University of Central Florida (UCF) PCB3233 Immunology Exam 2 Practice Test

Type I interferons directly engage natural killer cells to boost the innate antiviral response. When IFN-α/β bind to IFN receptors on NK cells, signaling pathways enhance their cytotoxic machinery—more perforin and granzymes—and increase their ability to kill virally infected targets. They alsodrive NK cells to produce IFN-γ, which in turn activates macrophages and supports a stronger Th1-type response. This rapid, antigen-independent activation of NK cell–mediated cytotoxicity is the hallmark of how Type I interferons mobilize the earliest innate defense against viral infection. Other cells can respond to interferons, but the most prominent and immediate innate activation is seen in NK cells; B cells are not the primary innate responders to interferon signaling.