Optimal conditions for the induction of human mononuclear leukocytes by complexed polyinosinic-polycytidylic acid.

We have defined the optimal circumstances for the induction of human interferon alpha (Hu IFN alpha) in peripheral blood mononuclear cells (PBMC) using complexed polyinosinic-polycytidylic acids (poly rIrC). We have found that a poly rIrC concentration of only 0.1 microgram m/ml or 100 fold less than commonly used in fibroblasts produced maximal yields. Similarly, we have found that the optimal concentration of DEAE-D was 250 micrograms m/ml. Only a minimum exposure period of 30 minutes to the poly rIrC-DEAE-D mixture was found necessary, but the temperature of this incubation was not found to be a critical variant. Finally, we found that addition of exogenous calcium to the inducing solution failed to influence the ultimate titers of the IFN produced.