Immune-enhancing effect of recombinant human interferon-beta produced in Escherichia coli on human peripheral blood mononuclear cells in vitro.

Highly purified recombinant fibroblast interferon produced by Escherichia coli (ReIFN-beta) was tested for its ability to stimulate natural killer (NK) cell activity, antibody-dependent cell-mediated cytotoxicity (ADCC) and monocyte-macrophage phagocytic activity in human peripheral blood mononuclear cells (PBM) in comparison with natural human fibroblast interferon (IFN-beta). The NK cell activity against target cells (K-562, Molt-3, CCRF-HSB-2, CCRF-CEM, Daudi, and HeLa S3) was enhanced by ReIFN-beta and IFN-beta. Augmentation of cytotoxicity of NK cells was observed at a concentration of ReIFN-beta as low as 1 U/ml and increased in a dose-dependent manner. The enhancing effect of ReIFN-beta was expressed sufficiently during a 1-hr incubation with effector cells, and IFN-beta showed kinetics and potency similar to those of ReIFN-beta. ADCC was measured with chicken red blood cells (CRBC) or CCRF-CEM coated with each antibody, as target cells. Pretreatment of PBM with ReIFN-beta caused a significant increase in ADCC activity against both targets, and the enhancing activity of ReIFN-beta was similar to that of IFN-beta. Phagocytic activity of adherent cells in PBM against CRBC was enhanced by ReIFN-beta and IFN-beta as determined by microscopical cytologic examination and by the 51Cr-labeled CRBC-uptake method. From these results, it can be concluded that recombinant human IFN-beta modulates NK cell activity, ADCC and phagocytic activity of human PBM as effectively as natural human IFN-beta.