Our goal is to enhance the efficacy of DNA vaccines using new bio-organic compounds to mediate oral deliver. Oral vaccination primarily protects an individual from oral pathogens, which include the AIDS retroviruses and opportunistic agents that accompany AIDS. Oral vaccination also confers some protection against pathogens that infect via other routes. Live oral vaccines have always been more effective than DNA vaccines in clinical trials, but recent technology allowing DNA delivery to specific cells provides new possibilities for DNA vaccines. Here we propose to test oral DNA vaccines for targeted delivery to dendritic cells (DC). using novel glyco-polyamines as the delivery vehicle. DC are the primary antigen-presenting cells and they express abundant cell surface carbohydrate receptors, such as mannose receptor and DC-SIGN. The cyclodextrin-based glyco-polyamines used in our studies consist of two functional domains: the multiple amino groups that bind and form complexes with DNA, and the sugar ligands that bind cell surface lectins and target the DNA complexes to DC. Enhancing the uptake of DNA by DC will enhance the immunogenicity of DNA vaccines. Cell culture studies have already demonstrated that mannosylated polyamines significantly enhance the uptake of plasmid DNA into DC. Here we propose to test the efficacy of targeted delivery in vivo. We hypothesize that DNA vaccines targeted to the cell surface carbohydrate receptors of dendritic cells will elicit enhanced cell-mediated responses. To test this hypothesis, we will employ the LCMV-infected murine model system that is known to elicit strong cell-mediated immune responses. We will have two specific aims.
In aim 1, we will synthesize novel glycosylated cyclodextrinbased polyamines (CDPA) and test the uptake and expression of reporter genes in dendritic cell culture. Mannose and oligomannose ligands will be introduced into CDPA for targeting to mannose receptors and DC-SIGN on dendritic cells, respectively.
In aim 2, we will test the magnitude of cell mediated immunity after oral inoculation with DNA vaccines in various formulations. Plasmid DNA encoding the LCMV NP gene will be orally delivered to mice as naked DNA or as DNA complexed with CDPA or glycosylated CDPA. Once we find a formulation that is optimum for eliciting cell-mediated immunity, we will replace the NP gene with DNA encoding an antigen associated with protective immunity in AIDS (p27 gag). We will determine, in the murine system, whether p27 DNA complexed with our compound can still elicit high cell-mediated immunity. These studies will lead to improved oral vaccines against AIDS and its attendant opportunistic infections. Once we have optimized the vaccine formulation in the murine model system, we will apply the targeted delivery system to monkey models and human clinic trials. ? ?
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| Carrion Jr, Ricardo; Patterson, Jean L; Johnson, Curtis et al. (2007) A ML29 reassortant virus protects guinea pigs against a distantly related Nigerian strain of Lassa virus and can provide sterilizing immunity. Vaccine 25:4093-102 |
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