CD40 and infection: Infection with the S. aureus USA300 WT or the S. aureus Δαβδ mutant strain induced the up-regulation of MHCII, CD86, CCR7, CD80, CD40, and PD-L2 on all DC subsets in the spleen starting 6 h pi compared to PBS-treated mice as analyzed by flow cytometry staining (Figure 2).