Genetics of non-H-2 antigen that stimulates 'unrestricted' helper T cells and MLR

The inheritance of antigens expressed by C3H/Tif B cells that stimulate MHC-unrestricted helper T cells from C3H/HeJ was investigated. F₁ hybrids between C3H/HeJ and C3H/Tif and 39 C3H/HeJ x F₁ backcross mice were characterized as to the ability of their spleen cells to stimulate a proliferative C3H/HeJ T helper cell response and to respond to helper cell activity by the development of polyclonal plaque-forming cell responses. Backcross progeny were also types for the following markers segregating in this cross: 1) Responsiveness to the B cell mitogen lipopolysaccharide (LPS); 2) LyM-1 allotype; 3) antigen(s) stimulating a primary non-H-2 MLR between these strains, previously ascribed to Mis locus differences, 4) expression of target antigens for cytotoxic T cells raised in the same strain combination. The antigen(s) recognized by helper cells and those stimulating primary MLR are controlled by autosomal gene(s) and segregate as a single trait. These antigens, however, are not encoded in genes linked to either the Lps or the Mls loci, and are not recognized by cytotoxic T cells raised in the same strain combination.