Research

Improve protective efficacy of a TB DNA-HSP65 vaccine by BCG priming

Eduardo DC Gonçalves¹ , Vânia Luiza D Bonato¹ , Denise M da Fonseca¹ , Edson G Soares³ , Izaíra T Brandão² , Ana Paula M Soares² and Célio L Silva¹

¹  Farmacore Biotecnologia Ltda, Rua dos Técnicos s/n, Campus da USP, Ribeirão Preto, SP, Brasil

²  Center for Tuberculosis Research, Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil

³  Department of Pathology, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil

author email corresponding author email

Genetic Vaccines and Therapy 2007, 5:7doi:10.1186/1479-0556-5-7

Published:	22 August 2007

Abstract

Vaccines are considered by many to be one of the most successful medical interventions against infectious diseases. But many significant obstacles remain, such as optimizing DNA vaccines for use in humans or large animals. The amount of doses, route and easiness of administration are also important points to consider in the design of new DNA vaccines. Heterologous prime-boost regimens probably represent the best hope for an improved DNA vaccine strategy. In this study, we have shown that heterologous prime-boost vaccination against tuberculosis (TB) using intranasal BCG priming/DNA-HSP65 boosting (BCGin/DNA) provided significantly greater protection than that afforded by a single subcutaneous or intranasal dose of BCG. In addition, BCGin/DNA immunization was also more efficient in controlling bacterial loads than were the other prime-boost schedules evaluated or three doses of DNA-HSP65 as a naked DNA. The single dose of DNA-HSP65 booster enhanced the immunogenicity of a single subcutaneous BCG vaccination, as evidenced by the significantly higher serum levels of anti-Hsp65 IgG2a Th1-induced antibodies, as well as by the significantly greater production of IFN-γ by antigen-specific spleen cells. The BCG prime/DNA-HSP65 booster was also associated with better preservation of lung parenchyma.

The improvement of the protective effect of BCG vaccine mediated by a DNA-HSP65 booster suggests that our strategy may hold promise as a safe and effective vaccine against TB.