Accelerated recovery of antigen-presenting cell activity by the administration of interleukin 1α in 5-fluorouracil-treated mice

In this study, we investigated the effect of human recombinant interleukin-1α (IL-1α) on antigen-presenting cell (APC) activity of spleen cells in mice treated with 5-fluorouracil (5-FU). APC activity was determined by the antigen-specific proliferation of T cell clone D10.G4.1 cells. When mice were injected with 5-FU, APC activity of spleen cells was suppressed. The administration of IL-1α accelerated the recovery from this suppression. The most accelerated recovery was observed when these mice were administered with IL-1α both before and after the 5-FU treatment. The recovery was also accelerated when the mice were injected with IL-1α after the 5-FU treatment, but not when injected before the 5-FU treatment. The injection of 5-FU also decreased the cell numbers of whole spleen cells, B cells, and non-T non-B cells (Ig − and Thy-1 − cells). The administration of IL-1α accelerated the recovery of the decreased cell numbers. Both B cells and non-T non-B cells possessed APC activity, but most APC activity of unseparated spleen cells was carried by non-T non-B cells. B cells possessed only 1 20 of the APC activity of non-T non-B cells. The injection of 5-FU decreased APC activity of both B cells and non-T non-B cells, but the administration of IL-1α accelerated its recovery. Thus, the accelerated recovery of APC activity by IL-1α was suggested to be due to the recovery in the numbers of APC activity-bearing cell subpopulations and also due to the recovery of the APC activity of each subpopulation. Possible mechanisms for the recovery were discussed.