Syncytia result from the fusion of an infected cell with neighboring cells, leading to the formation of multinucleated, enlarged cells. This process is triggered by the surface expression of viral fusion proteins that are fusogenic directly at the host cell membrane.
Syncytia can only arise with viruses that are able to fuse directly at the cell surface without requiring endocytosis.
Fusion from without directed by human immunodeficiency virus particles
F. Clavel, P. Charneau
J. Virol. February 1994; 68: 1179?1185
Fusion of intra- and extracellular forms of vaccinia virus with the cell membrane
R. W. Doms, R. Blumenthal, B. Moss
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Membrane fusion mediated by herpesvirus glycoproteins: the paradigm of varicella-zoster virus
Nancy L. Cole, Charles Grose
Rev. Med. Virol. August 2003; 13: 207?222
Glycoprotein interactions in paramyxovirus fusion
Ronald M. Iorio, Vanessa R. Melanson, Paul J. Mahon
Future Virol July 1, 2009; 4: 335?351
Characterization of cell-cell fusion mediated by herpes simplex virus 2 glycoproteins gB, gD, gH and gL in transfected cells
M. I. Muggeridge
J. Gen. Virol. August 2000; 81: 2017?2027
Reovirus FAST proteins: virus-encoded cellular fusogens
Marta Ciechonska, Roy Duncan
Trends Microbiol. December 2014; 22: 715?724