FIG. 4.
Cross-responses of M158-66 epitope-specific memory CTLs against pdmH1N1. (A) PBMCs from healthy HLA-A2-seropositive individuals were stimulated with influenza M158-66 peptide to expand the epitope-specific CTLs. T2 cells were loaded with influenza virus M1 (M1-T2) or negative control HPV peptide (HPV-T2) and then cocultured with M158-66 epitope-specific CTLs at the indicated E/T ratios. After 4 h, specific lysis was determined by flow cytometry. (B) M158-66 epitope-specific CTLs were cocultured with peptide-pulsed T2 cells in the presence of anti-CD107a antibody for 4 h. The surface expression of CD107a on CD8 T cells was examined. (C) Autologous B cells infected with or without H1N1, H3N2, or pdmH1N1 virus were cocultured with M158-66 epitope-specific CTLs for 6 h. B-cell death was analyzed by flow cytometry. (D) B cells were loaded with M158-66 (M1-B) or negative control HPV peptide (HPV-B) and then cocultured with M158-66 epitope-specific CTLs in the presence of anti-CD107a antibody. After 4 h, the surface expression of CD107a on CD8 T cells was examined. The results shown are representative of four independent experiments.