Presence of Ia-positive cells in the central nervous system of the rat during various pathological conditions.

The rat central nervous system (CNS) was analyzed immunohistochemically during various pathological conditions by using monoclonal antibodies specific for rat T lymphocytes, rat macrophages and Ia antigen. It was found that in immunologically mediated disease infiltrating macrophages do express the Ia antigen, whereas in nonimmunologically mediated disease they do not. The results suggest that based on the composition of the mononuclear phagocyte infiltrate a clear distinction can be made between different inflammatory reaction types within the CNS.