Natural Killer Cells

Natural killer (NK) cells are lymphocytes that are part of the body’s innate immune system. Unlike T cells and B cells, which are part of the adaptive immune response, NK cells can recognize and destroy infected or abnormal cells, such as tumor cells, without prior exposure to the pathogen. Key functions of NK cells include:

• Killing infected cells: NK cells target and eliminate virus-infected cells and cancer cells by inducing apoptosis.
• Releasing cytokines: They secrete signaling molecules that enhance the immune response by activating other immune cells like macrophages and dendritic cells.
• Recognizing abnormal cells: NK cells use surface receptors to detect cells that lack “self” markers (MHC class I molecules) typically found on healthy cells.

NK cells act as a first line of defense, providing rapid responses to infected or transformed cells.