The Immunomodulatory Drug Lenalidomide (CC5013; Revlimid), Enhances Antigen-Presenting Cell’s Function Leading to Effective Priming of CD4+ T-Lymphocytes.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2391-2391
Author(s):  
Hongwei Wang ◽  
Aung Naing ◽  
Fengdong Cheng ◽  
Pedro Horna ◽  
Ildelfonso Suarez ◽  
...  

Abstract Professional antigen-presenting cells (APCs) play an important role in the initiation of antigen-specific T-cell responses. The demonstration that these cells are also required for the induction of T-cell tolerance, placed APCs at the crossroads of immune activation versus immune tolerance. Recent studies have demonstrated that the inflammatory status of the APC at the time of antigen presentation is the central determinant of T-cell priming versus T-cell tolerance. As such, therapeutic induction of inflammatory APCs might override immune tolerance and enhance the efficacy of immunotherapeutic strategies targeting hematologic tumors. Lenalidomide (CC5013) is a thalidomide analogue with immunomodulatory properties. Phase I and Phase II clinical trials in patients with myelodysplastic syndrome (MDS) have shown high frequency of erythropoietic responses, particularly in patients with 5q31 deletion associated with emergence of polyclonal lymphoid infiltrate in responding patient bone marrows. This observation raised the question as to whether immunological mechanism(s) may mediate, at least in part, the beneficial effect of CC5013 in patients with MDS. To gain further insight into the effects of Lenalidomide on APC’s function and regulation of antigen-specific CD4+ T-cell responses, we treated peritoneal elicited macrophages (PEM) and bone marrow-derived dendritic cells (DCs) with escalating concentration of Lenalidomide in vitro. Enhanced expression of both B7.1 and B7.2 co-stimulatory molecules was observed in Lenalidomide-treated APCs relative to untreated APCs. No difference in the expression of MHC class II molecules or CD40 was detected. Assessment of cytokine production by ELISA showed that Lenalidomide-treated APCs produce higher levels of TNF-a, IL-6 and IL-10 in response to LPS stimulation as compared to untreated APCs. Next, we evaluated the ability of Lenalidomide-treated APCs to present cognate antigen to naïve and tolerant CD4+ T-cells specific for a MHC class II restricted epitope of influenza hemagglutinin (HA). We found that treatment of either PEM or DC with low doses of Lenalidomide (range: 1.5–12.5 uM) significantly enhanced their antigen-presenting capabilities leading to effective priming of naïve CD4+ T-cells confirmed by their increased production of IL-2 and IFN-gamma in response to cognate antigen. Taken together, our results shows that by inducing inflammatory APCs, Lenalidomide directs the outcome of antigen-specific T-cell responses. Furthermore, they have broadened the scope of this drug as a promising adjuvant in cancer immunotherapy.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2392-2392
Author(s):  
Hongwei Wang ◽  
Fengdong Cheng ◽  
P. Horna ◽  
I.V. Suarez ◽  
Jian Wu ◽  
...  

Abstract Tumor-antigen-specific T-cell tolerance imposes a significant barrier to the development of effective therapeutic cancer vaccines. Bone marrow-derived antigen presenting cells (APCs) are critical in the induction of this unresponsive state. The requirement for APCs in tolerance induction, together with their well-known role in priming T-cell antitumor responses place APCs at the crossroads of immune activation versus immune tolerance and points to manipulation of these cells as an enticing strategy to modulate T-cell responses against tumors. Identification of the intracellular mechanisms by which APCs induces either T-cell outcome represents therefore a critical step to better understand and overcome tumor-induced immune tolerance. Histones tail plays an important role in modulation of gene transcription. Emerging evidence suggest that inhibition of hystone deacetylases (HDAC) increases the expression of inflammatory genes. Given that the inflammatory status of the APC at the time of antigen presentation is central in determining T-cell priming versus T-cell tolerance, we evaluated the effects of the HDAC inhibitor LAQ842 (Novartis Pharmaceutical Inc.) on APC function and regulation of antigen-specific CD4+ T-cell responses. First, treatment of peritoneal elicited macrophages (PEM) or bone marrow derided dendritic cells (DCs) with increasing concentrations of LAQ842 resulted in enhanced acetylation of hystones H-2A, H-2B, H3 and H4. Analysis of the expression of MHC class molecules and co-stimulatory molecules revealed a significant increase in B7.2 and CD40 in LAQ842-treated APCs as compared to untreated APCs. Utilizing multi-template RNA probes and ELISA we found that LAQ842-treated APCs produce enhanced levels of several inflammatory mediators such as IL-1a, IL-1b, IL-6, TNF-a and RANTES relative to untreated APCs. Similarly, in response to LPS-stimulation, LAQ842-treated APCs produce significant higher levels of the pro-inflammatory cytokine IL-12 but reduce production of the anti-inflammatory cytokine IL-10 as determined by RT-PCR and ELISA. Furthermore, by chromatin immune precipitation (CHIP) assays we found that LAQ842-treated APCs display an increased acetylation of histones associated with the IL-12 promoter but a diminished acetylation of histones at the IL-10 promoter in response to LPS stimulation. Next, we evaluated whether the inflammatory APCs induced by LAQ842 were capable of effectively present antigen and prime productive antigen-specific T-cell responses. In vitro treatment of PEM or DCs with increasing concentrations of LAQ842 resulted in an enhanced presentation of HA-peptide to naïve CD4+ T cells specific for a MHC class II restricted epitope of influenza hemagglutinin (HA). Indeed, these clonotypic T cells display an enhanced HA-specific proliferation, IL-2 and IFN-gamma production relative to clonotypic T cells that encountered HA-antigen on untreated APCs. More importantly, LAQ842-treated APCs were able to restore the responsiveness of tolerant CD4+ T-cells isolated from lymphoma bearing hosts. By demonstrating that HDAC inhibitor induces inflammatory APCs capable of restoring the responsiveness of tolerant T-cells, our studies have unveiled a previously unknown immunological effect of these agents and have broadened their clinical scope as promising adjuvants in cancer immunotherapy.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 520-520
Author(s):  
Hongwei Wang ◽  
Zi Wang ◽  
Fengdong Cheng ◽  
Karrune V. Woan ◽  
Jennifer Rock-Klotz ◽  
...  

Abstract Abstract 520 Histones play a critical role in transcriptional regulation, cell cycle progression and developmental events. Histone acetylation/deacetylation alters chromatin structure and affects transcription factor access to DNA. Histone deacetylase inhibitors (HDI) induce growth arrest, cellular differentiation, and apoptosis and are being pursued as anticancer drugs. Interestingly, in addition to their antitumor properties, HDI have also been shown to modulate inflammatory responses. Recently, we have found that HDAC6 is required for the production of the immunosuppressive cytokine IL-10 by APCs. Given the role of this cytokine in T-cell tolerance induction we asked whether inhibition of HDAC6 with Tubastatin A, a potent and selective HDAC6 inhibitor would influence the inflammatory status of APCs and their ability to determine activation versus tolerance of antigen-specific CD4+ T cells in vitro. First, treatment of peritoneal elicited macrophages (PEM) with increasing concentration of Tubastatin A resulted in enhanced tubulin acetylation which was accompanied by enhanced expression of co-stimulatory molecules in treated cells. In addition, Tubastatin-A treated PEM were unable to produce IL-10 and TNF-a in response to LPS stimulation. In sharp contrast, Tubastatin-A treated PEM produce higher level of the pro-inflammatory cytokines IL-12 and IL-6. Next, we evaluated the ability of Tubastatin A-treated APCs to present cognate antigen to naïve and tolerant CD4+ T-cells specific for a MHC class II restricted epitope of influenza hemagglutinin (HA). We found that treatment of PEM with Tubastatin A significantly enhanced their antigen-presenting capabilities leading to effective priming of naïve CD4+ T-cells confirmed by their increased production of IL-2 and IFN-g in response to cognate antigen. More importantly, Tubastatin-A treated APCs were able to restore the responsiveness of tolerant CD4+ T cells isolated from lymphoma bearing mice. Taken together, selective HDAC6 inhibition with Tubastatin A provides a novel therapeutic approach to induce inflammatory APCs and overcome the significant barrier that T-cell tolerance has imposed to effective lymphoma immunotherapy. Disclosures: No relevant conflicts of interest to declare.


1993 ◽  
Vol 178 (5) ◽  
pp. 1789-1793 ◽  
Author(s):  
Y Wu ◽  
Y Guo ◽  
Y Liu

CTLA4 ligands are important costimulatory molecules because soluble CTLA4Ig blocks the induction of T cell responses and induces T cell tolerance. As CTLA4 immunoglobulin (CTLA4Ig) binds B7 when the latter is expressed on fibroblasts, it was widely assumed that CTLA4Ig blocks T cell costimulation by blocking the function of B7. Here we show that the major costimulatory ligand bound by CTLA4Ig (which we term CTLA4 ligand A) on antigen-presenting cells are not encoded by the B7 gene. CTLA4 ligand A also differs from B7 in cellular distribution and in the respective levels of expression. Both B7 and CTLA4 ligand A are critically involved in T cell costimulation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Sara Ness ◽  
Shiming Lin ◽  
John R. Gordon

Dendritic cells (DC) are antigen-presenting cells that can communicate with T cells both directly and indirectly, regulating our adaptive immune responses against environmental and self-antigens. Under some microenvironmental conditions DC develop into anti-inflammatory cells which can induce immunologic tolerance. A substantial body of literature has confirmed that in such settings regulatory DC (DCreg) induce T cell tolerance by suppression of effector T cells as well as by induction of regulatory T cells (Treg). Many in vitro studies have been undertaken with human DCreg which, as a surrogate marker of antigen-specific tolerogenic potential, only poorly activate allogeneic T cell responses. Fewer studies have addressed the abilities of, or mechanisms by which these human DCreg suppress autologous effector T cell responses and induce infectious tolerance-promoting Treg responses. Moreover, the agents and properties that render DC as tolerogenic are many and varied, as are the cells’ relative regulatory activities and mechanisms of action. Herein we review the most current human and, where gaps exist, murine DCreg literature that addresses the cellular and molecular biology of these cells. We also address the clinical relevance of human DCreg, highlighting the outcomes of pre-clinical mouse and non-human primate studies and early phase clinical trials that have been undertaken, as well as the impact of innate immune receptors and symbiotic microbial signaling on the immunobiology of DCreg.


Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.


2003 ◽  
Vol 197 (3) ◽  
pp. 375-385 ◽  
Author(s):  
Hiroeki Sahara ◽  
Nilabh Shastri

CD4 T cells regulate immune responses that cause chronic graft rejection and graft versus host disease but their target antigens remain virtually unknown. We developed a new method to identify CD4 T cell–stimulating antigens. LacZ-inducible CD4 T cells were used as a probe to detect their cognate peptide/MHC II ligand generated in dendritic cells fed with Escherichia coli expressing a library of target cell genes. The murine H46 locus on chromosome 7 was thus found to encode the interleukin 4–induced IL4i1 gene. The IL4i1 precursor contains the HAFVEAIPELQGHV peptide which is presented by Ab major histocompatibility complex class II molecule via an endogenous pathway in professional antigen presenting cells. Both allelic peptides bind Ab and a single alanine to methionine substitution at p2 defines nonself. These results reveal novel features of H loci that regulate CD4 T cell responses as well as provide a general strategy for identifying elusive antigens that elicit CD4 T cell responses to tumors or self-tissues in autoimmunity.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 584-584
Author(s):  
Regina Gary ◽  
Simon Voelkl ◽  
Ralf Palmisano ◽  
Andreas Mackensen

Abstract Abstract 584 Specific T-cell responses are initiated by T-cell receptor (TCR) recognition of peptide-MHC-complexes on antigen presenting cells (APCs). Upon specific interaction of T cells with APCs T cells capture membrane fragments and surface molecules of APCs in a process termed trogocytosis. Exchange of membrane molecules/antigens between immune cells has been observed for a long time, but the mechanisms and functional consequences of these transfers remain unclear. Here, we demonstrate that human antigen-specific CD8+ T cells do acquire the co-inhibitory molecule programmed death ligand 1 (PD-L1) from mature monocyte-derived dendritic cells (mDC) and tumor cells in an antigen-specific manner. The kinetics of PD-L1 transfer revealed a maximal PD-L1 expression on antigen-specific T cells within 3–4 hours after co-incubation with antigen-pulsed APCs, being detectable up to 72 hours. Antigen-pulsed immature DCs were less effective in transfering surface molecules such as PD-L1 onto CD8+ T cells after antigen-specific recognition. Using a transwell system we could show that the acquisition of PD-L1 requires cell-cell contact. Furthermore, PD-L1 cannot be acquired by T cells from a lysate of mDCs. The transfer process is impaired after pretreatment of T cells with concanamycin A, a specific inhibitor of vacuolar ATPases, playing an important role in membrane trafficking. Moreover, fixation of DCs with glutaraldehyde completely abrogated the acquisition of PD-L1 on T cells suggesting that an active interaction between APCs and T cells is required for trogocytosis. Of importance, CD8+ T cells which acquired PD-L1 complexes, were able to induce apoptosis of neighbouring PD-1 expressing CD8+ T cells, that could be completely blocked by an anti-PD-L1 antibody. In summary our data demonstrate for the first time that human antigen-specific CD8+ T cells take up functionally active PD-L1 from APCs in an antigen-specific fashion, leading to apoptosis of PD-1 expressing T cells. The transfer of functionally active co-inhibitory molecules from APCs onto human CD8+ T cells may serve to limit clonal expansion of antigen-specific T-cell responses but may also play a major role for T-cell exhaustion in chronic infection and tumor immunosurveillance. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2008 ◽  
Vol 111 (7) ◽  
pp. 3546-3552 ◽  
Author(s):  
Christian Schütz ◽  
Martin Fleck ◽  
Andreas Mackensen ◽  
Alessia Zoso ◽  
Dagmar Halbritter ◽  
...  

Abstract Several cell-based immunotherapy strategies have been developed to specifically modulate T cell–mediated immune responses. These methods frequently rely on the utilization of tolerogenic cell–based antigen-presenting cells (APCs). However, APCs are highly sensitive to cytotoxic T-cell responses, thus limiting their therapeutic capacity. Here, we describe a novel bead-based approach to modulate T-cell responses in an antigen-specific fashion. We have generated killer artificial APCs (κaAPCs) by coupling an apoptosis-inducing α-Fas (CD95) IgM mAb together with HLA-A2 Ig molecules onto beads. These κaAPCs deplete targeted antigen-specific T cells in a Fas/Fas ligand (FasL)–dependent fashion. T-cell depletion in cocultures is rapidly initiated (30 minutes), dependent on the amount of κaAPCs and independent of activation-induced cell death (AICD). κaAPCs represent a novel technology that can control T cell–mediated immune responses, and therefore has potential for use in treatment of autoimmune diseases and allograft rejection.


2010 ◽  
Vol 207 (5) ◽  
pp. 1081-1093 ◽  
Author(s):  
Andreas Hermansson ◽  
Daniel F.J. Ketelhuth ◽  
Daniela Strodthoff ◽  
Marion Wurm ◽  
Emil M. Hansson ◽  
...  

Immune responses to oxidized low-density lipoprotein (oxLDL) are proposed to be important in atherosclerosis. To identify the mechanisms of recognition that govern T cell responses to LDL particles, we generated T cell hybridomas from human ApoB100 transgenic (huB100tg) mice that were immunized with human oxLDL. Surprisingly, none of the hybridomas responded to oxidized LDL, only to native LDL and the purified LDL apolipoprotein ApoB100. However, sera from immunized mice contained IgG antibodies to oxLDL, suggesting that T cell responses to native ApoB100 help B cells making antibodies to oxLDL. ApoB100 responding CD4+ T cell hybridomas were MHC class II–restricted and expressed a single T cell receptor (TCR) variable (V) β chain, TRBV31, with different Vα chains. Immunization of huB100tgxLdlr−/− mice with a TRBV31-derived peptide induced anti-TRBV31 antibodies that blocked T cell recognition of ApoB100. This treatment significantly reduced atherosclerosis by 65%, with a concomitant reduction of macrophage infiltration and MHC class II expression in lesions. In conclusion, CD4+ T cells recognize epitopes on native ApoB100 protein, this response is associated with a limited set of clonotypic TCRs, and blocking TCR-dependent antigen recognition by these T cells protects against atherosclerosis.


2020 ◽  
Author(s):  
Gunnstein Norheim ◽  
Elisabeth Stubsrud ◽  
Lise Madelene Skullerud ◽  
Branislava Stankovic ◽  
Stalin Chellappa ◽  
...  

AbstractThe pandemic caused by the SARS-CoV-2 virus in 2020 has led to a global public health emergency, and non-pharmaceutical interventions required to limit the viral spread are severely affecting health and economies across the world. A vaccine providing rapid and persistent protection across populations is urgently needed to prevent disease and transmission. We here describe the development of novel COVID-19 DNA plasmid vaccines encoding homodimers consisting of a targeting unit that binds chemokine receptors on antigen-presenting cells (human MIP-1α /LD78β), a dimerization unit (derived from the hinge and CH3 exons of human IgG3), and an antigenic unit (Spike or the receptor-binding domain (RBD) from SARS-CoV-2). The candidate encoding the longest RBD variant (VB2060) demonstrated high secretion of a functional protein and induced rapid and dose-dependent RBD IgG antibody responses that persisted up to at least 3 months after a single dose of the vaccine in mice. Neutralizing antibody (nAb) titers against the live virus were detected from day 7 after one dose. All tested dose regimens reached titers that were higher or comparable to those seen in sera from human convalescent COVID-19 patients from day 28. T cell responses were detected already at day 7, and were subsequently characterized to be multifunctional CD8+ and Th1 dominated CD4+ T cells. Responses remained at sustained high levels until at least 3 months after a single vaccination, being further strongly boosted by a second vaccination at day 89. These findings, together with the simplicity and scalability of plasmid DNA manufacturing, safety data on the vaccine platform in clinical trials, low cost of goods, data indicating potential long term storage at +2° to 8°C and simple administration, suggests the VB2060 candidate is a promising second generation candidate to prevent COVID-19.


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