Induction of subacute murine measles encephalitis by monoclonal antibody to virus haemagglutinin

Although the events which predispose a host to measles virus persistence remain largely unknown, measles antibody has been shown to contribute to the production of a persistent infection by this virus both in vivo and in vitro. Thus, the addition of measles antibody to cells infected with measles virus promotes virus persistence^1,2. Latent measles infection occurs in newborn hamsters with maternally acquired antibody after inoculation with measles virus in the immediate neonatal period³. A subacute encephalitis with measles virus persistence has been induced in weanling BALB/c mice that received antibody after virus inoculation⁴ and in measles-immune primates infected with a virus derived from a patient with subacute sclerosing panencephalitis⁵. Measles virus consists of six polypeptides, and treatment of measles-infected cells with antibody has been shown⁶ to alter the pattern of their synthesis. As the antigenic specificity of the antibody responsible for these observations is not known, we decided to investigate the effects of monoclonal antibodies directed against the individual measles polypeptides. We report here that a monoclonal antibody directed against the virus haemagglutinin, unlike an antibody to the virus nucleocapsid protein, is able to induce a subacute encephalitis in vivo.