Immune response of lambs to vaccination with Ostertagia circumcincta surface antigens eliciting bile antibody responses

ArticleinInternational Journal for Parasitology 25(9):1111-21 · September 1995with8 Reads
DOI: 10.1016/0020-7519(95)00028-Z · Source: PubMed
Abstract
Immune responses to surface antigens of infective larvae of Ostertagia circumcincta recognized by bile antibodies of sheep immune to challenge were studied in 5-month-old Finn-Dorset male lambs. The sheep were vaccinated subcutaneously with 2 doses of 25 micrograms/kg body weight of surface proteins immunoprecipitated by bile antibodies derived from protected lambs. These antigens were purified from immune complexes by affinity chromatography and then injected with beryllium hydroxide as an adjuvant. The immunized lambs were challenged with 5 x 10(4) L3 and the worm burdens evaluated on day 21 post challenge. These were significantly (P < 0.01) lower in the vaccinated group than in the challenged controls (72% protection). The mucosal and bile IgM, recognizing the L3 surface, showed significantly higher levels in the vaccinated lambs compared to the challenge controls. Mucosal and bile IgA antibody levels against the same antigens were low and no significant differences were observed between vaccinated and control lambs.
    • "Please cite this article in press as: immunise hosts against parasitic nematodes [39] . In T. circumcincta , when detergent extracts of L3 were used as immunogen, anti-parasite responses were variable, but parasite burdens were significantly reduced (by up to 72%) and FWECs reduced by more than 70% [40,41]. Other attempts to protect sheep against T. circumcincta using native antigen preparations, for example lectin-binding integral membrane glycoproteins [42,43], were unsuccessful. "
    [Show abstract] [Hide abstract] ABSTRACT: Infection of humans and livestock with parasitic nematodes can have devastating effects on health and production, affecting food security in both developed and developing regions. Despite decades of research, the development of recombinant sub-unit vaccines against these pathogens has been largely unsuccessful. We have developed a strategy to identify protective antigens from Teladorsagia circumcincta, the major pathogen causing parasitic gastroenteritis in small ruminants in temperate regions, by studying IgA responses directed at proteins specific to post-infective larvae. Antigens were also selected on the basis of their potential immunomodulatory role at the host/parasite interface. Recombinant versions of eight molecules identified by immunoproteomics, homology with vaccine candidates in other nematodes and/or with potential immunoregulatory activities, were therefore administered to sheep in a single vaccine formulation. The vaccine was administered three times with Quil A adjuvant and the animals subsequently subjected to a repeated challenge infection designed to mimic field conditions. Levels of protection in the vaccinates were compared to those obtained in sheep administered with Quil A alone. The trial was performed on two occasions. In both trials, vaccinates had significantly lower mean fecal worm egg counts (FWECs) over the sampling period, with a mean reduction in egg output of 70% (Trial 1) and 58% (Trial 2). During the period of peak worm egg shedding, vaccinates shed 92% and 73% fewer eggs than did controls in Trials 1 and 2, respectively. At post mortem, vaccinates had 75% (Trial 1) and 56% (Trial 2) lower adult nematode burdens than the controls. These levels of protection are the highest observed in any system using a nematode recombinant sub-unit vaccine in the definitive ruminant host and indicate that control of parasitic helminths via vaccination with recombinant subunit vaccine cocktails is indeed an alternative option in the face of multi-drug resistance.
    Full-text · Article · May 2013
    • "Les essais de vaccination avec des sous-unités de cette glycoprotéine n'ont pas permis d'obtenir une immunisation comparable à celle obtenue par la vaccination avec la molécule entière, suggérant ainsi l'effet complémentaire des différentes sous-unités dans la vaccination [161]. (1992 et 1995), [200], [199] Bien que les strongles du genre Ostertagia ne soient pas hématophages, il semble qu'ils absorbent néanmoins des anticorps de l'hôte [122]. La vaccination avec ce type d'antigène peut ainsi être envisagée. "
    [Show abstract] [Hide abstract] ABSTRACT: Les strongyloses constituent une pathologie à répartition mondiale et elles engendrent des pertes de production et un coût économique non négligeables. L'apparition inquiétante de résistances, le coût des traitements et l'inquiétude des consommateurs quant à leur effet sur la santé et sur l'environnement amènent à s'intéresser aux mécanismes immunitaires mis en jeu et aux moyens de les exploiter. L'immunité au cours des strongyloses digestives est un phénomène complexe qui dépend de l'identité des strongles infestants, ainsi que de l'intensité et du moment de l'infestation. Elle fait intervenir des agents de l'immunité cellulaire et des éléments de l'immunité humorale. Au cours de la primo-infection, l'ensemble des acteurs immunitaires sont activés, mais les IgA jouent le rôle principal. L'efficacité de la défense est encore limitée, elle se dirige surtout contre les larves L3 et L4 et permet de limiter la prolificité de la population de strongles. Lors des épisodes de réinfections, ce sont les lymphocytes Th2 qui coordonnent la réaction immunitaire. Les larves L3 et lés adultes présents dans la lumière digestive sont piégés dans le mucus et soumis aux IgG, IgA et aux molécules toxiques libérées par les mastocytes. Les larves L4 présentes dans la muqueuse digestive subissent les mêmes effets, ainsi que l'action des éosinophiles. Le rôle majeur joué par les mastocytes et les éosinophiles, activés par leurs récepteurs IgE, prédispose à la dérive de la réaction immunitaire vers des réactions d'hypersensibilité immédiate et retardée. La réponse immunitaire varie en fonction de facteurs propres à l'animal, sa génétique et sa physiologie, ainsi qu'en fonction de facteurs extrinsèques, l'âge au sevrage, l'alimentation et les conditions d'infestation, régulées par la gestion du pâturage et des traitements anthelminthiques. L'approche des mécanismes immunitaires a permis de s'intéresser aux possibilités de leur stimulation et au développement de vaccins. La vaccination avec des antigènes extraits du tube digestif des strongles donne des résultats encourageants, mais il' n'y a à ce jour pas de vaccin polyvalent sur le marché.
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