Immunomodulatory activity of low doses of interferon alpha,beta in mice.

We evaluated the immunomodulatory effects of mouse interferon (IFN) alpha, beta on the specific humoral response of mice (OF1) to sheep erythrocytes and on cell-mediated immunity by studying the cytotoxic activity of allospecific T-cells (CTL) and natural killer (NK) cells. Four injections of 2 IU of IFN before administration of the antigen did not have an effect on the humoral response, whereas 4 injections of 2 x 10(-10) IU of IFN caused a significant increase in the number of antibody-secreting cells. When C57BL/6 mice were treated with 5 injections of 2 IU or 2 x 10(-10) IU of IFN before the second immunization with allogeneic cells, the CTL activity was not modified; but when the mice were also treated with 2 x 10(-10) IU 3 times after immunization, this activity was strongly stimulated. IFN caused a decrease in the activity of CTL from NZB at both doses. The cytotoxic response of NK cells was stimulated by 5 injections of 2 IU of IFN in both strains of mice. The results of our study suggest that very low doses of IFN alpha,beta have immunopharmacologic activity.