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Highly conserved Neisseria meningitidis surface protein confers protection against experimental infection.

Martin D, Cadieux N, Hamel J, Brodeur BR - J. Exp. Med. (1997)

Bottom Line: To further characterize the NspA protein and to evaluate the protective potential of recombinant NspA protein, the nspA gene was identified and cloned into a low copy expression vector.Nucleotide sequencing of the meningococcal insert revealed an ORF of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a predicted molecular weight of 18,404 and a isoelectric point of 9.93.The fact that the NspA protein can elicit the production of bactericidal and protective antibodies emphasize its potential as a vaccine candidate.

View Article: PubMed Central - PubMed

Affiliation: Unité de Recherche en Vaccinologie, Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec, Ste-Foy, Canada.

ABSTRACT
A new surface protein, named NspA, which is distinct from the previously described Neisseria meningitidis outer membrane proteins was identified. An NspA-specific mAb, named Me-1, reacted with 99% of the meningococcal strains tested indicating that the epitope recognized by this particular mAb is widely distributed and highly conserved. Western immunoblotting experiments indicated that mAb Me-1 is directed against a protein band with an approximate molecular mass of 22,000, but also recognized a minor protein band with an approximate molecular mass of 18,000. This mAb exhibited bactericidal activity against four meningococcal strains, two isolates of serogroup B, and one isolate from each serogroup A and C, and passively protected mice against an experimental infection. To further characterize the NspA protein and to evaluate the protective potential of recombinant NspA protein, the nspA gene was identified and cloned into a low copy expression vector. Nucleotide sequencing of the meningococcal insert revealed an ORF of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a predicted molecular weight of 18,404 and a isoelectric point of 9.93. Three injections of either 10 or 20 microg of the affinity-purified recombinant NspA protein efficiently protected 80% of the mice against a meningococcal deadly challenge comparatively to the 20% observed in the control groups. The fact that the NspA protein can elicit the production of bactericidal and protective antibodies emphasize its potential as a vaccine candidate.

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Bactericidal activity of protein A–purified mAb Me-1 against  N. meningitidis strain 608B. Guinea pig serum (closed circles) or heat inactivated guinea pig serum (open circles) were used as the source of complement to evaluate the bactericidal activity.
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Figure 5: Bactericidal activity of protein A–purified mAb Me-1 against N. meningitidis strain 608B. Guinea pig serum (closed circles) or heat inactivated guinea pig serum (open circles) were used as the source of complement to evaluate the bactericidal activity.

Mentions: To demonstrate the bactericidal activity of mAb Me-1 an in vitro assay was performed using guinea pig serum and protein A–purified mAb. The bactericidal activity of mAb Me-1 against the meningococcal strain 608B is presented in Fig. 5. 7 μg/ml of purified mAb Me-1 were required to kill 50% of the meningococcal cells. Higher concentrations of purified mAb resulted in a sharp decrease in the recorded CFU ⩽100%. Heat-inactivation for 30 min at 56°C of the guinea pig serum completely abolished the bactericidal activity of mAb Me-1. 50% of killing were recorded for three other meningococcal strains, one of each serogroup A (strain Z4063), B ([B: 15:P1.7] strain 164), and C (strain 3), when 20 μg/ml of purified Me-1 was used in the bactericidal assay.


Highly conserved Neisseria meningitidis surface protein confers protection against experimental infection.

Martin D, Cadieux N, Hamel J, Brodeur BR - J. Exp. Med. (1997)

Bactericidal activity of protein A–purified mAb Me-1 against  N. meningitidis strain 608B. Guinea pig serum (closed circles) or heat inactivated guinea pig serum (open circles) were used as the source of complement to evaluate the bactericidal activity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196255&req=5

Figure 5: Bactericidal activity of protein A–purified mAb Me-1 against N. meningitidis strain 608B. Guinea pig serum (closed circles) or heat inactivated guinea pig serum (open circles) were used as the source of complement to evaluate the bactericidal activity.
Mentions: To demonstrate the bactericidal activity of mAb Me-1 an in vitro assay was performed using guinea pig serum and protein A–purified mAb. The bactericidal activity of mAb Me-1 against the meningococcal strain 608B is presented in Fig. 5. 7 μg/ml of purified mAb Me-1 were required to kill 50% of the meningococcal cells. Higher concentrations of purified mAb resulted in a sharp decrease in the recorded CFU ⩽100%. Heat-inactivation for 30 min at 56°C of the guinea pig serum completely abolished the bactericidal activity of mAb Me-1. 50% of killing were recorded for three other meningococcal strains, one of each serogroup A (strain Z4063), B ([B: 15:P1.7] strain 164), and C (strain 3), when 20 μg/ml of purified Me-1 was used in the bactericidal assay.

Bottom Line: To further characterize the NspA protein and to evaluate the protective potential of recombinant NspA protein, the nspA gene was identified and cloned into a low copy expression vector.Nucleotide sequencing of the meningococcal insert revealed an ORF of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a predicted molecular weight of 18,404 and a isoelectric point of 9.93.The fact that the NspA protein can elicit the production of bactericidal and protective antibodies emphasize its potential as a vaccine candidate.

View Article: PubMed Central - PubMed

Affiliation: Unité de Recherche en Vaccinologie, Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec, Ste-Foy, Canada.

ABSTRACT
A new surface protein, named NspA, which is distinct from the previously described Neisseria meningitidis outer membrane proteins was identified. An NspA-specific mAb, named Me-1, reacted with 99% of the meningococcal strains tested indicating that the epitope recognized by this particular mAb is widely distributed and highly conserved. Western immunoblotting experiments indicated that mAb Me-1 is directed against a protein band with an approximate molecular mass of 22,000, but also recognized a minor protein band with an approximate molecular mass of 18,000. This mAb exhibited bactericidal activity against four meningococcal strains, two isolates of serogroup B, and one isolate from each serogroup A and C, and passively protected mice against an experimental infection. To further characterize the NspA protein and to evaluate the protective potential of recombinant NspA protein, the nspA gene was identified and cloned into a low copy expression vector. Nucleotide sequencing of the meningococcal insert revealed an ORF of 525 nucleotides coding for a polypeptide of 174 amino acid residues, with a predicted molecular weight of 18,404 and a isoelectric point of 9.93. Three injections of either 10 or 20 microg of the affinity-purified recombinant NspA protein efficiently protected 80% of the mice against a meningococcal deadly challenge comparatively to the 20% observed in the control groups. The fact that the NspA protein can elicit the production of bactericidal and protective antibodies emphasize its potential as a vaccine candidate.

Show MeSH
Related in: MedlinePlus