S50 nanocapsules for transcutaneous DNA vaccination

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DESCRIPTION (provided by applicant): The WHO estimates that 40 million individuals are infected with AIDS worldwide and that 16,000 new infections occur daily, lending continuing support for new approaches in vaccine technology. DNA vaccines offer the advantage over protein vaccines of improved cytotoxic T cells (CTL) responses by simulating infection by intracellular pathogens following effective transfection. Emerging evidence suggests, however, this transfection must be directed at dendritic cells (DC) and be coupled with significant maturation and migration of DCs. In the effort to develop an AIDS vaccine, early CTL responses rivaling natural infection have been achieved with DNA prime / viral boost protocols, but these responses have not persisted sufficiently in macaques to provide protection, suggesting the need for adjuvants or recombinant virus-like particles to provoke stronger initial T-cell responses. We have developed a sub-50 nm nanocapsule delivery vector, capable of caveolar uptake, that induces efficient transfection of large plasmids into activated, migrating Langerhans cells by passive topical application using an ex vivo porcine skin organ culture model. LCs, the dendritic cells of skin, are efficient for inducing a broad range of systemic and mucosal responses, but effective stimulation of migration has proven difficult in large animals by current transcutaneous methods. Due to anatomical similarities with humans, the porcine model is superior for evaluation of transcutaneous vaccines. In this pilot study, using the bacterial protein 13-galactosidse as a model antigen, we propose to prepare and test in organ culture and in weanling pigs, vaccine formulations comprised of hyaluronan and aluminum or nickel ion. Demonstration of improved cellular and humoral immune responses with decreased dosing will provide a strong foundation for follow-on studies in Rhesus macaques to improve mucosal immunity and T-cell responses against SIV.