Effect of 1,1-dimethylhydrazine on lymphoproliferation and interleukin 2 immunoregulatory function

The studies reported here suggest that the immunomodulatory effects of 1,1-dimethylhydrazine (UDMH) are associated, in part, with interference with interleukin 2 (IL-2) regulatory action. Concanavalin A (Con A)-stimulated DNA synthesis in murine splenocytes was inhibited from 18.6 to 44.1% at sub-toxic concentrations of UDMH (10 to 50 micrograms/ml) and IL-2-dependent DNA synthesis in CTLL-20 cells was inhibited from 11.3 to 41.58% at sub-toxic concentrations of UDMH (10 to 50 micrograms/ml). In addition, UDMH suppressed phorbol myristic acetate (PMA)-stimulated IL-2 production in EL-4 cells by up to 30% and slightly suppressed IL-2 production by Con A-stimulated murine splenocytes. In all cases, inhibition was evident at sub-toxic UDMH concentrations and was demonstrated to be independent of inactivation of IL-2 or interference with IL-2 absorption. It is suggested that UDMH has the potential to modify immune function through interference with IL-2 production and especially the lymphoproliferative response to IL-2.