Expression of endogenous retroviral envelope antigen in Ig(+) B cells of immunized 15I5 X 71 chickens.

In a previous study (1), we observed that antigen cross-reactive with structural protein of the endogenous retrovirus RAV-O is expressed in splenic Ig(+) B lymphocytes of immunized 15I5 X 71 chickens. The present experiments were undertaken to determine the relationship of this antigen to viral gag- and env-coded antigenic specificities. As analyzed by immunofluorescence with several antisera, group-specific determinants of the gp85 envelope glycoprotein as well as viral-related type E-specific determinants were detectable in islands of Ig(+) splenocytes; antigenic determinants of viral gag protein were not detected in the splenic islands. These observations indicated that antigen cross-reactive with endogenous retroviral envelope glycoprotein is expressed in Ig(+) B cells.