Fig. 3.

229E infection induces virus-specific T cell response and neutralizing antibodies in mice. (A–C) Ad5-hAPN-transduced IFNAR^−/− C57BL/6 mice were infected with 1.5 × 10⁵ TCID₅₀ of 229E. To identify 229E T cell responses, single-cell suspensions were prepared from the BALF of transduced/ infected IFNAR^−/− C57BL/6 mice and stimulated with 2 μM structural protein peptide pools for 5 to 6 h in the presence of brefeldin A. Flow plots [(A), 7 d.p.i.], and summary of frequencies and cell numbers of 229E-specific CD4⁺ (B) and CD8⁺ T cells (C) (determined by IFN-γ intracellular staining) are shown (n = 3 or 4 mice per group per time point). (D) To determine the kinetics of virus-specific T cell responses in 229E -infected IFNAR^−/− C57BL/6 mice, single-cell suspensions were prepared from the BALF of transduced/infected IFNAR^−/− C57BL/6 mice at indicated time points and stimulated with 2 μM ME or N protein peptide pools for 5 to 6 h in the presence of brefeldin A. The frequencies (Left) and cell numbers (Right) of 229E-specific T cells from BALF are shown (n = 3 mice per time point). (E) Confirmation of 229E-specific-CD4⁺ T cell epitopes in IFNAR^−/− C57BL/6 mice (7 d.p.i.). Flow plots (Left) and summary panels (Right) are shown. (F and G) Confirmation of 229E-specific-CD8⁺ T cell epitopes in IFNAR^−/− C57BL/6 mice (7 d.p.i.). Flow plots (F) and summary panels (G) are shown. (H) Characteristics of 229E-derived CD4⁺ and CD8⁺ T cell epitopes in IFNAR^−/− C57BL/6 mice. (I) TRNT₅₀ titers of the sera of hAPN-transduced/229E-infected IFNAR^−/− C57BL/6 mice were determined at the indicated time points. (n = 6 mice). (*P ≤ 0.05, **P ≤ 0.005, ***P ≤ 0.0005, ****P ≤ 0.0001).