Citations

Summary Intact Fcα fragments from five human IgA myeloma proteins were produced by two different methods, high temperature trypsinolysis and IgA protease digestion. Three of the Fcα fragments activated the classical pathway as determined by the titers of the individual complement components. Two other fragments did not fix complement by either pathway.

Abstract A lymphocyte surface glycoprotein designated urinary acidic antigen (UA) has been isolated from normal urine by a combination of preparative isoelectric focusing and ammonium sulfate precipitation. It has an m.w. of 14,000 to 17,500 daltons, and is approximately 60% carbohydrate and 40% amino acid in content. The protein exhibited the following physical properties: S20,omega = 1.24; v = 0.693 ml/g; E1%1 cm, 278 nm = 2.08; and pI-2.5. It appears to be unrelated to beta 2-microglobulin, protein HC, urinary proteose, microglobulin, or any previously described normal urine or human serum protein.

Abstract 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.