A new lymphocyte surface protein present in normal urine. II. Cellular distribution and biologic properties

A protein component present in normal human urine has been found on the surface of epidermal cells and lymphocytes. This protein, called urinary acidic antigen (UA), can not be detected in concentrated fractions of normal human serum by double immunodiffusion, suggesting that it is quickly cleared from the circulation. It is readily detected, however, in sera of patients with renal failure. Although it can be eliminated from the cell surface by repeated washings with PBS, it was shown to cap with anti-UA-specific antiserum. Anti-UA suppresses PWM-induced proliferation, but not the lymphocyte response to PHA, Con A, or allogeneic cells. Thus UA appears to have a specific relationship to the pokeweed response. Whether it is a structural component of the PWM receptor is uncertain.