IDENTIFICATION OF AN INTERLEUKIN-2 SUBSTANCE IN SPLENOCYTE CULTURE SUPERNATANT OF GRASS CARP CTENOPHARYNGODON IDELLUS AND CHINESE SOFT-SHELLED TURTLE TRIONYX SINENSIS

Interleukin 2(IL-2)activity by thymocyte(C57BL/6-8 mice)proliferation assay and fibroblast(L929fibroblasts)cytotoxicity assay has been found in supernatant of mitogen(ConA)stimulated splenocyte cultures of grass carp Ctenophaxyngodon idellus, Chinese soft shelled turtle Trionyx sinensis.This IL-2 activity was neutralized by polyclonal anti human IL-2 antisera.Besides, the splenocyte culture supernatant(IL-2)of Trionyx sinensis increased obviously thymocyte(Trionyx sinensis)proliferation,which was also neutralized by polyclonal anti human IL-2 antisera,and eliminated the suppressive effect of rabbit anti thymocyte(Trionyx sinensis)antisera(RATTS)on thymocyte(Trionyx sinensis).Further,with indirect immunohistochemistry technique,CD25(IL-2 receptor or IL-2R)cross reaction has been identified on lymphocyte membrane of Ctenophaxyngodon idellus and Trionyx sinensis using mouse monoclonal antibody directed against Human Leucocyte Differentiation Antigen CD25(IL-2R).