Highly efficient action of autocrine mouse interferon‐γ expressed via a retroviral vector

Following infection with a mouse interferon-gamma (IFN-gamma)-producing retrovirus, various types of mouse cell lines began to constitutively secrete IFN-gamma in the culture medium, but the IFN-gamma production level varied according to cell type. Effects of the IFN-gamma on the IFN-gamma-producing cell itself (autocrine effects) were examined. In the IFN-gamma-producing cells, the expression of the major histocompatibility complex class I genes was augmented; this augmentation was remarkable in T cell lines tested in this work, regardless of their poor IFN-gamma production. This autocrine effect was highly efficient and could not easily be abrogated by the exogenous addition of anti-IFN-gamma antibodies. Such antibody resistance was also observed for the antiviral effect of the autocrine IFN-gamma on an IFN-gamma gene-transferred fibroblast line. These results suggest that apparently low titers of physiological IFN-gamma might exert strong in vivo autocrine and possibly paracrine effects.