HIV latency represents a key barrier preventing the cure of infected individuals through the use of antiretroviral therapy (ART) alone. Historically, efforts to deplete latently-infected cells have been hampered by a lack of relevant small animal models that can be used to study HIV latency and evaluate methods for eliminating latent virus. To address this issue we recently developed a new in vivo model for HIV latency using the humanized BLT (bone marrow-liver-thymus) mouse. We demonstrated that HIV forms latency within infected BLT mice, and that the latent virus is integrated, activation-inducible, replicatio-competent, and responds to known HIV latency reversing agents (LRAs). This model represents a versatile tool for studying latent HIV. However, challenges still exist within the HIV latency field, particularly in accurately quantifying latently-infected cells and in evaluating activation-elimination approaches that cause significant but incomplete depletion of persistent/latent reservoirs of HIV. Here, we propose to develop a new system for analyzing HIV persistence and latency using genetically barcoded virus. We have created an HIV swarm composed of >200,000 different viral variants that are genetically identical except for the presence of a short non-expressed, phenotypically neutral barcode sequence. This barcoded virus replicates efficiently in vitro, is pathogenic in vivo in BLT mice, and has multiple potential applications in HIV cure research. We intend to further develop and test the barcoded virus in the context of the humanized BLT mouse latency model. We will use deep sequencing approaches to evaluate viral diversity following ex vivo stimulations of latently-infected cells from bulk tissue samples, and thereby compare the relative efficacy of different individual or combination LRAs. We will also test our hypothesis that barcoded virus will allow us to monitor the diversity of HIV plasma virus that emerges from reservoirs upon cessation of ART. This would set the stage for in vivo testing of LRAs, with reductions in barcode diversity serving as a new additional measure of the effectiveness of LRAs in a whole animal system. Together, these experiments will provide important new information on HIV latency and will form the basis of future in vivo modelling of HIV cure approaches.

Public Health Relevance

Antiretroviral therapy (ART) can prevent HIV replication and prevent disease progression, but does not cure the infection. Relevant in vivo model systems are required to study how HIV persists during ART, and to test methods for eliminating latent viral reservoirs. The current study describes the use of a novel, genetically barcoded virus in the humanized BLT mouse model of HIV latency, which represents a new approach for evaluating persistent HIV reservoirs and methods for eliminating them.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI124763-02
Application #
9221961
Study Section
Special Emphasis Panel (ZRG1-AARR-E (56)R)
Program Officer
Kuo, Lillian S
Project Start
2016-02-10
Project End
2018-01-31
Budget Start
2017-02-01
Budget End
2018-01-31
Support Year
2
Fiscal Year
2017
Total Cost
$231,000
Indirect Cost
$81,000
Name
University of California Los Angeles
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
092530369
City
Los Angeles
State
CA
Country
United States
Zip Code
90095