Description

Natural killer (NK) cells are a type of cytotoxic lymphocyte that plays a critical role in the innate immune system. They are a part of the body’s first line of defense against infected and malignant cells. Unlike other immune cells, NK cells do not require prior activation to exert their function. Instead, they constantly monitor the body for abnormal cells and rapidly respond to them.

NK cells can recognize and kill virus-infected cells, as well as cancerous cells, without prior sensitization. They do this by releasing cytotoxic granules containing perforin and granzymes, which induce apoptosis (cell death) in the target cell. Additionally, NK cells can also produce cytokines such as interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), which help regulate the immune response.

NK cells play a crucial role in immune surveillance, particularly in controlling the early stages of viral infections and preventing the development of tumors. Dysfunction or deficiency in NK cell activity has been associated with increased susceptibility to certain infections and a higher risk of cancer development.