Driving HIV-1 specific responses in immune suppressed recipients: Listeria as a vaccine vector (53.20)

Abstract

Abstract Malaria, TB and HIV-1 remain tremendous disease burdens in much of the world’s population and functional vaccines are desperately needed. Although Sub-Saharan populations are those that will benefit most from these vaccines, they are also coincident with areas of endemic helminth infection. Infection with one or more species of parasitic helminths suppresses the immune system and has been shown, by our lab and others, to suppress vaccine-specific responses. One goal of our research is to find vaccines that drive significant vaccine-specific immune responses in helminth infected recipients, without the need to eliminate helminth infection prior to vaccination. In the current study, we demonstrate that administration of a Listeria vector HIV-1 gag vaccine to mice chronically infected with the helminth parasite Schistosoma mansoni drives significant immune responses to HIV-1 gag CTL and helper epitopes. This observation suggests that Listeria vector vaccines are capable of driving vaccine-specific responses in helminth-infected populations. Kinetic studies show the antigen-specific responses are both durable and capable of inducing CD8+ central memory. In addition to HIV-1, Listeria vectors should be considered in the development of new generation malaria and TB vaccines to be administered to sub-Saharan Africa populations where helminth infection is endemic. Studies are underway to determine if other vectors are also capable of overcoming helminth-induced immune suppression.