Variable effect of anH-21 barrier on response to skin allografts in the mouse

(AQR×B10)F₁ mice were grafted with skin from donors differing in theK, I, KI, andISD regions of theH-2 complex. A dichotomy was observed in the fate of theH-2I-disparate grafts: either they were rejected acutely within the second week or were accepted indefinitely. Acceptances were much more common among male than female hosts. Acceptor status was limited to the I group, was unpredictable in occurrence, was not well-correlated with positive serum anti-Ia titers, and did not confer protection of grafts that were alike atH-2I but different atH-2K orH-2D. Since theH-2I barrier studied here elicited such divergent responses in genetically identical hosts, it is unlikely that any histocompatibility typing test could predict graft fate.Abbreviations used in this paper are MST median survival time - MHC major histocompatibility complex - CTL cytotoxic T lymphocyte - B10 C57 BL/10 - 6R BIO.T(6R) - B10.A BIO. ASn - H-2-Ia serologically detected antigens coded in theI region ofH-2 This term is used in preference toIa, since it has recently been shown that Ia-like alloantigens may be coded outside the MHC (Dickleret al. 1975).