Demonstration by immunofluorescence of the fixation of perfused antibody to human collagen in human kidney.

Rabbit serum containing antibody to human collagen, perfused through human infant kidneys obtained at autopsy, gives an immunofluorescent reaction with an antigen in the basement membranes of the glomeruli and the tubules. This reaction was shown to be specific by the absence of reaction with normal rabbit serum, antibody to carp collagen, or anti-human collagen serum absorbed with human collagen. Slight cross-reactions were found in the human kidneys with antibody to chicken or rat collagen. There was no evidence that a collagen-like protein in human serum or an antigen common to human erythrocytes and renal glomeruli enters into this immunofluorescent reaction. Perfusion of the kidneys with purified collagenase before the introduction of the antibody to human collagen altered the antigen so that antibody could not be demonstrated in the basement membranes by immunofluorescence. Testicular hyaluronidase used in the same way did not affect the immunofluorescent reaction. This method of perfusion provides another means for studying antigens in human organs by immunofluorescence. These observations in human kidneys extend our earlier findings in laboratory animals and indicate that an antigen, collagen, is also present in human renal glomerular and tubular basement membranes.