Increased Frequency of Regulatory T Cells Accompanies Increased Immune Activation in Rectal Mucosae of HIV-Positive Noncontrollers
- 1 November 2011
- journal article
- Published by American Society for Microbiology in Journal of Virology
- Vol. 85 (21), 11422-11434
- https://doi.org/10.1128/jvi.05608-11
Abstract
Gut-associated lymphoid tissue (GALT) is a major site of HIV replication and CD4+T cell depletion. Furthermore, microbial translocation facilitated by mucosal damage likely contributes to the generalized immune activation observed in HIV infection. Regulatory T cells (Treg) help maintain homeostasis and suppress harmful immune activation during infection; however, in the case of persistent viral infections such as HIV, their role is less clear. Although a number of studies have examined Treg in blood during chronic infection, few have explored Treg in the gastrointestinal mucosa. For this study, paired blood and rectal biopsy samples were obtained from 12 HIV noncontrollers (viral load of >10,000 copies/ml plasma), 10 HIV controllers (viral load of P= 0.001) or HIV controllers (P= 0.002). Mucosal Treg positively correlated with viral load (P= 0.01) and expression of immune activation markers by CD4+(P= 0.01) and CD8+(P= 0.07) T cells. Suppression assays indicated that mucosal and peripheral Treg of noncontrollers and controllers maintained their capacity to suppress non-Treg proliferation to a similar extent as Treg from seronegative subjects. Together, these findings reveal that rather than experiencing depletion, mucosal Treg frequency is enhanced during chronic HIV infection and is positively correlated with viral load and immune activation. Moreover, mucosal Treg maintain their suppressive ability during chronic HIV infection, potentially contributing to diminished HIV-specific T cell responses and viral persistence.Keywords
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