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  • Novel Radiation Therapy Paradigms and Immunomodulation: Heresies and Hope. Seminars in radiation oncology Dutt, S., Ahmed, M. M., Loo, B. W., Strober, S. 2020; 30 (2): 194–200

    Abstract

    Radiation therapy benefits the majority of patients across the spectrum of cancer types. However, both local and distant tumor recurrences limit its clinical success. While departing from the established tenet of fractionation in clinical radiotherapy, ablative-intensity hypofractionated radiotherapy, especially stereotactic radiosurgery and stereotactic ablative radiotherapy, has emerged as an alternative paradigm achieving unprecedented rates of local tumor control. Direct tumor cell killing has been assumed to be the primary therapeutic mode of action of such ablative radiation. But with increasing recognition that tumor responses also depend on the immunostimulatory or immunosuppressive status of the tumor microenvironment, the immunologic effect of ablative radiotherapy is emerging as a key contributor to antitumor response. More recently, novel radiation modalities, such as spatially fractionated radiotherapy and ultrahigh dose rate FLASH irradiation, that venture even further from conventional paradigms have shown promise of increasing the therapeutic index of radiation therapy with the potential of immunomodulation. Here, we review the immunomodulatory impact of novel radiation therapy paradigms, heretofore considered radiobiological heresies, a deeper understanding of which is imperative to realizing fully their potential for more curative cancer therapy.

    View details for DOI 10.1016/j.semradonc.2019.12.006

    View details for PubMedID 32381299

  • FLASH Irradiation Results in Reduced Severe Skin Toxicity Compared to Conventional-Dose-Rate Irradiation. Radiation research Soto, L. A., Casey, K. M., Wang, J., Blaney, A., Manjappa, R., Breitkreutz, D., Skinner, L., Dutt, S., Ko, R. B., Bush, K., Yu, A. S., Melemenidis, S., Strober, S., Englemann, E., Maxim, P. G., Graves, E. E., Loo, B. W. 2020

    Abstract

    Radiation therapy, along with surgery and chemotherapy, is one of the main treatments for cancer. While radiotherapy is highly effective in the treatment of localized tumors, its main limitation is its toxicity to normal tissue. Previous preclinical studies have reported that ultra-high dose-rate (FLASH) irradiation results in reduced toxicity to normal tissues while controlling tumor growth to a similar extent relative to conventional-dose-rate (CONV) irradiation. To our knowledge this is the first report of a dose-response study in mice comparing the effect of FLASH irradiation vs. CONV irradiation on skin toxicity. We found that FLASH irradiation results in both a lower incidence and lower severity of skin ulceration than CONV irradiation 8 weeks after single-fraction hemithoracic irradiation at high doses (30 and 40 Gy). Survival was also higher after FLASH hemithoracic irradiation (median survival >180 days at doses of 30 and 40 Gy) compared to CONV irradiation (median survival 100 and 52 days at 30 and 40 Gy, respectively). No ulceration was observed at doses 20 Gy or below in either FLASH or CONV. These results suggest a shifting of the dose-response curve for radiation-induced skin ulceration to the right for FLASH, compared to CONV irradiation, suggesting the potential for an enhanced therapeutic index for radiation therapy of cancer.

    View details for DOI 10.1667/RADE-20-00090

    View details for PubMedID 32853385

  • Chemotherapeutic Potential of Monensin as an Anti-microbial Agent. Current topics in medicinal chemistry Rajendran, V., Ilamathi, H., Dutt, S., Lakshminarayana, T. S., Ghosh, P. C. 2018

    Abstract

    Monensin is a lipid soluble naturally occurring bioactive ionophore produced by Streptomyces spp. Its antimicrobial activity is mediated by its ability to exchangeNa+ and K+ ions across the cell membrane thereby disrupting ionic gradients and altering cellular physiology. It is approved by Food and Drug Administration as a veterinary antibiotic to treat coccidiosis. Besides veterinary applications, monensin exhibits a broad spectrum activity against opportunistic pathogens of humans such as bacteria, virus, fungi and parasites in both drug sensitive and resistant strains. This ionophore can selectively kill pathogens with negligible toxic effect on mammalian cells. In this review, we discuss the therapeutic potential of monensin as a new broad spectrum anti-microbial agent that warrants further studies for clinical use.

    View details for PubMedID 30499391

  • Accelerated, but not conventional, radiotherapy of murine B-cell lymphoma induces potent T cell-mediated remissions. Blood advances Dutt, S., Atallah, M. B., Minamida, Y., Filatenkov, A., Jensen, K. P., Iliopoulou, B. P., Tamosiuniene, R., Waters, J., Engleman, E. G., Strober, S. 2018; 2 (19): 2568–80

    Abstract

    Conventional local tumor irradiation (LTI), delivered in small daily doses over several weeks, is used clinically as a palliative, rather than curative, treatment for chemotherapy-resistant diffuse large B-cell lymphoma (DLBCL) for patients who are ineligible for hematopoietic cell transplantation. Our goal was to test the hypothesis that accelerated, but not conventional, LTI would be more curative by inducing T cell-mediated durable remissions. We irradiated subcutaneous A20 and BL3750 lymphoma tumors in mice with a clinically relevant total radiation dose of 30 Gy LTI, delivered in 10 doses of 3 Gy over 4 days (accelerated irradiation) or as 10 doses of 3 Gy over 12 days (conventional irradiation). Compared with conventional LTI, accelerated LTI resulted in more complete and durable tumor remissions. The majority of these mice were resistant to rechallenge with lymphoma cells, demonstrating the induction of memory antitumor immunity. The increased efficacy of accelerated LTI correlated with higher levels of tumor cell necrosis vs apoptosis and expression of "immunogenic cell death" markers, including calreticulin, heat shock protein 70 (Hsp70), and Hsp90. Accelerated LTI-induced remissions were not seen in immunodeficient Rag-2-/- mice, CD8+ T-cell-depleted mice, or Batf-3-/- mice lacking CD8α+ and CD103+ dendritic cells. Accelerated, but not conventional, LTI in immunocompetent hosts induced marked increases in tumor-infiltrating CD4+ and CD8+ T cells and MHCII+CD103+CD11c+ dendritic cells and corresponding reductions in exhausted PD-1+Eomes+CD8+ T cells and CD4+CD25+FOXP3+ regulatory T cells. These findings raise the possibility that accelerated LTI can provide effective immune control of human DLBCL.

    View details for PubMedID 30301812

  • Stearylamine Liposomal Delivery of Monensin in Combination with Free Artemisinin Eliminates Blood Stages of Plasmodium falciparum in Culture and P-berghei Infection in Murine Malaria ANTIMICROBIAL AGENTS AND CHEMOTHERAPY Rajendran, V., Rohra, S., Raza, M., Hasan, G. M., Dutt, S., Ghosh, P. C. 2016; 60 (3): 1304-1318

    Abstract

    The global emergence of drug resistance in malaria is impeding the therapeutic efficacy of existing antimalarial drugs. Therefore, there is a critical need to develop an efficient drug delivery system to circumvent drug resistance. The anticoccidial drug monensin, a carboxylic ionophore, has been shown to have antimalarial properties. Here, we developed a liposome-based drug delivery of monensin and evaluated its antimalarial activity in lipid formulations of soya phosphatidylcholine (SPC) cholesterol (Chol) containing either stearylamine (SA) or phosphatidic acid (PA) and different densities of distearoyl phosphatidylethanolamine-methoxy-polyethylene glycol 2000 (DSPE-mPEG-2000). These formulations were found to be more effective than a comparable dose of free monensin in Plasmodium falciparum (3D7) cultures and established mice models of Plasmodium berghei strains NK65 and ANKA. Parasite killing was determined by a radiolabeled [(3)H]hypoxanthine incorporation assay (in vitro) and microscopic counting of Giemsa-stained infected erythrocytes (in vivo). The enhancement of antimalarial activity was dependent on the liposomal lipid composition and preferential uptake by infected red blood cells (RBCs). The antiplasmodial activity of monensin in SA liposome (50% inhibitory concentration [IC50], 0.74 nM) and SPC:Chol-liposome with 5 mol% DSPE-mPEG 2000 (IC50, 0.39 nM) was superior to that of free monensin (IC50, 3.17 nM), without causing hemolysis of erythrocytes. Liposomes exhibited a spherical shape, with sizes ranging from 90 to 120 nm, as measured by dynamic light scattering and high-resolution electron microscopy. Monensin in long-circulating liposomes of stearylamine with 5 mol% DSPE-mPEG 2000 in combination with free artemisinin resulted in enhanced killing of parasites, prevented parasite recrudescence, and improved survival. This is the first report to demonstrate that monensin in PEGylated stearylamine (SA) liposome has therapeutic potential against malaria infections.

    View details for DOI 10.1128/AAC.01796-15

    View details for Web of Science ID 000376490800017

    View details for PubMedCentralID PMC4775978

  • Lack of IL7Ra expression in T cells is a hallmark of T-cell immunodeficiency in Schimke immuno-osseous dysplasia (SIOD). Clinical immunology Sanyal, M., Morimoto, M., Baradaran-Heravi, A., Choi, K., Kambham, N., Jensen, K., Dutt, S., Dionis-Petersen, K. Y., Liu, L. X., Felix, K., Mayfield, C., Dekel, B., Bokenkamp, A., Fryssira, H., Guillen-Navarro, E., Lama, G., Brugnara, M., Lücke, T., Olney, A. H., Hunley, T. E., Polat, A. I., Yis, U., Bogdanovic, R., Mitrovic, K., Berry, S., Najera, L., Najafian, B., Gentile, M., Nur Semerci, C., Tsimaratos, M., Lewis, D. B., Boerkoel, C. F. 2015; 161 (2): 355-365

    Abstract

    Schimke immuno-osseous dysplasia (SIOD) is an autosomal recessive, fatal childhood disorder associated with skeletal dysplasia, renal dysfunction, and T-cell immunodeficiency. This disease is linked to biallelic loss-of-function mutations of the SMARCAL1 gene. Although recurrent infection, due to T-cell deficiency, is a leading cause of morbidity and mortality, the etiology of the T-cell immunodeficiency is unclear. Here, we demonstrate that the T cells of SIOD patients have undetectable levels of protein and mRNA for the IL-7 receptor alpha chain (IL7Rα) and are unresponsive to stimulation with IL-7, indicating a loss of functional receptor. No pathogenic mutations were detected in the exons of IL7R in these patients; however, CpG sites in the IL7R promoter were hypermethylated in SIOD T cells. We propose therefore that the lack of IL7Rα expression, associated with hypermethylation of the IL7R promoter, in T cells and possibly their earlier progenitors, restricts T-cell development in SIOD patients.

    View details for DOI 10.1016/j.clim.2015.10.005

    View details for PubMedID 26499378

  • Ablative Tumor Radiation Can Change the Tumor Immune Cell Microenvironment to Induce Durable Complete Remissions. Clinical cancer research Filatenkov, A., Baker, J., Mueller, A. M., Kenkel, J., Ahn, G., Dutt, S., Zhang, N., Kohrt, H., Jensen, K., Dejbakhsh-Jones, S., Shizuru, J. A., Negrin, R. N., Engleman, E. G., Strober, S. 2015; 21 (16): 3727-3739

    Abstract

    The goals of the study were to elucidate the immune mechanisms that contribute to desirable complete remissions of murine colon tumors treated with single radiation dose of 30 Gy. This dose is at the upper end of the ablative range used clinically to treat advanced or metastatic colorectal, liver, and non-small cell lung tumors.Changes in the tumor immune microenvironment of single tumor nodules exposed to radiation were studied using 21-day (>1 cm in diameter) CT26 and MC38 colon tumors. These are well-characterized weakly immunogenic tumors.We found that the high-dose radiation transformed the immunosuppressive tumor microenvironment resulting in an intense CD8(+) T-cell tumor infiltrate, and a loss of myeloid-derived suppressor cells (MDSC). The change was dependent on antigen cross-presenting CD8(+) dendritic cells, secretion of IFNγ, and CD4(+)T cells expressing CD40L. Antitumor CD8(+) T cells entered tumors shortly after radiotherapy, reversed MDSC infiltration, and mediated durable remissions in an IFNγ-dependent manner. Interestingly, extended fractionated radiation regimen did not result in robust CD8(+) T-cell infiltration.For immunologically sensitive tumors, these results indicate that remissions induced by a short course of high-dose radiotherapy depend on the development of antitumor immunity that is reflected by the nature and kinetics of changes induced in the tumor cell microenvironment. These results suggest that systematic examination of the tumor immune microenvironment may help in optimizing the radiation regimen used to treat tumors by adding a robust immune response. Clin Cancer Res; 21(16); 3727-39. ©2015 AACR.

    View details for DOI 10.1158/1078-0432.CCR-14-2824

    View details for PubMedID 25869387

  • Boosting Cancer Immunotherapy with Anti-CD137 Antibody Therapy CLINICAL CANCER RESEARCH Yonezawa, A., Dutt, S., Chester, C., Kim, J., Kohrt, H. E. 2015; 21 (14): 3113-3120

    Abstract

    In the past 5 years, immunomodulatory antibodies have revolutionized cancer immunotherapy. CD137, a member of the tumor necrosis factor receptor superfamily, represents a promising target for enhancing antitumor immune responses. CD137 helps regulate the activation of many immune cells, including CD4(+) T cells, CD8(+) T cells, dendritic cells, and natural killer cells. Recent studies indicate that the antitumor efficacy of therapeutic tumor-targeting antibodies can be augmented by the addition of agonistic antibodies targeting CD137. As ligation of CD137 provides a costimulatory signal in multiple immune cell subsets, combination therapy of CD137 antibody with therapeutic antibodies and/or vaccination has the potential to improve cancer treatment. Recently, clinical trials of combination therapies with agonistic anti-CD137 mAbs have been launched. In this review, we discuss the recent advances and clinical promise of agonistic anti-CD137 monoclonal antibody therapy.

    View details for DOI 10.1158/1078-0432.CCR-15-0263

    View details for Web of Science ID 000359324000005

    View details for PubMedID 25908780

  • Stearylamine Liposomal Delivery of Monensin in Combination with Free Artemisinin Eliminates Blood Stages of Plasmodium falciparum in Culture and P. berghei Infection in Murine Malaria. Antimicrobial agents and chemotherapy Rajendran, V., Rohra, S., Raza, M., Hasan, G. M., Dutt, S., Ghosh, P. C. 2015; 60 (3): 1304-1318

    Abstract

    The global emergence of drug resistance in malaria is impeding the therapeutic efficacy of existing antimalarial drugs. Therefore, there is a critical need to develop an efficient drug delivery system to circumvent drug resistance. The anticoccidial drug monensin, a carboxylic ionophore, has been shown to have antimalarial properties. Here, we developed a liposome-based drug delivery of monensin and evaluated its antimalarial activity in lipid formulations of soya phosphatidylcholine (SPC) cholesterol (Chol) containing either stearylamine (SA) or phosphatidic acid (PA) and different densities of distearoyl phosphatidylethanolamine-methoxy-polyethylene glycol 2000 (DSPE-mPEG-2000). These formulations were found to be more effective than a comparable dose of free monensin in Plasmodium falciparum (3D7) cultures and established mice models of Plasmodium berghei strains NK65 and ANKA. Parasite killing was determined by a radiolabeled [(3)H]hypoxanthine incorporation assay (in vitro) and microscopic counting of Giemsa-stained infected erythrocytes (in vivo). The enhancement of antimalarial activity was dependent on the liposomal lipid composition and preferential uptake by infected red blood cells (RBCs). The antiplasmodial activity of monensin in SA liposome (50% inhibitory concentration [IC50], 0.74 nM) and SPC:Chol-liposome with 5 mol% DSPE-mPEG 2000 (IC50, 0.39 nM) was superior to that of free monensin (IC50, 3.17 nM), without causing hemolysis of erythrocytes. Liposomes exhibited a spherical shape, with sizes ranging from 90 to 120 nm, as measured by dynamic light scattering and high-resolution electron microscopy. Monensin in long-circulating liposomes of stearylamine with 5 mol% DSPE-mPEG 2000 in combination with free artemisinin resulted in enhanced killing of parasites, prevented parasite recrudescence, and improved survival. This is the first report to demonstrate that monensin in PEGylated stearylamine (SA) liposome has therapeutic potential against malaria infections.

    View details for DOI 10.1128/AAC.01796-15

    View details for PubMedID 26666937

    View details for PubMedCentralID PMC4775978

  • Treatment of 4T1 Metastatic Breast Cancer with Combined Hypofractionated Irradiation and Autologous T-Cell Infusion. Radiation research Filatenkov, A., Baker, J., Müller, A. M., Ahn, G., Kohrt, H., Dutt, S., Jensen, K., Dejbakhsh-Jones, S., Negrin, R. S., Shizuru, J. A., Engleman, E. G., Strober, S. 2014; 182 (2): 163-169

    Abstract

    The goal of this study was to determine whether a combination of local tumor irradiation and autologous T-cell transplantation can effectively treat metastatic 4T1 breast cancer in mice. BALB/c mice were injected subcutaneously with luciferase-labeled 4T1 breast tumor cells and allowed to grow for 21 days, at which time metastases appeared in the lungs. Primary tumors were treated at that time with 3 daily fractions of 20 Gy of radiation each. Although this approach could eradicate primary tumors, tumors in the lungs grew progressively. We attempted to improve efficacy of the radiation by adding autologous T-cell infusions. Accordingly, T cells were purified from the spleens of tumor-bearing mice after completion of irradiation and cryopreserved. Cyclophosphamide was administered thereafter to induce lymphodepletion, followed by T-cell infusion. Although the addition of cyclophosphamide to irradiation did not improve survival or reduce tumor progression, the combination of radiation, cyclophosphamide and autologous T-cell infusion induced durable remissions and markedly improved survival. We conclude that the combination of radiation and autologous T-cell infusion is an effective treatment for metastatic 4T1 breast cancer.

    View details for DOI 10.1667/RR13471.1

    View details for PubMedID 24992165

  • Interactions between NKT cells and Tregs are required for tolerance to combined bone marrow and organ transplants BLOOD Hongo, D., Tang, X., Dutt, S., Nador, R. G., Strober, S. 2012; 119 (6): 1581-1589

    Abstract

    We used a model of combined bone marrow and heart transplantation, in which tolerance and stable chimerism is induced after conditioning with fractionated irradiation of the lymphoid tissues and anti-T-cell antibodies. Graft acceptance and chimerism required host CD4(+)CD25(+) Treg production of IL-10 that was in-turn enhanced by host invariant natural killer (NK) T-cell production of IL-4. Up-regulation of PD-1 on host Tregs, CD4(+)CD25(-) conventional T (Tcon) cells, and CD8(+) T cells was also enhanced by NKT cell production of IL-4. Up-regulated PD-1 expression on Tregs was linked to IL-10 secretion, on CD8(+) T cells was linked to Tim-3 expression, and on CD4(+) Tcon cells was associated with reduced IFNγ secretion. Changes in the expression of PD-1 were induced by the conditioning regimen, and declined after bone marrow transplantation. In conclusion, NKT cells in this model promoted changes in expression of negative costimulatory receptors and anti-inflammatory cytokines by Tregs and other T-cell subsets in an IL-4-dependent manner that resulted in tolerance to the bone marrow and organ grafts.

    View details for DOI 10.1182/blood-2011-08-371948

    View details for Web of Science ID 000300420900035

    View details for PubMedID 22174155

    View details for PubMedCentralID PMC3286219

  • Donor immunization with WT1 peptide augments antileukemic activity after MHC-matched bone marrow transplantation. Blood Kohrt, H. E., Müller, A., Baker, J., Goldstein, M. J., Newell, E., Dutt, S., Czerwinski, D., Lowsky, R., Strober, S. 2011; 118 (19): 5319-5329

    Abstract

    The curative potential of MHC-matched allogeneic bone marrow transplantation (BMT) is in part because of immunologic graft-versus-tumor (GvT) reactions mediated by donor T cells that recognize host minor histocompatibility antigens. Immunization with leukemia-associated antigens, such as Wilms Tumor 1 (WT1) peptides, induces a T-cell population that is tumor antigen specific. We determined whether allogeneic BMT combined with immunotherapy using WT1 peptide vaccination of donors induced more potent antitumor activity than either therapy alone. WT1 peptide vaccinations of healthy donor mice induced CD8(+) T cells that were specifically reactive to WT1-expressing FBL3 leukemia cells. We found that peptide immunization was effective as a prophylactic vaccination before tumor challenge, yet was ineffective as a therapeutic vaccination in tumor-bearing mice. BMT from vaccinated healthy MHC-matched donors, but not syngeneic donors, into recipient tumor-bearing mice was effective as a therapeutic maneuver and resulted in eradication of FBL3 leukemia. The transfer of total CD8(+) T cells from immunized donors was more effective than the transfer of WT1-tetramer(+)CD8(+) T cells and both required CD4(+) T-cell help for maximal antitumor activity. These findings show that WT1 peptide vaccination of donor mice can dramatically enhance GvT activity after MHC-matched allogeneic BMT.

    View details for DOI 10.1182/blood-2011-05-356238

    View details for PubMedID 21868578

    View details for PubMedCentralID PMC3217412

  • CD8(+)CD44(hi) but not CD4(+)CD44(hi) memory T cells mediate potent graft antilymphoma activity without GVHD BLOOD Dutt, S., Baker, J., Kohrt, H. E., Kambham, N., Sanyal, M., Negrin, R. S., Strober, S. 2011; 117 (11): 3230-3239

    Abstract

    Allogeneic hematopoietic cell transplantation can be curative in patients with leukemia and lymphoma. However, progressive growth of malignant cells, relapse after transplantation, and graft-versus-host disease (GVHD) remain important problems. The goal of the current murine study was to select a freshly isolated donor T-cell subset for infusion that separates antilymphoma activity from GVHD, and to determine whether the selected subset could effectively prevent or treat progressive growth of a naturally occurring B-cell lymphoma (BCL(1)) without GVHD after recipients were given T cell-depleted bone marrow transplantations from major histocompatibility complex-mismatched donors. Lethal GVHD was observed when total T cells, naive CD4(+) T cells, or naive CD8(+) T cells were used. Memory CD4(+)CD44(hi) and CD8(+)CD44(hi) T cells containing both central and effector memory cells did not induce lethal GVHD, but only memory CD8(+) T cells had potent antilymphoma activity and promoted complete chimerism. Infusion of CD8(+) memory T cells after transplantation was able to eradicate the BCL(1) lymphoma even after progressive growth without inducing severe GVHD. In conclusion, the memory CD8(+) T-cell subset separated graft antilymphoma activity from GVHD more effectively than naive T cells, memory CD4(+) T cells, or memory total T cells.

    View details for DOI 10.1182/blood-2010-10-312751

    View details for PubMedID 21239702

  • Naive and memory T cells induce different types of graft-versus-host disease JOURNAL OF IMMUNOLOGY Dutt, S., Tseng, D., Ermann, J., George, T. I., Liu, Y. P., Davis, C. R., Fathman, C. G., Strober, S. 2007; 179 (10): 6547-6554

    Abstract

    The goal of this study was to compare the ability of donor naive and alloantigen-primed effector memory T cells to induce graft-vs-host disease after bone marrow transplantation in MHC-mismatched irradiated host mice. Purified CD4(+) naive (CD62L(high)CD44(low)) T cells and CD4(+) effector memory (CD62L(low)CD44(high)) T cells obtained from unprimed donors and donors primed to host alloantigens, respectively, were injected into host mice, and the rapidity, severity, and pattern of tissue injury of graft-vs-host disease was assessed. Unexpectedly, the naive T cells induced a more acute and severe colitis than the primed memory cells. Whereas the naive T cells expressing CD62L and CCR7 lymph node homing receptors vigorously expanded in mesenteric lymph nodes and colon by day 6 after transplantation, the primed memory T cells without these receptors had 20- to 100-fold lower accumulation at this early time point. These differences were reflected in the significantly more rapid decline in survival and weight loss induced by naive T cells. The primed memory T cells had a greater capacity to induce chronic colitis and liver injury and secrete IL-2 and IFN-gamma in response to alloantigenic stimulation compared with memory T cells from unprimed donors. Nevertheless, the expected increase in potency as compared with naive T cells was not observed due to differences in the pattern and kinetics of tissue injury.

    View details for PubMedID 17982043

  • Host NKT cells can prevent graft-versus-host disease and permit graft antitumor activity after bone marrow transplantation JOURNAL OF IMMUNOLOGY Pillai, A. B., George, T. I., Dutt, S., Teo, P., Strober, S. 2007; 178 (10): 6242-6251

    Abstract

    Allogeneic bone marrow transplantation is a curative treatment for leukemia and lymphoma, but graft-vs-host disease (GVHD) remains a major complication. Using a GVHD protective nonmyeloablative conditioning regimen of total lymphoid irradiation and antithymocyte serum (TLI/ATS) in mice that has been recently adapted to clinical studies, we show that regulatory host NKT cells prevent the expansion and tissue inflammation induced by donor T cells, but allow retention of the killing activity of donor T cells against the BCL1 B cell lymphoma. Whereas wild-type hosts given transplants from wild-type donors were protected against progressive tumor growth and lethal GVHD, NKT cell-deficient CD1d-/- and Jalpha-18-/- host mice given wild-type transplants cleared the tumor cells but died of GVHD. In contrast, wild-type hosts given transplants from CD8-/- or perforin-/- donors had progressive tumor growth without GVHD. Injection of host-type NKT cells into Jalpha-18-/- host mice conditioned with TLI/ATS markedly reduced the early expansion and colon injury induced by donor T cells. In conclusion, after TLI/ATS host conditioning and allogeneic bone marrow transplantation, host NKT cells can separate the proinflammatory and tumor cytolytic functions of donor T cells.

    View details for PubMedID 17475852

  • L-selectin and beta(7) integrin on donor CD4 T cells are required for the early migration to host mesenteric lymph nodes and acute colitis of graft-versus-host disease BLOOD Dutt, S., Ermann, J., Tseng, D., Liu, Y. P., George, T. I., Fathman, C. G., Strober, S. 2005; 106 (12): 4009-4015

    Abstract

    The homing receptors L-selectin and alpha4beta7 integrin facilitate entry of T cells into the gut-associated organized lymphoid tissues such as the mesenteric lymph nodes and Peyer patches. We studied the impact of inactivation of genes encoding these receptors on the ability of purified donor CD4+ T cells to induce acute lethal graft-versus-host disease (GVHD) associated with severe colitis in irradiated major histocompatibility complex (MHC)-mismatched mice. Whereas lack of expression of a single receptor had no significant impact on the severity of colitis and GVHD, the lack of expression of both receptors markedly ameliorated colitis and early deaths observed with wild-type (WT) T cells. The changes in colitis and GVHD were reflected in a marked reduction in the early accumulation of donor T cells in the mesenteric lymph nodes and subsequently in the colon. The purified WT donor CD4+ T cells did not accumulate early in the Peyer patches and failed to induce acute injury to the small intestine. In conclusion, the combination of CD62L and beta7 integrin is required to induce acute colitis and facilitate entry of CD4+ donor T cells in the mesenteric nodes associated with lethal GVHD in allogeneic hosts.

    View details for DOI 10.1182/blood-2005-06-2339

    View details for PubMedID 16105972

  • Only the CD62L(+) subpopulation of CD4(+)CD25(+) regulatory T cells protects from lethal acute GVHD BLOOD Ermann, J., Hoffmann, P., Edinger, M., Dutt, S., Blankenberg, F. G., Higgins, J. P., Negrin, R. S., Fathman, C. G., Strober, S. 2005; 105 (5): 2220-2226

    Abstract

    CD4+CD25+ regulatory T (Treg) cells are potent modulators of alloimmune responses. In murine models of allogeneic bone marrow transplantation, adoptive transfer of donor CD4+CD25+ Treg cells protects recipient mice from lethal acute graft-versus-host disease (aGVHD) induced by donor CD4+CD25- T cells. Here we examined the differential effect of CD62L+ and CD62L- subsets of CD4+CD25+ Treg cells on aGVHD-related mortality. Both subpopulations showed the characteristic features of CD4+CD25+ Treg cells in vitro and did not induce aGVHD in vivo. However, in cotransfer with donor CD4+CD25- T cells, only the CD62L+ subset of CD4+CD25+ Treg cells prevented severe tissue damage to the colon and protected recipients from lethal aGVHD. Early after transplantation, a higher number of donor-type Treg cells accumulated in host mesenteric lymph node (LN) and spleen when CD4+CD25+CD62L+ Treg cells were transferred compared with the CD62L- subset. Subsequently, CD4+CD25+CD62L+ Treg cells showed a significantly higher capacity than their CD62L- counterpart to inhibit the expansion of donor CD4+CD25- T cells. The ability of Treg cells to efficiently enter the priming sites of pathogenic allo-reactive T cells appears to be a prerequisite for their protective function in aGVHD.

    View details for DOI 10.1182/blood-2004-05-2044

    View details for PubMedID 15546950

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