Time-dependent effect of cyclosporine on mitogenic responses and lymphocyte subset populations in rat spleen and submaxillary lymph nodes

Lipopolysaccharide (LPS)- and concanavalin A (ConA)-induced proliferation a nd T lymphocyte subsets were measured in spleen and submaxillary lymph node s of male rats injected with cyclosporine (5 mg/kg s.c. for 5 days, at 12.0 0 or 24.00 h; animals kept under light from 08.00 to 20.00 h daily). One ho ur before the third injection, Freund's complete adjuvant or its vehicle wa s administered. A suppressive effect of cyclosporine on the mitogenic actio n of LPS was seen in the spleen of rats injected with cyclosporine at noon whereas the effect of ConA remained unaffected, CD4+, CD8+ and CD4+-CD8+ ce lls decreased in spleen and lymph nodes of Freund's adjuvant-injected rats only with cyclosporine given at noon. The results further support occurrenc e of time-of-day-dependent effects of cyclosporine on lymphocyte subsets an d proliferation. Copyright (C) 2000 S. Karger AG, Basel.