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Pathogen recognition is an essential component to achieve the desired outcome of host protection. Nod‐like receptor pyrin containing domain 3 (NLRP3) is a cytoplasmic pattern recognition receptor (PRR) with a wide array of agonists, such as PAMPs, DAMPs, ATP, bacterial product and viral products. Stimulation of the NLRP3 inflammasome results in proteolytic activation of IL‐1β and IL‐18, cell pyroptosis and classically, the induction of proinflammatory responses. St. Croix (STC) sheep have resistance traits exhibiting the appropriate T‐helper type 2 immune response ensuing protection during helminth parasitic infection whereas parasite‐susceptible Suffolk (SUF) sheep have an impaired response resulting in parasite establishment and adverse symptoms. The objective of these experiments was to determine if NLRP3 protein in H. contortus‐infected SUF sheep was defective using the classical activation pathway of NLRP3 inflammasome. Peripheral blood mononuclear cells (PBMCs) derived from H. contortus‐infected STC and SUF sheep were isolated from whole blood and treated (MCC950 treatment for 2 h followed by LPS treatment for 3 h, 1400 W treatment for 2 h followed by LPS treatment for 3 h, LPS treatment for 3 h or culture media for 3 h). qPCR analysis of LPS‐stimulated PBMC revealed an upregulation in inflammatory associated genes IL‐1β, TLR4, TNFα and NFκB (p < 0.0001) in STC PBMC and downregulation in IFNγ, IL‐6 and iNOS for SUF PBMC. Pharmacological inhibition of iNOS in SUF PBMC resulted in an upregulation in the expression of IFNγ. These preliminary data begin to discover a relationship between NLRP3 activation and TLR4 signalling in PBMC of STC and SUF sheep. [ABSTRACT FROM AUTHOR]

The development of resistance in parasites due to overuse of anthelmintics has resulted in a marked decrease in the efficacy of these drug classes. Recent research efforts have focused on exploring alternatives such as selection for parasite-resistant breeds with the implication that immunocompetence may align with parasite resistance. Two breeds that are often investigated are the St. Croix (STC), a resistant hair breed, and Suffolk (SUF), a susceptible wool breed sheep. The liver has a vital role in metabolism in the body and metabolizes lipopolysaccharide (LPS), which triggers whole body response through the production of appropriate metabolites, cytokines and immune cells. The objective of this study was to investigate the breed differences in liver metabolome of sheep, with divergent resistance to parasites, in response to LPS. Both STC and SUF sheep (n = 9/breed) were challenged with LPS, intravenously and liver biopsies were collected prior to challenge (HR0), 2 h post-challenge (HR2) and 6 h post-challenge (HR6). Liver tissue samples were subjected to quantitative untargeted metabolome analysis using chemical isotope labelling/ liquid chromatography- mass spectrometry. A total of 874 metabolites were detected and identified. Metabolomics also revealed that 8 pathways (pyrimidine metabolism, pantothenate and CoA biosynthesis, beta-Alanine metabolism, valine, leucine and isoleucine degradation, valine, leucine and isoleucine biosynthesis, folate biosynthesis, arginine and proline metabolism and glutathione metabolism) were altered (P ≤ 0.05) between STC and SUF sheep prior to LPS challenge. A total of 10 pathways (folate biosynthesis, glycine, serine and threonine metabolism, tyrosine metabolism, glycerophospholipid metabolism, purine metabolism, cysteine and methionine metabolism, taurine and hypotaurine metabolism, glutathione metabolism, thiamine metabolism and pantothenate and CoA biosynthesis) were altered (P ≤ 0.05) between STC and SUF sheep at HR 2. Only 2 pathways (glycerophospholipid metabolism and purine metabolism) were altered (P ≤ 0.05) between STC and SUF sheep at HR 6. Results highlight the metabolic differences that exist between breeds as well as indicate the significance of amino acid metabolisms that drive cell proliferation, oxidative stress amelioration and inflammation in response to LPS. [ABSTRACT FROM AUTHOR]

Helminths induce potent T helper 2 ([T.sub.H]2)-type immune responses that can mediate worm expulsion, but the role of this response in controlling the acute tissue damage caused by migrating multicellular [...]

Internal parasites are one of the greatest threats to small ruminant production across the United States and parasitic resistance to anthelmintics continues to increase. Genetic selection and copper oxide wire particles (COWP) are two tools that could help reduce effects of parasites in small ruminants. The objective of this project was to determine the effects and interactions of COWP and genetic selection based on fecal egg count (FEC) estimated breeding value (EBV) on gastrointestinal nematode (GIN) infection and performance in naturally infected Katahdin lambs. Spring-born Katahdin ram lambs (n = 52) selected for extremely high FEC EBV (HighFEC, PFEC EBV = +100%) or low FEC EBV (LowFEC, PFEC EBV = -81%) were managed on a fescue-based pasture at the Southwest Virginia Agricultural Research and Extension Center (Glade Spring, VA). At weaning (June 29), lambs were dewormed with a three-combination treatment and rested for 21 d. At the start of the project (July 18), a random subset of lambs (HighFEC, n = 11; LowFEC, n = 15) were given a 2 g copper oxide wire particle bolus, while an equal number of remaining lambs were managed as controls without a copper bolus. All lambs were managed as one contemporary group. Fecal egg counts, FAMACHA scores, body weights, and packed cell volume (PCV) were measured bi-weekly for 10 weeks. Statistical analysis was performed using PROC Mixed Procedure of SAS (SAS Institute, Cary, NC) and FEC data were log transformed for normality. There were no effects of COWP treatment on FEC (P = 0.18). However, LowFEC-selected lambs had less FEC than HighFEC-selected lambs (230 vs. 565 eggs/g, respectively; P < 0.01). There was no interaction of COWP treatment and FEC genotype (P = 0.37). Copper oxide wire particle treatment had no effect on lamb body weight (P = 0.21), PCV (P = 0.69), FAMACHA score (P = 0.41), or overall ADG (P = 0.12). Lamb FEC genotype did not affect FAMACHA score or overall ADG (P = 0.10 and P = 0.22, respectively). LowFEC-selected lambs had lighter body weights (27.7 vs. 30.6 kg, respectively) and PCV (29.2% vs. 30.4%, respectively) than the HighFEC-selected lambs (P < 0.05). None of the 52 lambs met the requirement for deworming (FAMACHA > 3) during the study. These results indicate that lamb FEC genotype may have a greater effect on parasitism than COWP treatment when given once during the post-weaning period. Even so, multiple tools should be considered, in addition to selection, for an integrated parasite management plan. [ABSTRACT FROM AUTHOR]

Parasite-resistant St. Croix sheep (STC) generate a potent neutrophilic response to larval stages of Haemonchus contortus (Hc) as demonstrated by abomasal neutrophil infiltration as early as 3 days after infection. This phenomenon is delayed in parasite-susceptible Suffolk sheep (SUF) potentially contributing to larval establishment. An excretory/secretory (E/S) product, common to many helminths, is neutrophil inhibitory factor (NIF) which negatively affects neutrophil migration and activity. Due to differences in neutrophil accumulation between STC and SUF sheep, we hypothesized that Hc-NIF may inhibit migration of SUF and not STC neutrophils. To determine the concentration of NIF to use in subsequent experiments, neutrophils from STC and SUF were cultured with varying concentrations of Ancylostoma caninum-derived NIF (Ac-NIF) before exposure to larval Hc third-stage larval antigen (HcLA). Analysis of migration to stimuli revealed that the Ac-NIF concentration of 0.125 µg/mL yielded the greatest inhibition of migration towards HcLA between SUF and STC (8.70% and 11.64% migration, respectively; P = 0.0004).To test our hypothesis, neutrophils were cultured from STC and SUF sheep in the presence of Ancylostoma caninum-derived NIF (Ac-NIF) and measure chemo-taxis to Interleukin-8 (IL-8), HcLA or Hc third-stage excretory/secretory (E/S) products. Neutrophils were isolated then incubated with Ac-NIF (0.125µg/mL) or complete media for 1 h. Neutrophils (1,000,000 cell/mL) were applied to cell migration inserts, and placed into a reservoir containing HcLA (20 µg/mL), E/S (20 µg/mL), IL-8 (50 ng/mL), or complete media. Migration plates were incubated (37°C, 5% CO2) for 24 h, after which, migrating cells were quantified using fluorescence. Ac-NIF inhibited SUF neutrophil migration towards IL-8 compared with STC (6.47% vs 9.95%, respectively; P = 0.0025). In response to HcLA alone, 64.0% of STC neutrophils migrated, while only 40.9% of SUF had the ability to migrate (P < 0.001). Towards HcLA, Ac-NIF inhibited SUF neutrophil migration compared with STC (8.40% vs 13.8%, respectively) (P < 0.001). Even more dramatically, in response to E/S products alone, only 24.3% of SUF neutrophils had the ability to migrate, while 76.4% of STC neu-trophils migrated towards E/S (P < 0.001). In response to E/S, only 1.52% of SUF Ac-NIF-treated neutrophils were able to migrate, while 23.27% of STC neutrophils migrated (P < 0.001). Taken together, these data demonstrate that STC neutrophils are resistant to effects of neutrophil inhibition that is artificially applied or derived from HcE/S, which may explain breed differences in neutrophil migration in vivo. [ABSTRACT FROM AUTHOR]