在抗感染免疫和自身免疫反应中,淋巴样细胞,特别是T细胞,通过识别与细胞表面Ⅱ类移植抗原相连的微生物抗原或自身抗原而控制最终反应的程度.对T细胞与巨噬细胞、上皮朗罕氏细胞及脾脏树突状细胞间相互作用的研究表明,表达Ⅱ类抗原的细胞在T细胞激活中起重要作用.因为这些细胞能提呈抗原和产生淋巴因子.最近,组织切片的免疫形态学研究提示,不仅免疫系统的细胞表达Ⅱ类抗原,而且一些非淋巴样细胞(如内皮细胞和多种上皮细胞)也表达,但对其功能仍不清楚.在一个器官的完整结构中,可发现多种表达Ⅱ类移植抗原的留居细胞和游走细胞,因此,对各种表达Ⅱ类抗原细胞的表型、来源和定位的确切阐述将是了解许多局部免疫反应的基础.值得注意的是,Ⅱ类抗原的表达是不恒定的,随细胞功能特性而变化,特 In anti-infective and autoimmune responses, lymphoid cells, particularly T-cells, control the extent of the final reaction by identifying microbial antigens or autoantigens attached to cell surface class II transplant antigens. T lymphocytes, macrophages, Studies of the interaction between epithelial Langerhans cells and dendritic cells in the spleen have shown that cells that express class II antigens play an important role in T cell activation because these cells are capable of presenting antigens and producing lymphokines and recently, Immunomorphological studies suggest that not only the cells of the immune system express class II antigens, but also some non-lymphoid cells (such as endothelial cells and a variety of epithelial cells), but their function remains unclear.In the complete structure of an organ , A wide variety of resident cells and migratory cells can be found that express Class II transplant antigens and therefore an exact exposition of the phenotype, source, and location of various expressed Class II antigen cells will be the basis for understanding many of the local immune responses. Note that the expression of class II antigens is not constant, with changes in cellular function, special