Epstein-Barr virus lacking glycoprotein gp42 can bind to B cells but is not able to infect.
The Epstein-Barr virus gH-gL complex includes a third glycoprotein, gp42, which is the product of the BZLF2 open reading frame (ORF). gp42 has been implicated as critical to infection of the B lymphocyte by virtue of its interaction with HLA class II on the B-cell surface. A neutralizing antibody that reacts with gp42 inhibits virus-cell fusion and blocks binding of gp42 to HLA class II; antibody to HLA class II can inhibit infection, and B cells that lack HLA class II can only be infected if HLA class II expression is restored. To confirm whether gp42 is an essential component of the virion, we derived a recombinant virus with a selectable marker inserted into the BZLF2 ORF to interrupt expression of the protein. A complex of gH and gL was expressed by the recombinant virus in the absence of gp42. Recombinant virus egressed from the cell normally and could bind to receptor-positive cells. It had, however, lost the ability to infect or transform B lymphocytes. Treatment with polyethylene glycol restored the infectivity of recombinant virus, confirming that gp42 is essential for penetration of the B-cell membrane.
Wang
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X
School of Biological Sciences, University of Missouri-Kansas City, 64110, USA.
Hutt-Fletcher
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LM
D001402:B-Lymphocytes / Q000821:virology*; D002460:Cell Line; D002472:Cell Transformation, Viral / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D015870:Gene Expression; D005814:Genes, Viral; D005819:Genetic Markers; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D006801:Humans; D008561:Membrane Fusion / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D010957:Plasmids / Q000235:genetics; D011092:Polyethylene Glycols / Q000494:pharmacology; D011995:Recombination, Genetic; D014764:Viral Proteins / Q000235:genetics / Q000502:physiology*
C101688:BZLF2 protein, Herpesvirus 4, Human; D005819:Genetic Markers; D006023:Glycoproteins; D014764:Viral Proteins; D011092:Polyethylene Glycols