Fig. 7.
Proteasome activity contributes to MHC class II-restricted presentation during influenza virus infection. L-IEd (A) or B6-IEd (B) fibroblasts were left untreated or were pretreated with 0.5 μM epoxomicin (Epox) for 15 min, infected with PR8, and cultured with CD4+ T cells isolated from splenocytes of mice primed intranasally with PR8. Results shown in A and B are pooled data from three mice per group. (C) L-IEd fibroblasts were transfected with the indicated siRNAs for 48 h, infected with PR8, and cultured with CD4+ T cells isolated from splenocytes of CB6F1 (H2bxd) mice primed intranasally. (D) Flow cytometry analysis of fibroblasts expressing NA at high levels on the cell surface after siRNA transfection. Results are representative of at least two independent experiments.