proliferation, suppress cytokine production and limit effector cell cytotoxicity. We have also shown that increased serum levels of soluble sIL-2Rα is a prognostic factor in NHL and that sIL-2Rα can bind to IL-2 and promote its signaling thereby increasing TREG cell numbers. In this study, we developed a strategy to inhibit the binding of IL-2 to sIL-2Rα with the goal of suppressing the induction of FOXP3 and decreasing TREG cell numbers. To do this, we developed peptides designed to disrupt the interaction between IL2 and sILRα. In collaboration with CMDBioscienceSM, we developed and analyzed 22 peptide compounds derived by structure-based computational design. Initially, we screened each peptide at increasing concentrations using an ELISA assay to test the inhibition of IL-2/IL-2Rα binding by the solubilized peptide. Candidate peptides were then further tested using upregulation of pSTAT5 and FOXP3 in T-cells measured by flow cytometry as a measure of inhibition of IL-2 signaling. The peptides were developed according to different design hypotheses and grouped into different families; the screening ELISA results indicated 4 promising peptides that inhibited IL2/IL2Rα binding (up to 100% inhibition; max peptide concentration of 100uM). These peptides were then used to determine their effect on STAT5 and FOXP3 expression. A lead candidate peptide consistently reduced the expression of FOXP3 and STAT5 expression compared to cells not exposed to peptide. Use of the peptide to disrupt IL-2 signaling inhibited the development of cells with a TREG phenotype. We conclude that structure-based peptide design can be used to identify novel peptide inhibitors that block IL-2/IL-2Rα signaling and inhibit STAT5 and FOXP3 upregulation. These peptides could be used as new therapeutic agents to limit immune suppression by TREG cells and promote a more effective anti-tumor immune response in NHL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Subspecialization of Cxcr5+ T Cells

2001 ◽  
Vol 193 (12) ◽  
pp. 1373-1382 ◽  
Author(s):  
Chang H. Kim ◽  
Lusijah S. Rott ◽  
Ian Clark-Lewis ◽  
Daniel J. Campbell ◽  
Lijun Wu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Antibody Production ◽  
B Lymphocyte ◽  
Interleukin 10 ◽  
Small Subset ◽  
Lymphoid Tissues ◽  
B Cell Differentiation ◽  
Th Cells

The T helper (Th) cell pool is composed of specialized cells with heterogeneous effector functions. Apart from Th1 and 2 cells, CXCR5+ T cells have been suggested to be another type of effector T cell specialized for B cell help. We show here that CXCR5+ T cells are heterogeneous, and we identify subsets of CXCR5+ CD4 T cells that differ in function and microenvironmental localization in secondary lymphoid tissues. CD57+CXCR5 T cells, hereafter termed germinal center Th (GC-Th) cells, are localized only in GCs, lack CCR7, and are highly responsive to the follicular chemokine B lymphocyte chemoattractant but not to the T cell zone EBI1-ligand chemokine. Importantly, GC-Th cells are much more efficient than CD57−CXCR5+ T cells or CXCR5− T cells in inducing antibody production from B cells. Consistent with their function, GC-Th cells produce elevated levels of interleukin 10 upon stimulation which, with other cytokines and costimulatory molecules, may help confer their B cell helper activity. Our results demonstrate that CXCR5+ T cells are functionally heterogeneous and that the GC-Th cells, a small subset of CXCR5+ T cells, are the key helpers for B cell differentiation and antibody production in lymphoid tissues.

scholarly journals Increased Epitope-Specific CD8+ T Cells Prevent Murine Coronavirus Spread to the Spinal Cord and Subsequent Demyelination

2005 ◽  
Vol 79 (6) ◽  
pp. 3370-3381 ◽  
Author(s):  
Katherine C. MacNamara ◽  
Ming Ming Chua ◽  
Peter T. Nelson ◽  
Hao Shen ◽  
Susan R. Weiss
Keyword(s):  
Spinal Cord ◽  
T Cells ◽  
T Cell ◽  
Adoptive Transfer ◽  
Fluorescent Protein ◽  
Hepatitis Virus ◽  
Cell Epitope ◽  
Chronic Phase ◽  
T Cell Response ◽  
Transfer Model

ABSTRACT CD8+ T cells are important for clearance of neurotropic mouse hepatitis virus (MHV) strain A59, although their possible role in A59-induced demyelination is not well understood. We developed an adoptive-transfer model to more clearly elucidate the role of virus-specific CD8+ T cells during the acute and chronic phases of infection with A59 that is described as follows. C57BL/6 mice were infected with a recombinant A59 virus expressing the gp33 epitope, an H-2Db-restricted CD8+ T-cell epitope encoded in the glycoprotein of lymphocytic choriomeningitis virus, as a fusion with the enhanced green fluorescent protein (RA59-gfp/gp33). P14 splenocytes (transgenic for a T-cell receptor specific for the gp33 epitope) were transferred at different times pre- and postinfection (p.i.). Adoptive transfer of P14 splenocytes 1 day prior to infection with RA59-gfp/gp33, but not control virus lacking the gp33 epitope, RA59-gfp, reduced weight loss and viral replication and spread in the brain and to the spinal cord. Furthermore, demyelination was significantly reduced compared to that in nonrecipients. However, when P14 cells were transferred on day 3 or 5 p.i., no difference in acute or chronic disease was observed compared to that in nonrecipients. Protection in mice receiving P14 splenocytes prior to infection correlated with a robust gp33-specific immune response that was not observed in mice receiving the later transfers. Thus, an early robust CD8+ T-cell response was necessary to reduce virus replication and spread, specifically to the spinal cord, which protected against demyelination in the chronic phase of the disease.

A partial deficiency of interleukin-7Rα is sufficient to abrogate T-cell development and cause severe combined immunodeficiency

Blood ◽  
2000 ◽  
Vol 96 (8) ◽  
pp. 2803-2807 ◽  
Author(s):  
Chaim M. Roifman ◽  
Junyan Zhang ◽  
David Chitayat ◽  
Nigel Sharfe
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Clinical Presentation ◽  
Severe Combined Immunodeficiency ◽  
T Cell Development ◽  
Cell Development ◽  
Combined Immunodeficiency ◽  
Cell Numbers ◽  
Partial Deficiency

Abstract Both in vitro and in vivo studies established that interleukin 7 (IL-7) is essential for differentiation of immature T cells and B cells but not natural killer (NK) cells in the mouse. In humans, although both T-cell and B-cell progenitors express the functional IL-7 receptor that consists of IL-7Rα and the γcommon (γc) chain, this lymphocyte receptor system is critical for T lineage but not for B lineage development. Indeed, complete γc deficiency like IL-7Rα deficiency results in the arrest of T-cell but not B-cell development (T−B+ SCID). However, partial deficiency of γc caused by missense mutations results in a T+B+ phenotype and a delay of clinical presentation. It was therefore plausible to assume that partial deficiency of IL-7Rα, like partial γc deficiency may lead to a milder clinical and immunologic phenotype. A P132S mutation in the IL-7Rα was identified in 3 patients with severe combined immunodeficiency (SCID) within an extensively consanguineous family. Substitution of proline with serine in the extracellular portion of IL-7Rα did not affect IL-7Rα messenger RNA (mRNA) and protein expression, but severely compromised affinity to IL-7, resulting in defective signal transduction. In response to IL-7 stimulation, Jak-3 phosphorylation was markedly reduced in both patient cells as well as in COS cells reconstituted with mutant IL-7Rα. Surprisingly, this partial deficiency of IL-7Rα resulted in a severe phenotype, including markedly reduced circulating T cells while sparing B-cell numbers similar to γc chain deficiency. However, unlike the previously reported cases, serum immunoglobulins were virtually absent. Further, unlike γc deficiency, NK cell numbers and function was preserved. Despite the partial deficiency, clinical presentation was indistinguishable from a complete γc deficiency, including severe and persistent viral and protozoal infections and failure to thrive. Unlike partial γc deficiency, a partial deficiency of IL-7Rα results in an arrest of T-cell development, leading to typical severe combined immunodeficiency. This underscores the critical role of IL-7Rα chain in the differentiation of T cells.

Immunisation against Human c-MYC Elicits a T-Cell Response and Influences Growth of High Grade B-Cell Lymphoma in Mice.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 5120-5120
Author(s):  
Florian Helm ◽  
Andrea Wilke ◽  
Thomas Kammertoens ◽  
Christian Friese ◽  
Josef Mautner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Response ◽  
Conflicts Of Interest ◽  
Disease Free Survival ◽  
B Cell Lymphoma ◽  
T Cell Response ◽  
Transfer Model ◽  
High Grade ◽  
Myc Gene

Abstract Abstract 5120 Overexpression of the proto-oncogene c-myc due to chromosomal translocation is the hallmark of Burkitt-lymphoma. The evolving high grade lymphoma is dependent on the overexpression of c-myc, which provides the necessary signal to drive uncontrolled proliferation. Therefore loss of function or recognition of c-myc overexpressing cells by c-MYC specific T-cells should result in killing of the target and a halt to lymphoma progression. C-myc is also expressed in a variety of other human malignancies. Peptide prediction reveals several potential foreign epitopes in the context of murine H2b due to 87% homology between human and mouse c-MYC. In this study we explored whether the human c-myc gene product can be a target for T-cell therapy. Wildtype C57BL/6 mice were immunized with recombinant human c-MYC protein in combination with incomplete Freund′s adjuvans and CpG, and were boosted at various time points thereafter using either c-MYC protein or 40mer peptides encompassing the non homologous regions. Control animals were vaccinated with recombinant GFP or OVA protein. C-MYC vaccinated animals displayed a higher IFNg release upon re-stimulation with c-MYC pulsed dendritic cells compared to control vaccinated animals. In ELISPOT assays we observed a higher number of IFNg positive cells (299±17 vs. 122±8.5 (GFP vaccinated) vs. 66±8.5 (OVA vaccinated)). Vaccination using single peptides revealed that peptides spanning the region from amino acid 87-123, 216-255 and 334-376 produced similar results. In addition, using a human c-MYC specific ELISA we were able to detect c-MYC specific antibodies in serum from immunized mice in a concentration up to 40mg/l. Using established cell lines from l-hu-c-myc transgenic mice, where the human c-myc gene is overexpressed due to the juxtaposition of elements of the immunoglobuline lambda locus as found in t(8;22) of Burkitt's lymphoma, we investigated whether vaccination with human c-MYC protein would influence lymphoma growth in a lymphoma transfer model. Animals were s.c. challenged with 0.1 Mio 291cells overexpressing human c-MYC and were monitored for lymphoma growth. C-MYC vaccinated animals (n=15) displayed a delay in tumor onset and a significantly better disease free survival (28 vs. 22 days, p=0.012) compared to control (OVA) vaccinated animals (n=10). This delayed growth was associated with an increased number of infiltrating CD3+/Perforin+ cells. However, all mice eventually succumbed to lymphoma growth, indicating that the T-cell response was not sufficient to control lymphoma growth in the long term. From these data we conclude that the human c-MYC is a possible target antigen for T-cells, but responses are weak and presumably low in frequency. Disclosures No relevant conflicts of interest to declare.

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