Session 51Poster Presentations Novel Vaccine Approaches Session Day and Time: Thursday 1:30 - 3:30 pm Room: Hall D
429 High Cellular Immune Responses to SIV Antigens following Recombinant DNA Prime and Listeria Monocytogenes Boost in the Rhesus Macaque Model J. D. Boyer*1, T. Robinson1, M. Lewis2, S. Carlarota1, D. B. Weiner1, Y. Paterson1 1Univ of Pennsylvania, Philadelphia and 2Southern Res Inst, Frederick, MD
Background: There is a pressing need for an effective vaccine against human immunodeficiency virus (HIV) type 1. Furthermore, an HIV-1 specific cell mediated immune response will most likely be important in the ultimate control of HIV-1 replication. Recombinant Listeria monocytogenes has demonstrated the ability to induce robust cell mediated immune responses. In addition, DNA vaccines have demonstrated the ability to induce CD8 and CD4 cellular immune responses in a number of animal species and, importantly, DNA priming and live vector boosting is an effective way to induce a strong cellular immune response.
Methods: We, therefore, have combined these 2 methods of vaccination. Listeria monocytogenes and DNA vaccines that express and secrete SIV gag and env proteins were optimized and analyzed in the Rhesus macaque model. One group of primates was primed with SIV DNA vaccines and boosted orally with the SIV expressing L. monocytogenes. A second group of primates was immunized orally with the L. monocytogenes vectors alone.
Results: We observed strong SIV specific cellular immune responses as assessed by Elispot and ICC following immunization with the DNA and L. monocytogenes vectors. The SIV antigen specific immune responses were significantly augmented when Rhesus macaques primed with SIV DNA vaccines were boosted with the SIV expressing L. monocytogenes. Responses were as high as other viral vector boosts.
Conclusions: This study demonstrates that oral L. monocytogenes is a useful vaccine vector for HIV-1 and when combined with DNA vaccines appears highly affective for producing strong cellular immune responses.
