MACROPHAGES AND ENRICHED POPULATIONS OF T-LYMPHOCYTES INTERACT SYNERGISTICALLY FOR THE INDUCTION OF SEVERE, DESTRUCTIVE LYME ARTHRITIS

Hamsters receiving both macrophages exposed to Formalin-inactivated Bo rrelia burgdorferi (M phi-FBb) and enriched populations of either immu ne or naive T lymphocytes developed severe swelling of the hind paws w hen infected with B. burgdorferi. Swelling was detected 6 days after i nfection, peaked on day 10, and gradually decreased. Swelling was also observed in the hind paws of hamsters infused with only M phi-FBb or only enriched populations of either immune or naive T lymphocytes afte r infection with B. burgdorferi. However, the swelling detected in the se hamsters was less severe and of shorter duration. In addition, hams ters receiving both macrophages not exposed to Formalin-inactivated B. burgdorferi (M phi-NFBb) and enriched populations of either immune or naive T lymphocytes failed to develop severe swelling after infection with B. burgdorferi. No swelling was also observed in hamsters infuse d with both M phi-FBb and enriched populations of immune T lymphocytes and then inoculated with spirochetal growth medium. We further showed that macrophages and enriched populations of T lymphocytes did not in teract synergistically for controlling B. burgdorferi infection, as sp irochetes were readily recovered from the tissues of all cell transfer recipients infected with B. burgdorferi. These findings demonstrate t hat hamsters infused with both M phi-FBb and enriched populations of e ither immune or naive T lymphocytes develop a more fulminate arthritis after infection with B. burgdorferi than recipients infused with eith er cell type alone. These findings suggest that macrophages and T lymp hocytes interact synergistically for the induction of severe, destruct ive Lyme arthritis.