人体免疫活性细胞可分为T淋巴细胞和B淋巴细胞二大系统。B淋巴细胞承担体液免疫,即在抗体刺激下分化成为产生抗体的浆细胞。T细胞又可分为三个亚群,即杀伤性T细胞(T_C细胞),辅助或诱导性细胞(T_H细胞)和抑制性T细胞(T_S细胞)。T_C细胞专司细胞免疫,能杀伤含微生物的细胞、移植细胞、肿瘤细胞等。T_H细胞能辅助T Human immune cells can be divided into T lymphocytes and B lymphocytes two systems. B lymphocytes bear humoral immunity, that is, under the stimulation of antibodies, they differentiate into antibody-producing plasma cells. T cells can be subdivided into three subgroups: killer T cells (T_C cells), helper or induced cells (T_H cells) and suppressor T cells (T_S cells). T_C cell-specific cell immune, can kill microorganisms containing cells, transplanted cells, tumor cells. T_H cells can help T