Prevention ofexperimental autoimmuneuveoretinitis andexperimental autoimmunepinealitis in(Lewis x Brown-Norway)F1ratsby HgCl2injections

SUMMARY Mercuric chloride (HgCI2) induces inBrown-Norway (BN)and(Lewis x Brown-Norway) F1hybrid ratsatransient autoimmune disease characterized bytheproduction ofvarious antibodies toself and non-self antigens andbyadramatic increase ofserum IgE.Experimental autoimmune uveoretinitis (EAU)canbeinduced inLewis (LEW)and(LEWx BN)F.hybrid ratsbyasingle immunization with retinal S-antigen (S-Ag). Besides uveoretinitis, animals immunized withS-Agdevelop an autoimmune pinealitis (EAP). Wedemonstrate inthis study that (LEWx BN)F.hybrid rats,injected with HgCl27daysbefore S-Agimmunization, arequite efficiently protected against EAU andEAP.We alsoshowthatHgCl2-induced protection isneither duetoacytotoxic effect ofHgCl2 nor toCD8+Tcell dependent mechanisms nor totheHgCI2-induced increase ofserum IgEconcentration. Therole ofother hypothetical mechanisms, such asanti-S-Ag anti-idiotypic antibodies and/or HgCI2-induced unbalance between T-helper cell subsets, isdiscussed.