Emory Vaccine Center
Department of Microbiology and Immunology, Emory University School of Medicine
Yerkes National Primate Research Center
Emory Center for AIDS Research
The goal of our lab is to develop vaccines for HIV/AIDS. There are currently about 33 million individuals living with HIV worldwide. Without question the AIDS epidemic represents a major threat to public health, economic development, and cultural stability worldwide. The introduction of drugs that control virus replication and improved treatment regimens like HAART have succeeded only in prolonging the lives of some infected individuals fortunate enough to have access to the medications. These anti-viral drugs do not cure infection, and are associated with several significant problems, including serious side effects, prohibitively high cost, the need for rigorous adherence and the potential for developing viral resistance. For these reasons, development of a safe and effective HIV vaccine is imperative. Our efforts are focused on developing both prophylactic vaccines (given to people ahead of infection) as well as therapeutic vaccines (given to HIV+ individuals).
Our approach to developing a prophylactic vaccine is to generate strong anti-viral antibody responses and cytotoxic T cell responses. We use recombinant DNA and modified vaccinia Ankara (current smallpox vaccine) as vaccine delivery vectors. A HIV vaccine based on these vectors was shown to be safe in healthy human volunteers and is currently being tested for immunogenicity in humans. We developed newer versions of this vaccine that elicit stronger humoral immune responses and protect nearly 60-70% of the vaccinated animals completely from repeated infections. These newer versions of vaccines are about to enter human safety trials.
Our approach to developing a therapeutic vaccine is to reprogram the virus-specific CD8 T cells in the infected host. Cellular immune responses are critical for the control of HIV replication. In particular, CD8 T cells play a major role in restricting the growth of virus and eliminating virus-infected cells. In the presence of antigen and inflammatory signals, cognate naïve CD8 cells expand and traffic to infection sites, where they lyse virus-infected host cells. However, CD8 T cells from HIV-infected individuals have been shown to be non-functional meaning they are there but do not do their job. Our efforts are focused on how to reprogram these cells and to generate new cells so that they can clear the virus-infected cells.