PITPNB and infection: Microarray analysis is validated by qRT-PCR in the mRNA expression of HSCHR7_CTG4_4, PITPNB, OR8D1, ZFP36, JUN, KCTD11, and IL6 of in vitro M cells and Caco-2 cells after S. Typhimurium WT and ΔspeG infection