Characterisation of an influenza B virus-derived peptide presented by HLA-B*18:01.
Murdolo, L.D., Liwei Leong, S., Maddumage, J.C., Mifsud, N.A., Chatzileontiadou, D.S.M., Grant, E.J., Gras, S.(2025) Biochem J 482: 811-820
- PubMed: 40587260 
- DOI: https://doi.org/10.1042/BCJ20240739
- Primary Citation of Related Structures:  
9DY8 - PubMed Abstract: 
The influenza B virus (IBV) can pose a significant threat to global health. Despite this, IBV is understudied compared with influenza A virus (IAV). CD8+ T cells have proven highly effective in reducing influenza disease severity. In addition, pre-existing immune responses towards IAV epitopes may provide protection against homologous IBV-derived peptides due to T cell cross-reactivity. To exploit the advantages of T cells for future vaccine developments, a better understanding of the IBV-derived peptide presentation by the highly polymorphic human leukocyte antigen (HLA) is required. We previously determined that the IAV-derived PB1177-A peptide was presented by the HLA-B*18:01 molecule and induced CD8+ T cell responses. Here, we assessed the PB1177-A IBV homologue (PB1177-B). Intracellular cytokine staining assays showed that PB1177-B was unable to activate CD8+ T cells from several HLA-B*18:01+ samples tested. We determined that the IAVand IBV-derived PB1177 adopted different stability and conformation in the cleft of HLA-B*18:01. Molecular dynamics analysis on the crystal structure showed that PB1177-B had a central flexible region with a large hydrophobic patch formed by two phenylalanine residues, not present in PB1177-A. The flexibility and the lower stability of the HLA-B*18:01-PB1177-B complex may hinder CD8+ T cell receptor binding, underpinning the lack of CD8+ T cell activation observed. This provides additional insights into the differences between IAVand IBV-specific CD8+ T cell responses.
- Infection and Immunity Program, La Trobe Institute for Molecular Science (LIMS), Victoria, Bundoora VIC, Australia.
Organizational Affiliation: