Porcine differential gene expression in response to Salmonella enterica serovars Choleraesuis and Typhimurium

An investigation of the porcine response to gastrointestinal infection with Salmonella enterica serovars Choleraesuis (narrow host range) and Typhimurium (broad host range) revealed markedly different transcriptional profiles. Seven genes identified by suppression subtractive hybridization as up-regulated in the mesenteric lymph nodes at 24h (h) post-inoculation (p.i.) in serovar Choleraesuis-infected pigs (ARPC2, CCT7, HSPH1, LCP1, PTMA, SDCBP, VCP) and three genes in serovar Typhimurium-infected pigs (CD47/IAP, CXCL10, SCARB2) were analyzed by real-time PCR at 8h, 24 h, 48 h, 7 days (d) and 21 d p.i. A comparison between the two Salmonella infections revealed significant differences in transcriptional induction early in the infection (8-24h) for the serovar Typhimurium-infected pigs, whereas the serovar Choleraesuis-infected pigs exhibited significantly higher levels of gene expression at the later time points (48h-21 d), except for HSPH1. A similar gene expression trend was observed for immune-related genes involved in innate immunity and the inflammatory T helper 1 (Th1) response. Initial repression of gene expression in the serovar Choleraesuis-infected pigs from 8 to 48h p.i. (IFNG, IL12A, IL4, IL8, CSF2) coincided with extended transcriptional activation throughout the 21 d infection (IFNG, INDO, SOCS1, STAT1, IL1B, IL6, IL8, SLC11A1). The serovar Typhimurium-infected swine presented a more transient induction of immune-related genes (IFNG, INDO, IRF1, SOCS1, STAT1, IL1B, IL8, SLC11A1) early in the infection (24-48 h) followed by a significant repression of IL12A, IL12B, IL4, IL8 and CSF2. Collectively, these data reveal specific porcine genes with differences in gene expression kinetics that may be responsible for the variation in disease progression observed in swine infected with Typhimurium compared to Choleraesuis.