The primary function of natural killer cells is to?

Natural killer (NK) cells are a crucial component of the innate immune system, primarily known for their role in the direct elimination of virally infected and tumor cells. Their primary function is to identify and kill these compromised cells, which often display abnormal surface markers that differ from healthy cells. This ability to recognize and destroy cells that are infected by pathogens or transformed by cancer allows NK cells to help maintain the body’s health and prevent the spread of infection or malignancy.

While NK cells can also secrete cytokines and play a role in the immune response by modulating other immune cells, their standout function is their cytotoxic capability. In contrast, the other functions listed, such as facilitating antibody production and phagocytizing pathogens, are primarily carried out by different immune cells, such as B cells and macrophages, respectively. Therefore, the emphasis on the direct killing action of NK cells aligns with the definition of their primary role in the immune response.