Abstract
Abstract
Background
Increasing evidence supports a critical role of CD8+ T-cell immunity against influenza. Activation of mucosal CD8+ T cells, particularly tissue-resident memory T (TRM) cells recognizing conserved epitopes would mediate rapid and broad protection. Matrix protein 1 (M1) is a well-conserved internal protein.
Methods
We studied the capacity of modified vaccinia Ankara (MVA)–vectored vaccine expressing nucleoprotein (NP) and M1 (MVA-NP+M1) to activate M1-specific CD8+ T-cell response, including TRM cells, in nasopharynx-associated lymphoid tissue from children and adults.
Results
After MVA-NP+M1 stimulation, M1 was abundantly expressed in adenotonsillar epithelial cells and B cells. MVA-NP+M1 activated a marked interferon γ–secreting T-cell response to M1 peptides. Using tetramer staining, we showed the vaccine activated a marked increase in M158–66 peptide-specific CD8+ T cells in tonsillar mononuclear cells of HLA-matched individuals. We also demonstrated MVA-NP+M1 activated a substantial increase in TRM cells exhibiting effector memory T-cell phenotype. On recall antigen recognition, M1-specific T cells rapidly undergo cytotoxic degranulation, release granzyme B and proinflammatory cytokines, leading to target cell killing.
Conclusions
MVA-NP+M1 elicits a substantial M1-specific T-cell response, including TRM cells, in nasopharynx-associated lymphoid tissue, demonstrating its strong capacity to expand memory T-cell pool exhibiting effector memory T-cell phenotype, therefore offering great potential for rapid and broad protection against influenza reinfection.
Modified vaccinia Ankara–vectored vaccine expressing nucleoprotein and matrix protein 1 (MVA-NP+M1) activates a substantial increase in anti-influenza M1-specific T cells, including fast-reacting tissue-resident memory T cells in human nasopharynx mucosal tissue. It is therefore a promising mucosal vaccine candidate.