:ANTIGENICITY OF RAT COLLAGEN DEMONSTRATION OF ANTIBODY TO RAT COLLAGEN IN THE RENAL GLOMERULI O~" RATS BY FLUORESCENCE MICROSCOPY* Bx

In a previous study, diffuse lesions in renal glomeruli of rats prepared with Freund adjuvant were found after the injection of rabbit serum containing antibodies to rat collagen (1). However, neither the antibody nor adjuvant alone induced the injury. It was considered that these renal lesions might result from two antigen-antibody reactions: the fixation of the rabbit anti-rat collagen serum to an antigen in the glomeruli, presumably collagen, and the reaction of this antigen-antibody complex with anti-rabbit globulin produced in the rat by the stimulation of the adjuvant. That a reaction with the antibody to collagen did take place, however, in rats not prepared with adjuvant was demonstrated by the occurrence of reverse anaphylaxis following the intravenous injection of serum containing antibodies to rat collagen (2). The fluorescent antibody method developed by Coons and his associates (3, 4) provides a means of locating the site of specific antibody or antigen in tissues, and it was, therefore, utilized to determine whether the antibody to rat collagen localized in the renal glomeruli. The study here reported shows that injected collagen antibody does localize in the basement membrane of renal glomeruli, the site of injury in the adjuvantprepared rats. Injected antibody was also found in the renal glomerular basement membrane of rats not given adjuvant, although no injury was apparent in their kidneys. Materials and Methods