Previous studies have found that CD8+ T cells provide cross-protection against influenza A virus (IAV) strains, but it is unclear if this extends to influenza B and C viruses (IBV and ICV). The authors examined breadth of CD8+ T cell cross-recognition and found that cross-reactivity exists across IAV, IBV and ICV. They were also able to identify the immunodominant CD8+ T cell epitopes from IBVs that are protective in mice and found that memory CD8+ T cells are directed against universal and influenza virus type-specific epitopes in the blood and lungs of healthy humans. These lung-derived CD8+ T cells displayed tissue-resident memory phenotypes. In addition, CD38+Ki67+CD8+ effector T cells that are directed against novel epitopes were readily detected in both IAV- and IBV-infected children and adults. Therefore it appears that CD8+ T cells provide unprecedented cross-reactivity across all influenza viruses, suggesting some utility for the design of universal vaccines.
Read more here