Regulatory Immunotherapy in Bone Marrow Transplantation

Every year individuals receive hematopoietic stem cell transplantation (HSCT) to eradicate malignant and nonmalignant disease. The immunobiology of allotransplantation is an area of ongoing discovery, from the recipient's conditioning treatment prior to the transplant to the donor cell populations responsible for engraftment, graft-versus-host disease, and graft-versus-tumor effect. In this review, we focus on donor-type immunoregulatory T cells, namely, natural killer T cells (NKT) and regulatory T cells (Treg), and their current and potential roles in tolerance induction after allogeneic HSCT

Regulatory immunotherapy in bone marrow transplantation

Every year individuals receive hematopoietic stem cell transplantation (HSCT) to eradicate malignant and nonmalignant disease. The immunobiology of allotransplantation is an area of ongoing discovery, from the recipient's conditioning treatment prior to the transplant to the donor cell populations responsible for engraftment, graft-versus-host disease, and graft-versus-tumor effect. In this review, we focus on donor-type immunoregulatory T cells, namely, natural killer T cells (NKT) and regulatory T cells (Treg), and their current and potential roles in tolerance induction after allogeneic HSCT

Abstract 3512: Expanded human regulatory iNKT cells exhibit direct cytotoxicity against hematolymphoid tumor targets

Abstract CD1d-restricted invariant natural killer T (iNKT) cells are rare but potent innate regulatory cells capable of immune modulation via robust production of Th1/Th2 cytokines, as well as tumor immunosurveillance via direct cytotoxicity. Protocols to expand iNKT cells and augment their cytotoxicity would broaden their application in allogeneic transplantation and adjuvant anti-tumor immunotherapy. We have optimized a protocol for ex vivo expansion of highly purified human CD3+CD4negVα24+ iNKT cells from human peripheral blood mononuclear cells (PBMC). PBMCs were stimulated with an iNKT-specific glycolipid (α-GalCer), recombinant IL-2 and IL-7 and sorted to &amp;gt; 98% purity at day 7. Sorted iNKT cells were further expanded in the presence of irradiated allogeneic PBMCs, Vα24-specific TCR stimulation, and low-dose IL-2 and IL-7 for 21 days. This results in roughly 10^3-fold expansion, with peak yields of at day 21-28 of expansion (range 1.5 x 10^5 - 10.6 x 10^6 iNKT cells from 1 x 10^8 - 3.5 x 10^8 starting PBMC). At 28 days, these iNKT cells secrete high levels of IL-13, TNF-α, GM-CSF, and IL-4, moderate IL-2 and IFN-γ in anti-CD2/CD3/CD28 bead-stimulated Luminex supernatant assay. Day 28 expanded iNKT cells are dose-dependent suppressors of sorted autologous CD3+CD8+ effector T cells in 72-hr mixed leukocyte reaction (MLR). Anti-CD2/CD3/CD28 activation of these iNKT cells induced expression of high levels of key cytolytic effector molecules, including granzyme B. We therefore measured cytotoxicity of activated day 28 iNKT cells against various hematolymphoid tumor targets following co-incubation of iNKT cells versus control effector populations with firefly luciferase-transduced RS4:11 and Nalm6 (B-ALL), U937 (monocytic), and K562 (CML) targets. iNKT cell effectors (E) demonstrated dose-dependent cytotoxicity against B-lymphoid tumor targets (T) (e.g.: Nalm6: 37.7% at E:T 2:1, 17.7% at E:T 1:1, 7.7% at E:T 0.5:1), with no significant cytotoxicity against myeloid targets (e.g.: K562: 11.8% at E:T 2:1, 6.7 at E:T 1:1, 1.8 at E:T 0.5:1). Our results indicate that human iNKT cells expressing high levels of Th2 and regulatory cytokines can be potently expanded ex vivo and manifest cytotoxicity against B-ALL targets, supporting their potential application in tailored immunotherapy in the pre- and post-transplant setting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3512. doi:1538-7445.AM2012-3512</jats:p

Adhesion G protein-coupled receptor, ELTD1, is a potential therapeutic target for retinoblastoma migration and invasion

Abstract Background Prognosis for pediatric metastatic Retinoblastoma (Rb) is poor and current therapies are limited by high systemic toxicity rates and insufficient therapeutic efficacy for metastatic Rb. Tumor dissemination to the brain is promoted by the heterogeneous adhesive and invasive properties of Rb cells within the tumor. In this study we evaluate, for the first time, the expression, and roles of the ELTD1 and GPR125 adhesion G protein-coupled receptors (GPCRs) in Rb cell migration, viability and invasion. Methods We characterized the RNA expression of adhesion-GPCRs in 64 Rb tumors compared to 11 fetal retinas using the database from the Childhood Solid Tumor Network from St Jude Children’s Research Hospital. The role of ELTD1 and GPR125 in Rb were investigated ex vivo by microarray analysis, in vitro by cell viability, Western blot and migration assays, in addition to imaging of the subcellular localization of the GPCRs. To elucidate their role in vivo we utilized siRNA technology in an established Rb orthotopic xenograft murine model. Results Our investigation demonstrates, for the first time, that ELTD1 but not GPR125, is significantly increased in Rb tumors compared to fetal retinas. We utilized established the Rb cell lines Y79 and Weri-Rb-1, which represent an aggressive, metastatic, and non-metastatic phenotype, respectively, for the in vitro analyses. The studies demonstrated that ELTD1 is enriched in Weri-Rb-1 cells, while GPR125 is enriched in Y79 cells. The measured differences extended to their subcellular localization as ELTD1 labeling displayed punctate clusters in cell-to-cell adhesion sites of Weri-Rb-1 cells, while GPR125 displayed a polarized distribution in Y79 cells. Lastly, we demonstrated the lack of both adhesion receptors does not affect Rb cell viability, yet inhibition of ELTD1 decreases Y79 cell migration in vitro and invasion in vivo. Conclusion Taken together, our data suggest that ELTD1, is a potential target to prevent extraocular Rb. The results within establish ELTD1 as a potential therapeutic target for metastatic Rb.http://deepblue.lib.umich.edu/bitstream/2027.42/173538/1/12885_2020_Article_7768.pd