A comparison of the ability of serum and monoclonal antibodies to gastric inhibitory polypeptide to detect immunoreactive cells in the gastroenteropancreatic system of mammals and reptiles.

A monoclonal antibody raised to gastric inhibitory polypeptide (GIP) has been compared with conventional rabbit and guinea-pig antisera to GIP. Four staining methods were tested and of these the peroxidase antiperoxidase (PAP) method proved to give the best results with both the mouse and rabbit antibodies. The monoclonal antibody, when used to stain pancreatic tissue, gave negative results whereas a distinct population of gut endocrine cells was readily demonstrable, suggesting that GIP is not a constituent of the mammalian pancreas. The monoclonal antibody was found to be the most sensitive for immunocytochemistry achieving the titre of 1:10(6) in rat gut. A C-terminal specific antibody, with a high affinity and avidity to GIP, it was clearly the preferred antibody for immunocytochemical studies.