The Effects of Chronic Infection with a Superantigen-producing Virus

Mice homozygous for a β2-microglobulin (β2-m) gene disruption lack β2-m protein and aredeficient for functional major histocompatibility complex class I (MHC-I) molecules. The mutantmice have normal numbers of CD4+8 - T helper cells, but lack MHC-I-directed CD4-8 +cytotoxic T lymphocytes (CTLs). In this study we used the β2-m mutant mice to study theimportance of MHC-I-directed immunity in skin graft rejection. Our results indicate that MHCI-directed CD8 + CTLs are not essential in the rejection of allografts with whole MHC ormultiple minor H differences. However, the absence of MHC-I-guided immunity profoundlyreduces the ability of mutant mice to reject H-Y disparate grafts. In addition, we show thatnatural killer cells which vigorously reject MHC-I-deficient bone marrow grafts, are not effectivein the destruction of MHC-I-deficient skin grafts.