Lymph node cells from rats with Heymann's nephritis produce in vitro autoantibodies directed against purified renal tubular antigen.

A method is described for the purification and identification of the nephritogenic glycoprotein in renal tubular epithelium (RTE-Gp) from Wistar and Lewis rats. This antigen is responsible for the induction of Heymann's nephritis (HN) in Lewis rats. RTE-Gp was detected in chromatographic fractions by an enzyme-linked immunosorbent assay using rat antibodies eluted from glomeruli of Lewis rats with active HN. In each step of the purification procedure, an absolute correlation between detection of RTE-Gp in vitro and nephritogenicity in vivo was demonstrated. Lymph node cells obtained from rats with HN produced in vitro autoantibodies in a linear dose-response fashion against both allogeneic and autologous RTE-Gp, as detected by an enzyme-linked immune protein sorbent assay. During a 2 hr incubation period, 10(6) lymph node cells produced 10-40 ng of IgG. Antibody production above background levels could be detected with an input of 10(5) lymph node cells. This study shows that the specific autoimmune response in rats with NH can be measured at the cellular level.