Survival of rat or mouse ventral mesencephalon neurons after cotransplantation with rat sertoli cells in the mouse striatum. 
Transplanting cells across species (xenotransplantation) for the treatment of Parkinson's disease has been considered an option to alleviate ethical concerns and shortage of tissues.  However, using this approach leads to decreased cell survival; the xenografted cells are often rejected.  Sertoli cells (SCs) are testis-derived cells that provide immunological protection to developing germ cells and can enhance survival of both allografted and xenografted cells.  It is not clear whether these cells will maintain their immunosuppressive support of cografted cells if they are transplanted across species.  In this study, we investigated the immune modulatory capacity of SCs and the feasibility of xenografting these cells alone or with allografted and xenografted neural tissue.  Transplanting xenografts of rat SCs into the mouse striatum with either rat or mouse ventral mesencephalon prevented astrocytic infiltration of the graft site, although all transplants showed activated microglia within the core of the graft.  Surviving tyrosine hydroxylase-positive neurons were observed in all conditions, but the size of the grafts was small at best.  SCs were found at 1 and 2 weeks posttransplant.  However, few SCs were found at 2 months posttransplant.  Further investigation is under way to characterize the immune capabilities of SCs in a xenogeneic environment.