The relationship between IgA activity against 4th-stage larvae and density-dependent effects on the number of 4th-stage larvae of<i>Teladorsagia circumcincta</i>in naturally infected sheep

Stear, M. J.; Bairden, K.; Innocent, Giles; Mitchell, Stewart; Strain, S.; Bishop, S.C.

doi:10.1017/s0031182004005736

Cited by 62 publications

(60 citation statements)

References 28 publications

(37 reference statements)

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“…Similar correlations have been observed in Santa Ines, Suffolk, and Ile de France lambs infected by H. contortus , Scottish Blackface lambs infected by H. contortus , and Churra lambs infected with T. circumcincta [57–59]. In addition, Scottish Blackface lambs that were naturally infected with T. circumcincta have shown a similar relationship [53, 60]. …”

Section: The Role Of Iga In Nematode Resistancesupporting

confidence: 65%

“…However, the high value reported by Smith et al may have been an artefact created by pooling data from sheep of different ages. The level of variation in nematode parasite worm length due to L4 parasite-specific IgA activity has been independently estimated as ~38% in Churra sheep [59], with similar estimates reported by Sinski et al [61], Strain and Stear [57], Strain et al [60], Stear et al [53], Amarante et al [58], and Henderson and Stear [56]. …”

Section: The Role Of Iga In Nematode Resistancementioning

confidence: 55%

“…Pooling data across age classes produced an extremely strong correlation between the increased IgA response and increased numbers of inhibited larvae. A large study in naturally infected sheep supported this finding by showing that lambs with higher peripheral IgA activity against fourth-stage larvae showed inhibition of a higher proportion of larvae [53]. …”

Section: The Role Of Iga In Nematode Resistancementioning

confidence: 94%

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The Influence of MHC and Immunoglobulins A and E on Host Resistance to Gastrointestinal Nematodes in Sheep

Lee

Munyard

Gregg

et al. 2011

Journal of Parasitology Research

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Gastrointestinal nematode parasites in farmed animals are of particular importance due to their effects on production. In Australia, it is estimated that the direct and indirect effects of parasite infestation cost the animal production industries hundreds of millions of dollars each year. The main factors considered by immunologists when studying gastrointestinal nematode infections are the effects the host's response has on the parasite, which immunological components are responsible for these effects, genetic factors involved in controlling immunological responses, and the interactions between these forming an interconnecting multilevel relationship. In this paper, we describe the roles of immunoglobulins, in particular IgA and IgE, and the major histocompatibility complex in resistance to gastrointestinal parasites in sheep. We also draw evidence from other animal models to support the involvement of these immune components. Finally, we examine how IgA and IgE exert their influence and how methods may be developed to manage susceptible animals.

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Section: The Role Of Iga In Nematode Resistancesupporting

confidence: 65%

Section: The Role Of Iga In Nematode Resistancementioning

confidence: 55%

Section: The Role Of Iga In Nematode Resistancementioning

confidence: 94%

See 1 more Smart Citation

The Influence of MHC and Immunoglobulins A and E on Host Resistance to Gastrointestinal Nematodes in Sheep

Lee

Munyard

Gregg

et al. 2011

Journal of Parasitology Research

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“…As the intensity of infection with T. circumcincta increases, an increasing number of larvae arrest development (Stear et al 2004) while those that do develop into adults produce fewer eggs per day. We used previously published results to predict egg output from the number of adult parasites Bishop and Stear, 2000).…”

Section: Discussionmentioning

confidence: 99%

Variation among faecal egg counts following natural nematode infection in Scottish Blackface lambs

et al. 2005

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Faecal egg counts were examined in 2 flocks of naturally infected Scottish Blackface sheep in southern and central Scotland. The distribution of mean counts was right skewed and similar to a gamma distribution. The counts varied with month, with mean counts rising from May to July, then falling but rising again in October, although data within each year did not always show such a clear pattern. There was no significant difference in mean egg count between the 2 farms examined. The distribution of egg count variances was also right skewed and conformed to a gamma distribution. There was a strong relationship between the mean and the variance for each population, implying that variation among populations in variances largely mirrored variation in mean egg counts. Populations with high mean egg counts and variances did not necessarily have more adult nematodes but had a greater number of adult nematodes from species other than Teladorsagia circumcincta, particularly Cooperia spp., Trichostrongylus axei and Trichostrongylus vitrinus. The contribution of different parasite species to the egg count explains the relatively poor and inconsistent fit of the negative binomial distribution to faecal egg counts in lambs.

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“…A greater number of eosinophils and mucosal mast cells in Native exists, it is presumed that the biologically active antibody is secretory IgA, which is actively secreted across the mucosal epithelium of the abomasum (Macpherson et al 2008;Venturina et al, 2013). The mechanisms of IgA action are not clear, even though IgA can bind to both larvae and adults or to nematode secretions, thus controlling larval development and egg production (Stear et al, 2004;Halliday et al, 2007). One report suggests that secretory IgA can inhibit larval establishment by provoking eosinophil degranulation (Li et al, 2012), despite the fact that eosinophils and antibodies are on different sides of the epithelial barrier (Venturina et al, 2013).…”

Section: The Role Of Immunoglobulin a (Iga) And Immunoglobulin E (Ige)mentioning

confidence: 99%

Immune and other factors modulating host resistance against gastrointestinal nematode parasites in sheep

Arsenopoulos

Symeonidou

Papadopoulos

2018

J Hellenic Vet Med Soc

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Infection of small ruminants with gastrointestinal nematode (GIN) parasites is a significant problem with crucial impact on meat and milk production. The strategy of administrating anthelminthic drugs has been implemented for many years and has resulted in the development of resistant strains of parasites. Meanwhile, consumers demand for free of drugs products have led to the adoption of alternative control methods, which involve the selective breeding of animals, which are resistant to parasitism. The development of immunity and therefore, resistance against gastrointestinal parasites is based on the activation of specific host genes. Gene analysis has revealed areas (QTLs), which affect resistance or susceptibility of sheep to gastrointestinal infestations between animals of different breeds and between individuals of the same breed. The role of cytokines and T helper cells has been enhanced as research, strongly, supports the connection of Th2 cells with resistance and Th1 cells with susceptibility against GIN. Latest data implicates T regulatory cells and a specific cell type, Th17, in immune response mechanisms. Specific adhesion molecules (integrins, lectins, cadherins) are produced in the gut lumen in sufficient amounts and appear to boost immunity and reduce clinical signs in sheep. Additionally, the immunoglobulins IgA and IgE have been positively correlated with increased resistance against GIN. In several cases of GIN, where an increased number of eosinophils and mast cells in the intestinal epithelium have been recorded, the animals had a reduced number of parasite eggs in their feces. The genes of the Major Histocompatibility Complex have been referred to as potential resistance or susceptibility markers. Other enzymes, like chitinases, enhance the resilience of animals and protect them effectively. Animal’s nutritional status is another determinant factor of immune capability against GIN in sheep, both systemic, as well as locally. Regarding the effect of reactive oxygen and nitrogen species, some researchers support their direct effect against GIN, resulting in a natural reduction of their number, while others claim the indirect action in the intestinal epithelium by reducing local immunity. Consequently, the detection of genes associated with resistance or susceptibility to gastrointestinal infestations is promising and in line with modern requirements.

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The relationship between IgA activity against 4th-stage larvae and density-dependent effects on the number of 4th-stage larvae ofTeladorsagia circumcinctain naturally infected sheep

Cited by 62 publications

References 28 publications

The Influence of MHC and Immunoglobulins A and E on Host Resistance to Gastrointestinal Nematodes in Sheep

The Influence of MHC and Immunoglobulins A and E on Host Resistance to Gastrointestinal Nematodes in Sheep

Variation among faecal egg counts following natural nematode infection in Scottish Blackface lambs

Immune and other factors modulating host resistance against gastrointestinal nematode parasites in sheep

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