FLOW CYTOMETRIC STAINING OF PANCREATIC ENDOCRINE-CELLS

Few distinct surface markers have been identified for endocrine cells, but antibodies directed against hormonal epitopes are widely availabl e. In this study, human fetal pancreatic beta cells were identified on the flow cytometer by intracellular staining for insulin. A paraforma ldehyde based permeabilization scheme was used which preserves surface staining and helps maintain cell integrity while allowing antibodies access to compartments within the cell interior. Cells were first stai ned for surface antigens, fixed in paraformaldehyde, and then permeabi lized in phosphate buffered saline containing 0.2 percent Tween. Intra cellular staining was accomplished using a fluorescein conjugated anti -insulin monoclonal antibody. In this manner, major histocompatibility complex Class II antigen expression was documented on beta cells expo sed to interferon gamma. This study demonstrates the feasibility of us ing hormonal content to identify endocrine cells by flow cytometry whi le simultaneously staining for surface antigens.