DOWN-REGULATION OF SURFACE-ANTIGENS RECOGNIZED BY SYSTEMIC LUPUS-ERYTHEMATOSUS ANTIBODIES ON EMBRYONAL CELLS FOLLOWING DIFFERENTIATION AND EXPOSURE TO CORTICOSTEROIDS

We have previously suggested that anti-DNA antibodies present in syste mic lupus erythematosus patients can bind directly to tissues as a res ult of cross-reactivity with embryonal tissue-based antigens. Here we have analyzed the interaction between polyclonal and monoclonal mouse and human lupus autoantibodies and an embryonal cell line. We report t hat a murine embryonal stem cell line (ES) expresses a surface antigen which is recognized by mouse and human lupus autoantibodies. This sur face antigen is down-regulated following maturation of the cells or in cubation with corticosteroids. Adhesion molecules may serve as the tar get membrane antigen in ES cells since preincubation with these antibo dies decreases the ability of ES cells to adhere to the plate.