Evaluation of a new DNA-Hsp65 vaccine construct with a nuclear localizing sequence carried by hyaluronic acid liposomes and delivery by intranasal route, in the prophylaxis and therapy of experimental tuberculosis

Abstract

DNA vaccines have been extensively studied since 1992 as a new strategy to control infection diseases. Although these vaccines have been shown highly efficient in several experimental models and, in some situations, in humans clinical trials they require high amounts of DNA to induce protective immune response. In this way, the development of approachs that use lower amounts of plasmid DNA but maintain the protective immune response has been one of the main goals in DNA vaccines research. The DNA-Hsp65 vaccine of Mycobacterium leprae, has demonstrated an efficient prophylactic and therapeutic activity against experimental tuberculosis, when administered by intramuscular injection using a total dose of 300 ug of DNA. One the best approach to improvement of DNA vaccines could be done using lower DNA doses delivery by different carriers and/or route of administration. In my master degree, I have demonstrated that two doses of the DRV liposomal construction with 50 ug DNA, by intramuscular route, was able to confer an enhanced protection against M. tuberculosis challenge when compared to naked DNA. Remarkably, the protection was improved if the formulation was delivery by intranasal route using only one dose of 25 ug DNA (ROSADA, 2006). Based in these first goods results, the goal of this project is explore the intranasal rote using others formulations such as mucoadesive liposomal with a lower DNA dose than previous used and analized the specific immune response induced. Furthermore, we also will use a formulation contained a nuclear localizing sequence (NLS) attached to plasmid DNA for optimization the DNA-Hsp65 entry into cell nucleus. These new approach can be a promising strategy to improved the protection induced by DNA vaccines using a non invasive route in the protection against tuberculosis.