[Expression of an Epstein-Barr virus early antigen and cell fusion]

Superinfection of Raji cells with Epstein-Barr virus (EBV) derived from P3HR-1 (P3H-EBV) leads to syncytium formation. Studies using inhibitors of DNA and protein synthesis suggest that the fusion-inducing factor belongs to the early antigen of virus-specified proteins. Induction of early antigen (EA) in Raji cells by using various chemicals also leads to syncytium formation. However, A2L/AH hybrid cells, which were prepared by fusion between epithelial cells of adenoid origin and lymphocytes transformed by B95-8 virus, could not be superinfected with P3H-EBV. But, the syncytium formation was observed when EBV-EA was induced by chemicals in A2L/AH cells. It was considered that the synthesis of viral protein in superinfected Raji cells is essential for fusion and that the viral genes, inducible in Raji and A2L/AH cells by treatment with chemicals code for the necessary functions that lead to syncytia formation.