NK细胞是淋巴细胞的一个异质亚群,既不属于T淋巴细胞,也不属于B淋巴细胞,与大颗粒淋巴细胞(LGL)关系密切,在外周血中活性最高,然后依次为脾、淋巴结和骨髓。NK细胞具有与其它类型淋巴细胞不同的特点,它无吞噬能力也无粘附性,具有自发性抗多种肿瘤细胞、病毒感染细胞以及某些正常细胞的细胞毒活性. NK cells are a heterogeneous subpopulation of lymphocytes. They are neither T lymphocytes nor B lymphocytes. They are closely related to large granular lymphocytes (LGL). They have the highest activity in peripheral blood, followed by spleen and lymph nodes. And bone marrow. NK cells have different characteristics from other types of lymphocytes, it has no phagocytic ability and no adhesion, and has a cytotoxic activity against a variety of tumor cells, virus-infected cells and some normal cells.