CTL Responses Against Tumor Associated Antigens Are Part of the Graft Versus Leukemia-Effect and Protect from Relapse after Allogeneic Hematopoetic Stem Cell Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3231-3231
Author(s):  
Markus Kapp ◽  
Stefan Stevanovic ◽  
Kerstin Fick ◽  
Juergen Loeffler ◽  
Sen Mui Tan ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Cd8 T Cells ◽  
T Cell Responses ◽  
Proteinase 3 ◽  
Post Transplantation ◽  
Cell Responses

Abstract The Graft-versus-Leukemia (GVL) effect following allogeneic hematopoetic stem cell transplantation (HSCT) is one of the most prominent examples showing the ability of the immune system to eliminate malignant diseases. This effect was a strictly clinically described phenomenon, but in the last years T-cell responses against tumor-associated antigens (TAA) could partly be set in correlation with clinical benefit. Previously, TAA such as WT1 and proteinase-3 have been proposed as the targets for T-cells to establish a GVL effect. Now, we examined in addition other TAA (MUC1 and HM1.24) as possible T-cell targets of GVL related immune responses. We have defined new peptide epitopes from the MUC1 and HM1.24 antigens by the reverse immunology approach to increase the number of patients who can be screened and to expand the repertoire of immunologic monitoring as well as therapeutic approaches. A total of 25 patients after allogeneic stem cell transplantation have been screened and we are able to detect T-cell responses to both the MUC1 and HM1.24 antigens on top of the WT1 and the proteinase-3 antigen. Interestingly, we could detect a significant relationship between relapse and the absence of a T-cell response to TAA: Only 1/10 patients (10%) with TAA-specific CTL relapsed in contrast to 8/15 patients (53.3%) without TAA-specific CTL responses (p < 0.05). Furthermore, we demonstrated MUC1 peptides presented by HLA A*6801, B*0702 and B*4402 to be specifically recognized by CD3+/CD8+ T-cells. In conclusion, CD8+ T-cell responses directed to TAA might contribute to the GVL effect and are not limited to WT1 and proteinase-3. These observations clearly highlight both the importance and the potential of immunotherapeutic approaches in allogeneic stem cell recipients. Figure 1: New defined HLA class I epitopes predicted by computer analysis are recognized by specific CTL in patients post allogeneic HSCT. IFN-γ staining of PBMC from, patient No. 17 (AML, CR), 672 days post transplantation (A), patient No. 8 (AML, CR), 1035 days post transplantation (B) Cells were stimulated with 10μg/ml of the indicated peptides. Gates were set on lymphocytes by forward/side scattering (R1) and on CD3+/CD8+ cells (R2). Percentage numbers show peptide-specific CD3+/CD8+ T-cells from all CD3+/CD8+ T-cells. Figure 1:. New defined HLA class I epitopes predicted by computer analysis are recognized by specific CTL in patients post allogeneic HSCT. . / IFN-γ staining of PBMC from, patient No. 17 (AML, CR), 672 days post transplantation (A), patient No. 8 (AML, CR), 1035 days post transplantation (B) Cells were stimulated with 10μg/ml of the indicated peptides. Gates were set on lymphocytes by forward/side scattering (R1) and on CD3+/CD8+ cells (R2). Percentage numbers show peptide-specific CD3+/CD8+ T-cells from all CD3+/CD8+ T-cells.

Detection of Th1 Driven T-Cell Responses in Peripheral Could Guide Individualized Immunosuppression and Risk of Viral Reactivation Under GvHD Prophylaxis Following Allogeneic Stem Cell Transplantation.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3047-3047
Author(s):  
Judith Feucht ◽  
Kathrin Opherk ◽  
Cornelia Neinhaus ◽  
Simone Kayser ◽  
Wolfgang A. Bethge ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Allogeneic Stem Cell Transplantation ◽  
T Cell Responses ◽  
Cell Responses ◽  
Cell Immunity

Abstract Abstract 3047 Allogeneic stem cell transplantation (SCT) can expose patients to a transient but marked immunosuppression, during which viral infections are an important cause of morbidity and mortality. The control of these infections will ultimately depend on the restoration of adequate T-cell immunity. Most viral infections after SCT are caused by endogenous reactivation of persistent pathogens such as cytomegalovirus (CMV), adenovirus (ADV) and Epstein-Barr-virus (EBV). Risk of viral complications is even higher under GvHD treatment or prophylaxis like calcineurin inhibitors and steroids. Post transplant often the immunosuppression needs to be reduced to improve viral complications with the risk of GvHD. The virus-specific T-cell responses in peripheral blood have been shown to be a good marker of immunological protection, but has not been used for clinical decision making and the guidance of drug plasma levels. Therefore, we performed a prospective clinical trial in 33 adult and pediatric patients after allogeneic stem cell transplantation receiving pharmacologic immunosuppression with steroids, Cyclosporin A, Tacrolimus, Everolimus or Mycophenolate. Median Age was 16 years. T-cell responses were analyzed ex vivo against Cytomegalovirus (pp65), Adenovirus (hexon antigen) and Epstein-Barr Virus (EBNA, LMP) using intracellular cytokine staining. In addition in vitro analysis of the proliferation responses using CFSE were performed. Responses were compared to healthy donors. The T-cell responses in vitro under low, high and supraphysiologic plasma concentrations of the respective drugs were investigated. Under the direct influence of steroids, activated, virus-specific T-cells underwent apoptosis. Among the Calcineurin inhibitors, Tacrolimus had the strongest inhibition on virus-specific T-cell immunity, followed by Cyclosporin A. But, under low therapeutic levels, Virus speciffic T-cell responses have been able to develop in PBMCs. Mycophenolate had only in high concentrations a strong effect on the T-cell response against viral pathogens. Relevant differences in the frequency of virus-specific T-cells secreting IFN-g could be detected within the CD4 compartment in correlation to the level of immunosuppression. In conclusion we could show that detection of virus-specific T-cells could be used to guide the level of immunosuppression in case of viral complications after allogeneic stem cell transplantation, since emergence of in vivo T-cell responses was closely associated with a clearance or reduction of the viral load. Disclosures: No relevant conflicts of interest to declare.

PR1-Specific T Cell Responses in the First Months Following T-Cell Depleted Allogeneic Stem Cell Transplantation Occur in Both Myeloid and Non-Myeloid Malignancies but Are Only Associated with a GVL Effect in Myeloid Leukemias.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5195-5195
Author(s):  
Katayoun Rezvani ◽  
Yong Agnes ◽  
Rhoda B. Eniafe ◽  
Stephan Mielke ◽  
Bipin N. Savani ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Self Antigens

Abstract The immune milieu in the first few months post-stem cell transplantation (SCT) is favorable for graft-versus-leukemia (GVL) responses. A homeostatic drive caused by lymphopenia stimulates expansions of transplanted donor T-cells responding to diverse antigenic stimuli in the recipient. Human leukemia antigens such as proteinase 3 (PR3) and elastase (ELA2) are self-antigens which induce low but detectable frequencies of autoreactive T cells in normal individuals. PR1, an HLA-A*0201 restricted peptide shared by PR3 and ELA2, is expressed in normal neutrophils and overexpressed in myeloid (but not lymphoid) leukemias. T-cell responses against PR1 have been linked to GVL. We studied patients early post SCT to look for early induction of T cell responses to PR1, and correlate them with ELA2 and PR3 expression and GVL effects. Using PR1/HLA-A*0201 tetramers and flow cytometry for intracellular IFN-gamma, we analyzed PBMC for CD8+ T-cell responses against PR1 on days 30, 60, 90 and 120 following a T-depleted SCT in 28 patients (13 CML, 10 ALL, 5 solid tumor). Ten patients with CML, 6 with ALL and 3 with solid tumors had detectable PR1 responses post-SCT. PR1 specific CD8+ T cells had a predominantly effector-memory phenotype (CD45RO+CD27−CD57+). PR3 and ELA2 gene expression in these samples was assessed by RQ-PCR and found to be significantly correlated (P < 0.001). There was a strong association between the expression of PR3 and ELA2 and the emergence of PR1 specific CD8+ T-cell responses. Conversely, reduction or disappearance of PR3 and ELA-2 expression from blood coincided with reduction or disappearance of PR1 specific CD8+ T-cell responses (P <0.001) (as depicted below). The in-vivo anti-leukemia effect of the PR1 response was assessed in CML patients by BCR-ABL transcript numbers at day 90 post-SCT. Eight of ten patients with significant PR1 responses post-SCT were BCR-ABL negative at day 90 compared to 1 of 3 without PR1 responses (P <0.001). This GVL association was restricted to CML patients: in ALL using WT1 gene expression as a measure of minimal residual disease (MRD) 2 of 5 patients with PR1 responses and 3 of 5 patients without were MRD positive on day 90 post-SCT (P =0.36). Since PR1 responses were not restricted to CML and because these transplant approaches usually induce 100% donor myeloid chimerism by day 30 post-SCT, the recovering donor marrow is the likely antigenic source of PR3 and ELA2 driving the PR1 response. Our findings suggest that the post-SCT milieu is favorable for exaggerating weak autoimmune responses to self antigens such as PR1 causing antigen-specific T-cell proliferation. GVL effects may follow if the self antigen is expressed on the leukemia as occurs in CML. These results suggest that vaccination in conjunction with induction of T cell homeostatic proliferation is likely to enhance the anti-leukemia response and effectiveness of a transplant procedure. Figure Figure

scholarly journals Vulnerability to reservoir reseeding due to high immune activation after allogeneic hematopoietic stem cell transplantation in individuals with HIV-1

2020 ◽  
Vol 12 (542) ◽  
pp. eaay9355
Author(s):  
Johanna M. Eberhard ◽  
Mathieu Angin ◽  
Caroline Passaes ◽  
Maria Salgado ◽  
Valerie Monceaux ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
De Novo ◽  
T Cell Responses ◽  
Hematopoietic Stem ◽  
Cell Responses

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only medical intervention that has led to an HIV cure. Whereas the HIV reservoir sharply decreases after allo-HSCT, the dynamics of the T cell reconstitution has not been comprehensively described. We analyzed the activation and differentiation of CD4+ and CD8+ T cells, and the breadth and quality of HIV- and CMV-specific CD8+ T cell responses in 16 patients with HIV who underwent allo-HSCT (including five individuals who received cells from CCR5Δ32/Δ32 donors) to treat their underlying hematological malignancy and who remained on antiretroviral therapy (ART). We found that reconstitution of the T cell compartment after allo-HSCT was slow and heterogeneous with an initial expansion of activated CD4+ T cells that preceded the expansion of CD8+ T cells. Although HIV-specific CD8+ T cells disappeared immediately after allo-HSCT, weak HIV-specific CD8+ T cell responses were detectable several weeks after transplant and could still be detected at the time of full T cell chimerism, indicating that de novo priming, and hence antigen exposure, occurred during the time of T cell expansion. These HIV-specific T cells had limited functionality compared with CMV-specific CD8+ T cells and persisted years after allo-HSCT. In conclusion, immune reconstitution was slow, heterogeneous, and incomplete and coincided with de novo detection of weak HIV-specific T cell responses. The initial short phase of high T cell activation, in which HIV antigens were present, may constitute a window of vulnerability for the reseeding of viral reservoirs, emphasizing the importance of maintaining ART directly after allo-HSCT.

WT1-Specific CD8+ T Lymphocytes May Participate in the Elimination of Acute Lymphoblastic Leukemia Following Allogeneic Stem Cell Transplantation.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3679-3679 ◽  
Author(s):  
Katayoun Rezvani ◽  
Agnes Yong ◽  
Stephan Mielke ◽  
Bipin N. Savani ◽  
David A. Price ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Cd8 T Cells ◽  
Lymphoblastic Leukemia ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Wt1 Gene ◽  
Cell Responses

Abstract There is clinical evidence that a graft-versus-leukemia (GVL) effect occurs following allogeneic stem cell transplantation for acute lymphoblastic leukemia (ALL). However, the potency of this GVL effect is often associated with unwanted graft-versus-host-disease (GVHD) and disease relapse remains a major contributor to treatment failure. Wilms’ tumor gene 1 (WT1) is overexpressed in 70–90% of cases of ALL and has been identified as a convenient minimal residual disease (MRD) marker. WT1 is an attractive immunotherapeutic target in ALL because peptides derived from WT1 can induce CD8+ T-cell responses, and being non-allelic, WT1 would be unlikely to provoke GVHD. We investigated whether CD8+ T-cells directed against an HLA-A*0201 restricted epitope of WT1 (WT126) occur in ALL patients during the early phase of immune reconstitution post-SCT (days 30–180). We analyzed CD8+ T-cell responses against WT1 in 10 HLA-A*0201+ ALL SCT recipients and their respective donors using WT1/HLA-A*0201 tetrameric complexes and flow cytometry for intracellular IFN-gamma. We studied the kinetics WT1-specific CD8+ T-cell responses in consecutive samples obtained post-SCT. CD8+ T-cells recognizing WT1 were detected ex vivo in samples from 5 of 10 ALL patients post-SCT but not in patients pre-SCT. WT1-tetramer+ CD8+ T cells had a predominantly effector memory phenotype (CD45RO+CD27−CD57+). WT1 gene expression in pre-SCT and donor samples was assayed by quantitative real-time PCR (RQ-PCR). WT1 expression in PBMC from healthy donors was significantly lower than in patients (median 0, range 0–66 ×10−4 WT1/ABL compared to patients, median 12, range 0–2275 ×10−4 WT1/ABL) (P < 0.01). There was a strong correlation between the emergence of WT1-specific CD8+ T cells and a reduction in WT1 gene expression (P < 0.001) (as depicted below) suggesting direct anti-ALL activity post-SCT. Disappearance of WT1-specific CD8+ T-cells from the blood coincided with reappearance of WT1 gene transcripts, consistent with a molecular relapse, further supporting the direct involvement of WT1-specific CD8+ T-cells in the GVL response. These results provide evidence for the first time of spontaneous T-cell reactivity against a leukemia antigen in ALL patients. Our results support the immunogenicity of WT1 in ALL patients post-SCT and a potential application for WT1 peptides in post-transplant immunotherapy of ALL. Figure Figure

Exhaustion of CMV Specific T Cells with Enhanced PD-1 Expression In Persistent Cytomegalovirus Infection After Allogeneic Stem Cell Transplantation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3912-3912 ◽  
Author(s):  
Tomonori Kato ◽  
Tetsuya Nishida ◽  
Miho Murase ◽  
Makoto Murata ◽  
Tomoki Naoe
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Cd8 T Cells ◽  
Culture Media ◽  
Cmv Infection ◽  
Control Serum ◽  
And Control

Abstract Abstract 3912 Cytomegalovirus (CMV) is one of the most common pathogens causing morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT), despite preemptive treatments employing antiviral drugs. Cytotoxic T cells are indispensable to control CMV infections. Chronic viral infections with human immunodeficiency virus or hepatitis C virus were shown to be associated with exhausted T cells with high expression of the inhibitory molecule programmed death 1 (PD-1). Recently, it has been reported that PD-1 up-regulation on CMV specific T cells was associated with CMV infection after renal and liver transplantation. PD-1 expression on CMV specific T cells after HSCT has not been well examined. We evaluated the involvements of exhausted CMV specific T cells characterized by high PD-1 expression in persistent CMV infection after allogeneic HSCT. Peripheral blood mononuclear cells (PBMC) and serum were obtained from an HLA-A*2402-positive patient who had received bone marrow transplantation from an HLA-A, B, C and DR matched unrelated donor. This patient failed to eliminate CMV for more than one year after transplantation despite intermittent administration of ganciclovir and foscarnet. Control PBMC and serum were obtained from an HLA-A*2402-positive healthy volunteer because the Japan Marrow Donor Program prohibits blood collection for research use from donor. All blood was collected with written informed consent. We at first analyzed frequencies of CMV-specific CD8+ T cells in patient and control PBMC by flow cytometer using QYDPVAALF/A*2402-specific tetramer and CD8 antibodies. QYDPVAALF is derived from CMV pp65 protein and presented by the HLA-A*2402 molecule. Tetramer stained cells were detected in the patient PBMC but control PBMC (0.11% versus undetectable). Patient and control PBMC were stimulated by a synthetic peptide QYDPVAALF in culture media containing IL-2 for 14 days, and stained with QYD/A*2402-specific tetramer. Remarkably, post-stimulated patient PBMC contained only 0.54% of tetramer stained CD8+ T cells, whereas a more dramatic increase (14.1%) in control PBMC. We analyzed frequencies of IFN-g secreting CD8+ T cells in PBMC after stimulation with a peptide pool covering the whole CMV pp65 protein for 4 hours. Less patient CD8+ T cells produced IFN-g, compared with the control CD8+ T cells (0.5% versus 1.1%) These data demonstrate dysfunction of CMV-specific CD8+ T cells in the patient with persistent CMV infection. To examine the mechanism of dysfunction of CMV-specific CD8+ T cells, we analyzed the expression of PD-1 on CMV-specific CD8+ T cells 14 days after stimulation with QYDPVAALF peptide. Multiparameter flow cytometry and tetramer assay exhibited higher expression of PD-1 on CMV-specific CD8+ T cells generated from patient PBMC, compared with CMV-specific CD8+ T cells generated from control PBMC. To find out whether the engagement of PD-1 to its ligand (PD-L1) leads to T cell exhaustion, we stimulated patient PBMC with QYDPVAALF peptide for 14 days in the presence or absence of anti PD-L1 antibody which blocks PD-1/PD-L1 inhibitory pathway. Blockade of PD-1/PD-L1 pathway resulted in 3.9-fold increase in patient CMV specific T cells. These findings demonstrate that PD-1 is associated with the exhaustion of CMV specific CD8+ T cells during persistent CMV infection in this patient. To examine the effect of patient serum on CMV specific CD8+ T cells, we stimulated patient PBMC with QYDPVAALF peptide for 14 days in culture media with patient or control serum. CMV specific CD8+ T cells increased 4-fold and 55-fold in the presence of patient and control serum, respectively. Patient serum led to higher PD-1 expression on CMV specific CD8+ T cells, compared with control serum (Fig). These findings suggest that patient serum may contain what regulates PD-1 expression level of exhausted T cells. Further investigations to identify factors regulating PD-1 expression in patient serum are in progress. The identification of the factors may provide new strategies to improve exhausted T cell function. Disclosures: No relevant conflicts of interest to declare.

WT1-Specific Immune Responses in Patients with High-Risk Multiple Myeloma Undergoing Allogeneic T Cell-Depleted Hematopoietic Stem Cell Transplantation Followed by Donor Lymphocyte Infusions

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1993-1993 ◽  
Author(s):  
Eleanor Tyler ◽  
Achim A Jungbluth ◽  
Richard J. O'Reilly ◽  
Guenther Koehne
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Immune Responses ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Hematologic Malignancies ◽  
Hematopoietic Stem ◽  
Cell Responses

Abstract Abstract 1993 Wilm's tumor protein-1 (WT1) is over-expressed in a number of solid and hematologic malignancies including multiple myeloma (MM). The emergence of WT1-specific T cells has been shown to correlate with better relapse-free survival after allogeneic stem cell transplantation in patients (pts) with hematologic malignancies, such as leukemia. In MM, the expression of WT1 in the bone marrow has been shown to correlate with numerous negative prognostic factors, including disease stage and M protein ratio. Taken together, these findings suggest that immunotherapeutic augmentation of WT1-specific immune responses, such as adoptive transfer of WT1-specific T cells, may be capable of eradicating minimal residual disease and preventing relapse in MM. Thus, we examined the significance of WT1-specific cellular immune responses in pts with relapsed MM and high-risk cytogenetics who are undergoing allogeneic T cell-depleted hematopoietic stem cell transplantation (TCD HSCT). In this study, pts were eligible to receive low doses of donor lymphocyte infusions (DLI, 5×105-1×106 CD3+/kg) no earlier than 5 months post TCD HSCT. WT1-specific T-cell frequencies were measured in freshly isolated peripheral blood and bone marrow specimens. Frequencies were detected by staining for intracellular IFN-γ production in response to WT1 peptides, and/or by tetramer analysis, where available. Of 17 pts evaluated, all pts exhibited low frequencies of WT1-specific T-cell responses pre TCD HSCT. Ten of these pts received DLI post TCD HSCT. All 10 pts developed WT1-specific T cell responses post DLI. These increments in WT1-specific T-cell frequencies were associated with reduction in circulating myeloma proteins in all pts. Long-term evaluation demonstrated fluctuations in persisting WT1-specific T-cell frequencies following DLI. In one representative patient, a peak of 3.5% (72/ml) WT1-specific CD8+ T cells were detected in the peripheral blood by staining with the tetramer HLA-A*0201 RMF. This peak T-cell response occurred post TCD HSCT and DLI, and coincided with disease regression. This patient has remained in complete remission for more than 3 years post transplant, with fluctuating levels of WT1-specific CD8+ T cells ranging from 0.3–1.5% still persisting. Findings from concurrent molecular chimerism studies conducted on isolated T cells post TCD HSCT suggest that the WT1-specific T cells are of donor origin. Immunohistochemical analyses of WT1 and CD138 staining in MM bone marrow specimens demonstrated consistent co-expression within malignant plasma cells. WT1 expression in the bone marrow of all 6 pts tested correlated with the extent of malignant plasma cell infiltration. In contrast, no WT1 expression was observed when disease was low or absent. Taken together, our findings suggest a correlation between the emergence of WT1-specific T cells post DLI, and disease regression in pts being treated for relapsed MM. The present data support the development of adoptive immunotherapeutic approaches utilizing WT1-specific T cells for pts with MM. Disclosures: No relevant conflicts of interest to declare.

New Interleukin-15 Superagonist (IL-15 SA) Significantly Enhances Graft-Versus-Tumor Activity After Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3254-3254
Author(s):  
Cavan P Bailey ◽  
Christopher Sauter ◽  
Michelle M Panis ◽  
Tulin Budak-Alpdogan ◽  
Hing Wong ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Cd8 T Cells ◽  
T Cell Proliferation ◽  
Hematopoietic Stem ◽  
Interleukin 15 ◽  
And Function

Abstract Interleukin-15 (IL-15) is a pleiotropic cytokine, which plays various roles in the innate and adaptive immune system, including the development, activation, homing and survival of immune effector cells. IL-15 has been previously shown to increase CD8+ T and NK cells number and function in normal mice and recipients of stem cell transplantation. However, obstacles remain in using IL-15 therapeutically, specifically its low potency and short in vivo half-life. To overcome this, a new IL-15 mutant (IL-15N72D, J. Immunol, 2009; 183:3598) has been developed, with increased biological activity. Co-expressing IL-15N72D, in conjunction with IL-15RαSu/Fc produced a biologically active and highly potent IL-15 superagonist complex (IL-15SA, also known as ALT-803, Cytokine, 2011; 56:804). We evaluated the effects of IL-15-SA on immune reconstitution and graft-versus-tumor (GVT) activity in recipients of allogeneic hematopoietic stem cell transplantation (HSCT). Lethally irradiated BALB/c recipients were transplanted with T-cell depleted (TCD) bone marrow (BM) cells from B6 mice. IL-15 SA was administered via IP injection in two doses on days +17 and +24 after transplant. Animals were sacrificed at day 28. Administration of IL-15 significantly increased the numbers of CD8+ T cells and NK cells. IL-15 SA also augmented interferon-γ secretion from CD8+ T cells. We observed similar activity in B6CBA→CB6F1 transplant model. Interestingly IL-15 SA upregulates NKG2D and CD107a expression on CD8+ T cells. IL-15 SA administration also specifically increased slow-proliferative CD8+ T-cell proliferation in conjunction with robust IFN-γ and TNF-α secretion in CD8+ T cells in recipients of CFSE (carboxyfluorescein succinimidyl ester) labeled-T-cell infusion, whereas there was no effect on CD4+ T-cell proliferation. We then tested the anti-tumor activity of IL-15 SA in three different tumor models; murine mastocytoma (P815), murine B cell lymphoma (A20) and murine renal cell carcinoma (Renca). We found that IL-15 SA administration enhanced GVT activity against P815 and A20 in recipients of allogeneic HSCT though this activity required a low-dose T cell infusion with HSCT. Interestingly, augmented GVT activity against to Renca after IL-15 SA administration in recipients of allogeneic HSCT did not require T cell infusion. We conclude that IL-15 SA is a very potent cytokine complex for enhancing CD8+ and NK cell reconstitution and function after HSCT, which would be a candidate for post-transplant immunotherapy. Disclosures: Wong: Altor Bioscience: Employment.

scholarly journals CCR1/CCL5 (RANTES) receptor-ligand interactions modulate allogeneic T-cell responses and graft-versus-host disease following stem-cell transplantation

Blood ◽  
2007 ◽  
Vol 110 (9) ◽  
pp. 3447-3455 ◽  
Author(s):  
Sung W. Choi ◽  
Gerhard C. Hildebrandt ◽  
Krystyna M. Olkiewicz ◽  
David A. Hanauer ◽  
Meghana N. Chaudhary ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
T Cell Responses ◽  
Receptor Ligand ◽  
Graft Versus Host ◽  
Cell Responses ◽  
Donor Cells ◽  
Ligand Interactions

Abstract Acute graft-versus-host disease (GVHD) and leukemic relapse are serious complications of allogeneic stem-cell transplantation (SCT). Recruitment of activated T cells to host target tissues or sites of leukemic infiltration (graft-versus-leukemia [GVL]) is likely mediated by chemokine receptor–ligand interactions. We examined the contribution of donor cell CCR1 expression to the development of GVHD and GVL using a well-established murine SCT model (B6 → B6D2F1) and CCR1-deficient mice (CCR1−/−). Allo-SCT with CCR1−/− donor cells significantly reduced systemic and target organ GVHD severity, and CCR1 expression on both T cells and accessory cells contributed to GVHD mortality. Significant GVL activity was preserved following CCR1−/− SCT, but the survival advantage diminished with increasing tumor burden. We then explored the effects of CCR1 expression on allo-specific T-cell responses. Although cytolytic effector function was maintained on a per-cell basis, T-cell proliferation and IFNγ secretion were significantly reduced both in vivo and in vitro. T-cell function was partially dependent on interactions between CCR1 and CCL5. Collectively, these data demonstrate that CCR1 expression on donor cells contributes to the development of both GVHD and GVL, and suggest that CCR1/CCL5 receptor-ligand interactions modulate allo-specific T-cell responses occurring in this context.

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