Nephritogenic glycoprotein. XIII. Isolation and its immunochemical characterization of the antigenic substance of membranous glomerulonephritis induced by a single injection of crude nephritogenoside in homologous animals.

Abstract

Studies on the immunochemical characterization were made on the antigenic substance of membranous glomerulonephritis (MG) that is induced, in homologous animals, by a single footpad injection of rat crude nephritogenoside (CNG). In rats injected with rat CNG, typical MG with immunofluorescent granular pattern (immune complex type nephritis) was produced 3-4 months after the injection. Since CNG nephritis is a model which induces MG only in homologous animals, the development of MG in this model should be explained by antigen-autoantibody immune complex mechanism. Thus, the features of the antigenic substance contained in CNG was immunochemically investigated, utilizing the serum (autoantibody) of rats with MG as well as rabbit antiserum to rat tubular brush border antigen (FXIA) (heteroantibody). As a result, two different fractions (fr. 31 and fr. 36) were separated from the antigenic substance contained in CNG: that is, fr. 31 reacts only with rabbit antiserum to rat tubular brush border antigen (FXIA) (heteroantibody) but does not react with the serum (autoantibody) of rats with MG. Fr. 36 does not react with rabbit antiserum to FXIA (heteroantibody) and reacts only with the serum (autoantibody) of rats with MG (which was induced by a single footpad injection of CNG or soluble FXIA). These results suggest immunologically that fr. 36 is the main antigen responsible for the development of MG which is induced in homologous animals by a single footpad injection of CNG.