An auto-reactive A-like ovarian determinant distinct from xeno-reactive A-like structures.

The "natural" anti-A antibody of the mouse is an autoantibody due to the age-dependent appearance of an A-like auto-reactive determinant, which is predominantly displayed by ovarian tissue and probably occurs in other tissues below the level of detection. The present study shows that this determinant is distinct from murine structures which react with xenogeneic anti-A antibody, and that it does not involve the widespread heterogenetic (Forssman-type) A-related specificity. Whereas xeno-reactive A-like structures, which combine with the human "natural" anti-A antibody, are exhibited by several murine tissues and Forssman-type structures by all of them, the murine "natural" anti-A antibody solely reflects the autoantigenic power of the particular determinant discovered in ovarian tissue. This determinant, which undergoes a unique genetic regulation, is present in both the ovary of the C57BL/10 inbred mouse and that of the NMRI outbred mouse and may thus represent a common murine component.