Allo-reactivity of mesenchymal stem cells in rhesus macaques is dose and haplotype dependent and limits durable cell engraftment in vivo.

The emerging paradigm that MSCs are immune privileged has fostered the use of "off-the-shelf" allogeneic MSC-based therapies in human clinical trials. However, this approach ignores studies in experimental animals wherein transplantation of MSCs across MHC boundaries elicits measurable allo-immune responses. To determine if MSCs are hypo-immunogeneic, we characterized the immune response in rhesus macaques following intracranial administration of allogeneic vs.

Cell-dose-dependent increases in circulating levels of immune effector cells in rhesus macaques following intracranial injection of allogeneic MSCs.

Objective: Mesenchymal stem cells (MSCs) possess potent immunomodulatory activity, but whether they evade immune surveillance in an allogeneic transplant setting remains controversial. Herein we evaluated whether administration of major histocompatibility complex (MHC) class I-mismatched MSCs induce an immune response in rhesus macaques.

Materials And Methods: MSCs from a male donor were injected intracranially at two different doses into eight immunocompetent female infant rhesus macaques.