Virus-induced cell fusion enhanced by phytohaemagglutinin

ONCOGENIC transformation by viruses or chemicals^1-5, treatment with proteolytic enzymes^1,6 and infection with nononcogenic enveloped viruses^7,8, produce cell surface alterations that increase cellular susceptibility to agglutination by plant lectins. More recently, lectins have been used to modify the replication and cytopathogenicity of enveloped viruses grown in normal cells^9,10. It has been shown that treatment of cells with con A inhibits paramyxovirus-induced cell fusion.¹¹ In contrast, the results reported here indicate that another plant lectin, phytohaemagglutinin (PHA), can enhance the fusion of cells infected with the paramyxovirus Newcastle disease virus (NDV).