有关动物和人的许多研究结果表明,肿瘤抗原可被宿主的免疫系统视为“非己”.尽管存在着针对肿瘤抗原的细胞免疫反应和体液免疫反应,但是肿瘤还是持续而进行性地生长.虽然,在早期宿主的免疫功能可能是完整的,但随着肿瘤进行性地生长和播散,免疫反应发生普遍损害.有待解答的几个问题是:当宿主抗肿瘤的免疫反应完整无缺时,为什么肿瘤能进行性生长?在肿瘤进行性生长时是哪些因素引起免疫抑制?这种抑制作用究竟是由肿瘤直接引起的,或者它只是宿主进行性虚弱的表现,还是来源于宿主的多种因素的精心之作?为了解答上述提问,本文概述了近年有关研究的结果. Many studies on animals and humans have shown that tumor antigens can be considered as “non-self” by the host’s immune system. Despite the presence of cellular and humoral immune responses to tumor antigens, tumors continue to progress continuously. Growth. Although, the immune function of the host may be intact in the early stages, but as the tumor progressively grows and spreads, the immune response is generally compromised. Several questions remain to be answered: When the host anti-tumor immune response is intact Why does the tumor undergo progressive growth? What are the factors that cause immunosuppression during progressive tumor growth? Is this inhibition directly caused by the tumor, or is it simply the performance of the host’s progressive weakness, or is it from the host? In order to answer these questions, this article outlines the results of recent studies.