This unit describes methods for inducing autoimmune disease in Brown Norway rats through HgCl(2) injections as well for assessing parameters that characterize the disease by serum IgE concentration assays, anti-laminin antibody measurement, and renal immunofluorescence studies to detect autoantibodies. Also covered are disease induction using autoreactive CD4(+) T(H)2 anti-self MHC class II molecules and preparation of T cell lines. IL-4 is produced very early after the first HgCl(2) injection (beginning at day 3, peaking at day 14, and continuing up to day 30). Thus, IL-4 mRNA expression may be detected in spleen and lymph nodes from HgCl(2)-injected BN rats. The fact that HgCl(2) induces in vitro mRNA IL-4 gene expression in normal BN T cells but not in LEW T cells is probably crucial to susceptibility to the development of autoimmunity in the sense that it may condition the development of autoreactive T cells into pathogenic T(H)2 cells; a test for this condition is therefore also included.