Models for the production of stable hematopoietic chimerism across major histocompatibility barriers in adults.

Abstract
Experiments presented in this paper indicate that DBA/2J (H-2d) mice parabiosed for more than 100 days to the F1 hybrid between DBA/2J and C3H/HeJ (H-2k) contain in their serum an anti-H-2k antibody that is preferentially reactive with hematopoietic tissue and is also capable of killing C3H/HeJ colony-forming stem cells in vivo (CFU-S). These findings make the antibody a likely participant in the "takeover" reaction, in which DBA/2J red and white cells eventually replace the F1 hybrid blood system. With these observations used as a basis, 10(8) DBA/2J spleen cells were injected along with anti-H-2Kk (anti-host) monoclonal antibody into 10-wk-old (DBA/2J x C3H/HeJ)F1 hybrid hosts. The recipients had a high surivival rate and exhibited long-term chimerism. Unlike the situation in the parabionts, the DBA/2J lymphoid cells in the injection chimeras were found to be unresponsive to C3H/HeJ alloantigens. This could result from the continued presence of F1 hybrid stimulator cells, which are missing in the parabionts. The injection chimeras indicate that one can establish stable chimerism in adult mice without irradiation or metabolic poisoning.