In the early 1970s, Dr. Ronald Herberman made a groundbreaking discovery in immunology by identifying a novel class of lymphocytes, which he named natural killer (NK) cells. These cells are a critical component of the innate immune system and play a central role in the body’s defense against tumors and virally infected cells. NK cells are unique in their ability to recognize and destroy malignant or infected cells without prior sensitization, distinguishing them from other immune cells like T and B lymphocytes.

NK cells are activated by key cytokines, particularly interleukin-2 (IL-2), interleukin-12 (IL-12), and interleukin-15 (IL-15), which enhance their cytotoxic activity. Upon activation, NK cells release powerful cytokines such as interferon-gamma (IFN-γ). IFN-γ has potent immune-modulating effects and contributes to the direct lysis of susceptible target cells by promoting the destruction of cancerous or infected cells. This ability to rapidly respond to and eliminate abnormal cells has made NK cells a focal point in immunotherapy research, especially in cancer treatment and viral infections.