Human interferons alpha and beta have more potent priming activities than interferon gamma.

The priming activities of human IFN-alpha, IFN-beta and IFN-gamma were compared on the same antiviral basis using human buffy coat leukocytes stimulated with Sendai virus or concanavalin A (Con A) to produce IFN-alpha or IFN-gamma, respectively. Pretreatment of leukocytes with any type of IFN enhanced their IFN-alpha and IFN-gamma production, but IFN-alpha and IFN-beta had more potent priming activities than IFN-gamma. IFN-alpha and IFN-gamma did not potentiate the priming activity of each other in either the IFN-alpha or the IFN-gamma producing system. Pretreatment of leukocytes with relatively high doses of IFN-alpha or IFN-beta (1000 to 3000 IU/ml) resulted in a 40- to 50-fold increase in the IFN-gamma production of Con A-stimulated leukocytes. This observation will be of use in producing IFN-gamma with a high titre.