Identification of the nuclear antigen involved in mercury-induced glomerulopathy in the rat

Low doses of inorganic mercury may cause an immune complex glomerulopathy in man and in experimental animals. In the PVG/C rat this mercury-induced glomerulopathy coincides with the occurrence of anti-nuclear antibodies in the serum. The same anti-nuclear activity can be demonstrated in the acid-eluted glomerular immune deposits. The characterization of the pathogenic nuclear antigen, to which these antibodies are induced, is the subject of this study. The effect of acid, fixatives, nucleases and proteases on indirect immunofluorescence of anti-nuclear antisera and IgG purified from these sera is studied, combined with absorption with several nuclear constituents and specific antigen blocking by Concanavalin A. The results show that the nuclear antigen involved is part of the nonhistone chromatin protein fraction.