The genetic control of IgA activity against <i>Teladorsagia circumcincta</i> and its association with parasite resistance in naturally infected sheep

Strain, S.; Bishop, Stephen; Henderson, Neil; Kerr, A.; McKellar, Quintin; Mitchell, Stewart; Stear, M. J.

doi:10.1017/s0031182002001531

Cited by 105 publications

(122 citation statements)

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“…But in contrast to studies in Texel and Castellana sheep showing a stronger IgG and IgA response in animals previously exposed to infection (Schallig et al, 1995;Gomez-Munoz et al, 1999), in Creole kids naturally parasitized on pasture before the experimental infection, a weak response was observed except for IgA anti-ESP which showed amounts similar to primo-infected sheep. Previous studies in sheep suggest that IgA may be the major mechanism controlling fecundity of H. contortus and worm length and fecundity of Teladorsagia cicumcincta (Stear et al, 1995b;Strain et al, 2002 (Amarante et al, 2005). A significant IgA response was observed in both groups against H. contortus, but no relationship was found between IgA anti-L3 or IgA anti-ESP and FEC.…”

Section: Discussionmentioning

confidence: 71%

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Bambou¹,

Chevrotière²,

Varo³

et al. 2008

Veterinary Parasitology

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The objective of this study was to evaluate the relationship of parasite-specific serum antibodies with the resistance status of Creole kids. The average breeding values on egg output predicted in a context of natural infection at 11 months of age were distant of 1.07 genetic standard deviation between resistant and susceptible animals. After drenching the animals were maintained worm-free during 1 month until experimental infection with 10,000 Haemonchus contortus infective larvae (L3). Enzyme-linked immunosorbent assay was carried out in serum samples to determine the level of IgG, IgA and IgE anti-H. contortus L3 crude extracts and adult excretion/secretion products (ESP). Parasitological and blood immunological parameters were measured on the 2 extreme groups. Despite the absence of any typical signs of haemonchosis, susceptible kids had more than 11 times higher faecal egg counts (FEC) at 35 days post-infection (d.p.i.) than resistant kids had. Levels of immunoglobulin against H. contortus L3 and ESP increased significantly after infection in both groups. However, no difference in the host immune response mediated by immunoglobulin against H. contortus was evidenced between groups. This finding suggests that, in goats previously infected by H. contortus, a degree of protection occurred and the phenotypic and genetic segregation in resistant and susceptible animals were not related to the humoral immune response. The correlation coefficients between FEC and IgE anti-ESP (r = 0.593; P < 0.05 was significant in both resistant and susceptible animals. Such correlation suggesting a hypersensitivity reaction dependent on worm prolificacy has never been described. This result needs further studies to understand the mechanisms underlying this observation. #

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Section: Discussionmentioning

confidence: 71%

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Bambou¹,

Chevrotière²,

Varo³

et al. 2008

Veterinary Parasitology

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“…Faecal samples were collected from the rectum of each lamb at the time of weighing and used for FEC assays, using the modified McMaster technique as described by Gordon and Whitlock (1939) and Bairden (1991). The activity of plasma IgA against a somatic extract of third-stage larvae from Teladorsagia was measured by indirect ELISA, as described by Strain et al (2002), using blood samples collected at 24 weeks of age. The relative IgA activity was calculated according to the formula suggested by Sinski et al (1995).…”

Section: Methodsmentioning

confidence: 99%

Accuracy of genomic prediction within and across populations for nematode resistance and body weight traits in sheep

Riggio

Abdel-Aziz

Matika

et al. 2014

Animal

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Genomic prediction utilizes single nucleotide polymorphism (SNP) chip data to predict animal genetic merit. It has the advantage of potentially capturing the effects of the majority of loci that contribute to genetic variation in a trait, even when the effects of the individual loci are very small. To implement genomic prediction, marker effects are estimated with a training set, including individuals with marker genotypes and trait phenotypes; subsequently, genomic estimated breeding values (GEBV) for any genotyped individual in the population can be calculated using the estimated marker effects. In this study, we aimed to: (i) evaluate the potential of genomic prediction to predict GEBV for nematode resistance traits and BW in sheep, within and across populations; (ii) evaluate the accuracy of these predictions through within-population cross-validation; and (iii) explore the impact of population structure on the accuracy of prediction. Four data sets comprising 752 lambs from a Scottish Blackface population, 2371 from a Sarda × Lacaune backcross population, 1000 from a Martinik Black-Belly × Romane backcross population and 64 from a British Texel population were used in this study. Traits available for the analysis were faecal egg count for Nematodirus and Strongyles and BW at different ages or as average effect, depending on the population. Moreover, immunoglobulin A was also available for the Scottish Blackface population. Results show that GEBV had moderate to good within-population predictive accuracy, whereas across-population predictions had accuracies close to zero. This can be explained by our finding that in most cases the accuracy estimates were mostly because of additive genetic relatedness between animals, rather than linkage disequilibrium between SNP and quantitative trait loci. Therefore, our results suggest that genomic prediction for nematode resistance and BW may be of value in closely related animals, but that with the current SNP chip genomic predictions are unlikely to work across breeds.

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“…They were measured by indirect enzyme-linked immunosorbent assay, as described by Strain et al (2002), on blood samples collected at 24 weeks of age. Relative IgA activity was measured as: (observed-standard)/(high control-standard), where the observed value is the sample mean from three replicates for the animal, the standard is the mean of three replicates from a pooled sample of helminth-naive lambs and the high control is the mean of three replicates from a pool of high-responder lambs (Sinski et al, 1995).…”

Section: Phenotypic Measurementsmentioning

confidence: 99%

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

et al. 2013

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The genetic architecture underlying nematode resistance and body weight in Blackface lambs was evaluated comparing genome-wide association (GWA) and regional heritability mapping (RHM) approaches. The traits analysed were faecal egg count (FEC) and immunoglobulin A activity against third-stage larvae from Teladorsagia circumcincta, as indicators of nematode resistance, and body weight in a population of 752 Scottish Blackface lambs, genotyped with the 50k single-nucleotide polymorphism (SNP) chip. FEC for both Nematodirus and Strongyles nematodes (excluding Nematodirus), as well as body weight were collected at approximately 16, 20 and 24 weeks of age. In addition, a weighted average animal effect was estimated for both FEC and body weight traits. After quality control, 44 388 SNPs were available for the GWA analysis and 42 841 for the RHM, which utilises only mapped SNPs. The same fixed effects were used in both analyses: sex, year, management group, litter size and age of dam, with day of birth as covariate. Some genomic regions of interest for both nematode resistance and body weight traits were identified, using both GWA and RHM approaches. For both methods, strong evidence for association was found on chromosome 14 for Nematodirus average animal effect, chromosome 6 for Strongyles FEC at 16 weeks and chromosome 6 for body weight at 16 weeks. Across the entire data set, RHM identified more regions reaching the suggestive level than GWA, suggesting that RHM is capable of capturing some of the variation not detected by GWA analyses.

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The genetic control of IgA activity against Teladorsagia circumcincta and its association with parasite resistance in naturally infected sheep

Cited by 105 publications

References 0 publications

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Serum antibody responses in Creole kids experimentally infected with Haemonchus contortus

Accuracy of genomic prediction within and across populations for nematode resistance and body weight traits in sheep

Genome-wide association and regional heritability mapping to identify loci underlying variation in nematode resistance and body weight in Scottish Blackface lambs

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