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Identification and therapeutic potential of a vitronectin binding region of meningococcal msf.

Hill DJ, Griffiths NJ, Borodina E, Andreae CA, Sessions RB, Virji M - PLoS ONE (2015)

Bottom Line: Using several recombinant Msf fragments spanning its surface-exposed region, the smallest aVn-binding recombinants were found to span residues 1-86 and 39-124.Recombinant fragments which bound to aVn were able to reduce the survival advantage conveyed by aVn-interaction in serum bactericidal assays.Overall, this study identifies an aVn-binding region of Msf, an adhesin known to impart serum resistance properties to the pathogen; and shows that this region of Msf can elicit antibodies with dual properties which reduce pathogen survival within the host and thus has potential as a vaccine antigen.

View Article: PubMed Central - PubMed

Affiliation: School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 ITD, United Kingdom.

ABSTRACT
The human pathogen Neisseria meningitides (Nm) attains serum resistance via a number of mechanisms, one of which involves binding to the host complement regulator protein vitronectin. We have shown previously that the Meningococcal surface fibril (Msf), a trimeric autotransporter, binds to the activated form of vitronectin (aVn) to increase Nm survival in human serum. In this study, we aimed to identify the aVn-binding region of Msf to assess its potential as an antigen which can elicit antibodies that block aVn binding and/or possess bactericidal properties. Using several recombinant Msf fragments spanning its surface-exposed region, the smallest aVn-binding recombinants were found to span residues 1-86 and 39-124. The use of further deletion constructs and overlapping recombinant Msf fragments suggested that a region of Msf comprising residues 39-82 may be primarily important for aVn binding and that other regions may also be involved but to a lesser extent. Molecular modelling implicated K66 and K68, conserved in all available Msf sequences, to be involved in the interaction. Recombinant fragments which bound to aVn were able to reduce the survival advantage conveyed by aVn-interaction in serum bactericidal assays. Antibodies raised against one such fragment inhibited aVn binding to Msf. In addition, the antibodies enhanced specific killing of Msf-expressing Nm in a dose-dependent manner. Overall, this study identifies an aVn-binding region of Msf, an adhesin known to impart serum resistance properties to the pathogen; and shows that this region of Msf can elicit antibodies with dual properties which reduce pathogen survival within the host and thus has potential as a vaccine antigen.

No MeSH data available.


Related in: MedlinePlus

Inhibition of aVn binding by anti-Msf1–203 antibodies.ELISA plates coated with Msf1–203 (A) or Msf1–422 (B) were overlaid with aVn (74 nM) in the presence of purified anti-Msf1–203 (solid lines) or anti-CEACAM rabbit polyclonal antibody control (dashed lines). Anti-Msf1–203 inhibited aVn binding to both Msf proteins in a dose dependent manner. Data shown are means of three independent experiments ± SD. * P<0.05, ** P<0.001 and *** P<0.0001 as indicated.
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pone.0124133.g007: Inhibition of aVn binding by anti-Msf1–203 antibodies.ELISA plates coated with Msf1–203 (A) or Msf1–422 (B) were overlaid with aVn (74 nM) in the presence of purified anti-Msf1–203 (solid lines) or anti-CEACAM rabbit polyclonal antibody control (dashed lines). Anti-Msf1–203 inhibited aVn binding to both Msf proteins in a dose dependent manner. Data shown are means of three independent experiments ± SD. * P<0.05, ** P<0.001 and *** P<0.0001 as indicated.

Mentions: In order to determine if anti-Msf1–203 antibodies could block aVn binding, rabbit antiserum against Msf1–203 was generated and affinity purified antibodies used in inhibition ELISAs. A dose-dependent inhibition of aVn binding to Msf1–203 and Msf1–422 was observed in the presence of anti-Msf1–203 but not the control antibody (A0115 purified rabbit anti-CEACAM polyclonal antibody; Fig 7). Inhibition of Vn binding was much more pronounced for Msf1–203 than Msf1–422. The data support the hypothesis that whilst Vn binding predominates within Msf amino acids 39–82, other regions of Msf may also interact with Vn. An alternative explanation is that structures of Msf outside amino acids 1–203 constrain the access of the antibodies in some way. Further studies are required to clarify these points.


Identification and therapeutic potential of a vitronectin binding region of meningococcal msf.

Hill DJ, Griffiths NJ, Borodina E, Andreae CA, Sessions RB, Virji M - PLoS ONE (2015)

Inhibition of aVn binding by anti-Msf1–203 antibodies.ELISA plates coated with Msf1–203 (A) or Msf1–422 (B) were overlaid with aVn (74 nM) in the presence of purified anti-Msf1–203 (solid lines) or anti-CEACAM rabbit polyclonal antibody control (dashed lines). Anti-Msf1–203 inhibited aVn binding to both Msf proteins in a dose dependent manner. Data shown are means of three independent experiments ± SD. * P<0.05, ** P<0.001 and *** P<0.0001 as indicated.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380367&req=5

pone.0124133.g007: Inhibition of aVn binding by anti-Msf1–203 antibodies.ELISA plates coated with Msf1–203 (A) or Msf1–422 (B) were overlaid with aVn (74 nM) in the presence of purified anti-Msf1–203 (solid lines) or anti-CEACAM rabbit polyclonal antibody control (dashed lines). Anti-Msf1–203 inhibited aVn binding to both Msf proteins in a dose dependent manner. Data shown are means of three independent experiments ± SD. * P<0.05, ** P<0.001 and *** P<0.0001 as indicated.
Mentions: In order to determine if anti-Msf1–203 antibodies could block aVn binding, rabbit antiserum against Msf1–203 was generated and affinity purified antibodies used in inhibition ELISAs. A dose-dependent inhibition of aVn binding to Msf1–203 and Msf1–422 was observed in the presence of anti-Msf1–203 but not the control antibody (A0115 purified rabbit anti-CEACAM polyclonal antibody; Fig 7). Inhibition of Vn binding was much more pronounced for Msf1–203 than Msf1–422. The data support the hypothesis that whilst Vn binding predominates within Msf amino acids 39–82, other regions of Msf may also interact with Vn. An alternative explanation is that structures of Msf outside amino acids 1–203 constrain the access of the antibodies in some way. Further studies are required to clarify these points.

Bottom Line: Using several recombinant Msf fragments spanning its surface-exposed region, the smallest aVn-binding recombinants were found to span residues 1-86 and 39-124.Recombinant fragments which bound to aVn were able to reduce the survival advantage conveyed by aVn-interaction in serum bactericidal assays.Overall, this study identifies an aVn-binding region of Msf, an adhesin known to impart serum resistance properties to the pathogen; and shows that this region of Msf can elicit antibodies with dual properties which reduce pathogen survival within the host and thus has potential as a vaccine antigen.

View Article: PubMed Central - PubMed

Affiliation: School of Cellular & Molecular Medicine, Medical Sciences Building, University Walk, University of Bristol, Bristol, BS8 ITD, United Kingdom.

ABSTRACT
The human pathogen Neisseria meningitides (Nm) attains serum resistance via a number of mechanisms, one of which involves binding to the host complement regulator protein vitronectin. We have shown previously that the Meningococcal surface fibril (Msf), a trimeric autotransporter, binds to the activated form of vitronectin (aVn) to increase Nm survival in human serum. In this study, we aimed to identify the aVn-binding region of Msf to assess its potential as an antigen which can elicit antibodies that block aVn binding and/or possess bactericidal properties. Using several recombinant Msf fragments spanning its surface-exposed region, the smallest aVn-binding recombinants were found to span residues 1-86 and 39-124. The use of further deletion constructs and overlapping recombinant Msf fragments suggested that a region of Msf comprising residues 39-82 may be primarily important for aVn binding and that other regions may also be involved but to a lesser extent. Molecular modelling implicated K66 and K68, conserved in all available Msf sequences, to be involved in the interaction. Recombinant fragments which bound to aVn were able to reduce the survival advantage conveyed by aVn-interaction in serum bactericidal assays. Antibodies raised against one such fragment inhibited aVn binding to Msf. In addition, the antibodies enhanced specific killing of Msf-expressing Nm in a dose-dependent manner. Overall, this study identifies an aVn-binding region of Msf, an adhesin known to impart serum resistance properties to the pathogen; and shows that this region of Msf can elicit antibodies with dual properties which reduce pathogen survival within the host and thus has potential as a vaccine antigen.

No MeSH data available.


Related in: MedlinePlus