Induction of susceptibility to HgCl2 immune glomerulonephritis in the Lewis rat by immunocompetent cells from susceptible F1 hybrids

HgCl2 induces nonspecific immunosuppression in Lewis rats

Brown-Norway (BN) rats injected with HgCl2 have been previously shown to develop a variety of autoimmune abnormalities. The susceptibility of BN rats is genetically controlled, and Lewis rats bearing a different RT1 haplotype are resistant. It will be shown in the present study that the number of MRC OX-8+ (suppressor/cytotoxic) cells increases in the spleen and lymph nodes of Lewis rats injected with HgCl2. The responsiveness to T cell mitogens and to alloantigens is concomitantly inhibited. Spleen cells from Lewis rats injected with HgCl2 fail to induce a local graft-vs.-host reaction. Data presented show that MRC OX-8+ cells are involved in the immunosuppression in Lewis rats treated with HgCl2. Furthermore, lymph node cells and MRC OX-8+ cells from these rats are able to inhibit the normal mixed lymphocyte reaction indicating that suppression is active. Thus, HgCl2 is able to trigger immune dysregulation leading either to autoimmunity or to immunosuppression depending upon the genetic background of the rat strain tested.

Polyclonal effect of HgCl2 in the rat, its possible role in an experimental autoimmune disease

Mercuric chloride induces an autoimmune glomerulonephritis in Brown-Norway (BN) but not in Lewis (LEW) rats. Injection of HGCl2 into BN rats regularly produced a transient appearance of plaque-forming cells (PFC) of anti-2,4,6-trinitrophenyl and anti-sheep red blood cell specificity and circulating anti-single-stranded DNA antibodies. Addition of HgCl2 to spleen cell cultures from BN rats induced an increase in anti-trinitrophenyl PFC and reverse PFC. This effect was no longer observed when nylon wool column-depleted or anti-Thy-1 antiserum-treated spleen cells were cultured in the presence of HgCl1. These data suggest that HgCl2 acts as a polyclonal activator on spleen cells in BN rats, but not on isolated B lymphocytes. In contrast, no effect of HgCl2 on immunoglobulin production was observed in LEW rats. Since polyclonal activation and immune-type nephritis are both seen in BN but not in LEW rats, polyclonal activation may participate in the pathogenesis of the HgCl2-induced autoimmune disease of BN rats.