I region-associated antigen system (Ia) of the mouse H-2 gene complex: Further definition of la specificities with restricted anti-ia antisera¹

Restricted anti-la antisera were produced by immunizing the following F₁ mice with A.TL (I^k) tissues: (A.TH X B10)F1; (A.TH X 129)F₁; (A.TH X C3H.Q)F1; (A.TH X B10.D2)F₁, (A.TH X B10.M)F₁ Analyses of these antisera suggested that specificity la.3 (Lna.3) should be subdivided into three specificities, Ia.l, la.3, and la.7, associated with the I^b, I^d and I^f regions, respectively. Immunization of (A.TL X B10.M)F₁ and (A.TL X A.TB)F₁ with A.TH tissue produced anti-la.4 antibodies which were specific for I^s strains. These suggested that a single specificity, la.5, is shared by the I^s and the I^f, I^p, and I^q regions. The current view of the la antigenic makeup of various inbred and recombinant H-2 haplotypes and postulated I region map positions of their determinants are summarized.