Abstract
We hypothesized that PD-1expressed by regulatory T cells (Tregs) would be functional and their expression levels may associate with activation status of CD4+ T and CD8+ T cells and the disease progression of HIV-1-infected patients. To prove it, we dynamically examined PD-1 expression levels by Tregs in peripheral blood of HIV-1-infected individuals not receiving antiretroviral therapy. Eighty-one HIV-1-infected individuals not undergoing antiretroviral therapy and 22 HIV-1-seronegative donors were enrolled in our study. Tregs were defined as CD4+CD25+CD127lo/− by flow cytometry. Expression of PD-1 and the activation markers CD38, HLA-DR, and Ki67 by Tregs and CD4+ T and CD8+ T cells was also determined by flow cytometry. TGF-β and IL-10 were measured to evaluate the suppressive function of Tregs. In all Tregs, the proportion of PD-1+ Tregs observed in HIV-1-infected persons was significantly greater than that seen in HIV-1-seronegative donors, and correlated with the activation of Tregs and CD4+ T and CD8+ T cells. This increased proportion of Tregs was also statistically associated with the disease progression. Blockade of PD-1/PD-L1 pathway with anti-PD-L1 mAb profoundly increased the level of intracellular TGF-β and IL-10 in CD4+CD25+CD127lo/− Tregs. Our data not only support that PD-1 plays a critical role to predict the activation status of cellular immunity and disease progression during HIV-1 infection but also indicate that blockade of PD-1/PD-L1 pathway represents a novel therapeutic approach to AIDS.
Get full access to this article
View all access options for this article.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
