In the present study, the recognition of epitope variants of influenza A viruses by human CTL was investigated. To this end, human CD8(+) CTL clones, specific for natural variants of the HLA-B*3501-restricted epitope in the nucleoprotein (NP(418-426)), were generated. As determined in (51)Cr release assays and by flow cytometry with HLA-B*3501-peptide tetrameric complexes, CTL clones were found to be specific for epitopes within one subtype or cross-reactive with heterosubtypic variants of the epitope. Using eight natural variants of the epitope, positions in the 9-mer important for T cell recognition and involved in escape from CTL immunity were identified and visualized using multidimensional scaling. It was shown that positions 4 and 5 in the 9-mer epitope were important determinants of T cell specificity. The in vivo existence of CD8(+) cells cross-reactive with homo- and heterosubtypic variants of the epitope was further confirmed using polyclonal T cell populations obtained after stimulation of PBMC with different influenza A viruses. Based on the observed recognition patterns of the clonal and polyclonal T cell populations and serology, it is hypothesized that consecutive infections with influenza viruses containing different variants of the epitope select for cross-reactive T cells in vivo.

*Cytotoxicity Tests, Immunologic/methods, Adult, Antigens, Viral/immunology/metabolism, CD8-Positive T-Lymphocytes/chemistry/*immunology/metabolism/*virology, Cell Line, Transformed, Clone Cells, Epitopes, T-Lymphocyte/chemistry/*immunology/metabolism, HLA-B35 Antigen/chemistry/immunology/metabolism, Humans, Influenza A virus/classification/*immunology, Leukocytes, Mononuclear/chemistry/immunology/virology, Middle aged, Nucleocapsid Proteins, Nucleoproteins/chemistry/*immunology/metabolism, Peptide Fragments/chemistry/immunology/metabolism, Protein Binding/immunology, Research Support, Non-U.S. Gov't, Serotyping, Staining and Labeling, Viral Core Proteins/chemistry/*immunology/metabolism
Journal of Immunology
Erasmus MC: University Medical Center Rotterdam

Boon, A.C.M, de Mutsert, G, van Baarle, D, Smith, D.J, Lapedes, A.S, Fouchier, R.A.M, … Osterhaus, A.D.M.E. (2004). Recognition of homo- and heterosubtypic variants of influenza A viruses by human CD8+ T lymphocytes. Journal of Immunology. Retrieved from