Effect of capsular material from Haemophilus actinomycetemcomitans on bone collagen synthesis in vitro

Capsular material was extracted from Haemophilus actinomycetemcomitans, an organism associated with localised juvenile periodontitis, and examined for its effect on the in vitro synthesis of collagen and DNA in mouse calvaria. The material was found to cause a significant inhibition of both collagen and DNA synthesis at concentrations as low as 10 ng ml-1. The ability of capsular material to inhibit bone formation, together with its previously described bone resorbing activity, suggests that it may contribute to the rapid alveolar bone loss which is characteristic of localised juvenile periodontitis.