Based on a multitude of data there are several features desired in an HIV Vaccine immunogen. Such an immunogen should induce strong and broad humoral and cellular immunity. Furthermore, as HIV is in general a sexually transmitted disease and the cells of the gut are preferentially targeted for viral destruction, an immunogen should be capable of inducing in particular mucosal as well as systemic immune responses. Currently there is no approach that can be simply administered that induces such a response. This proposal will focus on the induction of mucosal immune responses through a systemic vaccination strategy. We believe that this proposal has important implications for the development of HIV vaccines. There are 3 highly interrelated and highly novel projects that comprise this program. Project 1 (D. Weiner) will test the hypothesis in rodent models that a systemic vaccination which redirects T cells from mucosal sites to systemic sites in vivo can result in enhanced mucosal humoral and cellular immunity. Project 2 (P. Marx) Will extend the studies and test the mucosal redirection hypothesis in the critically important the macaque model. Project 3 (M. Betts) Will test several hypotheses regarding the functional nature of the induced immune responses using the latest polyfunctional immune methods in both mice and macaques in concert with project 1 and 2. Program Oversight is provided by an experienced Administrative Core (D. Weiner).
The specific Aims of the Administrative core are:
Aim 1 : Administration and coordination of the entire program project.
Aim 2 : Organizing the Annual SAB meeting. A stellar Scientific Advisory Board will provide additional guidance and direction to facilitate the success of the overall program. PROJECT 1: DNA Vaccine for Induction of Mucosal Immunity (Weiner, D.) PROJECT 1 DESCRIPTION (provided by applicant): Based on a multitude of data there are several features desired in an HIV Vaccine immunogen. Such an immunogen should induce strong and broad humoral and cellular immunity. Furthermore, as HIV is in general a sexually transmitted disease and the cells of the gut are preferentially targeted for viral destruction, an immunogen should be capable of inducing in particular mucosal as well as systemic immune responses. Currently there is no approach that can be simply administered that induces such a response. In this regard, Dr. Weiner's laboratory first reported that they could redirect immune cells in vivo using chemokines encoded as part of a DMA vaccine cocktail, and recent work further confirmed and elegantly extended these findings through modification of vaccine induced immune cell trafficking by utilizing chemokines (immune trafficking signals) to attract peripheral immune cell populations. It is now the goal of this application to extend this work and develop a mucosal vaccine strategy that will result in the redirection of cells of the mucosal compartment in response to a DNA vaccine administered in the systemic compartment. Our preliminary data support that this strategy generates features of mucosal immunity by systemic vaccination. This application will further investigate this novel approach in this exceptionally important area of vaccine development. We will study the ability of specific chemokines as DNA vaccine adjuvants to modulate immune cell trafficking and redirect effector T and B cell responses to mucosal sites. There are 4 Specific Aims outlined in Project 1 of this program that will address the following questions: First, will delivery of chemokine immunoadjuvants systemically by DNA vaccines induce antigen specific immune responses in mucosal sites, and secondly, can mucosal-derived chemokine-induced immunogenicity be explained by a mechanism in which chemokines induce """"""""retrafficking"""""""" of organ specific homing routes? Alternatively, is it such that the """"""""imprinting"""""""" dogma for peripheral/mucosal immune cells, in fact, is reversible, resulting from chemokine-induced activation and """"""""re-education"""""""" of target cells displaying new homing potentials. Finally, we will test whether chemokine adjuvants can elicit physiologically relevant cellular and humoral immune responses that can protect mice from a lethal mucosal challenge. This project will also generate all constructs for the macaque studies for Project 2 and support the polyfunctional flow studies in Project 3. These studies have great significance for our basic understanding of lymphocyte homing to the gut, mucosal phenotype commitment and for the development of an HIV vaccine that delivers antigens to generate mucosal immunity.
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