Localization of acid phosphatase in lamellar bodies of tannic acid treated alveolar type II cells.

Acid phosphatase was demonstrated in well preserved lamellar bodies of rats' alveolar type II cells. The highly ordered lamellar organization was preserved by using tannic acid in the tissue procession protocol. Acid phosphatase reaction products were observed in the amorphous regions of the lamellar bodies adjacent to the limiting membranes and in the central core regions. No reaction product was observed in the lamellar areas. 85% +/- 5% of the lamellar bodies were positively reactive, unrelated to their size. Multivesicular bodies were only partially reactive (approx. 50%), except for those attached to lamellar bodies which all had reaction product.