Tissue Distribution of Human α₁-Microglobulin

• Text
• PDF

Abstract

Human α1-microglobulin was isolated from the urine of patients with tubular proteinuria, and its molecular weight was established by sodium dodecyl sulfate-polyacrylamide gel electrophoresis at 33,000 daltons. The carbohydrate content was 21.7%. Anti-α1-microglobulin serum was prepared and observed to react monospecifically in gel diffusion to purified α1-microglobulin, as well as to normal human serum and urine. Sera from the domestic chicken, mouse, rat, rabbit, dog, calf, cow, goat, sheep, and horse, however, did not react to anti-α1-microglobulin serum in immunodiffusion. The lymphocyte culture supernate was found to contain α1-microglobulin. Both thymus-derived(T)- and bone marrow-derived(B)-lymphocyte culture media clearly displayed a specific precipitin line against anti-α1-microglobulin serum when tested with the Ouchterlony immunodiffusion method. The tissue distribution of α1-microglobulin was studied under immunofluorescence, and a positive staining was recognized on the lymphocyte surface. Identical staining patterns were noted on both T and B lymphocytes, though B lymphocytes took a more intense stain. It would thus seem quite possible that lymphocytes are the primary source of α1-microglobulin and that this is filtered through the glomerular basement membrane and partly reabsorbed by the renal tubules. This, then, would suggest the possibility that α1-microglobulin shares some immunological role in vivo with lymphocytes and(or) is one of the membrane proteins of lymphocytes.

Authors

Kimiteru Takagi, Kohjin Kin, Yoshihisa Itoh, Tadashi Kawai, Tadashi Kasahara, Toshihiko Shimoda, Toshio Shikata