Abstract
Systemic injection of high doses of antigen into a preimmunized animal results in transient unresponsiveness of cell-mediated immune responses. This phenomenon is known as desensitization. Serum interleukin 2 (IL-2) activity was found transiently in desensitized mice 3 hr after the antigen challenge. These mice did not reveal antigen-nonspecific delayed-type hypersensitivity (DTH) 1 day after the challenge. Spesific suppression of DTH was observed in later stages. Sera from 3 hr-desensitized mice had suppressive effects on DTH in preimmunized mice. Administration of recombinant IL-2 into preimmunized mice led to the failure of development of DTH to antigens. These observations indicate that IL-2 play is important in a suppressive environment.
