No abstract

Summary Soluble fractions obtained from pooled human glomeruli and the cell membrane of nephritogenic streptococci were shown to be immunologically cross-reactive. One of the components present in the glomerular extract was shown to be unrelated to the streptococcal cross-reactive material but related to a component present on all human red cells tested. Chemical and physical analysis of soluble fractions obtained from isolated human glomeruli and streptococcal cell membranes indicated that they are low molecular weight glycoproteins. The glomerular extract has approximately 78.9% protein and 13 to 15% carbohydrate whereas the streptococcal extract has 80% protein and 7% carbohydrate. The glomerular fraction contains 1.5 to 2% sialic acid but no appreciable phosphorous whereas the streptococcal fraction has no sialic acid but 3.7% phosphorous.

Experimental glomerulonephritis was induced in rhesus monkeys both actively and passively. The actively induced disease was brought about by immunizing the animals with alum-precipitated PGT CM (soluble glycoprotein from the nephritogenic streptococcal protoplasmic membrane) and the passively induced disease by intravenous injection of rabbit anti-PGT CM γ globulin-rich fraction. In both instances the disease was moderate in intensity and relatively short in duration. Of special interest however, was that in both instances the γ globulin (whether heterologous or autologous) and C3 deposition was grossly granular and located in the mesangium. Analytical and preparative acrylamide gel electrophoresis of PGT CM would tend to explain the moderate disease induced in that only a small portion of the immunogen employed (12% or less) is cross-reactive with glomerular basement membrane.