查看文章

Stem cells reside in a specialized regulatory microenvironment or niche^,, where they receive appropriate support for maintaining self-renewal and multi-lineage differentiation capacity^,,. The niche may also protect stem cells from environmental insults including cytotoxic chemotherapy and perhaps pathogenic immunity. The testis, hair follicle and placenta are all sites of residence for stem cells and are immune-suppressive environments, called immune-privileged sites, where multiple mechanisms cooperate to prevent immune attack, even enabling prolonged survival of foreign allografts without immunosuppression. We sought to determine if somatic stem-cell niches more broadly are immune-privileged sites by examining the haematopoietic stem/progenitor cell (HSPC) niche^,,,, in the bone marrow, a site where immune reactivity exists^,. We observed persistence of HSPCs from allogeneic donor mice (allo-HSPCs …