ABSTRACT
We examined mRNA expression of eight genes, TLR4, TLR5, TLR15, interleukin (IL)-1ß, IL-6, transforming growth factor-ß4 (TGF-ß4), CXCLi2, and a macrophage inflammatory protein (MIP) family chemokine called CCLi2, in peripheral blood mononuclear cells (PBMCs) isolated from the blood of chickens after in vitro exposure to Salmonella enterica serovar Enteritidis (SE). The chickens of four Chinese native lines, Qingjiaoma, Sanhuang, Wugu, and Xueshanma, were evaluated for mRNA expression levels at 2 and 4h post-infection using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). TLR4 and TLR15 mRNA were in particular highly expressed in PBMCs of Wugu and Xueshanma chickens exposed to SE, while TLR5 was expressed less in the Sanhuang chickens than in others. Breed effect was significant (P<0.05) for IL-1ß, IL-6, CXCLi2, and CCLi2 mRNA expression, all of which were expressed to a greater extent in Wugu and Xueshanma than in the other two lines. These findings demonstrate the difference of mRNA expression profiles for innate immune molecules in PBMCs infected to SE among different lines.
Subject(s)
Chickens/metabolism , Gene Expression Regulation/immunology , Leukocytes, Mononuclear/metabolism , Salmonella enteritidis/immunology , Animals , Cells, Cultured , Chickens/genetics , Chickens/immunology , Cytokines/genetics , Cytokines/metabolism , Leukocytes, Mononuclear/immunology , RNA, Messenger/genetics , RNA, Messenger/metabolism , Toll-Like Receptors/genetics , Toll-Like Receptors/metabolismABSTRACT
Recombinant attenuated Salmonella vaccines have been extensively studied, with a focus on eliciting specific immune responses against foreign antigens. However, very little is known about the innate immune responses, particularly the role of flagellin, in the induction of innate immunity triggered by recombinant attenuated Salmonella in chickens. In the present report, we describe two Salmonella enterica serovar Typhimurium vaccine strains, wild-type (WT) or flagellin-deficient (flhD) Salmonella, both expressing the fusion protein (F) gene of Newcastle disease virus. We examined the bacterial load and spatiotemporal kinetics of expression of inflammatory cytokine, chemokine, and Toll-like receptor 5 (TLR5) genes in the cecum, spleen, liver, and heterophils following oral immunization of chickens with the two Salmonella strains. The flhD mutant exhibited an enhanced ability to establish systemic infection compared to the WT. In contrast, the WT strain induced higher levels of interleukin-1ß (IL-1ß), CXCLi2, and TLR5 mRNAs in cecum, the spleen, and the heterophils than the flhD mutant at different times postinfection. Collectively, the present data reveal a fundamental role of flagellin in the innate immune responses induced by recombinant attenuated Salmonella vaccines in chickens that should be considered for the rational design of novel vaccines for poultry.
Subject(s)
Flagellin/immunology , Immunity, Innate , Poultry Diseases/immunology , Salmonella Infections, Animal/immunology , Salmonella Vaccines/immunology , Salmonella typhimurium/immunology , Animals , Cecum/immunology , Chickens , Flagellin/genetics , Gene Deletion , Gene Expression Profiling , Interleukins/biosynthesis , Liver/immunology , Newcastle disease virus/genetics , Newcastle disease virus/immunology , Poultry Diseases/prevention & control , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Salmonella Infections, Animal/prevention & control , Salmonella Vaccines/administration & dosage , Salmonella Vaccines/genetics , Salmonella typhimurium/genetics , Salmonella typhimurium/pathogenicity , Spleen/immunology , Toll-Like Receptor 5/biosynthesis , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Viral Fusion Proteins/genetics , Viral Fusion Proteins/immunology , Virulence Factors/deficiency , Virulence Factors/immunologyABSTRACT
There are few data available for the trends of antimicrobial resistance of Salmonella enterica subspecies enterica serovar Pullorum (S. Pullorum) in China and other parts of the world. Thus, the objective of this study was to evaluate the changes in antimicrobial resistance of S. Pullorum isolated from diseased chickens in China from 1962 to 2007. A total of 450 S. Pullorum isolates were tested for their susceptibility to 17 antimicrobials in a disk diffusion method. 39-95% of the isolates displayed a high level of resistance, particularly against ampicillin, carbenicillin, streptomycin, tetracycline, trimethoprim and sulfafurazole. Isolates exhibited increased resistance to carbenicillin, spectinomycin, trimethoprim, trimethoprim/sulfamethoxazole and nalidixic acid during the study period. Moreover, 56.2% of the isolates exhibited multiple drug resistance (MDR; resistance> or =4 antimicrobials) and showed an increasing trend between 1970-1979 and 2000-2007. Therefore, the results suggest that certain measures, including continued surveillance of antimicrobial resistance and the rational use of antimicrobials, are necessary and important in order to control the rapid increase in antimicrobial resistance in S. Pullorum.
