Monoclonal antibody against histiocytosis X cells.

Monoclonal antibody against histiocytosis X cells (HXCs) was established. The antigen was the cell membrane of HXCs from the submandibular lesion of a 63-year-old man who had been diagnosed as an adult type of histiocytosis X (HX) and whose HXCs had numerous Birbeck granules (BGs). The obtained monoclonal antibody, named MI1, reacted with the antigenic cell membrane of HXC. Immunoblotting showed that MI1 bound to the cell membrane of 28500 mw. MI1 also reacted with interdigitating reticulum cells (IDCs) in the tonsil and Langerhans cells (LCs) in the epidermis. MI1 reacted with the BGs which connected to the cell membrane, but not with those located near the nucleus.