A role for TLX antigens in pregnancy.

Maternal responses to allotypic TLX antigens are proposed as necessary in the immunological maintenance of human pregnancy. The TLX antigens are strategically and strongly expressed in semen and on the extraembryonic tissues which form the anatomical materno-fetal interfaces. Recent findings suggest that CD 46 proteins (a membrane cofactor which protects self tissues from autologous complement damage) in association with the activated complement component, C 3b produce a novel antigenic epitope recognized by both rabbit and human anti-TLX antisera. Control of TLX immunity involves an idiotype-antiidiotype network. We now report the development of rabbit antiidiotypes specific for cross-reactive idiotypes on human anti-TLX IgG antibodies. These antiidiotypes appear to recognize different TLX allotypes and will be useful for gaining additional insight into the immunogenetics of human reproduction.