OR8D1 and infection: The expression levels of OR8D1 were significantly downregulated in the in vitro M cells after S. Typhimurium WT and ΔspeG infection compared with the uninfected cells according to qRT-PCR analysis (Fig 3); however, they were nonsignificantly downregulated (−1.197- and −1.339-fold change, respectively) according to the microarray data.