Project description:Innate immunity is expected to play a primary role in conferring resistance to novel infectious diseases, but few studies have attempted to examine its role in the evolution of resistance to emerging pathogens in wild vertebrate populations. Here we used experimental infections and cDNA microarrays to examine whether changes in the innate and/or acquired immune responses likely accompanied the emergence of resistance in house finches (Carpodacus mexicanus) in the eastern United States subject to a recent outbreak of conjunctivitis-causing bacterium (Mycoplasma gallisepticum- MG). Three days following experimental infection with MG, we observed differences in the splenic transcriptional responses between House Finches from eastern U.S. populations, with a 12-year history of MG exposure, versus western U.S. populations, with no history of exposure to MG. In particular, western birds down-regulated gene expression, while eastern finches showed no expression change relative to controls. Studies involving poultry have shown that MG can manipulate host immunity, and our observations suggest that pathogen manipulation occurred only in finches from the western populations, outside the range of MG. Fourteen days after infection, eastern finches, but not western finches, up-regulated genes associated with acquired immunity (cell-mediated immunity) relative to controls. These observations suggest population differences in the temporal course of the response to infection with MG, and imply that innate immune processes were targets of selection in response to MG in the eastern U.S. population. Birds were randomly selected to be kept either as controls or infected via ocular inoculation with 20 μl of culture containing 1 x 104 to 1 x 106 color changing units/ml of an early 2007 Auburn MG isolate. All infected birds were inoculated with precisely the same volume of the same culture. Control birds were sham infected using sterile SP4 medium (Whitcomb 1983). Infected birds were euthanized three days (N=6 from Arizona and N=11 from Alabama) and 14 days (N=11 from Arizona and N=12 from Alabama) after treatment. Control birds were euthanized 14 days after sham-inoculation; Control (N=11 birds from Arizona and 9 from Alabama) and infected birds were maintained under identical conditions, but in separate rooms of an aviary. Infected birds were euthanized three days (N=6 from Arizona and N=11 from Alabama) and 14 days (N=11 from Arizona and N=12 from Alabama) after treatment. Control birds were euthanized 14 days after sham-inoculation. We used a common reference design (Yang & Speed 2002), in which we pooled 2 to 6 spleens from birds from the same population in the same treatment to generate enough mRNA for microarray hybridizations and hybridized two pools for each treatment from each population.

Project description:Background: Avian infectious bronchitis (IB) is an acute and highly contagious disease of the upper-respiratory tract caused by infectious bronchitis virus (IBV). Understanding the molecular mechanisms involved in the interaction between innate and adaptive immune responses to IBV infection is a crucial element for further improvements in strategies to control IB. To this end, two chicken lines, selected for high and low serum concentration of mannose-binding lectin (MBL), a soluble pattern recognition receptor, were studied. In total, 32 birds from each line (designated L10H for high and L10L for low MBL serum concentration, respectively) were used. Sixteen birds from each line were infected with IBV at 3 weeks of age and sixteen birds were left uninfected. Eight uninfected and eight infected birds from each line were euthanized at 1 and 3 weeks post infection. RNA sequencing was performed on spleen samples from all 64 birds used in the experiment. Differential gene expression analysis was performed for four comparisons: L10L line versus L10H line for uninfected birds at weeks 1 and 3, respectively, and L10L line versus L10H line for infected birds at weeks 1 and 3, respectively. Functional analysis based on the differentially expressed genes was performed using Gene Ontology (GO) Immune System Process terms specific for Gallus gallus. Results: Comparing uninfected L10H and L10L birds, we identified 1698 and 1424 differentially expressed (DE) genes at weeks 1 and 3, respectively. For the IBV-infected birds, 1934 and 866 DE genes were identified between the two lines at weeks 1 and 3, respectively. In both cases DE genes had FDR-adjusted p-value <0.05. The two most enriched GO terms emerging from the comparison of uninfected birds between the two lines were “Lymphocyte activation involved in immune response” (GO:0002285) and “Somatic recombination of immunoglobulin genes involved in immune response” (GO:0002204) at weeks 1 and 3, respectively. When comparing IBV-infected birds between the two lines, the most enriched GO terms were “Alpha-beta T cell activation” (GO:0046631) and “Positive regulation of leukocyte activation” (GO:0002696) at weeks 1 and 3, respectively. Conclusion: Healthy birds from the two lines showed significant differences in expression profiles for subsets of both adaptive and innate immunity-related genes, whereas comparison of the IBV-infected birds from the two lines showed differences in expression of immunity-related genes involved in T cell activation and proliferation. The observed transcriptome differences between the two lines indicate that selection for MBL had a much wider effect than solely on serum MBL concentration, and in addition influenced the innate and adaptive immune responses. Future research will focus on identifying signatures of selection in order to further understand molecular pathways be responsible for differences between the two lines as well as for efficient IBV immune protection.

Project description:Salmonella causes inflammation in infected hosts. Inflammation is a well-characterized defensive mechanism of innate immunity. The recognition and engagement of lipopolysaccharide (LPS) endotoxins in the outer membranes of Salmonella to Toll-like receptor 4 of immune cells (macrophages and dendritic cells) trigger inflammatory responses characterized by secretion of pro-inflammatory cytokines, including TNF-beta, IL-1 and IL-6. These cytokines cause fever, anorexia, bodyweight losses, and catabolism of skeletal muscles and adipose tissues. However, molecular events underlying innate immune responses and metabolic activities during the later stage of inflammation are poorly understood. Additionally, the effects of prebiotics and antibiotics on innate immunity and nutrient metabolism are not yet reported. The objective of this study is to investigate the effects of a mannanoligosaccharide (MOS) prebiotic and virginiamycin (VIRG) sub-therapeutic antibiotic on innate immunity and glucose metabolism during late inflammation. We induced Salmonella LPS-systemic inflammation in a chicken model. Differentially regulated gene expressions were measured using 2 colour focussed oligonucleotide chicken-specific microarrays. Microarray analysis was performed on liver, intestinal and skeletal muscle tissues. We found that late inflammation was principally modulated by interleukin 3 (IL 3) and that glucose was mobilized from gluconeogenesis occurring in the intestines only. MOS and VIRG modulated innate immunity and metabolic genes differently. In contrast to VIRG, MOS terminated inflammatory responses earlier. Our results indicate IL 3 gene up-regulation in VIRG-fed chickens. To meet the higher energy requirements of VIRG chickens, genes for intestinal gluconeogenesis and liver glycolysis were respectively induced. Our study reveals the potential mechanisms by which prebiotic and antibiotic modulated innate immunity and glucose metabolism during late inflammation. 14-day old chickens were injected i.p. with saline or LPS. For each tissue and experimental conditions (saline or LPS challenge), a total of 12 microarrays (6 MOS birds + 6 VIRG birds) were used in a 2 x 2 factorial design and complete interwoven loop arrangement. We compared gene expression from prebiotic-fed birds with antibiotic-fed birds without including reference RNA. LPS challenge, antibiotic or prebiotic, innate immunity, glucose metabolism

			Action	DRS
	SRR14640500_1.fastq.gz	Fastqsanger.gz
	SRR14640500_2.fastq.gz	Fastqsanger.gz
	SRR14640501_1.fastq.gz	Fastqsanger.gz
	SRR14640501_2.fastq.gz	Fastqsanger.gz
	SRR14640502_1.fastq.gz	Fastqsanger.gz

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