Characterization of Antibodies in Human Urine.

Human urine contains proteins that have been demonstrated to be antigenically identical with serum immunoglobulins (1-8). The immunoglobulins usually present in urine have been 7 S -y-globulin and 382A-globulin (3,7), whereas /82M-globulin has been found in only a few cases (9). A low molecular weight protein, antigenically related to 7 S y-globulin, has also been observed (2, 4-8). This low molecular weight y-globulin ('yL) 1 has been reported to be identical to the light (L) polypeptide chains that form part of the 7 S y-globulin molecule, and it has been suggested that they were free L chains representing the normal counterparts to Bence Jones proteins (10-12). Antibody activity in urine has been demonstrated against several microorganisms. Agglutinins reacting with Vibrio cholera and Salmonella typhi (13) and precipitins against diphtheria and tetanus toxoid (14), as well as neutralizing activity against polio virus (15), have been described. Usually, the antibodies responsible for these activities have not been further characterized immunologically or physicochemically. The reports of Remington, Merler, and their colleagues (16, 17), however, present evidence that precipitating activity against tetanus toxoid and neturalizing activity against polio virus reside in a protein fraction of a molecular weight of 12,900. These authors found no antibody activity in material that