Suppressive effect of kanglemycin C on T- and B-lymphocyte activation

To elucidate the suppressive effect of kanglemycin C (Kan) on lymphocyte proliferation and T-lymphocyte subsets.

Splenocyte proliferation was quantified with [3H]thymidine ([3H]TdR) pulsing method or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetery. L3T4+ and Lyt2+ T-cell subsets were measured with fluorescence-activated cell sorter (FACS). Splenocyte viability was assessed with trypan blue exclusion.

Like ciclosporin (Cic), Kan 8, 40, 80, and 400 nmol.L-1 inhibited the proliferation of 20%-80% incubated mouse splenocytes stimulated by concanavalin A (Con A) 5 mg.L-1, phytohemagglutinin (PHA) 5 mg.L-1, tetradecanoylphorbol acetate (TPA) 10 micrograms.L-1 + ionomycin (IM) 0.5 mg.L-1, and alloantigen (mixed lymphocyte reaction). Kan had no toxicity to the splenocytes at the treated doses. Suppression by Kan was declined with addition time of Kan after culture onset. Furthermore, the suppressive effect of Kan on splenocyte proliferation stimulated by lipopolysaccharides (LPS) 10 mg.L-1 was similar to that on splenocyte proliferation mediated by Con A. Unlike Cic, Kan reversed the ratio of L3T4+/Lyt2+ T-cell subsets.

Kan had a suppressive action on proliferation of T- and B-lymphocytes and had a selective effect on helper-inducer T-lymphocyte (Th) subset from Cic. Suppression by Kan was time-dependent and not associated with toxicity of Kan.