Host-specific tolerance and delayed rejection of third-party hearts by murine adult full-term fetal blood recipients across major histocompatibility barrier.

Hearts from BALB/c (H-2^d, recipient-strain heart [A]) and C3H/HeJ (H-2^k, third-party heart [B]) newborn mice (< 48 hours old) were transplanted into pouches created in the pinnae of left and right ears of the mice, respectively. The cardiac transplantation was done between day 118 and day 145 after stem cell transplantation. Heart graft survival was assessed daily by visual evaluation of the presence or absence of heart contractions. Each group contained at least 4 mice. For recipient-strain graft (A), P < .01, C57BL/6 mice versus other groups. For third-party graft (B),P < .05, allogeneic T-cell–depleted bone marrow recipients versus other groups; P < .05, allogeneic full-term fetal blood recipients versus other groups.