LACTIC-DEHYDROGENASE VIRUS-INFECTION PREVENTS DEVELOPMENT OF ANTINUCLEAR ANTIBODY IN (NZB X NZW)F1 MICE - ROLE OF PROSTAGLANDIN-E2 AND MACROPHAGE-IA ANTIGEN EXPRESSION

Persistent lactic dehydrogenase virus (LDV) infection prevents the development of antinuclear antibody (ANA) in (NZB x NZW)F1 mice. To assess the suppressive mechanisms, we focused on the role of the E series of prostaglandin(PGE), since previously we have shown enhanced production of PGE by macrophages from chronically LDV-infected mice. Treatment with PGE2 suppressed ANA titres more markedly in non-infected mice than in LDV-infected mice. Indomethacin enhanced ANA titres more markedly in LDV-infected mice than in non-infected mice. The number of Ia antigen positive(Ia+) macrophages was less in LDV-infected mice than in uninfected mice. The number of Ia+ macrophages was decreased in non-infected mice by PGE2 treatment and increased in LDV-infected mice by indomethacin treatment. These results suggest that the low ANA production in LDV-infected (NZB x NZW)F1 mice may be related to the decreased number of Ia+ macrophages and that one of the factors responsible for suppression of Ia+ macrophages may be the enhanced PGE2 production in the LDV-infected mice.