CD40 and infection: Regardless of the differences between the previous study and the current study (e.g., different animals, infection doses, challenge times, and platforms), 13 out of these 55 up-regulated genes were also detected to be significantly up-regulated in this study during IMI with high concentration of S. aureus, including genes for cytokine, chemokine and intercellular signaling (CCL20, CSF3, HCK, IL1B, IL6, PLAUR, and S100A12), cell surface receptors (CD14 and CD40), transcription regulator (NFKB2 and NFKBIA), and apoptosis (BCL2A1 and BIRC3).