New Tools to Expand Regulatory T Cells from HIV-1-infected Individuals

Abstract

CD4+ Regulatory T cells (Tregs) are potent immune modulators and serve an important function in human immune homeostasis. Depletion of Tregs has led to measurable increases in antigen-specific T cell responses in vaccine settings for cancer and infectious pathogens. However, their role in HIV-1 immuno-pathogenesis remains controversial, as they could either serve to suppress deleterious HIV-1-associated immune activation and thus slow HIV-1 disease progression or alternatively suppress HIV-1-specific immunity and thereby promote virus spread. Understanding and modulating Treg function in the context of HIV-1 could lead to potential new strategies for immunotherapy or HIV vaccines. However, important open questions remain on their role in the context of HIV-1 infection, which needs to be carefully studied. Representing roughly 5% of human CD4+ T cells in the peripheral blood, studying the Treg population has proven to be difficult, especially in HIV-1 infected individuals where HIV-1-associated CD4 T cell and with that Treg depletion occurs. The characterization of regulatory T cells in individuals with advanced HIV-1 disease or tissue samples, for which only very small biological samples can be obtained, is therefore extremely challenging. We propose a technical solution to overcome these limitations using isolation and expansion of Tregs from HIV-1-positive individuals. Here we describe an easy and robust method to successfully expand Tregs isolated from HIV-1-infected individuals in vitro. Flow-sorted CD3+CD4+CD25+CD127low Tregs were stimulated with anti-CD3/anti-CD28 coated beads and cultured in the presence of IL-2. The expanded Tregs expressed high levels of FOXP3, CTLA4 and HELIOS compared to conventional T cells and were shown to be highly suppressive. Easier access to large numbers of Tregs will allow researchers to address important questions concerning their role in HIV-1 immunopathogenesis. We believe answering these questions may provide useful insight for the development of an effective HIV-1 vaccine.

Ex Vivo Cytosolic Delivery of Functional Macromolecules to Immune Cells

“…Regulatory T cells (Tregs) were isolated and expanded as previously described [ 23 , 24 ]. Briefly CD4+ T Cell-enriched PBMC were isolated from peripheral blood of healthy individuals by density centrifugation using the CD4+ T cells RosetteSep enrichment kit (Sigma-Aldrich and STEMCELL Technologies) and labeled with anti-CD3-PE-Cy7, CD4-FITC, CD25-APC and CD127-PE.…”

Nanotechnology as a New Therapeutic Approach to Prevent the HIV-Infection of Treg Cells

“…However, the capacity of the HIV-1 to infect these cells impairing its functionality restricts the potential therapeutic use of this strategy in HIV-1-infected subjects. In fact, Angin M et al describes that Treg cells can be isolated from HIV-1-infected subjects and expanded in vitro [ 35 , 36 ], but the capacity of HIV-1 to replicate in these cultured Treg cells compromises the efficacy of these cells and subsequent transfer to the subjects. Here, we clearly demonstrated that the use in vitro of anionic dendrimers could prevent the HIV-1 replication and the infection of expanded Treg cells in culture, which theoretically raises the possibility to use Treg cells therapeutically in HIV-1-infected subjects.…”