Characteristics of Norovirus capsid protein-specific CD8⁺ T-Cell responses in previously infected individuals

Norovirus (NV) infection causes acute gastroenteritis in children and adults. Upon infection with NV, specific CD8⁺ T cells, which play an important role in anti-infective immunity, are activated in the host. Owing to the NV's wide genotypic variability, it is challenging to develop vaccines with cross-protective abilities against infection. To aid effective vaccine development, we examined specific CD8⁺ T-cell responses towards viral-structural protein (VP) epitopes, which enable binding to host susceptibility receptors. We isolated peripheral blood mononuclear cells from 196 participants to screen and identify predominant core peptides towards NV main and small envelope proteins using ex vivo and in vitro intracellular cytokine staining assays. Human leukocyte antigen (HLA) restriction characteristics were detected using next-generation sequencing. Three conservative immunodominant VP-derived CD8⁺ T-cell epitopes, VP2_94-102 (TDAARGAIN), VP2_153-161 (RGPSNKSSN), and VP1_141-148 (FPHIIVDV), were identified and restrictively presented by HLA-Cw * 0102, HLA-Cw * 0702, and HLA-A *1101 alleles, separately. Our findings provide useful insights into the development of future vaccines and treatments for NV infection.