THE EFFECT ON CHICK OSTEOCLASTS OF INFECTION WITH PARAMYXOVIRUSES

The detection of virus in osteoclasts from Pagetic patients is now wel l known, but it has yet to be shown convincingly that the presence of virus in Pagetic osteoclasts influences their behaviour. Tn this study , osteoclasts from embryonic chick tibiae were infected with canine di stemper virus or measles virus and compared with mock-infected control s. Infection was confirmed using virus-specific fluorescent antibodies . It was found that virus infection did not alter osteoclast morpholog y or tartrate-resistant acid phosphatase (TRAP) activity, Both infecte d and mock-infected osteoclasts produced resorption pits on bovine bon e slices; these could be divided into two distinct size classes with a computer-based measuring system. Virus infection significantly increa sed the proportion of the larger size class of resorption pit. These r esults suggest that virus infection can increase bone resorption by os teoclasts, lending further support to the hypothesis that viruses play a role in Paget's disease of bone.