[Intracerebroventricular injection of interleukin 1 receptor antagonist antagonises on the generation of immuno-suppressive factor in restraint mice].

Our previous work showed that a lymphocyte proliferation suppressing factor could be found in the serum of restraint mice. In the present work, it was found that intracerebroventricular (icv) injection of IL-1 receptor antagonist (IL-1Ra) was found capable of suppressing the production of such a serum protein under restraint stress. Nearly complete suppression could be achieved by 5.0 micrograms IL-1Ra. Intracerebroventricular injection of IL-1 beta (1 pg), however, increased the generation of the supressive protein. Neither intraperitoneal (ip) injection of IL-1Ra or IL-1 beta had any effect on the generation of the protein. The fact that icv. injection of a very small dose of IL-1 beta (0.06 fmol) was effective on the generation of the supressive protein led us to suggest that IL-1 in brain might act as an important mediator between CNS and the immune system.