C3H/B6D2F1 mixed BM chimeras were established in lethally irradiated C3H mice. Skin grafts from C57BL/6 mice were transplanted 30 d later. After an additional 30 d, splenocytes from B6C3F1 mice were transplanted to establish splenocytic BM chimeras using total splenocytes (group A), CD90+-depleted splenocytes (group B), CD4+-depleted splenocytes (group C), or CD8+-depleted splenocytes (group D).
In group A, the BM switched to splenocyte-derived BM chimeras. Total B6C3F1 splenocytes created stable splenocyte BM chimeras that permitted long-term retention of skin grafts, without rejection. In groups B and D, the splenocytes failed to replace the recipient BM, and there was no decrease in the?number of recipient-derived BM cells compared with group A from d 14 to 28 after splenocyte injection, as was the case for CD8+ T cells. In group C mice, the recipient BM was slowly and incompletely replaced.
Partially MHC-matched donor CD8+ T?cells are indispensable for generating splenocyte chimeras in BM and maintaining allogeneic skin grafts.