Augmentation of lymphocyte and macrophage proliferation by caprine arthritis-encephalitis virus contributes to the development of progressive arthritis.

Infection by the lentivirus, caprine arthritis-encephalitis virus (CAEV), may lead to an intermittent arthritis due to the presence of lymphocytes and macrophages in synovial membranes. We have observed that the presence of CAEV increases the division of lymphocytes and macrophages. In association, antigen-induced arthritis is more severe in goats concurrently infected by CAEV than in noninfected goats. From these observations we propose that infection by this lentivirus increases reactivity of lymphocytes and macrophages to immune and nonimmune stimuli, leading to the increased likelihood of progressive arthritis in infected animals.