Specific Movement of Cell Membranes Fused with HVJ (Sendai Virus)

When Ehrlich ascites tumor cells fused with UV-inactivated HVJ (Sendai virus) were cultured, the viral envelope antigens, which had been integrated at random into the cell membranes, accumulated at one site on the fused cell. The site showed a specific structure, namely, a projection of the cytoplasm from the spherical fused cell surface with clusters of many long microvillilike protrusions from it. When the fused cells were conjugated with antibody against Ehrlich ascites tumor cells and cultured, the antigen-antibody complex also accumulated on the projection.Associated with the development of the projection and accumulation of viral antigens, vacuoles developed at the base of the projection in the cytoplasm of the fused cells in culture. The development of the projection and vacuoles and the accumulation of viral antigens were all inhibited by glucose, mannose, galactose, sodium azide, and cycloheximide, and these inhibitions were reversible. All these structures were observed in multinucleated cells, but few in mononucleated cells after reaction with HVJ (Sendai virus). We consider that these three phenomena correlate with each other and may result from changes in cell-membrane systems caused by fusion of cells.