Article

DNA vaccines expressing pneumococcal surface protein A (PspA) elicit protection levels comparable to recombinant protein.

Centro de Biotecnologia, Instituto Butantan, Av. Vital Brasil 1500, 05503-900, São Paulo, SP, Brazil.
Journal of Medical Microbiology (impact factor: 2.5). 05/2006; 55(Pt 4):375-8. DOI:10.1099/jmm.0.46217-0 pp.375-8
Source: PubMed

ABSTRACT Pneumococcal surface protein A (PspA) is a promising candidate for the development of cost-effective vaccines against Streptococcus pneumoniae. In the present study, BALB/c mice were immunized with DNA vaccine vectors expressing the N-terminal region of PspA. Animals immunized with a vector expressing secreted PspA developed higher levels of antibody than mice immunized with the vector expressing the antigen in the cytosol. However, both immunogens elicited similar levels of protection against intraperitoneal challenge. Furthermore, immunization with exactly the same fragment in the form of a recombinant protein, with aluminium hydroxide as an adjuvant, elicited even higher antibody levels, but this increased humoral response did not correlate with enhanced protection. These results show that DNA vaccines expressing PspA are able to elicit protection levels comparable to recombinant protein, even though total anti-PspA IgG response is considerably lower.

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Keywords

Animals immunized
 
cost-effective vaccines
 
DNA vaccine vectors
 
DNA vaccines
 
elicit protection levels comparable
 
immunogens elicited similar levels
 
increased humoral response
 
intraperitoneal challenge
 
mice immunized
 
N-terminal region
 
Pneumococcal surface protein
 
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PspA
 
secreted PspA
 
Streptococcus pneumoniae
 
total anti-PspA IgG response
 
vector