Localization of Heat Shock Proteins in Human Tonsils with Special Reference to Follicular Dendritic Cells, Interdigitating Cells and Fibroblastic Reticulum Cells.

Abstract

The localization of four heat shock proteins (HSPs), ubiquitin, HSP27, HSP72/73 and HSP90, was studied immunohistochemically in human tonsils. Ubiquitin was positive in follicular dendritic cells (FDCs) in the germinal centers (GCs), and interdigitating cells (IDCs) in the interfollicular areas. Fibroblastic reticulum cells (FRCs) in the mantle zones were weakly stained. Ubiquitin was localized in the cytoplasm and nucleus. HSP27 was expressed in FDCs, and in some IDCs and FRCs. HSP27 was localized mainly in the cytoplasm, showing a diffuse distribution. HSP72/73 was stained in FDCs in the light zones (LZs) of GCs. IDCs and FRCs also showed staining for HSP72/73. HSP72/73 was localized diffusely in the cytoplasm and/or granularly in the nucleus. HSP90 was positive in FDCs in the LZs. IDCs and FRCs were also stained for HSP90, which was localized heterogeneously in the cytoplasm. Our results show that HSP72/73 and HSP90 are strongly expressed in FDCs in the LZs, and the presence of HSP72/73 in the nucleus as well as cytoplasm of these FDCs suggests that this type of cell might be stressed. Furthermore, HSP27 appears to be reacted to only FDCs, and also some IDCs and FRCs.