Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.

Pneumococcal surface protein A (PspA) and Pneumolysin derivatives (Pds) are important vaccine candidates, which can confer protection in different models of pneumococcal infection. Furthermore, the combination of these two proteins was able to increase protection against pneumococcal sepsis in mice....

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Main Authors: Cibelly Goulart, Thais Raquel da Silva, Dunia Rodriguez, Walter Rodrigo Politano, Luciana C C Leite, Michelle Darrieux
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3606166?pdf=render
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author Cibelly Goulart
Thais Raquel da Silva
Dunia Rodriguez
Walter Rodrigo Politano
Luciana C C Leite
Michelle Darrieux
author_facet Cibelly Goulart
Thais Raquel da Silva
Dunia Rodriguez
Walter Rodrigo Politano
Luciana C C Leite
Michelle Darrieux
author_sort Cibelly Goulart
collection DOAJ
description Pneumococcal surface protein A (PspA) and Pneumolysin derivatives (Pds) are important vaccine candidates, which can confer protection in different models of pneumococcal infection. Furthermore, the combination of these two proteins was able to increase protection against pneumococcal sepsis in mice. The present study investigated the potential of hybrid proteins generated by genetic fusion of PspA fragments to Pds to increase cross-protection against fatal pneumococcal infection. Pneumolisoids were fused to the N-terminus of clade 1 or clade 2 pspA gene fragments. Mouse immunization with the fusion proteins induced high levels of antibodies against PspA and Pds, able to bind to intact pneumococci expressing a homologous PspA with the same intensity as antibodies to rPspA alone or the co-administered proteins. However, when antibody binding to pneumococci with heterologous PspAs was examined, antisera to the PspA-Pds fusion molecules showed stronger antibody binding and C3 deposition than antisera to co-administered proteins. In agreement with these results, antisera against the hybrid proteins were more effective in promoting the phagocytosis of bacteria bearing heterologous PspAs in vitro, leading to a significant reduction in the number of bacteria when compared to co-administered proteins. The respective antisera were also capable of neutralizing the lytic activity of Pneumolysin on sheep red blood cells. Finally, mice immunized with fusion proteins were protected against fatal challenge with pneumococcal strains expressing heterologous PspAs. Taken together, the results suggest that PspA-Pd fusion proteins comprise a promising vaccine strategy, able to increase the immune response mediated by cross-reactive antibodies and complement deposition to heterologous strains, and to confer protection against fatal challenge.
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spelling doaj.art-39407d33acdf415c92dde18deb2d62642022-12-22T00:51:01ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0183e5960510.1371/journal.pone.0059605Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.Cibelly GoulartThais Raquel da SilvaDunia RodriguezWalter Rodrigo PolitanoLuciana C C LeiteMichelle DarrieuxPneumococcal surface protein A (PspA) and Pneumolysin derivatives (Pds) are important vaccine candidates, which can confer protection in different models of pneumococcal infection. Furthermore, the combination of these two proteins was able to increase protection against pneumococcal sepsis in mice. The present study investigated the potential of hybrid proteins generated by genetic fusion of PspA fragments to Pds to increase cross-protection against fatal pneumococcal infection. Pneumolisoids were fused to the N-terminus of clade 1 or clade 2 pspA gene fragments. Mouse immunization with the fusion proteins induced high levels of antibodies against PspA and Pds, able to bind to intact pneumococci expressing a homologous PspA with the same intensity as antibodies to rPspA alone or the co-administered proteins. However, when antibody binding to pneumococci with heterologous PspAs was examined, antisera to the PspA-Pds fusion molecules showed stronger antibody binding and C3 deposition than antisera to co-administered proteins. In agreement with these results, antisera against the hybrid proteins were more effective in promoting the phagocytosis of bacteria bearing heterologous PspAs in vitro, leading to a significant reduction in the number of bacteria when compared to co-administered proteins. The respective antisera were also capable of neutralizing the lytic activity of Pneumolysin on sheep red blood cells. Finally, mice immunized with fusion proteins were protected against fatal challenge with pneumococcal strains expressing heterologous PspAs. Taken together, the results suggest that PspA-Pd fusion proteins comprise a promising vaccine strategy, able to increase the immune response mediated by cross-reactive antibodies and complement deposition to heterologous strains, and to confer protection against fatal challenge.http://europepmc.org/articles/PMC3606166?pdf=render
spellingShingle Cibelly Goulart
Thais Raquel da Silva
Dunia Rodriguez
Walter Rodrigo Politano
Luciana C C Leite
Michelle Darrieux
Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
PLoS ONE
title Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
title_full Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
title_fullStr Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
title_full_unstemmed Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
title_short Characterization of protective immune responses induced by pneumococcal surface protein A in fusion with pneumolysin derivatives.
title_sort characterization of protective immune responses induced by pneumococcal surface protein a in fusion with pneumolysin derivatives
url http://europepmc.org/articles/PMC3606166?pdf=render
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