Immunocytochemical characterization of monoclonal antibody A2B5 in the rat gastric antrum.

Immunocytochemical characterization of monoclonal antibody A2B5 was carried out in the rat gastric antrum, in which immunoreactive cells were found mainly around the middle of the pyloric glands. In serial sections, most cells were identified as gastrin cells, but only 60.6 + 5.9% (mean + SD, n = 5) of them reacted with the antibody. Somatostatin cells did not react with antibody A2B5. The different reaction of antibody A2B5 to gastrin cells indicated that gastrin cells may have a variety of cell surface receptors and have different physiological functions. From these findings, it was concluded that antibody A2B5 did not satisfy the requirements for the cell surface marker of gastrointestinal endocrine cells, though it could be useful in studies of cell surface receptors, concerning which little is known about gastrointestinal endocrine cells.