Supplementary Methods, Supplementary Figure S1, Transplantation of VIP-KO cells or treatment with VIPhyb did not increase GVHD; Supplementary Figure S2, VIPhyb did not suppress lymphoblastic leukemia growth in vitro; Supplementary Figure S3, VIPhyb-treatment reprogramed homing patterns of donor T-cells in allo-BMT recipients; Supplementary Figure S4, VIPhyb-treatment enhanced expression of co-stimulatory and effector molecules after allo-BMT; Supplementary Figure S5, VIPhyb treated allo-BMT recipients were resistant to leukemia re-challenge; Supplementary Figure S6, VIPhyb-treatment led to increased expression of effector molecules and reduced expression of co-inhibitory molecules after leukemia re-challenge; Supplementary Figure S7, VIPhyb treatment increased levels of donor TCM in allo-BMT recipients; Supplementary Table S1. Mice with GvL had distinct oligoclonal TCR-β sequences versus GvHD mice.
ARTICLE ABSTRACT
The goal of allogeneic bone marrow transplantation (allo-BMT) is elimination of leukemia cells through the graft-versus-leukemia (GvL) activity of donor cells, while limiting graft-versus-host disease (GvHD). Immune checkpoint pathways regulate GvL and GvHD activities, but blocking antibodies or genetic inactivation of these pathways can cause lethal GVHD. Vasoactive intestinal peptide (VIP) is an immunosuppressive neuropeptide that regulates coinhibitory pathways; its role in allo-BMT has not been studied. We found VIP transiently expressed in donor NK, NK-T, dendritic cells, and T cells after allo transplant, as well as host leukocytes. A peptide antagonist of VIP signaling (VIPhyb) increased T-cell proliferation in vitro and reduced IL10 expression in donor T cells. Treatment of allo-BMT recipients with VIPhyb, or transplanting donor grafts lacking VIP (VIP-KO), activated donor T-cells in lymphoid organs, reduced T-cell homing to GvHD target organs, and enhanced GvL without increasing GvHD in multiple allo-BMT models. Genetic or ex vivo depletion of donor NK cells or CD8+ T cells from allografts abrogated the VIPhyb-enhanced GvL activity. VIPhyb treatment led to downregulation of PD-1 and PD-L1 expression on donor immune cells, increased effector molecule expression, and expanded oligoclonal CD8+ T cells that protected secondary allo transplant recipients from leukemia. Blocking VIP signaling thus represents a novel pharmacologic approach to separate GvL from GvHD and enhance adaptive T-cell responses to leukemia-associated antigens in allo-BMT. Cancer Res; 76(23); 6802–15. ©2016 AACR.
