(二)体液因素的作用体液因素对于肿瘤有有利和不利两方面作用。前者如体液性抗体有助于抑制肿瘤细胞的生长,后者如封闭因子等有利于肿瘤细胞的生长。 1.体液性抗体 (1)细胞毒性抗体(依赖于补体的抗体):在补体的参加下能杀伤肿瘤细胞、抑制肿瘤生长的抗体称为细胞毒性抗体,属于免疫球蛋白M。一般肿瘤患者中,细胞毒性抗体的效价很低。血液中抗体的 (B) The role of humoral factors Humoral factors have beneficial and unfavorable effects on tumors. The former, such as humoral antibodies, help inhibit the growth of tumor cells. The latter, such as the blocking factor, is beneficial to the growth of tumor cells. 1. Humoral antibodies (1) Cytotoxic antibodies (complement-dependent antibodies): Antibodies that kill tumor cells and inhibit tumor growth with the participation of complement are called cytotoxic antibodies and belong to immunoglobulin M. In general cancer patients, the titer of cytotoxic antibodies is very low. Blood antibodies