ABSTRACT
Fresh cryostat sections from the thymus of BALB/c adult mice were processed with semipermeable membrane technique for demonstration of non-specific esterase (NE). The various cell types and the pattern of their distribution may be showed, because this technique may preserve the total enzyme activity of cells. The NE activity of epithelial reticular cells (ERC), thymic nurse cells (TNC), and interdigitating cells (IDC) are lower, but macrophages (M?) show a high activity. Cortical ERCs appear as a sponge-like network. Medullary ERCs may be divided into two cell types, i. e. low and high activity cells. The distribution of the latter shows foci-like pattern. M? present in both the cortex and medulla, in the cortico-medullary border they are prominent and may form rosettes-like structure with thymocytes. The thymus was also studied with immunohistochemical method using the monoclonal antibody of rat-anti-mouse thymic stromal ceils (MTS-6). This observation enable studies on the type of thymic stromal cells formed thymic microenvironment under LM.