Immune response gene function correlates with the expression of an Ia antigen. I. Preferential association of certain Ae and E alpha chains results in a quantitative deficiency in expression of an Ae:E alpha complex.

Abstract

I-Eu fails to interact with I-Ak or I-As in F1 mice to allow a response to the antigen pigeon cytochrome c, unlike I-E subregions derived from other Ia.7+ halotypes. Serological and biochemical analyses were performed to determine whether cells from these F1 mice express the .**GRAPHIC**. complexes that should function as restriction elements for T cell recognition of pigeon cytochrome c on antigen-presenting cells. The Y-17 monoclonal antibody, which recognizes the combinatorial or conformational determinant Ia.m44 on certain Ae:E.alpha. complexes, was used to distinguish between .**GRAPHIC**. and .**GRAPHIC**. complexes on cell surfaces. Although complement-dependent microcytotoxicity with Y-17 failed to detect .**GRAPHIC**. complexes on cells from appropriate F1 mice, these molecules were detected by quantitative absorption and quantitative immunofluorescence studies. .**GRAPHIC**. complexes were found to be present at levels only 1/8-1/7 the levels expressed by homozygous I-Ab, I-Ek; I-Ak, I-Ek; and I-As, I-Ek cells. The results of 2-dimensional polyacrylamide gel electrophoresis analyses suggest that the low levels of expression of .**GRAPHIC**. complexes are a consequence of the preferential association of .**GRAPHIC**. and .**GRAPHIC**. chains with each other in the F1 cells.