Description of Research Expertise

Research Interests
HIV-1 latency.

Key words: HIV, latency, reservoirs, dendritic cells, viral pathogenesis, proviral integration, retrovirus, virology, T cell activation, resting T cells.

Description of Research
Highly active anti-retroviral therapy can clear the blood of HIV-1 virions. But, despite long-term suppression of virus, when the drugs are stopped the virus returns. Thus, reservoirs of latent, treatment-resistant HIV-1 exist in infected individuals and are a major barrier to cure. Our lab has developed an in vitro model of HIV-1 latency. We use quantitative and imaging methods to study how HIV-1 establishes latent infection in resting CD4+ T cells.

Current dogma holds that latent HIV-1 infection occurs only when T cells are activated. Our findings challenge this. Using novel quantitative assays we made three discoveries about latent HIV-1 infection in CD4+ T cells. One, HIV-1 can integrate into resting CD4+ T cells. Two, the T cells bearing integrated HIV-1 genomes do not produce new virions unless stimulated. Three after stimulation a percentage of these cells produce virus. Thus, in our system HIV-1 establishes latent infection in resting T cells in the absence of activating stimuli. We now want to determine if reservoirs form more efficiently in the presence of subtle stimuli and if reservoirs form preferentially in subsets of resting T cells that are more permissive for HIV-1 integration. We are attempting to quantify the contribution of memory and naive cells to reservoirs in vivo. Finally, we are interested to determine how reservoirs are maintained in vivo. To study this, we are first developing assays that can sensitively detect ongoing replication.

In addition, a new focus in our lab is to enhance transduction of resting CD4+ T cells with gene therapy vectors based on the HIV genome.

In summary, we have developed an in vitro model of HIV-1 latency and our studies promise to provide new insights into reservoir formation in HIV-1 infected individuals and may eventually lead to novel therapies.

Rotation Projects for 2008-2009
1. Measure the percentage of resting T cells that contain provirus (integrated viral DNA) in HIV-infected individuals in various CD4+ T cell subpopulations including memory and naïve subsets to understand the contribution of both of these cell types to reservoirs.
2. Measure total, linear and integrated HIV DNA to determine if ongoing replication occurs on HAART.
3. Quantify the frequency of multiply infected cells after single round infection of resting CD4+ T cells to determine if hypersusceptible cells exist among naive and memory cells.
4. Determine the susceptibilities of other primary WBC (dendritic cells and progenitor cells to HIV integration).

Lab personnel:

Jenny Yu - Research Specialist
Angela Mexas - Postdoctoral fellow
Luis Agosto - graduate student
Matt Pace - graduate student
Erin Graf - graduate student