A survey of ORF8 sequence and immunoinformatics features during alpha, delta, and wild type peaks of the SARS-CoV-2 pandemic in Iran.

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic influences all around the world. The SARS-CoV-2 ORF8 accessory gene represents multiple functions in virus-host interaction. The current study aimed to compare the ORF8 substitutions and epitope features of these substitutions in the various SARS-CoV-2 outbreaks including delta, alpha, and wild type variants in Iran from 2020 to 2022. In addition, we evaluate B cell, HLA I and II epitopes, by in-silico approach to ORF8 binding site prediction.

METHODS: The samples were collected from patients diagnosed with SARS-CoV-2 infection via a real-time PCR assay. Then, a conventional PCR was carried out for ORF8 mutations analysis and further Sanger sequencing. Possible important alterations in epitope features of the ORF8 were evaluated by epitope mapping. B cell, HLA class I and II epitopes, evaluated by online databases ABCpred, NetMHCpan-4.1, and NetMHCIIpan-3.2, respectively.

RESULTS: The current study results could not represent novel variations in seven full-length ORF8 sequences or major ORF8 deletions in 80 evaluated samples. In addition, we could not find any ORF8 A382 during each outbreak of variants. Epitope mapping represents differences between the Alpha and other variants, especially in B cell potential epitopes and HLA I.

CONCLUSION: The immunoinformatic evaluation of ORF8 suggested epitopes represent major differences for the Alpha variant in comparison with other variants. In addition, having mild pathogenesis of the Omicron variant does not seem to be associated with ORF8 alteration by phylogenetic evaluation. Future in-vitro studies for a clear conclusion about the epitope features of ORF8 are required.