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Vaccination against Streptococcus pneumoniae using truncated derivatives of polyhistidine triad protein D.

Plumptre CD, Ogunniyi AD, Paton JC - PLoS ONE (2013)

Bottom Line: In this study, we purified recombinant truncated derivatives of PhtD and examined their secondary structural composition, as well as their capacity to bind antibodies from polyclonal murine serum generated against the full length protein.This allowed the identification of a particularly immunogenic fragment of PhtD, which was also purified and characterised.These experiments revealed that whilst the immunogenic region identified may be a promising candidate to protect against sepsis, the full length PhtD was ineffective at conferring significant protective immunity.

View Article: PubMed Central - PubMed

Affiliation: Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.

ABSTRACT
Polyhistidine triad protein D (PhtD) has been described as a promising vaccine candidate for use against Streptococcus pneumoniae, but there has been a lack of examination of its structure and of which region(s) of the protein are targeted by protective immune responses. In this study, we purified recombinant truncated derivatives of PhtD and examined their secondary structural composition, as well as their capacity to bind antibodies from polyclonal murine serum generated against the full length protein. This allowed the identification of a particularly immunogenic fragment of PhtD, which was also purified and characterised. The truncated derivatives were tested as vaccine antigens in mouse models of pneumococcal sepsis and colonisation, using alum and E. coli heat labile toxin B subunit respectively as adjuvants. These experiments revealed that whilst the immunogenic region identified may be a promising candidate to protect against sepsis, the full length PhtD was ineffective at conferring significant protective immunity. These results are significant for the potential for PhtD to be used in novel vaccines, which are currently being tested in clinical trials.

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Related in: MedlinePlus

Truncated forms of PhtD used in this study.Proteins are shown with known or predicted domains annotated. The N termini are to the left.
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pone-0078916-g002: Truncated forms of PhtD used in this study.Proteins are shown with known or predicted domains annotated. The N termini are to the left.

Mentions: Primers were designed to amplify truncated derivatives of PhtD lacking approximately 200 amino acids and multiples thereof from both the C- and N-terminus of the protein. The first 57 nucleotides, which are predicted to encode the protein's signal peptide, were excluded from all constructs such that this region was not present in the expressed proteins. In order to minimise potential disruption to overall protein structure, the exact positions of the truncations were designed to fall between coiled-coil domains as predicted by the Coils server [24] (see Figure 1). The truncated derivatives that were constructed are represented in Figure 2 and the amino acids included are listed in Table 1.


Vaccination against Streptococcus pneumoniae using truncated derivatives of polyhistidine triad protein D.

Plumptre CD, Ogunniyi AD, Paton JC - PLoS ONE (2013)

Truncated forms of PhtD used in this study.Proteins are shown with known or predicted domains annotated. The N termini are to the left.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3814962&req=5

pone-0078916-g002: Truncated forms of PhtD used in this study.Proteins are shown with known or predicted domains annotated. The N termini are to the left.
Mentions: Primers were designed to amplify truncated derivatives of PhtD lacking approximately 200 amino acids and multiples thereof from both the C- and N-terminus of the protein. The first 57 nucleotides, which are predicted to encode the protein's signal peptide, were excluded from all constructs such that this region was not present in the expressed proteins. In order to minimise potential disruption to overall protein structure, the exact positions of the truncations were designed to fall between coiled-coil domains as predicted by the Coils server [24] (see Figure 1). The truncated derivatives that were constructed are represented in Figure 2 and the amino acids included are listed in Table 1.

Bottom Line: In this study, we purified recombinant truncated derivatives of PhtD and examined their secondary structural composition, as well as their capacity to bind antibodies from polyclonal murine serum generated against the full length protein.This allowed the identification of a particularly immunogenic fragment of PhtD, which was also purified and characterised.These experiments revealed that whilst the immunogenic region identified may be a promising candidate to protect against sepsis, the full length PhtD was ineffective at conferring significant protective immunity.

View Article: PubMed Central - PubMed

Affiliation: Research Centre for Infectious Diseases, School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia, Australia.

ABSTRACT
Polyhistidine triad protein D (PhtD) has been described as a promising vaccine candidate for use against Streptococcus pneumoniae, but there has been a lack of examination of its structure and of which region(s) of the protein are targeted by protective immune responses. In this study, we purified recombinant truncated derivatives of PhtD and examined their secondary structural composition, as well as their capacity to bind antibodies from polyclonal murine serum generated against the full length protein. This allowed the identification of a particularly immunogenic fragment of PhtD, which was also purified and characterised. The truncated derivatives were tested as vaccine antigens in mouse models of pneumococcal sepsis and colonisation, using alum and E. coli heat labile toxin B subunit respectively as adjuvants. These experiments revealed that whilst the immunogenic region identified may be a promising candidate to protect against sepsis, the full length PhtD was ineffective at conferring significant protective immunity. These results are significant for the potential for PhtD to be used in novel vaccines, which are currently being tested in clinical trials.

Show MeSH
Related in: MedlinePlus