The immunoperoxidase localization of type X collagen in chick cartilage and lung.

We have localized type X collagen in chick cartilage and lung by use of affinity-purified antibodies raised against the purified protein. Examination of the centers of primary endochondral development in the embryonic sternum, developing cartilage in the embryonic tubular bones and growth plate cartilages demonstrated the specific association of type X collagen with regions of hypertrophic chondrocytes in these tissues. Furthermore these studies revealed a tendency for type X collagen to accumulate adjacent to regions of active vascular invasion and an apparent lag between the initial intracellular accumulation and the matrix deposition of type X collagen. A lag in the matrix accumulation of type X collagen was also shown biochemically and immunohistochemically in chondrocytes in culture. In chick lung type X collagen was localized to the smooth muscle of the blood vessels and to smooth muscle surrounding alveolar ducts.