Regulatory cells generated by testicular tolerization to retinal S-antigen: possible involvement of IL-4, IL-10, and TGF-beta in the suppression of experimental autoimmune uveoretinitis.
Intratesticular injection of a retinal protein (S-antigen) into Lewis rats induces systemic immunotolerance (designated orchidic tolerance) and renders animals refractory to experimental autoimmune uveoretinitis (EAU) produced by S-antigen immunization. We demonstrated in this work that the immunotolerance could be transferred to syngeneic naive rats by both CD4+ and CD8+ regulatory cells. Attempts were then made to characterize the cytokines involved in the immunosuppressive activity of these regulatory cells. Using the in vitro lymphoproliferation assay, the inhibitory effect of CD4+ cells on effector cells was found to be reversed by antibodies against IL-4 and IL-10 but not by anti-TGF-beta antibody. IL-4 (IC50 = 1.6 ng/10(6) cells) and IL-10 (IC50 = 0.6 ng/10(6) cells) added to the assay medium were potent inhibitors of effector cell proliferation. Increased immunoreactivity and mRNA expression for IL-4 and IL-10 was observed for CD4+ regulatory cells. The inhibitory effect of CD8+ regulatory cells was reversed by anti-TGF-beta antibody but not by antibodies against IL-4 and IL-10. Compared with control CD8+ cells, CD8+ cells from tolerized rats demonstrated higher immunoreactivity for TGF-beta but did not show an enhanced expression of mRNA for TGF-beta. TGF-beta 1 and TGF-beta 2 added to effector cells showed dichotomous effects; both isoforms stimulated cell proliferation at 2.5 ng/10(6) cells and inhibited at lower or higher concentrations. These results led us to conclude that IL-4 and IL-10 are important cytokines for the immunosuppressive effect of CD4+ regulatory cells generated in orchidic tolerance. TGF-beta is an important immunosuppressive cytokine for CD8+ regulatory cells but further studies will determine whether other cytokines are also involved.
Yotsukura
J
J
Department of Ophthalmology, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA.
Huang
H
H
Singh
A K
AK
Shichi
H
H
D000818:Animals; D019393:Arrestin / Q000276:immunology*; D001327:Autoimmune Diseases / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D004195:Disease Models, Animal; D007108:Immune Tolerance; D066298:In Vitro Techniques; D016753:Interleukin-10 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D015847:Interleukin-4 / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D008213:Lymphocyte Activation; D008297:Male; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011917:Rats, Inbred Lew; D012173:Retinitis / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D013737:Testis / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000096:biosynthesis / Q000235:genetics / Q000494:pharmacology; D014605:Uveitis / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*
D019393:Arrestin; D016207:Cytokines; D017931:DNA Primers; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D016753:Interleukin-10; D015847:Interleukin-4