ヒトリンパろ胞内サイトカイン及びサイトカイン・レセプターの発現

Abstract

Lymphoid tissues are composed of B-cell dependent area (lymphoid follicle), and T-cell dependent paracortical and interfollicular areas. In lymphoid follicles, B lymphocytes and follicular dendritic cells (FDCs) play a central role of humoral immunity. B lymphocytes mature to memory B cells or plasmablasts through the proliferation in the dark zone (DZ), the selection in the basal light zone (BLZ), and the differentiation in the apical light zone (ALZ). In these processes, the importance of many cytokines has been pointed.There is, however, little information in the interature about the cytokine receptors in lymphoid follicles. The aim of our study was to investigate the localization of cytokines and theirreceptorsinhuman lymphoid tissues using immunohistochemical and immunocytochemical methods. FDCs were positive for transforming growth factor beta receptor type II (TGF-beta R II) in ALZ, interleukin 1 receptor type II (IL-1 R II, CD121a), interleukin 2 receptor beta (IL-2 R-beta, CD122), interleukin 4 receptor (IL-4R, CD124), interleukin 6 receptor (IL-6R, CD126), granulocyte macrophage-colony stimulating factor receptor (GM-CSF R, CD116w) in the BLZ and ALZ. Many cytokine inverstigated in this study were negative on FDCs except the TGF-beta, but positive on many T cells in lymphoid follicles.Furthermore, we investigated the relationship between IgA positive plasma cells and the expression of TGF-beta and its receptor in lymphoid follicles. The data indicated that lymphoid follicles containing more IgA-positive plasma cells tended to be, simultaneously, more frequently labeled by TGF-beta and its receptor.These data indicated that cytokines produced by T-cells not only may directly affect on B-cells, but also indirectly via FDCs expressing receptors for some cytokines. Simultaneous evaluation of both cytokines and their receptors may provide a powerful strategy of clarifying the cytokine network and transduction in lymphoid follicles.