2015 DEPARTMENT OF MEDICINE RESEARCH DAY
Title of Poster: CD4+ T Cells Harbor the Majority of Latent HIV Provirus in the Gut
Compartment
Presenter: Jennifer A. Fulcher
Division: Infectious Diseases
☐Faculty ☒Fellow ☐Resident ☐Post-doc Research Fellow ☐Graduate Student ☐Medical Student ☐Other
Principal Investigator/Mentor: Peter Anton
Co-Investigators: Martha J. Lewis, Julie Elliott
Thematic Poster Category: Infections, Injury and Repair, Inflammation, Host Defense, Immunology, Hemostasis and
Atherosclerosis
Abstract
Background: The gut is an established source of persistent virus in HIV patients on fully suppressive
combination antiretroviral therapy. However, the mechanism and cellular source of viral persistence in
this tissue compartment is not understood. In this study, we sought to examine the relative
contribution of the major gut mucosa cellular subsets to the pool of latent provirus in this
compartment.
Methods: Sigmoid colon biopsies were obtained from aviremic HIV+ subjects on antiretroviral
therapy. Mucosal mononuclear cells (MMCs) were isolated then stained for CD45, CD3 and CD4. After
gating on CD45+ cells, this population was sorted into double positive, single positive, and double
negative populations using CD3 and CD4. Genomic DNA was isolated from each subset and used for
proviral qPCR as well as sequencing of nef, env, gag, and pol.
Results: Cell sorting of isolated MMCs yielded distinct cellular subsets for all subjects with the
following ranges: CD3+ CD4+ (167,178 – 460,494 cells), CD3- CD4+ (262,925 – 300,115 cells),
CD3+ CD4- (113,858 – 377,367 cells), CD3- CD4- (42,835 – 466,436 cells). In all subjects, the
majority of quantifiable provirus was detected in the CD3+ CD4+ cell population (2677  3649
copies/million cells), though there was also detectable provirus in the CD4 single positive (224  551
copies/million cells) and double negative (52  87 copies/million cells) populations. No provirus was
detected in the CD3 single positive population. Phylogenetic analysis using a minimum of 10 clones
per population showed little sequence diversity for all genes examined (nef, env, gag, pol), with nearly
identical clones observed in sequences obtain from the CD3+ CD4+ population and total MMCs.
Finally, no PRO or RT drug resistance mutations were detected in sequences from any cell
compartment.
Conclusions: CD4+ T cells appear to be the dominant source of persistent HIV in the gut of aviremic
individuals. This represents an important target for new therapy and eradication strategies. Further
studies to examine the longitudinal dynamics of this compartment may provide additional insight into
the mechanism of persistence.