The immune system responds to viral infections by introducing a complex interplay of immune cells and factors, whose goal is to eliminate the intruding pathogen. One such effector cell in the antiviral response is the Natural Killer (NK) cell, which secretes inflammatory cytokines and directly kills infected cells. The focus of our research is aimed at defining the signals that NK cells require to mount an effective immune response against pathogens. We are also exploring the regulatory mechanisms keeping NK cells in check, thereby safeguarding against potential autoimmunity.