Effects of metal ions on cyprinid fish immune response: in vitro effects of Zn2+ and Mn2+ on the mitogenic response of carp pronephros lymphocytes.

Lymphocytes from the pronephros of carp (Cyprinus carpio L) have been subjected to transformation by mitogens, concanavalin A (Con A), phytohemagglutinin (PHA), and lipopolysaccharides (LPS), with Zn or Mn at varying concentrations. Addition of Zn2+ (10(-7) to 10(-3) M) to mitogen-stimulated T and B cells enhanced [3H]thymidine incorporation. Addition of 10(-5) M Zn2+ inhibited the response to Con A, PHA, and LPS. At this concentration, Zn was toxic. Addition of Mn2+ (10(-7) to 10(-3) M) to mitogen-stimulated lymphocytes enhanced [3H]thymidine incorporation. This effect was observed with Con A- and PHA-stimulated lymphocytes, but not with LPS-stimulated lymphocytes. In contrast, addition of 10(-1) M Mn2+ to lymphocyte cultures exerted an inhibitor on the response to Con A or to PHA, while the response to LPS was unaffected. Addition of 10(-1) M Mn2+ to Con A- or PHA-stimulated cultures at different times after initiation of stimulation indicated that Mn2+ was inhibitory only when it was added before the first 16 hr of cultures. The inhibition induced by 10(-1) M Mn2+ could be reversed by adding 2 mM CaCl2 to the culture.