The Effects of a Stable Analogue of PGE 1 on the IgG Subclass Response to Particulate Bovine Tubular Basement Membrane in the Brown-Norway Rat

Abstract

Abstract

The IgG subclass and the IgM isotype response to immunization with particulate bovine tubular basement membrane (TBM) and adjuvants was studied in Brown-Norway rats receiving daily injections of a stable analogue of PGE₁ (M-PGE₁). M-PGE₁ slightly reduced the average quantity of circulating TBM antibody as well as the average quantity of eluted IgG per gram of renal tissue as compared to controls. However, M-PGE₁ did not qualitatively affect the distribution of the IgG subclass or IgM isotype response to TBM. The IgG response, which occurred predominantly in the IgG₁ and IgG_2a subclasses, increased from Days 8 to 14 after immunization, while the IgM response decreased over the same time period. The percentage of TBM antibody in the IgG_2b subclass was markedly decreased as compared to the percentage of IgG_2b antibody in total IgG. A substantial heterogeneity in the IgG subclass response was noted among individual rats with IgG₁ constituting from 46 to 82% of circulating TBM antibody. Although no correlation between the IgG subclass response and the severity of tubulointerstitial nephritis was noted, heterogeneity in the IgG subclass response to autoantigens may, nevertheless, theoretically play an important role in the pathogenesis of autoimmune inflammatory phenomena.