Author(s): Li QT, Zhu YZ, Chu JY, Dong K, He P
To investigate a new strategy to enhance the efficacy of a recombinant pertussis DNA vaccine. The strategy is co-injection with cytokine plasmids as prime, and boosted with purified homologous proteins.
A recombinant pertussis DNA vaccine containing the pertussis toxin subunit 1 (PTS1), fragments of the filamentous hemagglutinin (FHA) gene and pertactin (PRN) gene encoding filamentous hemagglutinin and pertactin were constructed. Balb/c mice were immunized with several DNA vaccines and antigen-specific antibodies anti-PTS1,anti-PRN, anti-FHA,cytokines interleukin (IL)-10, IL-4, IFN-gamma,TNF-alpha,and splenocyte-proliferation assay were used to describe immune responses.
The recombinant DNA vaccine could elicit similar immune responses in mice as that of separate plasmids encoding the 3 fragments, respectively. Mice immunized with DNA and boosted with the corresponding protein elicited more antibodies than those that received DNA as boost. In particular, when the mice were co-immunized with murine granulocyte-macrophage colony-stimulating factor plasmids and boosted with proteins, all 4 cytokines and the 3 antigen-specific antibodies were significantly increased compared to the pVAX1 group. Anti-PTS1, anti- FHA, IL-4 and TNF-alpha elicited in the colony stimulating factor (CSF) prime-protein boost group showed significant increase compared to all the other groups.
This prime and boost strategy has proven to be very useful in improving the immunogenicity of DNA vaccines against pertussis.