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Experimental vaccination of sheep and cattle against tick infestation using recombinant 5'-nucleotidase.

Hope M, Jiang X, Gough J, Cadogan L, Josh P, Jonsson N, Willadsen P - Parasite Immunol. (2010)

Bottom Line: Although Bm86 showed typical efficacy, no significant protection was seen in cattle vaccinated with 5'-nucleotidase.Cattle receiving a dual antigen formulation were no better protected than those receiving Bm86 alone.This demonstrates a limitation of using a model host like sheep in vaccine studies.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Livestock Industries, St Lucia, Queensland, Australia.

ABSTRACT
Limited prior evidence suggests that 5'-nucleotidase, an ectoenzyme principally located in the Malpighian tubules of the tick Rhipicephalus (Boophilus) microplus, could be an effective antigen in an anti-tick vaccine. To assess this, recombinant 5'-nucleotidase was expressed in Escherichia coli and used in vaccination trials with both sheep and cattle. Vaccinated sheep were challenged with freshly moulted adult ticks. Those with high titres of anti-nucleotidase antibodies showed significant protection against tick infestation, although protection was less than that found with the previously characterized antigen, Bm86. Cattle were vaccinated, in separate groups, with 5'-nucleotidase, Bm86 and both antigens combined. Cattle, as the natural host, were challenged with larval ticks. Although Bm86 showed typical efficacy, no significant protection was seen in cattle vaccinated with 5'-nucleotidase. Cattle receiving a dual antigen formulation were no better protected than those receiving Bm86 alone. One possible reason for the difference between host species, namely antibody titre, was examined and shown to be an unlikely explanation. This demonstrates a limitation of using a model host like sheep in vaccine studies.

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Related in: MedlinePlus

ELISA assays of pooled, high titre bovine (•) and ovine (▴) sera against recombinant 5′-nucleotidase. The detection reagent was peroxidase-coupled protein G at dilutions of (from left to right) 1 in 500; 1 in 1000 and 1 in 1500.
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fig02: ELISA assays of pooled, high titre bovine (•) and ovine (▴) sera against recombinant 5′-nucleotidase. The detection reagent was peroxidase-coupled protein G at dilutions of (from left to right) 1 in 500; 1 in 1000 and 1 in 1500.

Mentions: The fact that 5′-nucleotidase, at least at high antibody titres, seemed to be quite efficacious against tick infestation in sheep but completely ineffective in cattle is important to understand. For sheep, the evidence suggests that efficacy may correlate with antibody titre and this mirrors the experience of large numbers of trials with the Bm86 antigen in cattle. Therefore, one obvious explanation of the difference in protection between sheep and cattle would be a difference in anti-nucleotidase antibody titres. This was examined in two ways. In both experiments, the antisera used were pools of ovine and bovine sera of peak antibody titres. In the first experimental approach, ELISAs were performed as described in Materials and methods using recombinant 5′-nucleotidase as antigen and peroxidase-coupled protein G as the reagent to detect bound IgG. Protein G reacts strongly with both ovine and bovine IgG and so may minimize differences in the sensitivity of species-specific second antibody reagents. Peroxidase-protein G was used at three dilutions. The results are shown in Figure 2 and suggest that there was little difference in the titres of ovine and bovine anti-nucleotidase antibodies.


Experimental vaccination of sheep and cattle against tick infestation using recombinant 5'-nucleotidase.

Hope M, Jiang X, Gough J, Cadogan L, Josh P, Jonsson N, Willadsen P - Parasite Immunol. (2010)

ELISA assays of pooled, high titre bovine (•) and ovine (▴) sera against recombinant 5′-nucleotidase. The detection reagent was peroxidase-coupled protein G at dilutions of (from left to right) 1 in 500; 1 in 1000 and 1 in 1500.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2821529&req=5

fig02: ELISA assays of pooled, high titre bovine (•) and ovine (▴) sera against recombinant 5′-nucleotidase. The detection reagent was peroxidase-coupled protein G at dilutions of (from left to right) 1 in 500; 1 in 1000 and 1 in 1500.
Mentions: The fact that 5′-nucleotidase, at least at high antibody titres, seemed to be quite efficacious against tick infestation in sheep but completely ineffective in cattle is important to understand. For sheep, the evidence suggests that efficacy may correlate with antibody titre and this mirrors the experience of large numbers of trials with the Bm86 antigen in cattle. Therefore, one obvious explanation of the difference in protection between sheep and cattle would be a difference in anti-nucleotidase antibody titres. This was examined in two ways. In both experiments, the antisera used were pools of ovine and bovine sera of peak antibody titres. In the first experimental approach, ELISAs were performed as described in Materials and methods using recombinant 5′-nucleotidase as antigen and peroxidase-coupled protein G as the reagent to detect bound IgG. Protein G reacts strongly with both ovine and bovine IgG and so may minimize differences in the sensitivity of species-specific second antibody reagents. Peroxidase-protein G was used at three dilutions. The results are shown in Figure 2 and suggest that there was little difference in the titres of ovine and bovine anti-nucleotidase antibodies.

Bottom Line: Although Bm86 showed typical efficacy, no significant protection was seen in cattle vaccinated with 5'-nucleotidase.Cattle receiving a dual antigen formulation were no better protected than those receiving Bm86 alone.This demonstrates a limitation of using a model host like sheep in vaccine studies.

View Article: PubMed Central - PubMed

Affiliation: CSIRO Livestock Industries, St Lucia, Queensland, Australia.

ABSTRACT
Limited prior evidence suggests that 5'-nucleotidase, an ectoenzyme principally located in the Malpighian tubules of the tick Rhipicephalus (Boophilus) microplus, could be an effective antigen in an anti-tick vaccine. To assess this, recombinant 5'-nucleotidase was expressed in Escherichia coli and used in vaccination trials with both sheep and cattle. Vaccinated sheep were challenged with freshly moulted adult ticks. Those with high titres of anti-nucleotidase antibodies showed significant protection against tick infestation, although protection was less than that found with the previously characterized antigen, Bm86. Cattle were vaccinated, in separate groups, with 5'-nucleotidase, Bm86 and both antigens combined. Cattle, as the natural host, were challenged with larval ticks. Although Bm86 showed typical efficacy, no significant protection was seen in cattle vaccinated with 5'-nucleotidase. Cattle receiving a dual antigen formulation were no better protected than those receiving Bm86 alone. One possible reason for the difference between host species, namely antibody titre, was examined and shown to be an unlikely explanation. This demonstrates a limitation of using a model host like sheep in vaccine studies.

Show MeSH
Related in: MedlinePlus