Adenovirus-Mediated Murine Interferon-γ Receptor Transfer Enhances the Efficacy of IFN-γ in Vivo

Interferon gamma (IFN-gamma) plays an important role in immune response, apoptosis, and anti-tumor activity. Its biological activity depends on expression of IFN-gamma receptor (IFN-gammaR). To address whether increased expression of IFN-gammaR is associated in vivo with a higher biological response by IFN-gamma, we constructed an adenovirus vector including murine IFN-gammaR (Ad-mIFN-gammaR). We confirmed the appropriate function of mIFN-gammaR derived from Ad-mIFN-gammaR based on the observation of signal transduction and transcription. We also found that elevated expression of mIFN-gammaR increases sensitivity to recombinant murine IFN-gamma (rmIFN-gamma) in vitro in target cells. Furthermore, we demonstrated that the growth rate of tumors transfected with Ad-mIFN-gammaR is suppressed in response to rmIFN-gamma in vivo and that such growth suppression is partly due to apoptosis. To our knowledge, this is the first report of adenovirus-mediated IFN-gammaR gene transfer being effective in augmenting the biological activity of IFN-gamma, and the strategy employed in the present study will be useful in studying other kinds of cytokine receptors and applications to gene therapy for cancer and infectious diseases.