Abstract
Monoclonal antibodies directed against VP3, the envelope glycoprotein of lactate dehydrogenase-elevating virus (LDV), were found to neutralize a large proportion of the virus population. This effect of monoclonal anti-VP3 antibodies was significantly increased by a murine monoclonal rheumatoid factor, indicating that the same antiviral antibodies can either neutralize or sensitize different fractions of the virus. This observation could be explained by heterogeneity in LDV particles, resulting in diverse responses to antibodies and therefore to the persistence of the virus in vivo.