title: Innate immune gene expression differentiates the early avian intestinal response between Salmonella and Campylobacter.
abstract: Salmonella enterica serovar Typhimurium and Campylobacter jejuni are major human pathogens, yet colonise chickens without causing pathology. The aim of this study was to compare intestinal innate immune responses to both bacterial species, in a 4-week-old broiler chicken model. Challenged and control birds were sacrificed and tissue samples taken for histopathology and RNA extraction. No significant clinical or pathological changes were observed in response to infection with either bacterial species. Expression of selected genes involved in pathogen detection and the innate immune response were profiled in caecal tissues by quantitative real-time PCR. TLR4 and TLR21 gene expression was transiently increased in response to both bacterial species (P<0.05). Significant increases in TLR5 and TLR15 gene expression were detected in response to S. Typhimurium but not to C. jejuni. Transient increases of proinflammatory cytokine (IL6 and IFNG) and chemokine (IL8 and K60) genes increased as early as 6h in response to S. Typhimurium. Minimal cytokine gene expression was detected in response to C. jejuni after 20h. IL8 gene expression however, was significantly increased by 24-fold (P<0.01). The differential expression profiles of innate immune genes in both infection models shed light on the tailored responses of the host immune system to specific microbes. It is further evidence that innate regulation of these responses is an important prerequisite to preventing development of disease.
authors.affiliation: Comparative Immunology Group, School of Biochemistry and Immunology, Trinity College, Dublin 2, Ireland.
authors.forename: Ronan G
authors.initials: RG
authors.lastname: Shaughnessy
authors.forename: Kieran G
authors.initials: KG
authors.lastname: Meade
authors.forename: Sarah
authors.initials: S
authors.lastname: Cahalane
authors.forename: Brenda
authors.initials: B
authors.lastname: Allan
authors.forename: Carla
authors.initials: C
authors.lastname: Reiman
authors.forename: John J
authors.initials: JJ
authors.lastname: Callanan
authors.forename: Cliona
authors.initials: C
authors.lastname: O'Farrelly
mesh_terms: D000818:Animals; D016123:Campylobacter jejuni / Q000276:immunology* / Q000472:pathogenicity; D002432:Cecum / Q000276:immunology* / Q000382:microbiology*; D018925:Chemokines / Q000235:genetics; D002645:Chickens / Q000235:genetics* / Q000276:immunology*; D016207:Cytokines / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics*; D016209:Interleukin-8 / Q000235:genetics; D017493:Leukocyte Common Antigens / Q000235:genetics; D012486:Salmonella typhimurium / Q000276:immunology* / Q000472:pathogenicity; D013045:Species Specificity; D051193:Toll-Like Receptors / Q000235:genetics
chemical_list: D018925:Chemokines; D016207:Cytokines; D016209:Interleukin-8; D051193:Toll-Like Receptors; D017493:Leukocyte Common Antigens