Detection of substance P in the central nervous system by a monoclonal antibody

Peptides with transmitter-like characteristics are being found in many brain areas. The application of immunocytochemical and radioimmunoassay methods has contributed much to the clarification of these neuronal systems. Here we report the development of a rat monoclonal antibody produced by a hybrid myeloma and its application to the study of one of these peptides, substance P. The hybrid clone, isolated after fusion of mouse myeloma cells with hyperimmune rat spleen cells, allowed us to obtain a standardized and permanent source of monoclonal substance P antibodies in a culture cell system. This antibody recognizes the COOH-terminal part of substance P in radioimmunoassay down to 10-20 fmol. It does not crossreact with other known mammalian brain peptides tested. By immunofluorescence the antibody was shown to bind specifically and with a remarkably low background to nerve terminals and cell bodies located in clearly defined nuclear organizations of the central nervous system.