An Immunoelectronmicroscopic Study on The Pancreatic B-Cells of Mouse

Recently developed protein A-gold technique for detection of intracellular antigenic sites on thin sections was used to localize a secretory protein, insulin in the pancreatic B-cells of mouse. Treatment of thin sections of glutaraldehyde-fixed, osmium tetroxide-postfixed pancreatic tissue with saturated aqueous solution of sodium metaperiodate, followed by incubation with anti-insulin antibody and protein A-gold complex, restored the labeling without altering the structural preservation. The good ultrastructural preservation obtained led to superior resolution in the labeling. Pancreatic secretory protein, insulin was observed over perfectly preserved secretory granules of the pancreatic B-cells. The protein A-gold technique is proposed as general method for visualization of antigenic sites on thin sections.