在肿瘤免疫的研究中虽然明确地发现癌组织中有免疫活性细胞的存在,但并未能获得抗肿瘤免疫的效果,因此认为肿瘤机体内存在着抑制抗肿瘤免疫力的因素,其中研究较活跃的因素之一是封闭因子。目前对于封闭因子的实质仍无定论,可能性有:(1)肿瘤抗原;(2)肿瘤抗体;(3)肿瘤抗原抗体复合物。因为肿瘤引流淋巴结是肿瘤免疫反应最早和最主要的部位,因此,我们以引流淋巴结的组织形态学改变 Although the existence of immunocompetent cells in cancer tissues was clearly found in the study of tumor immunity, the effect of anti-tumor immunity was not obtained. Therefore, it is considered that there are factors suppressing the anti-tumor immunity in tumor bodies, among which the research is more active. One of the factors is the blocking factor. At present, the essence of the blocking factor is still inconclusive. The possibilities are: (1) tumor antigen; (2) tumor antibody; (3) tumor antigen-antibody complex. Since the tumor-draining lymph nodes are the earliest and most important site of tumor immune response, we have organized morphological changes in the draining lymph nodes.