Analysis of the genotyping of circulating strains and characteristics of Glycoprotein E of Varicella-Zoster Virus in Shanxi Province, China.

BACKGROUND

Varicella-zoster virus (VZV), a neurotropic and epidermotropic herpesvirus, causes varicella (chickenpox) upon primary infection and reactivates later in life to cause herpes zoster (HZ), which is associated with significant morbidity, particularly postherpetic neuralgia (PHN). VZV genotyping and characterization of key viral proteins, such as glycoprotein E (gE), are critical for understanding viral circulation, distinguishing vaccine from wild-type strains, and optimizing vaccine strategies. In China, clade 2 is the predominant VZV genotype, but data from Shanxi Province remain limited.

METHODS

Forty herpes fluid specimens from clinically diagnosed herpes zoster (HZ) patients in Shanxi Province were collected. Quantitative polymerase chain reaction (qPCR) was used to detect viral DNA for definitive diagnosis. Six single-nucleotide polymorphisms (SNPs) in the open reading frame (ORF) 22 and ORF 38 fragments of positive specimens were analyzed by PCR and Sanger sequencing to determine viral genotypes. Four SNPs in ORF 38 and ORF 62 were analyzed to distinguish between vaccine and wild-type strains. The full-length nucleotide sequences of the gE gene in VZV-positive clinical specimens were determined. Sequence analysis was performed using Sequencher 5.4.6 and MEGA 11.0.11 software, with comparative reference to VZV strains retrieved from GenBank, to analyze the genetic characteristics of the VZV gE in Shanxi Province. The potential impact of amino acid substitutions caused by nucleotide mutations on the function of the gE protein was predicted using PROVEAN. Mutations in the gE protein were visualized using AlphaFold2 and PyMOL 2.6.0.

RESULTS

All 40 specimens tested positive for VZV and were identified as wild-type clade 2 strains. Strain SX-17 exhibited a T → C mutation at position 107252. Notably, two strains (SX-01 and SX-04) lacked the 69424 SNP locus in ORF 38. gE gene sequencing revealed amino acid substitutions compared to the Dumas reference strain, including T40I (39 strains), H98P (SX-18), V489L (SX-04 and SX-05), and N529S (SX-08). PROVEAN analysis classified all mutations as neutral (scores > -2.5), with no impact on critical gE functional domains.

CONCLUSIONS

The dominant VZV genotype in Shanxi Province is wild-type clade 2. A T → C mutation at position 107252 exists in clade 2 strains. The mutation sites of gE identified so far have not exerted a significant impact on the VZV functions, suggesting that VZV vaccination can serve as a critical measure for herpes zoster prevention in Shanxi Province.