生发中心淋巴细胞凋亡与小结树突细胞关系的研究

APOPTOSIS OF B LYMPHOCYTES IN GERMINAL CENTER CORREL ATED WITH FOLLICULAR DENDRITIC CELLS(FDCs)

目的研究人淋巴结和扁桃体生发中心内的凋亡细胞与小结树突细胞（ｆｏｌｉｃｕｌａｒｄｅｎｄｒｉｔｉｃｃｅｌｓ，ＦＤＣ）之间的关系。方法用ＴＵＮＥＬ和免疫细胞化学方法分别检测凋亡细胞、ＦＤＣ和Ｂｃｌ－２蛋白的表达。结果在生发中心有散在的凋亡细胞且多被巨噬细胞所吞噬；ＦＤＣ主要分布在生发中心亮区，其突起彼此连结成网，网眼内充满了Ｂ淋巴细胞；Ｂｃｌ－２主要分布在次级淋巴小结的帽状区，生发中心阴性。结论生发中心亮区的ＦＤＣ形成的网状结构，有利于ＦＤＣ与中心细胞的接触，只有那些有高度亲合性的中心Ｂ淋巴细胞才得以生存，生发中心凋亡细胞被认为是选择过程的结果。Ｂｃｌ－２蛋白在生发中心的减少或消失有助于细胞的凋亡，而帽状区Ｂｃｌ－２表达可能与保护Ｂ细胞的继续分化和抑制细胞凋亡有关。

Objective\ To study the relationship between the apoptotic cells and follicular dendritic cells (FDCs) in germinal center of human lymph nodes and tonsils. Methods\ TUNEL and immunocytochemical methods have been used to detect the apoptotic cells, FDCs and Bcl 2 protein. Results\ Apoptotic cells displaying in germinal center were almost phagocytozed by macrophages. The FDCs principally located in the light zone of germinal center. They have rich dendritic processes to form dense networks. Bcl 2 protein mainly distributed in the mantle zone of secondary follicles, while germinal center was negative. Conclusions\ FDCs formed in networks in light zone were facilitated to form the contact between centrocytes and FDC, and led to the selection of high affinity centrocytes by rescusing. Apoptosis might be considered as the result of selection process, and lack of Bcl 2 protein might be contributed to apoptosis. However, the Bcl 2 in the mantle zone was assumed to help B cells continue differentiation and inhibit the induction of apoptosis. ;