General considerations in the interpretation of I-J genetic restrictions: evidence that the antigen-binding chain of antigen-specific T-suppressor factor has two recognition sites for members of the I-J hierarchy.

SUMMARY (CBA × B10)F1 [(H-2k x H-2b)] mice produce two types of antigen-specific T-suppressor factor (TsF), which can be separated by affinity chromatography on anti-I-J monoclonal antibody. After reduction and alkylation, both chains of F1 TsF are required for biological activity. However, the antigen-binding chain (AgBC) of F1 TsFk (AgBCk) is only complemented by I-Jk and likewise for F1 TsFb. In other words, interchain complementation shows the same genetic restriction in interchain complementation in parental and F1 mice. F1 TsF bearing, for example, I-Jk (TsFk), interacts with haptenized ‘antigen-presenting cells’ (‘APC’) of both parental haplotypes, and may be described as showing dua…