Antigenic marker on a functional subpopulation of B cells, controlled by the I-A subregion of the H-2 complex.

CBA/N mice have an X-linked recessive effect that results in the absence of a subpopulation of B cells carrying the Lyb3 surface marker. It has been shown previously that this marker is present on a mature subset of B cells in all mouse strains. In this paper the Lyb3+ B cell population in C57BL/6 mice was analyzed further. This subset of B cells selectively expresses a surface marker controlled by the I-A subregion of the H-2 complex. A cytotoxic antiserum recognizing this marker was raised by immunizing defective (CBA/N X C57BL/6)F1 male mice with C57BL/6 spleen cells. This antiserum also contained noncytotoxic, non-strain-restricted anti-Lyb3 antibodies. The possible functional relevance of this surface marker is discussed.