Zinc (Zn2+) and fish immune response effect on carp IL2-like production and activity

Supernatants obtained from PHA-activated pronephric carp lymphocytes were able to provoke the growth of carp blasts but not from fresh lymphocytes without mitogens. These supernatants contain certainly soluble growth factor(s) such as IL2. The addition of Zn2+ (1 mM) to lymphocyte cultures could not enhance supernatants' ability to promote blast proliferation. When Zn2+ and PHA (50 micrograms/ml) were added, respectively, supernatants obtained could enhance significant tritiated thymidine incorporation in blasts. Zn2+ by itself is not able to provoke the growth of blasts in vitro. In contrast, the addition of Zn2+ and PHA-stimulated lymphocyte supernatants in vitro to blasts or nonstimulated lymphocyte cultures enhances their mitotic capacity.