cyclosporin-g and Retinitis

Two analogs of cyclosporine A (CsA), cyclosporine G (CsG) and cyclosporine D (CsD), were compared to CsA with regards to their effects on experimental autoimmune uveoretinitis (EAU) as well as their adverse effects on renal functions. When administered daily on days 0-14 after immunization with S-antigen, CsA was the most effective of all in inhibiting EAU followed by CsG: 20-30 mg/kg/day of CsG appeared to have the same effect as 5 mg/kg/day of CsA. The effect of CsD was the least. When administered from day 7 after immunization, CsA and CsG were also effective in inhibiting the development of EAU. As for the adverse side effects, CsA was the most nephrotoxic: the toxic changes were morphologically found with doses of CsA at 10 mg/kg/day or higher. CsG and CsD were not nephrotoxic even at 30 mg/kg/day. The effects of CsG on immune responses were very similar to those of CsA. Both agents exhibited selective inhibition on the cell-mediated immune responses to S-antigen, while having no effect on antibody production.

Topics: Animals; Antibody Formation; Antigens; Arrestin; Autoimmune Diseases; Cyclosporine; Cyclosporins; Eye Proteins; Immunity, Cellular; Kidney; Kidney Function Tests; Male; Rats; Rats, Inbred Lew; Retinitis; Skin Tests; Uveitis

The effect and relative efficiency of cyclosporin A (CsA) and cyclosporin G (CsG) on suppressing the activation of primed autoimmune rat T-helper lymphocytes were assayed. The autoimmune T-helper cells (ThS) are a long-term line specific to the retinal soluble antigen (SAg) and can adoptively transfer experimental autoimmune uveoretinitis (EAU), after in vitro reactivation with antigen or mitogen, to naive syngeneic hosts. Antigen-driven production of interleukin-2 (IL-2) and antigen-driven proliferation were inhibited in a dose-dependent manner and to a similar extent at each of the respective cyclosporin concentrations. CsA was 8-10 times more potent than CsG, with ID50-CsA occurring at 0.5 to 2 ng/ml, and ID50-CsG at 5 to 20 ng/ml, depending on the experiment and the cyclosporin batch. Addition of exogenous lymphokines in the form of rat spleen concanavalin A (Con A)-conditioned medium (SCM) or recombinant IL-2 (but not recombinant IL-1) was able to reverse only about half of the inhibition, as measured along the linear part of the dose-response curve. Inhibition of IL-2 production was lost if a maximally inhibitory dose of cyclosporin was added to the cultures later than 8 hr after antigen stimulation, while proliferation was still suppressed to 50% by cyclosporin added as late as 12 hr and could not be restored by addition of SCM. Both cyclosporins at concentrations that blocked proliferation and IL-2 production significantly suppressed the generation of high-affinity and low-affinity IL-2 receptors by ThS in response to antigen (as assayed by direct binding of 125I-IL-2). These results suggest that CsA and CsG inhibit antigen-induced expansion of ThS by interfering with more than one activation step. In contrast, the in vitro activation of the uveitogenic potential of ThS cells, incubated with antigen in the presence of CsA or CsG and adoptively transferred into untreated recipients, was not affected by the cyclosporins. Thus, triggering of the pathogenic potential of primed autoimmune T-helper lymphocytes can take place in the presence of cyclosporin and in the absence of cellular proliferation.

Topics: Animals; Antigens; Arrestin; Autoimmune Diseases; Cyclosporine; Cyclosporins; Eye Proteins; Immunosuppression Therapy; Interleukin-1; Interleukin-2; Lymphocyte Activation; Lymphocyte Cooperation; Pineal Gland; Rats; Rats, Inbred Lew; Receptors, Immunologic; Receptors, Interleukin-2; Recombinant Proteins; Retinitis; T-Lymphocytes, Helper-Inducer; Uveitis

Topics: Animals; Autoimmune Diseases; Cyclosporine; Cyclosporins; Kidney; Rats; Rats, Inbred Lew; Retinitis; Uveitis