Comparison of murine and human nectin1 binding to herpes simplex virus glycoprotein D (gD) reveals a weak interaction of murine nectin1 to gD and a gD-dependent pathway of entry.
The murine nectin1alpha (mNectin1alpha), a homolog of human nectin1alpha (hNectin1alpha, or PRR1, HveC), mediates the entry of herpes simplex virus (HSV) into cells. Previously, we reported that the binding of hNectin1 to HSV glycoprotein D (gD) was readily detectable, whereas the binding of mNectin1 to gD was not detectable, thus raising the question whether mNectin1 mediates a gD-dependent or a gD-independent pathway of entry. Here we report comparative binding studies of murine- and human-nectin1alpha to virions and to gD. The assays consistently showed either a very weak binding or no detectable binding of murine nectin1alpha to gD. They included (i) binding of soluble mNectin1-Fc or hNectin1-Fc to virions and competition of the binding by soluble gD(Delta290-299t) and by monoclonal antibodies to gD; (ii) pull-down experiments of wt gD from lysates of infected cells; and (iii) ELISA binding of soluble gD(Delta290-299t) to cells expressing mNectin1 or hNectin1. In contrast to the binding studies, the entry studies readily showed that entry mediated by mNectin1 was dependent on gD. Thus, a gDnull (gD-/-) mutant virus was unable to enter mNectin1-expressing cells, and entry of wild-type virus was inhibited by antibodies to gD or soluble gD at similar concentrations. We infer that gD represents a weak ligand in the interaction between mNectin1 and virions, whereas it represents a strong and the major ligand for hNectin1. Yet gD is required in HSV-1 entry mediated by mNectin1alpha. We conclude that a high-affinity binding of the receptor to gD is not a requirement in the gD-dependent pathway of HSV entry to cells.
Menotti
L
L
Department of Experimental Pathology, Section on Microbiology and Virology, University of Bologna, Via San Giacomo, 12, Bologna, 40126, Italy.
Avitabile
E
E
Dubreuil
P
P
Lopez
M
M
Campadelli-Fiume
G
G
D000818:Animals; D000911:Antibodies, Monoclonal; D001667:Binding, Competitive; D019921:Biotinylation; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D051379:Mice; D000075983:Nectins; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D011991:Receptors, Virus / Q000378:metabolism*; D017384:Sequence Deletion; D018139:Simplexvirus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D012995:Solubility; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D000911:Antibodies, Monoclonal; D015815:Cell Adhesion Molecules; C000619010:NECTIN1 protein, human; C000619015:Nectin1 protein, mouse; D000075983:Nectins; D020033:Protein Isoforms; D011991:Receptors, Virus; D014759:Viral Envelope Proteins; C039447:glycoprotein D, Human herpesvirus 1