Dichotomy of glycoprotein g gene in herpes simplex virus type 1 isolates.
Herpes simplex virus type 1 (HSV-1) encodes 11 envelope glycoproteins, of which glycoprotein G-1 (gG-1) induces a type-specific antibody response. Variability of the gG-1 gene among wild-type strains may be a factor of importance for a reliable serodiagnosis and typing of HSV-1 isolates. Here, we used a gG-1 type-specific monoclonal antibody (MAb) to screen for mutations in the immunodominant region of this protein in 108 clinical HSV-1 isolates. Of these, 42 isolates showed no reactivity to the anti-gG-1 MAb. One hundred five strains were further examined by DNA sequencing of the middle part of the gG-1 gene, encompassing 106 amino acids including the immunodominant region and epitope of the anti-gG-1 MAb. By phylogenetic comparisons based on the sequence data, we observed two (main) genetic variants of the gG-1 gene among the clinical isolates corresponding to reactivity or nonreactivity to the anti-gG-1 MAb. Furthermore, four strains appeared to be recombinants of the two gG-1 variants. In addition, one strain displayed a gG-1-negative phenotype due to a frameshift mutation, in the form of insertion of a cytosine nucleotide. When immunoglobulin G reactivity to HSV-1 in sera from patients infected with either of the two variants was investigated, no significant differences were found between the two groups, either in a type-common enzyme-linked immunosorbent assay (ELISA) or in a type-specific gG-1 antigen-based ELISA. Despite the here-documented existence of two variants of the gG-1 gene affecting the immunodominant region of the protein, other circumstances, such as early phase of infection, might be sought for explaining the seronegativity to gG-1 commonly found in a proportion of the HSV-1-infected patients.
Department of Clinical Virology, Göteborg University, Göteborg, Sweden. elham.rekabdar@microbio.gu.se
Elham
E
Rekabdar
Petra
P
Tunbäck
Jan-Ake
JA
Liljeqvist
Magnus
M
Lindh
Tomas
T
Bergström
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology; D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D016368:Frameshift Mutation; D014644:Genetic Variation; D006561:Herpes Simplex / Q000821:virology*; D018259:Herpesvirus 1, Human / Q000145:classification* / Q000235:genetics* / Q000276:immunology; D006801:Humans; D016056:Immunodominant Epitopes; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D016056:Immunodominant Epitopes; D014759:Viral Envelope Proteins; C050591:glycoprotein gG-1, herpes simplex virus type 1