Research

A DNA vaccine against tuberculosis based on the 65 kDa heat-shock protein differentially activates human macrophages and dendritic cells

Luís H Franco¹ , Pryscilla F Wowk¹ , Célio L Silva¹ , Ana PF Trombone¹ , Arlete AM Coelho-Castelo¹ , Constance Oliver³ , Maria C Jamur³ , Edson L Moretto² and Vânia LD Bonato¹

¹  Núcleo de Pesquisas em Tuberculose, Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo. Av. Bandeirantes, 3900, 14049-900, Ribeirão Preto, SP, Brasil

²  Laboratório de Fracionamento e Estoque – Centro Regional de Hemoterapia do Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo. Rua Tenente Catão Roxo 2501, Ribeirão Preto, SP, Brasil

³  Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo. Av. Bandeirantes, 3900, 14049-900, Ribeirão Preto, SP, Brasil

author email corresponding author email

Genetic Vaccines and Therapy 2008, 6:3doi:10.1186/1479-0556-6-3

Published:	21 January 2008

Abstract

Background

A number of reports have demonstrated that rodents immunized with DNA vaccines can produce antibodies and cellular immune responses presenting a long-lasting protective immunity. These findings have attracted considerable interest in the field of DNA vaccination. We have previously described the prophylactic and therapeutic effects of a DNA vaccine encoding the Mycobacterium leprae 65 kDa heat shock protein (DNA-HSP65) in a murine model of tuberculosis. As DNA vaccines are often less effective in humans, we aimed to find out how the DNA-HSP65 stimulates human immune responses.

Methods

To address this question, we analysed the activation of both human macrophages and dendritic cells (DCs) cultured with DNA-HSP65. Then, these cells stimulated with the DNA vaccine were evaluated regarding the expression of surface markers, cytokine production and microbicidal activity.

Results

It was observed that DCs and macrophages presented different ability to uptake DNA vaccine. Under DNA stimulation, macrophages, characterized as CD11b⁺/CD86⁺/HLA-DR⁺, produced high levels of TNF-alpha, IL-6 (pro-inflammatory cytokines), and IL-10 (anti-inflammatory cytokine). Besides, they also presented a microbicidal activity higher than that observed in DCs after infection with M. tuberculosis. On the other hand, DCs, characterized as CD11c⁺/CD86⁺/CD123^-/BDCA-4⁺/IFN-alpha^-, produced high levels of IL-12 and low levels of TNF-alpha, IL-6 and IL-10. Finally, the DNA-HSP65 vaccine was able to induce proliferation of peripheral blood lymphocytes.

Conclusion

Our data suggest that the immune response is differently activated by the DNA-HSP65 vaccine in humans. These findings provide important clues to the design of new strategies for using DNA vaccines in human immunotherapy.