Monoclonal antibodies against the flavivirus West Nile.

Monoclonal antibodies having three different specificities have been prepared against the Egypt 101 strain of West Nile virus (WNV). All were reactive against the envelope glycoprotein in radioimmune precipitation tests, and all enhanced WNV replication in the mouse macrophage line P388D1. One antibody, which is of IgG2a subclass, had strong neutralizing activity against the homologous virus, although it failed to neutralize a different WNV strain. The other two antibodies, both of IgG1 subclass, had little neutralizing activity, but one had strong reactivity with the haemagglutinin of the inducing virus and other flavivirus haemagglutinins.