Vaccination against fasciolosis by a multivalent vaccine of stage-specific antigens
- Authors: Jayaraj, Ramamoorthi , Piedrafita, David , Dynon, Kemperley , Grams, Rudi , Spithill, Terry , Smooker, Peter
- Date: 2008
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 160, no. 3-4 (2008), p. 230-236
- Full Text: false
- Reviewed:
- Description: Liver flukes produce cathepsin B and cathepsin L in their excretory–secretory material. These proteases are proposed to be key virulence factors for parasite infection, and are therefore targets for vaccination. Cathepsin B is predominately released in the juvenile stage of the life cycle, while different cathepsin L's are released throughout the cycle. Three proteases (cathepsin L5, cathepsin L1g and cathepsin B) were expressed in yeast from cDNA clones isolated from adult, metacercariae and newly excysted juvenile flukes respectively. Each was used singly or in combination to vaccinate rats that were subsequently challenged with Fasciola hepatica metercercariae. Each protein induced an immune response, and all groups vaccinated with recombinant protein yielded significantly fewer and smaller flukes than the control group. Maximal protection of 83% was seen in the group vaccinated with cathepsin B and cathepsin L5 in combination.
Innate and adaptive resistance of Indonesian Thin Tail sheep to liver fluke: A comparative analysis of Fasciola gigantica and Fasciola hepatica infection
- Authors: Pleasance, Jill , Raadsma, Herman , Estuningsih, S. , Widjajanti, Sri , Meeusen, Els , Piedrafita, David
- Date: 2011
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 178, no. 3-4 (2011), p. 264-272
- Full Text: false
- Reviewed:
- Description: In the current study, three independent trials directly compared Fasciola gigantica and Fasciola hepatica infection of ITT sheep. In all trials, F. hepatica infection resulted in higher worm burden recoveries and greater physiological damage to ITT sheep. Developmental differences of the two Fasciola species were also observed during the first twelve weeks of a primary infection, where the migration and growth of F. hepatica was more rapid than F. gigantica. Various immunological blood parameters were measured and indicated similar kinetics in the humoral and cellular responses during the time course of infection with each Fasciola species. In contrast to F. hepatica infection, we demonstrate an innate and adaptive comparative ability of ITT sheep to resist the early stages of infection with F. gigantica infection. Unraveling the mechanisms leading to this differential resistance may potentially lead to new methods for the control of fasciolosis and other human liver flukes.
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.
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.
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.
Quantifying the sources of variation in eosinophilia among Scottish blackface lambs with mixed, predominantly Teladorsagia circumcincta nematode infection
- Authors: Jenvey, Caitlin , Almasi, Fazel , Halliwell, Emma , Piedrafita, David , Preston, Sarah
- Date: 2021
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 300, no. (2021), p.
- Full Text:
- Reviewed:
- Description: Eosinophils play a key role in defence against gastrointestinal nematodes. There is considerable variation among animals in the intensity of eosinophilia following nematode infection. However, the statistical distribution of eosinophils among animals has still to be determined. A better description of the variation among animals could provide biological insight and determine the most appropriate way to analyse the effect of eosinophils. We estimated blood eosinophil numbers in a flock of Scottish Blackface sheep that were naturally exposed to mixed, predominantly Teladorsagia circumcincta infection. Three of the four eosinophil counts were better described by a gamma distribution than by a lognormal distribution. The scale and shape parameters of the gamma distribution varied over time. Eosinophil counts differed among animals kept on separate fields before weaning and between singletons and twins but were not significantly different between years and genders. Eosinophil counts also differed among offspring from different sires and dams. The parameters of the gamma distribution were used to enable a power analysis. Large numbers of animals were required to reliably detect even large differences between two groups. These results indicate that methods appropriate for gamma distributions, such as generalized linear mixed models, will provide more reliable inferences than traditional methods of analysis and experimental design. © 2021 The Author(s). **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “David Piedrafita and Sarah Preston” is provided in this record**