Which type of cells is responsible for nonspecific killing of tumor cells?

Natural killer (NK) cells are essential components of the innate immune system, specifically involved in the nonspecific killing of tumor cells and virally infected cells. Unlike T lymphocytes (which are part of the adaptive immune system and require specific antigen recognition), NK cells do not need prior sensitization to detect and eliminate target cells. They can recognize and destroy stressed, infected, or transformed cells without the need for antibodies or major histocompatibility complex (MHC) molecules.

NK cells perform their function by releasing cytotoxic granules that contain perforin and granzymes, which lead to the lysis of the target cells. They play a crucial role in surveillance against tumors, helping to control early stages of tumor development and progression. Additionally, they can secrete various cytokines that enhance immune responses and recruit other immune cells to the site of infection or tumor.

In contrast, T lymphocytes, while also critical for immune responses, primarily target cells that present specific antigens through MHC molecules and are part of the adaptive immune response. B lymphocytes are responsible for antibody production which directly neutralizes pathogens, rather than performing direct cytotoxic functions. Macrophages are versatile immune cells that can phagocytose pathogens and dead cells, but their