Modulation of Haemonchus contortus infection by depletion of γδ+ T cells in parasite resistant Canaria Hair Breed sheep
- Authors: Hernández, Julia , Meeusen, Els , Stear, Michael , Rodríguez, Francisco , Piedrafita, David , Gonzalez, Jorge
- Date: 2017
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 237, no. (2017), p. 57-62
- Full Text: false
- Description: Canaria Hair Breed (CHB) sheep display resistance against the adult stage of the nematode, Haemonchus contortus. Previous studies have suggested significant correlations between γδ+ T lymphocytes and fecundity of female adult worms, suggesting a novel role in immune modulation by these cells. The largest proportion of γδ+ T lymphocytes in sheep are the subpopulation of γδ+/WC1+ T cells. The aim of this study was to evaluate the effect of γδ+/WC1+ T cell depletion via infusion of anti-γδ/WC1 monoclonal antibody (mAb) on the subsequent immune response of CHB sheep infected with H. contortus. Significantly lower γδ+ T cell levels in both peripheral blood and in the basal layers of the abomasal tissue resulted following anti-γδ/WC1 mAb infusion of CHB sheep compared to control animals. Worms recovered from the anti-γδ/WC1 mAb treated CHB sheep had significantly longer female worms with correspondingly more eggs in utero than the saline control group. Significant correlations between eosinophils and worm length and fecundity were no longer apparent in the anti-γδ/WC1 mAb treated CHB sheep. These results support the notion that γδ+ T cells in CHB sheep play a critical role in fecundity regulation (length and eggs in utero) of H. contortus adult female worms, and highlights a new mechanism of modulation by this lymphocyte population, possibly involving eosinophil activation. © 2017 Elsevier B.V.
Immunity to Haemonchus contortus and Vaccine development
- Authors: Nisbet, Alasdair , Meeusen, Els , Gonzalez, Jorge , Piedrafita, David
- Date: 2016
- Type: Text , Book chapter
- Relation: Haemonchus contortus and Haemonchosis ? Past, Present and Future Trends, 2016 (Advances in Parasitology series) Chapter 8 p. 353-396
- Full Text: false
- Reviewed:
- Description: Sheep are capable of developing protective immunity to Haemonchus contortus through repeated exposure to this parasite, although this immune protection is the result of a complex interaction among age, gender, physiological status, pregnancy, lactation, nutrition and innate and adaptive immunity in the host animal. There are multiple effectors of the protective immune response, which differ depending on the developmental stage of the parasite being targeted, and our understanding of the effector mechanisms has developed considerably in the 2000s. The rational design of vaccines based on 'natural' or 'exposed' antigens depends on an understanding of this exposure-induced immunity. However, the most effective current vaccines rely on protection via the induction of high circulating antibody levels to 'hidden' gut antigens of H. contortus. The success of this latter strategy has resulted in the launch of a vaccine, which is based on extracts of the parasite's gut, to aid in the control of Haemonchus in Australia. The development of recombinant subunit vaccines based on the components of the successful native vaccine has not yet been achieved and most of the recent successes with recombinant subunit vaccines have focussed on antigens unrelated to the gut antigens. The future integration of an understanding of the immunobiology of this parasite with advances in antigen identification, expression (or synthesis) and presentation is likely to be pivotal to the further development of these recombinant subunit vaccines. Recent progress in each of the components underpinning this integrated approach is summarized in this review. © 2016 Elsevier Ltd.
- Description: Advances in Parasitology
Potential role for mucosal IgA in modulating Haemonchus contortus adult worm infection in sheep
- Authors: Hernández, Julia , Hernández, Alvaro , Stear, Michael , Conde-Felipe, Magnolia , Rodríguez, Eduardo , Piedrafita, David , Gonzalez, Jorge
- Date: 2016
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 223, no. (2016), p. 153-158
- Full Text: false
- Reviewed:
- Description: Haemonchus contortus (H. contortus) is a haematophagous parasite which causes important economic losses in small ruminants. On the island of Gran Canaria, two sheep breeds coexist which differ in their susceptibility to the infection with H. contortus; the resistant Canaria Hair Breed (CHB) sheep and the susceptible Canaria Sheep (CS) breed. The major target of resistance mechanisms in CHB sheep are directed to the adult parasite stage, reducing the worm burden, and decreased length and fecundity of surviving worms. Mucosal IgA (mIgA) has been shown to be an important regulator of immunity in Haemonchus and Teladorsagia infections; through correlations with larval stages where such mechanisms as antibody-dependent cell cytotoxicity and enzyme inhibition may mediate resistance. Here for the first time, we demonstrate a significant negative correlation between mIgA and adult worm length and fecundity only in the resistant CHB sheep. In contrast, and as reported in other sheep breeds, mIgA was only negatively correlated against the larval stage in the more susceptible CS breed. This study suggests mIgA may play a role in resistance to both larval and adult stages. © 2016 Elsevier B.V.
Current status for gastrointestinal nematode diagnosis in small ruminants: where are we and where are we going?
- Authors: Preston, Sarah , Sandeman, Mark , Gonzalez, Jorge , Piedrafita, David
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of immunology research Vol. 2014, no. September (2014), p. Article no. 210350
- Full Text:
- Reviewed:
- Description: Gastrointestinal nematode (GIN) parasites pose a significant economic burden particularly in small ruminant production systems. Anthelmintic resistance is a serious concern to the effective control of GIN parasites and has fuelled the focus to design and promote sustainable control of practices of parasite control. Many facets of sustainable GIN parasite control programs rely on the ability to diagnose infection both qualitatively and quantitatively. Diagnostics are required to determine anthelmintic efficacies, for targeted treatment programs and selection of animals for parasite resistant breeding. This review describes much of the research investigated to date to improve the current diagnostic for the above practices which is based on counting the number of parasite eggs in faeces.
Fecundity in adult Haemonchus contortus parasites is correlated with abomasal tissue eosinophils and gamma-delta T cells in resistant Canaria Hair Breed sheep
- Authors: Gonzalez, Jorge , Hernandez, Alvaro , Meeusen, Els , Rodríguez, Francisco , Molina, Jose , Jaber, Jose , Raadsma, Herman , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 178, no. 3-4 (2011), p. 286-292
- Full Text: false
- Reviewed:
- Description: Canaria Hair Breed (CHB) sheep are more resistant than Canaria sheep (CS) to experimental Haemonchus contortus infection. Protective responses appear effective against the adult stage of the parasite, not as commonly reported in other breeds against the larval stages. In this study we have quantified several abomasal immune cells and correlated these with parasitological variables for each breed. A significant negative correlation between CD4+ T cell numbers and worm burden or length at 28 dpi was seen only in CS sheep. Significant negative correlations for both abomasal eosinophils and
Increased production through parasite control : can ancient breeds of sheep teach us new lessons?
- Authors: Piedrafita, David , Raadsma, Herman , Gonzalez, Jorge , Meeusen, Els
- Date: 2010
- Type: Text , Journal article
- Relation: Trends in Parasitology Vol. 26, no. 12 (2010), p. 568-573
- Full Text: false
- Reviewed:
- Description: With a rising world population and economic development, the global demand for meat, milk and other animal products is increasing dramatically. Controlling parasitic diseases in livestock, in particular helminth infections, could rapidly improve productivity and resource utilization. There is a growing interest in indigenous ruminant breeds because these animals have adapted to survive with minimal maintenance in the presence of high exposure to parasite infection. Recent findings on the mechanisms of parasite resistance in indigenous breeds are discussed, and the possibility that such studies may lead to new insight into the immunity and control of parasites proposed. These findings have important implications for the preservation of poorly characterized local indigenous breeds.
Comparative experimental Haemonchus contortus infection of two sheep breeds native to the Canary Islands
- Authors: Gonzalez, Jorge , Hernandez, Alvaro , Molina, Jose , Fernandez, Antonio , Raadsma, Herman , Meeusen, Els , Piedrafita, David
- Date: 2008
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 153, no. 304 (2008), p. 374-378
- Full Text: false
- Reviewed:
- Description: This study compares the susceptibility to Haemonchus contortus infection in two breeds of sheep endemic to the Canary Islands, the Canaria Hair Breed sheep and the Canaria sheep. Sheep were experimentally infected with 20,000 larvae of H. contortus and animals killed on days 7 and 28 post-infection. No difference between sheep breeds were detected in immature worm counts at days 7 or 28 post-infection. However, in comparison to the Canaria sheep breed, the Canaria Hair Breed sheep showed lower mean faecal egg counts, lower adult worm counts, lower number of eggs in utero and female worm stunting. Overall, these data suggest that the Canaria Hair Breed sheep has a greater resistance to H. contortus infection than Canaria sheep, and that this resistance may act at the level of the adult parasite.