Host-determined T cell fine specificity for self-H-2 in radiation bone-marrow chimeras of standard C57BL/6 (H-2^b) mutant Hz1 (H-2^ba), and F₁ mice

Reciprocal radiation bone-marrow chimeras were produced between the standard C57BL/6 (=B6) and the mutant B6.C -H-2^ba (=Hz1) strain. When infected with vaccinia virus, these chimeras, as well as an (Hz1 × B6)=→ Hz1 chimera, produced cytotoxic cells that killed vaccinia-infected H-2K^kH-2D^b target cells but failed to kill virus-infected H-2K^bH-2D^d cells. Virus-infected (Hz1 × B6)F₁ → B6 chimeras, however, killed both types of target. These experiments demonstrate strict T-cell specificity capable of differentiating between two molecules that apparently differ by a single amino acid substitution.