The role of gingival lymphocytes on the establishment of IgG dominant B cell lesion in periodontitis.

人类牙周炎已被证实是一种富含IgG细胞的病变。我们检测到<T4^+>和<T8^+>细胞以及免疫球蛋白，特别是IgG，在牙周病变中产生细胞。HLA-DR（Ia）的发生率在<T4^+>和<T8^+>细胞群中也大致相等。提示辅助和抑制功能参与了牙周病变的形成。另一方面，由于多种牙周菌群具有激活B细胞的多克隆能力，B细胞可能在牙周病变中被多克隆激活。我们证明了IgG抗体形成细胞可以从表面IgG阳性的B细胞分化，但不能从表面IgG阴性的B细胞分化。结果提示，被抗原激活的记忆B细胞可能迁移到牙周病变处，然后被多克隆激活，发育为IgG生成细胞。因此，牙周病变可能是由T细胞和巨噬细胞与PBA共同作用的免疫调节机制引起的。事实上，T细胞，特别是辅助性/诱导剂T （Th/i）细胞，通过T非依赖型B细胞激活剂（TI-PBAs），如LPS和粘胶放线菌制剂，可以增强B细胞的IgG合成。t /i细胞通过识别B细胞上表达的Ia而被激活。经TI-PBAs刺激的B细胞Ia增加。活化的Th/i细胞产生可溶性因子，增强了TI-PBAs活化的B细胞的IgG合成。人们强烈建议T细胞参与牙周病变的发展。

Human periodontitis has been confirmed to be IgG producing cell rich lesion. We detected <T4^+> and <T8^+> cells as well as immunoglobulins, particularly IgG, producing cells in periodontal lesions. The incidence of HLA-DR(Ia) was also approximately equal in both <T4^+> and <T8^+> cell population. These results suggested that helper and suppressor functions could participate in the establishment of periodontal lesions.On the other hand, B cells might be activated polyclonally in periodontal lesion, because a variety of periodontal flora possessed polyclonal B cell activating capacities. We demonstrated that IgG antibody forming cells differentiated from surface IgG positive B cells but not from surface IgG negative B cells. The results suggested that the memory B cells primed with antigens might migrate into periodontal lesions, then they might be activated polyclonally and developed into IgG producing cells.Periodontal lesion could be, therefore, induced by the collaboration of the immunoregulatory mechanisms by T cells and macrophages with PBA. In fact, T cells, particularly helper/inducer T (Th/i) cells, enhanced IgG synthesis of B cells activated with T-independent B cell activators (TI-PBAs) such as LPS and Actinomyces viscosus preparation. Th/i cells were activated by recognition of Ia expressed on B cells. Ia increased on B cells stimulated with TI-PBAs. Activated Th/i cells produced soluble factors which enhanced IgG synthesis of B cells activated with TI-PBAs. T cells were strongly suggested to participate in the development of periodontal lesions.