Localization of thymulin (FTS-Zn) in mouse thymus. Comparative data using monoclonal antibodies following different plastic embedding procedures

Abstract

The distribution of thymulin (FTS-Zn) was studied in thymuses from normal mice (OF1) or autoimmune mice (NZB). Thymulin localization was investigated using immunocytochemical techiques on sections of GMA and epon-embedded mouse thymuses. Two monoclonal antibodies were used: anti-synthetic thymulin and anti-intracellular thymulin. In the immunofluorescence assay GMA sections allows a more subtle localization of thymulin in the cytoplasm of epithelial cells (with a vacuolar pattern) compared to the epon sections (with a homogeneous fluorescence in the cytoplasm). In both cases, the number of labeled cells was greater in the medullary region than in the cortex of the thymus. At the EM level, immunolabeling of epon ultrathin sections showed ferritin distributed in some of the epithelial cell vacuoles. The 2 monoclonal antibodies revealed similar distributions of the thymulin in the thymus. The amount of thymulin is greater in the epithelial cells of normal compared to autoimmune thymuses.