Immunomodulatory effects of linomide in animals immunized with immunopathogenic retinal antigens: dissociation between different immune functions.

Linomide (LS-2616, quinoline-3-carboxamide) has been reported to exert a diverse range of effects on the immune system. On one hand, this drug was found to stimulate the immune system and to enhance activities such as DTH or allograft rejection. On the other hand, linomide was shown to inhibit the induction of experimental autoimmune encephalomyelitis and myasthenia gravis, as well as the development of diabetes in non-obese diabetic (NOD) mice. Here we report the effects of linomide in animals immunized with uveitogenic retinal antigens. Treatment with linomide completely inhibited the development of experimental autoimmune uveoretinitis (EAU) in mice immunized with interphotoreceptor retinoid-binding protein and markedly suppressed EAU in rats immunized with S-antigen (S-Ag). In addition, linomide-treated rats exhibited reduced antibody production and lymphocyte proliferative response to S-Ag. In contrast to these suppressive activities, linomide treatment did not affect the development of adoptively transferred EAU in rats and moderately enhanced the DTH reactions to S-Ag in immunized rats in which EAU and other immune responses to this antigen were suppressed.