免疫活性细胞是指能胜任免疫作用的淋巴细胞,它们能识别异物,并能通过增殖分化产生抗体或淋巴因子,从而发挥特异性免疫反应的细胞。由于单核-巨噬细胞系,白细胞(嗜中性、嗜酸性和嗜碱性粒细胞),肥大细胞和血小板等也参加免疫反应,因此,从广义上来讲,这些细胞也属于免疫活性细胞。 (一)起源免疫活性细胞多为血细胞,巨噬细胞虽不属血细胞,但它也发生于血源性细胞。因此,免疫细胞发生与血细胞发生过程是一致的,均来自造血干细胞。哺乳类的干细胞在胚胎早期主要来自卵黄囊的血岛,然后由胚肝、胚脾和骨髓产生(图1)。人类胚胎期造血分三期:早期在卵黄囊 Immunocompetent cells are lymphocytes that are capable of playing an immunological role. They recognize foreign bodies and can produce antibodies or lymphokines to proliferate and differentiate to exert specific immune responses. Since monocyte-macrophage cell lines, leucocytes (neutrophilic, eosinophilic and basophil), mast cells and platelets also participate in the immune response, they are broadly classified as immunocompetent cells. (A) the origin of immune cells and more blood cells, macrophages, although not blood cells, but it also occurs in blood-derived cells. Therefore, the occurrence of immune cells is consistent with the process of hematopoiesis, all from hematopoietic stem cells. Mammalian stem cells are predominantly derived from the blood island of the yolk sac early in the embryo and are then produced by embryonic liver, embryo spleen and bone marrow (Figure 1). Human embryonic hematopoiesis in three phases: early in the yolk sac