IL-7 is an important cytokine for T cell lymphopoiesis. Blockade of the IL-7 signaling pathway has been shown to induce long-term graft survival or graft tolerance in murine transplant models through inhibiting T cell homeostasis and favoring immunoregulation. In human transplantation, it has been suggested that T cell homeostasis following some immunosuppressive therapies might be detrimental to transplant patients. In this study, we assessed for the first time the effects of an anti-human CD127 mAb administered in combination with low-dose tacrolimus (n=4) or thymoglobulin (n=4) in a life-sustaining kidney allograft model in baboons. Contrary to our expectation, the addition of anti-CD127 mAb to low-dose tacrolimus or thymoglobulin did not prolong graft survival compared to low-dose tacrolimus alone or thymoglobulin alone, respectively. Anti-CD127 mAb administration leaded to full CD127 receptor occupancy during the follow-up period. However, all anti-CD127 mAb-treated animals lost their kidney graft between one and two weeks after transplantation. Pathological study of explanted kidney grafts revealed 2 mixed acute T cell-mediated rejection (TCMR) and acute antibody-mediated rejection (AMR), 3 TCMR, and 3 ischemic necrosis. Donor-specific antibodies were not detected using flow cytometry method, despite prominent peritubular capillary C4d deposition in 2 animals with AMR. Unlike in rodents, anti-CD127 mAb treatment did not decrease the absolute numbers of lymphocyte and lymphocyte subsets and did not effectively inhibit post-depletional T cell proliferation and homeostasis in nonhuman primates. Thus, unlike in mice, IL-7 does not seem to be a limiting factor for T cell homeostasis in primates.