Herpes Simplex Virus Glycoproteins Associated with Different Morphological Entities Projecting from the Virion Envelope

1 Department of Medical Microbiology, University of Cape Town Medical School, Observatory, Cape Town, South Africa 7925 and 2 Department of Molecular Genetics and Cell Biology and Committee on Virology, University of Chicago, 910 East 58th Street, Chicago, Illinois 60637, U.S.A. Spikes of different kinds, distinct in size and appearance were detected on the surfaces of herpes simplex virions by electron microscopy of negatively stained preparations. Use of monoclonal antibodies coupled to colloidal gold permitted identification of viral glycoproteins present in different structures projecting from the virion envelope. Antibodies specific for the glycoprotein designated gB bound to the most prominent spikes, which were about 14 nm long and, in side view, had a flattened T-shaped top. Antibodies specific for gC bound to structures that, in some instances, appeared to extend as much as 24 nm from the surface of the envelope and were too thin to resolve. Antibodies specific for gD bound to structures that extended as much as 8 to 10 nm from the surface of the envelope. The gB spikes were invariably clustered, usually in protrusions of the envelope varying from small bulbous distentions to long tail-like projections. The gC components were randomly distributed and widely spaced and the gD components were irregularly clustered in patterns distinct from those of the gB spikes. These three glycoproteins therefore form structures that are different in size, morphology and distribution in the envelope. Keywords: HSV-1, electron microscopy, spikes Received 11 July 1986; accepted 12 November 1986.