Immunohistochemical localization of carbonic anhydrase isoenzymes I and II in human bone, cartilage and giant cell tumor.

Carbonic anhydrase isoenzymes I and II have been localized in human bone and cartilage. Osteoclasts are strongly positive for carbonic anhydrase II but very little if any reaction is observed for carbonic anhydrase I. In tendon giant cell tumor osteoclastlike-giant cells contained high amounts of carbonic anhydrase II suggesting the close relation of these cells to normal osteoclasts. In growth plate cartilage strong staining was obtained in late proliferative and hypertrophic chondrocytes as well as in extracellular matrix of hypertrophic zone also only with anti-human carbonic anhydrase II.