Complement component C3b binds directly to purified glycoprotein C of herpes simplex virus types 1 and 2

Microb Pathog. 1987 Dec;3(6):423-35. doi: 10.1016/0882-4010(87)90012-x.


Cells infected with herpes simplex virus type 1 (HSV-1), but not HSV-2, express on their surfaces a receptor for the complement component C3b. Receptor activity is markedly enhanced by treatment of the infected cells with neuraminidase. Employing a direct binding assay, consisting of purified HSV glycoproteins immobilized on nitrocellulose and iodinated C3b as a probe, we found that C3b binds directly to gC-1, as well as to gC-2, but not to gB or gD from either serotype. C3b binding was enhanced by treatment of gC-1 or gC-2 with neuraminidase. Endo F or endo H treatment of gC-1 had no effect on C3b binding. However, treatment of gC-2 with these endoglycosidases had a marked negative effect on C3b binding. These results suggest that N-linked oligosaccharides are involved in binding of C3b to gC-2, but not gC-1. Alternatively, removal of N-linked oligosaccharides from gC-2 might adversely affect polypeptide conformation. Glycoprotein C-2 also differs from gC-1 in its effects on the complement cascade. Whereas gC-1 accelerated the decay of the alternative pathway C3 convertase and impaired the efficiency of lysis by the components C5 through C9, gC-2 stabilized the active C3 convertase and had little effect on the late-acting components. The dissimilarity of gC-1 and gC-2 with regard to their effects on the complement cascade may have implications regarding the role of these glycoproteins in confronting the host immune response.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Line
  • Complement C3b / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Glycoside Hydrolases / pharmacology
  • Immunoblotting
  • Neuraminidase / pharmacology
  • Simplexvirus / immunology*
  • Viral Envelope Proteins / metabolism*


  • Viral Envelope Proteins
  • glycoprotein C, herpes simplex virus type 2
  • glycoprotein gC, herpes simplex virus type 1
  • Complement C3b
  • Glycoside Hydrolases
  • Neuraminidase