scholarly journals P01.24 The selective HDAC6 inhibitor ITF3756 increases the differentiation to central memory T cells with reduced exhaustion phenotype

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A19.2-A20
Author(s):  
C Ripamonti ◽  
C Steinkuhler ◽  
G Fossati

BackgroundCentral memory T cells show superior persistence and antitumor immunity compared to effector memory and effector T cells. T effector cells respond quickly to tumors, but they are terminally differentiated and undergo apoptosis upon killing activity. T memory differentiate rapidly into T effector cells and maintain a pool of cells that can continuously differentiate thus sustaining a more lasting response. In adoptive cell therapy (ACT), T cells infused into patients may have a limited time of activity if they are terminally differentiated, and may rapidly undergo exhaustion and apoptosis. The development of new strategies based on novel agents able to generate memory T cells ex-vivo is important for a successful clinical application of ACT.We have studied the effect of a potent and selective HDAC6 inhibitor, ITF3756, on CD8 T cells differentiation during an in vitro induced exhaustion process.Materials and MethodsTo induce exhaustion purified human CD8+ cells were stimulated twice with anti-CD3/CD28 beads (1:2) during 5 days, with or without ITF3756 1μM or 2μM added at all times of stimulation. At day 3 and 5 the expression of exhaustion, memory and effector T cells markers were analyzed by flow cytometry. Cells were also collected at day 5 for genes expression analysis. Expression of exhaustion, T phenotype, metabolic pathway and inflammatory cytokines were investigated by qPCR. Paired two-tailed t-tests was used to determine statistical significance between control versus treatment group at day 3 and 5 in 10 different donors. P-values ≤ 0.05 were considered significant.ResultsITF3756 1μM increased significantly the T central memory phenotype (CD45RO+CD62L+CCR7+) and decreased significantly the T effector phenotype (CD45RO+CD62L-CCR7-). The expression of CD62L in T central memory cells was significantly increased in agreement with the high expression of this marker in naïve and memory T cells. ITF3756 treatment decreased significantly the expression of exhaustion markers PD-1 and LAG-3. No effect was observed on TIM-3 expression. In agreement with the data obtained with protein analysis, treatment with ITF3756 reduced the mRNA level of Pd-1 and Lag-3. Gene expression of Tim-3 was also downmodulated, but this effect did not result in reduction of protein expression at the time of detection. ITF3756 reduced the expression of t-bet (Tbx21) driving T effector differentiation and increased genes related to T memory phenotype (Eomes, Lef-1 and albeit slightly, Tcf-7). T cell activation requires a metabolic reprogramming that supports highly proliferative phenotype and T effector differentiation. ITF3756 treatment decreased both Hif-1α and Glut-1 gene expression that are associated with TCR activation during the exhaustion process. T central memory cells produce less cytokines compared to T effector and effector memory cells. ITF3756 treatment decreased the genes expression of Il-2, Ifn-γ and Tnf-α. All these effects resulted dose dependent.ConclusionsThe selective inhibitor of HDAC6 ITF3756 delays the terminal differentiation of CD8 T cells and increases the percentage of memory T cells with a reduced expression of exhaustion markers in vitro. These results are the basis to further explore the possible use of ITF3756 as a safe ex vivo treatment of CD8 T cells for adoptive cell transfer.Disclosure InformationC. Ripamonti: A. Employment (full or part-time); Significant; Italfarmaco SpA. C. Steinkuhler: A. Employment (full or part-time); Significant; Italfarmaco SpA. G. Fossati: A. Employment (full or part-time); Significant; Italfarmaco SpA.

2006 ◽  
Vol 204 (1) ◽  
pp. 79-91 ◽  
Author(s):  
Catherine Riou ◽  
Bader Yassine-Diab ◽  
Julien Van grevenynghe ◽  
Roland Somogyi ◽  
Larry D. Greller ◽  
...  

The molecular events involved in the establishment and maintenance of CD4+ central memory and effector memory T cells (TCM and TEM, respectively) are poorly understood. In this study, we demonstrate that ex vivo isolated TCM are more resistant to both spontaneous and Fas-induced apoptosis than TEM and have an increased capacity to proliferate and persist in vitro. Using global gene expression profiling, single cell proteomics, and functional assays, we show that the survival of CD4+ TCM depends, at least in part, on the activation and phosphorylation of signal transducer and activator of transcription 5a (STAT5a) and forkhead box O3a (FOXO3a). TCM showed a significant increase in the levels of phosphorylation of STAT5a compared with TEM in response to both IL-2 (P < 0.04) and IL-7 (P < 0.002); the latter is well known for its capacity to enhance T cell survival. Moreover, ex vivo TCM express higher levels of the transcriptionally inactive phosphorylated forms of FOXO3a and concomitantly lower levels of the proapoptotic FOXO3a target, Bim. Experiments aimed at blocking FOXO3a phosphorylation confirmed the role of this phosphoprotein in protecting TCM from apoptosis. Our results provide, for the first time in humans, an insight into molecular mechanisms that could be responsible for the longevity and persistence of CD4+ TCM.


2020 ◽  
Vol 22 (5) ◽  
pp. 837-846
Author(s):  
E. A. Blinova ◽  
A. V. Kolerova ◽  
V. E. Balyasnikov ◽  
V. A. Kozlov

IL-7 is a key factor for the survival and maintenance of CD4+ central (Tcm) and effector (Tem) memory cells in the whole body. In many autoimmune diseases, an elevated level of IL-7 is detected in blood serum and at the site of inflammation, thus suggesting participation of this homeostatic factor in the survival of memory T cells, including auto-reactive clones, in inflammatory disorders. The aim of the study was to investigate the mechanisms of maintaining CD4+ memory T cells under normal and inflammatory conditions. We developed an in vitro model of inflammation, based on induction of pro-inflammatory cytokines, and then evaluated the effects of IL-7 upon purified sorted populations of CD4+Tcm and Tem under normal conditions and in vitro inflammatory model. IL-7 treatment promoted maintenance of CD4+Tcm phenotype in all variants of cultures. In the absence of contact with adherent cell fraction, the IL-7-induced proliferation of Tcm and Tem was slightly reduced, both under normal and inflammatory conditions, thus suggesting low sensitivity of memory T cells to contacts with MHC, and, probably, a requirement for additional signals to provide complete stimulation with IL-7. The last suggestion is also supported by data about CD127 and CD132 expression, i.e., in the absence of contact with MHC, the proportion of CD127+CD132+ cells was decreased in both subpopulations of CD4+ memory cells. Upon in vitro cultures, IL-7 contributed to decreased expression of CD127, and increased expression of CD132 on CD4+Tcm and Tem. We have evaluated the CD4+Tcm and Tem populations by affinity of T cell receptor (TCR), using the level of CD5 expression. Т cells with high TCR affinity for self-antigens are known to have higher expression of CD5. In comparison to Tem, the Tcm contained more CD5high cells. In cultures, IL-7 promoted a high level of CD5 expression on Tcm, which was comparable to levels observed in peripheral blood cells. High CD5 expression on Tem was observed after stimulation with IL-7 in the in vitro inflammatory model. In the absence of contact with MHC, the number of CD5high cells decreased among CD4+Tem and Tcm. Thus, CD4+Tcm cells with high affinity for autologous antigens are probably dependent on the presence of homeostatic factors, in particular, IL-7, and contacts with antigen-presenting cells (APCs). Under conditions of inflammation, no changes were revealed in the mechanism of maintaining CD4+Tcm, in contrast to CD4+Tem. Being less dependent on IL-7 under normal conditions, CD4+CD5highTem are accumulated in the presence of IL-7 under in vitro inflammatory conditions.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1071-1071
Author(s):  
Melody M. Smith ◽  
Cynthia R. Giver ◽  
Edmund K. Waller ◽  
Christopher R. Flowers

Abstract Ex vivo modification of donor lymphocytes with purine analogs (mDL) may help to minimize graft versus host disease (GvHD) while providing beneficial graft versus leukemia (GvL) effects. In a murine model system, we have shown that allogeneic donor splenocytes, treated with fludarabine ex vivo have significantly reduced GvHD activity when transferred to irradiated recipient mice, and retain anti-viral and GvL activities (Giver, 2003). This effect appears to be mediated by relative depletion of donor CD4 CD44low, “naive” T-cells. As a first step toward developing mDL for use in patients, we sought to evaluate the effects of ex vivo fludarabine exposure on human T-cell subsets, and to determine the minimum dose of fludarabine required to achieve this effect. Methods: Peripheral blood mononuclear cell samples from 6 healthy volunteers were evaluated at 0, 24, 48, and 72 hour time points after ex vivo incubation in varying dosages of fludarabine: 2, 5, and 10(n=3) mcg/ml. Fludarabine incubated samples were compared to samples that received no fludarabine (untreated). The total viable cell number was determined and the fractions and absolute numbers of viable CD4 and CD8 naïve and memory T-cells were determined using flow cytometry after incubation with 7-AAD (dead cell stain), CD4, CD8, CD45RA, CD62L, and CCR7 antibodies, and measuring the total viable cells/ml. Results: The numbers of viable CD4 and CD8 T-cells remained relatively stable in control cultures. Without fludarabine, the average viability at 72 hr of naive and memory T-cells were 92% and 77% for CD4 and 86% and 63% for CD 8 (Fig. 1A). Naive CD4 T-cells were more sensitive to fludarabine-induced death than memory CD4 cells. At 72 hr, the average viability of fludarabine-treated naive CD4 T-cells was 33% at 2 mcg/ml (8.2X the reduction observed in untreated cells) and 30% at 5 mcg/ml, while memory CD4 T-cells averaged 47% viability at 2 mcg/ml (2.3X the reduction observed in untreated cells) (Fig. 1B) and 38% at 5 mcg/ml. The average viability of naive CD8 T-cells at 72 hr was 27% at 2 mcg/ml and 20% at 5 mcg/ml, while memory CD8 T-cell viability was 22% at 2 mcg/ml and 17% at 5 mcg/ml. Analyses on central memory, effector memory, and Temra T-cells, and B-cell and dendritic cell subsets are ongoing. The 5 and 10 mcg/ml doses also yielded similar results in 3 initial subjects, suggesting that 2 mcg/ml or a lower dose of fludarabine is sufficient to achieve relative depletion of the naive T-cell subset. Conclusions: Future work will determine the minimal dose of fludarabine to achieve this effect, test the feasibility of using ex vivo nucleoside analog incubation to reduce alloreactivity in samples from patient/donor pairs, and determine the maximum tolerated dose of mDL in a phase 1 clinical trial with patients at high risk for relapse and infectious complications following allogeneic transplantation. Figure Figure


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3242-3242
Author(s):  
Robbert van der Voort ◽  
Claudia Brandao ◽  
Thomas J. Volman ◽  
Viviènne Verweij ◽  
Klaas van Gisbergen ◽  
...  

Abstract Abstract 3242 Although the importance of the bone marrow (BM) in hematopoiesis is well known, its function in adaptive immune responses has only recently been acknowledged. Currently it is known that the BM contains fully functional CD4+ and CD8+ T cells that can engage in both primary and secondary immune responses. Interestingly, most of these T cells belong to the memory T cell lineage, identifying the BM as one of the largest memory T cell reservoirs in the body. Since not much is known about the trafficking of BM T cells, we compared the homing phenotype and function of T cell subsets in the BM, blood, spleen and peripheral lymph nodes (pLN). In addition, we determined the expression of chemokine mRNA and protein levels in the BM and other lymphoid organs. We confirmed that at least 80% of the CD4+ and 60% of the CD8+ BM T cells have a memory phenotype, and that most CD4+ T cells belong to the effector memory lineage, while the CD8+ population predominantly consists of central memory T cells. Most BM T cells expressed the chemokine receptor CXCR3, the adhesion molecules P-selectin glycoprotein ligand 1 and VLA-4, and increased levels of CD44 and LFA-1, as compared to T cells from the spleen. In addition, L-selectin was absent from most CD4+ BM T cells, but present on virtually all CD8+ T cells. Notably, the percentage of CXCR3+ T cells within the effector memory and central memory subsets from BM was higher than within the same subsets from pLN. Furthermore, BM contained significant mRNA levels of the CXCR3 ligands CXCL9, CXCL10 and CXCL11. An in vivo migration assay using a mixture of fluorescent-labeled T cells from CXCR3-deficient mice and control mice indicated however that during homeostasis CXCR3 does not play a major role in BM entry or retention. These data suggest that CXCR3 expressed by memory T cells is rather involved in BM exit, than in BM entry. Indeed, we observed that, as compared to control mice, CXCR3−/− mice contained significantly more CD4+ and CD8+ T cells in their BM. Additional in vitro assays demonstrated that CD4+ and CD8+ BM T cells migrated vigorously in response to CXCL9 and CXCL10, generally released in high concentrations during inflammation. Finally, we demonstrate that CXCR3−/− effector/effector memory T cells, but not wild type T cells, accumulate in the BM of mice infected with lymphocytic choriomeningitis virus. Altogether, these data demonstrate that the BM is a major reservoir of memory T cells that employ CXCR3 to quickly respond to chemotactic signals from inflamed tissues. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4805-4805
Author(s):  
Tzu-Yun Kuo ◽  
Aisha Hasan ◽  
Richard J O'Reilly

Abstract Initial clinical trials of adoptive immunotherapy have shown that the efficacy of adoptively transferred T-cells in man is often limited by the failure of cultured T cells, particularly cloned CD8 T cells, to persist in vivo. These studies demonstrated that the transferred T cells induced only transient responses and that persistence of the transferred T-cell clonotypes correlated with disease regression. A previous study suggested that CMV virus-specific CD8 T cell clones derived from central memory T cells (TCM), but not effector memory T cells (TEM), persisted long-term in non-human primates. On the other hand, another study comparing TCM and TEM derived SIV virus specific CD8 T-cell clones that were adoptively transferred in non-human primates demonstrated limited persistence of both TCM and TEM derived transferred T cells, and failed to show any difference between the two cell types. Because of these conflicting data, we have reexamed the persistence of adoptively transferred viral antigen specific T-cells derived from TCM and TEM population. Accordingly, we developed a NOG mouse model for studying the ability of human CMVpp65-specific T cells derived from central memory and effector memory populations to migrate to and accumulate in human tumor xenografts expressing CMVpp65, to alter the growth of these tumors and to persist in the tumors. This model also allows us to test immunomodulating agents and their ability to enhance targeted T-cell accumulations, antitumor activity and persistence. We analyzed CMVpp65-specific CD8 T cells derived from TCM and TEM precursors in vitro and in vivo. To tract the T-cells in vivo, we transduced membrane-bound Gaussia luciferase into TCM and TEM populations and monitored T cell trafficking by in vivo bioluminescence. Contrary to expectation, our results initially showed no differences between TCM and TEM derived CMVpp65-specific T-cell in mice co-treated with IL-2 in the time to accumulation, ultimate level of accumulation, degree of CMVpp65+ tumor regression or T-cell persistence. However, in mice cotreated with IL-15/IL-15Rα complex, both TCM and TEM exhibited more sustained engraftment and more prolonged accumulation in both the targeted tumor and in the marrow. In mice treated with IL-15/IL-15Rα, TCM and TEM derived T cells showed a similar effector memory phenotype and a similar level of regression of tumor growth. Thus, adoptive transfer of CMVpp65 specific TCM or TEM when combined with IL-15/IL-15Rα complex may support better persistence of antigen-specific T-cells following adoptive immunotherapy. Studies comparing IL-15/IL-15Rα complex with IL-15 alone are in progress. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3269-3269
Author(s):  
Anniek B. van der Waart ◽  
Noortje van der Weem ◽  
Luca Gattinoni ◽  
Nicolaas PM Schaap ◽  
Robbert van der Voort ◽  
...  

Abstract Allogeneic hematopoietic stem cell transplantation (allo-SCT) followed by donor lymphocyte infusion (DLI) is a potential curative treatment for patients suffering from a hematological malignancy. Efficacy is attributed to the graft-versus-tumor (GVT) response, during which engrafted donor T cells become activated by recipient minor histocompatibility antigens (MiHA) presented on dendritic cells (DC). Subsequently, these activated T cells expand, acquire effector functions and kill MiHA-positive tumor cells. However, persistence and recurrence of malignant disease is often observed, indicating that insufficient GVT immunity is induced. This imperfect alloreactive response is probably due to insufficient numbers of MiHA-specific effector T cells and/or defective antigen-presentation and costimulation. Therefore, adoptive transfer of potent ex vivo-generated MiHA-specific T cells, restricted to the hematopoietic system, would boost the GVT-effect without increasing the risk for GVHD. Although successful in vitro induction of MiHA-specific CD8+ T cells from naive precursors has been reported, the resulting antigen-experienced T cell population consist of fully differentiated effector-memory T cells (TEM). Over the past years it has been described that this T cell subset is not the most potent memory subset in anti-tumor responses in vivo following T cell transfer. In this regard, the less-differentiated memory subset called stem cell memory T cells (TSCM) with superior in vivo expansion, self-renewal capacity and plasticity to differentiate in potent effectors would generate a stronger GVT response. In this study, we aimed to investigate the in vivo availability and ex vivo generation of TSCM-like MiHA-specific T cells as additive treatment option for allo-SCT patients. First, we investigated whether in allo-SCT patients MiHA-specific T cells could be detected with a TSCM phenotype defined by the expression of CD45RO, CCR7, CD27 and CD95. Though TSCM cells could be clearly detected within CMV-specific CD8+ T cells in allo-SCT patients, similar to healthy controls, no MiHA-specific TSCM cells could be detected. This emphasises the need for more potent adoptive MiHA-specific T cell therapy following allo-SCT. Therefore, we next explored the possibility of generating TSCM-like CD8+ T cells by interfering with the Akt signalling pathway. Emerging findings indicate that the differentiation program of CD8+ T cells is dictated by the strength and duration of AKT activity. Therefore, we explored whether the pharmacological inhibition of this signaling pathway could results in the generation of TSCM-like CD8+ T cells. We stimulated CCR7+CD45RA+ naive CD8+ T cells with CD3/CD28 beads plus IL-2, IL-7 and/or IL-15 in the presence an Akt inhibitor. Interestingly, CD8+ T cells in these Akt-cultures were inhibited in their differentiation stage, expressing higher levels of CD45RA and CCR7 compared to controls. In addition, expression of CD95, IL2Rβ, and IL7Rα was also elevated confirming the TSCM-like phenotype. Although proliferation of the Akt-inhibited CD8+ T cells was decreased as shown by less PBSE dilution, expansion could be significantly preserved. Next, we investigated whether the established culture conditions could be used to generate MiHA-specific TSCM-like cells. Therefore, CD8+ T cells from MiHA-negative donors were primed using autologous MiHA peptide-loaded moDCs in the presence of the Akt-inhibitor. Interestingly, MiHA-specific T cell priming could be induced, consisting of mainly TCM and TSCM-like cells compared to almost entirely TEM cells in the control setting. Akt-inhibited MiHA-specific T cells showed higher expression of CCR7, CD45RA, CD62L, CD28, CD95, and IL7Rα. Importantly, for the Akt-inhibited MiHA-specific T cells, proliferation was reserved, resulting in robust proliferation capacity during restimulation after removal of the Akt-inhibitor. The resulting TEFF cells were highly functional, showing capacity to degranulate and produce IFNγ upon peptide restimulation. In conclusion, by inhibiting the Akt-pathway, in vitro CD8+ T cell differentiation can be reduced. Therefore, Akt signalling inhibition can be exploited for generating TSCM-like MiHA-specific T cells in adoptive immunotherapy after allo-SCT. Disclosures: No relevant conflicts of interest to declare.


2018 ◽  
Vol 37 (5) ◽  
pp. 373-382 ◽  
Author(s):  
Marcin Włodarczyk ◽  
Elżbieta Ograczyk ◽  
Magdalena Kowalewicz-Kulbat ◽  
Magdalena Druszczyńska ◽  
Wiesława Rudnicka ◽  
...  

Immunological memory is a key feature of adaptive immunity. It provides the organism with long-lived and robust protection against infection. The important question is whether cyclophosphamide (CP), as immunosuppressive agent used in cancer therapy and in some autoimmune diseases, may act on the memory T-cell population. We investigated the effect of CP on the percentage of central memory T cells (TCM) and effector memory T cells (TEM) in the mouse model of CP-induced immunosuppression (8-10-week-old male C57BL/6 mice CP treated for 7 days at the daily dose of 50 μg/g body weight [bw], manifested the best immunosuppression status, as compared to lower doses of CP: 10 or 20 μg/g bw). The CP induced a significant decrease in the percentage of CD8+ (TCM), compared to nonimmunosuppressed mice. This effect was not observed in the case of CD4+ TCM population. The percentage of gated TEM with CD4 and CD8 phenotype was significantly decreased in CP-treated mice, as compared to the control ones. Taken together, the above data indicate that CP-induced immunosuppression in mice leads to a reduction in the abundance of central memory cells possessing preferentially CD8+ phenotype as well as to a reduction in the percentage of effector memory cells (splenocytes both CD4+ and CD8+), compared to the cells from nonimmunosuppressed mice. These findings in mice described in this article may contribute to the understanding of the complexity of the immunological responses in humans and extend research on the impact of the CP model of immunosuppression in mice and memory T-cell populations.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 4389-4389
Author(s):  
Melania Carlisi ◽  
Salvatrice Mancuso ◽  
Marco Pio La Manna ◽  
Valentina Orlando ◽  
Nadia Caccamo ◽  
...  

Background: CD8+ T cell responses are an essential component of the adaptive immune system. After resolution of infection a small population of memory cells is formed. In relation to circulatory patterns, different subsets of memory CD8+ T cells can be identified: the central memory (CM) and the effector memory T cells (EM) (Martin MD, et al., Front Immunol. 2018). In addition, it has been described a subset of resident memory T cells (TRM) permanently living in peripheral tissues, including the bone marrow (BM) (Di Rosa F., et al., Nat Rev Immunol. 2016). It is conceivable that these cells can contribute to the defence toward haematological tumours infiltrating the BM. Therefore, we performed a study to evaluate the frequency and the phenotype of BM CD8+ TRM in patients with multiple myeloma (MM). Moreover, to evaluate the contribution that the microenvironment can have on the homeostatic and functional maintenance of these cells, we performed in vitro experiments of BM-derived mononucleate cells of MM patients cultured in the presence of different homeostatic cytokines. Patients and Methods: we prospectively analysed 21 patients, 16 with a new diagnosis of IgA, IgG and light chain multiple myeloma (MM) and 5 with IgA and IgG smoldering myeloma (SM). At the time of the bone marrow assessment, we collected a sample for the flow cytometry analysis and in vitro cell culture. The ex vivo evaluation of CD8+ TRM frequency and phenotype in BM samples was performed using anti-human mAbs to CD3, CD103, CD69, CD45, CD8, CD45RA and CCR7 (CD197). The sequential gating strategy was: gate on lymphocytes population with CD45 vs. SSC, 7AAD negative cells, exclusion of doublets with FSC-H vs. FSC-A, CD8+CD3+ and evaluation of percentage of CD103+CD69+ cells. Was also established the subsets using CCR7 and CD45RA. Moreover, to evaluate the role of the microenvironment on maintenance of these cells, we performed in vitro experiments of BM-derived mononucleate cells of MM patients cultured in the presence of homeostatic cytokines in maintaining these cells for a long time. BM derived mononucleate cells from patients were then cultured in vitro in complete RPMI with 10% of human serum for 4 days with IL15 (25 ng/ml), IL7 (25 ng/ml) and TGF-β (2 ng/ml), in different combination and in RPMI alone. After culture, we analyzed the frequency of CD8+ TRM and the proliferating fraction with intracellular staining with anti human Ki67 APC. Non parametric Mann-Whitney and Kruskall-wallis tests were performed to determine statistical differences in the distribution of the results using GraphPad Prism 7.00. Values of * p<0.05 were considered significant. Results: the ex vivo average frequency of CD8+ TRM in 16 MM patients was of 0.48% and the phenotype was represented mainly by TEM (72,9%) followed by TEMRA (12.3%) and (7,6%) of naïve cells and (7,2%) of TCM (Fig. A). The comparison with the ex vivo frequency of CD8 TRM in SM patients did not show any significant difference between two groups (data not showed). To evaluate factors capable of maintaining or to induce the expansion of these cells in vitro, we maintained BM-derived mononucleate cells from MM patients for 4 days in presence of homeostatic cytokines, IL-15, IL-7 plus IL-15 and IL-7 together with IL-15 and TGF-β. The result showed an increase of the percentage of CD8+ TRM in all conditions tested, especially in presence of all cytokines (Fig. B), with a percentage of CD8 TRM of 2,74%. Regarding the phenotype distribution, we observed an expansion of CM compared to the other subsets (Fig. C). We also analysed the percentage of CD8+ TRM proliferating through the identification of Ki67 positive cells. Data highlight that IL-15 gives the strongest proliferative input, but also other cytokines contribute to the homeostatic maintenance of these cells (Fig. D). Conclusions: we evaluated the frequency and the phenotype of CD8 TRM in BM of MM patients compared to SM patients with the conclusion that these cells do not differ significantly in percentage and phenotypic distribution in both conditions. In MM patients, the increase of CD8+ TRM cells with a CM phenotype after in vitro culture with the three cytokines could have an anti-tumor role in the control of MM. Further studies are needed to investigate the cytotoxic capacity of these cells against myeloma cells, in order to study their functional role, also in the perspective of a possible use in future therapeutic programs. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3048-3048
Author(s):  
Yi Zhang ◽  
Gerard Joe ◽  
Elizabeth Hexner ◽  
Stephen G. Emerson

Abstract Memory CD8+ T cells are an important component of long-term immunity against infectious pathogens because of their higher frequency of antigen-specific CD8+ T cells as well as their ability to proliferate, produce inflammatory cytokines, and kill target cells more rapidly upon secondary antigen encounter than naïve CD8+ T cells. How the pool of memory CD8+ T cells is generated and maintained is key issue to understanding and perhaps manipulating long-term memory response, such as graft-versus-host disease (GVHD) where host antigens persist. Using a major histocompatibility complex (MHC)-identical but minor histocmpatibility (miHA)-mismatched mouse model of human allogeneic BM transplantation (allo-BMT), we recently identified alloreactive memory CD8+ T cells responsible for persistent GVHD. We found that donor CD44hiCD62Llo effector memory and CD44hiCD62Lhi central memory CD8+ T cells recovered 42 days after allo-BMT (d42-CD8+ T cells) from B6 mice receiving normal C3H.SW CD44loCD8+ T cells and T cell-depleted (T−BM) caused lethal GVHD in secondary B6 recipient mice. Interestingly, in addition to these classical memory phenotypes, a third population of donor CD44loCD62LhiCD8+ T cells, which accounted for 2% to 6% of whole d42-donor CD8+ T cells, was identified in the spleens and livers of these B6 recipients with ongoing GVHD. When cultured in the presence of B6 dendritic cells (DCs)+IL-2+IL-15, these d42-CD44loCD62LhiCD8+ T cells rapidly and vigorously proliferated as compared to d42-CD44hiCD62Llo and d42-CD44hiCD62LhiCD8+ T cells. By day 15 following this ex vivo culture, d42-CD44loCD62LhiCD8+ T cells expanded as many as 92.0-fold, whereas CD44hiCD62Llo effector/effector memory and CD44hiCD62Lhi central memory CD8+ T cells only expanded 2.1-fold and 11.0-fold, respectively. Furthermore, ex vivo stimulation of d42-CD44hiCD62LloCD8+ T cells with B6 DCs+IL-2+IL-15 only induced the generation of CD44hiCD62Llo effector/effector memory CD8+ T cells, whereas d42-CD44hiCD62hiCD8+ T cells generated both CD44hiCD62Llo and CD44hiCD62Lhi cells. In contrast, d42-CD44loCD62LhiCD8+ T cells generated all three T cells subsets, e.g., CD44hiCD62Llo, CD44hiCD62Lhi and CD44loCD62Lhi CD8+ T cells. These data suggest that d42-CD44loCD62Lhi CD8+ T cells have more potent ability than any other CD8+ T memory cell subsets to proliferate and differentiate into effector/memory T cells upon re-exposure to specific host miHAs as well as the ability to self-renew, resembling to the property of stem cells. Of note, these d42-CD44loCD62Lhi CD8+ T cells expressed much higher levels of CD122 and CD127 than donor naive CD44loCD8+ T cells. When cultured in the presence of B6 DCs+IL-2+IL-15 for 5 days, there were significantly more donor CD8+ T cells recovered from d42-CD4loCD62LhiCD8+ T cell cultures than that from truly naive CD44loCD8+ T cells(7.9-fold vs. 2.1 fold). Thus, d42-CD44loCD62LhiCD8+ T cells found in B6 mice with GVHD are distinguishable from truly naïve CD44loCD8+ T cells of normal C3H.SW mice and are responsible for sustaining the generation of both alloreactive effector memory and central memory CD8+ T cells. In summary, these data identify a heretofore unrecognized population of CD8+ T memory stem cells that may be key cellular targets for the prevention and treatment of persistent acute and chronic GVHD.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3243-3243
Author(s):  
Kazuaki Yokoyama ◽  
Tokiko Nagamura-Inoue ◽  
Shin Nakayama ◽  
Ikuo Ishige ◽  
Kazuo Ogami ◽  
...  

Abstract CD26 is a transmembrane glycoprotein with intrinsic dipeptidyl peptidase IV (DPPIV) activity as well as costimulatory activity of mitotic signals triggered by the CD3/TCR complex. Based on the expression level of CD26, CD4+ and CD8+ T cells can be divided into 3 (high/intermediate/low or negative) subsets. The significance of CD26 has been studied mainly on CD4+ T cells, and CD26highCD4+ T cells are considered to represent effector memory T cells of a typical Th1 phenotype producing IL2 and IFNg. Furthermore, we reported a significant decrease of this subset in CML patients under imatinib therapy in comparison to those under IFNa therapy and normal volunteers. In contrast, the role of each subset of CD8+ T cells has not yet been clarified. Multi-parameter flow cytometry analysis was performed to characterize CD8+ T cells differentially expressing CD26 in combination with intracellular detection of effector molecules such as perforin (P) and granzyme B (Gr). The capacity to secrete effector cytokines such as IFNg following short-term stimulation was also assessed. As a result, according to the expression level of CD26, we could clearly categorize CD8+ T cells as follows: CD26highCD8+ T cells are defined as central memory T cells which has a phenotype of CD45RO+CD28+CD27+ IFNg+Gr−P+/−, CD26intCD8+ T cells as naïve T cells of CD45ROCD28+ CD27+ IFNg−Gr−P−, and CD26lowCD8+ T cells as effector memory/effector T cells of CD45RO−/+ CD28−CD27−IFNg++Gr++P++, respectively. We next investigated the effects of imatinib on 3 distinct subsets during CD8+ T cell differentiation program. Peripheral blood mononuclear cells were primed with anti-CD3/CD28 MAb and subjected to the grading doses of imatinib for short term culture, followed by flow cytometory. CFSE labeling was used for monitoring cell proliferation. Intriguingly, we found that imatinib dose-dependently inhibits activation, cytokine production and proliferation of CD26highCD8+ central memory T cell subsets in a differentiation stage-specific manner. Finally, we compared the absolute number of peripheral blood CD26highCD8+ T cell subsets between 20 patients with CML in imatinib-induced CCR and 20 normal volunteers, clearly indicating a significant decrease of this subset in CML patients (22.30/ml vs 45.60/ml, p<0.01). The present study offers another evidence for immunomodulatory effects of imatinib or the critical role of Abl (-related) kinase in T cell development, and draws special attention to susceptibility to viral infection of CML patients under long-term imatinib therapy. Figure Figure


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