Cloning and expression of the complement receptor glycoprotein C from Herpesvirus simiae (herpes B virus): protection from complement-mediated cell lysis.
Simian herpes B virus (SHBV) is the herpes simplex virus (HSV) homologue for the species MACACA: Unlike in its natural host, and unlike other animal herpesviruses, SHBV causes high mortality in accidentally infected humans. SHBV-infected cells, like those infected with HSV-1 and equine herpesvirus types 1 and 4, express complement C3 receptor activity. To study immunoregulatory functions involved in susceptibility/resistance against interspecies transmission, the SHBV glycoprotein C (gC(SHBV)) gene (encoding 467 aa) was isolated. Sequence analysis revealed amino acid identity with gC proteins from HSV-2 (46.9 %), HSV-1 (44.5 %) and pseudorabies virus (21.2 %). Highly conserved cysteine residues were also noted. Similar to gC(HSV-2), gC(SHBV) is less glycosylated than gC(HSV-1), resulting in a molecular mass of 65 kDa if expressed in replication-deficient vaccinia virus Ankara. Stable transfectants expressing full-length gC(SHBV) on the cell surface induced C3 receptor activity and were substantially protected from complement-mediated lysis; no protection was observed with control constructs. This suggests that expression of the gC homologues on infected cell surfaces might also contribute to the survival of infected cells in addition to decreased virion inactivation. Interestingly, soluble gC(SHBV) isolated from protein-free culture supernatants did not interfere with the binding of the alternative complement pathway activator properdin to C3b, which is similar to our findings with gC(HSV-2) and could be attributed to major differences in the amino-terminal portion of the protein with extended deletions in both gC(SHBV) and gC(HSV-2). Binding of recombinant gC(SHBV) to polysulphates was observed. This, together with the heparin-sensitivity of the gC(SHBV)-C3 interaction on the infected cell surface, suggests a role in adherence to heparan sulphate, similar to the gC proteins of other herpesviruses.
Huemer
Hartwig P
HP
Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg, Austria.|Institute for Hygiene and Social Medicine, University of Innsbruck, Fritz-Pregl-Str. 3, A-6020 Innsbruck, Austria.
Wechselberger
Christian
C
Institute of Molecular Biology, Austrian Academy of Sciences, Salzburg, Austria.
Bennett
Alice M
AM
Department of Microbiology, CBD Porton Down, Salisbury, UK.
Falke
Dietrich
D
Institute of Virology, University of Mainz, Germany.
Harrington
Lesley
L
Department of Microbiology, CBD Porton Down, Salisbury, UK.
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D003179:Complement C3b / Q000276:immunology*; D003170:Complement Pathway, Alternative / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006568:Herpesvirus 1, Cercopithecine / Q000472:pathogenicity*; D006801:Humans; D008969:Molecular Sequence Data; D017463:Receptors, Complement 3b / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014162:Transfection; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D017463:Receptors, Complement 3b; D014759:Viral Envelope Proteins; C038535:glycoprotein gC, herpes simplex virus type 1; D003179:Complement C3b