The influence of environmental temperature on the lymphocyte populations in carp (Cyprinus carpio L.)

The influence of environmental temperature upon the lymphocyte populations in carp (Cyprinus carpio L.) has been studied by immunoperoxidase labeling using different antisera. In carps kept in a warm and a cool environment, respectively, rabbit anti-carp IgM as well as rabbit anti-carp Fc antiserum showed different percentages of Ig-positive lymphocytes, whereas the percentage remained unaffected by temperature after the use of rabbit anti-carp Fab antiserum with a specificity against L-chains. It is clear from these observations that the "B" lymphocytes of carp are not temperature-dependent, while the "T" lymphocytes are extremely temperature-dependent, decreasing at low temperatures and increasing at elevated temperatures. The possible causes of the variation with temperature in the numerical ratios of lymphocyte populations and their importance for immunoreactivity are discussed.