BackgroundIncreasing 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.MethodsWe 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.ResultsAfter 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.ConclusionsMVA-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.
Journal article
The Journal of infectious diseases
08/2020
222
807 - 819
Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
Nasopharynx, Respiratory Mucosa, Adenoids, CD8-Positive T-Lymphocytes, Cells, Cultured, Humans, Nucleocapsid Proteins, Viral Matrix Proteins, Viral Vaccines, Lymphocyte Activation, Cell Proliferation, Cell Degranulation, Immunity, Cellular, Immunologic Memory, Adolescent, Adult, Child, Child, Preschool, Lysosomal-Associated Membrane Protein 1, Influenza A Virus, H3N2 Subtype, Granzymes, Interferon-gamma, Palatine Tonsil, Young Adult