Immunology and Infection
Published: May 30th, 2013
CD4+ Regulatory T cells are potent immune-modulators and serve important functions in immune homeostasis. The paucity of these cells in peripheral blood makes functional studies challenging, specifically in the context of HIV-1-infection. We here describe a method to isolate and expand functional CD4+ Tregs from peripheral blood from HIV-1-infected individuals.
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.
With more than 34 million individuals living with HIV/AIDS worldwide and an estimated 2.5 million people newly infected in 2011, the need for an effective HIV vaccine to curb the worldwide HIV epidemic remains paramount. However, despite three decades of intense research efforts, the HIV-1 vaccine efficacy trials to date have resulted in only modest protection 1-3 and the correlates of protective immunity remain poorly understood. Elucidating the nature of the immune response needed for protection is essential for the strategic design of an effective HIV-1 vaccine and other immunotherapeutic strategies targeting HIV-1 infection.
1. Regulatory T cell isolation from HIV-1 Positive Blood
The expression of interleukin 2 receptor (CD25) and the interleukin 7 receptor (CD127) have been described as reliable surface markers to identify functional Treg populations 13 and have been shown to correlate with CD4+CD25+FOXP3+ Tregs 9,12. Figure 1 represents the gating strategy used to flow-sort single CD3+CD4+CD25+CD127low Tregs from PBMC isolated from an HIV-1-positive individual. The CD25/CD127 anti.......
Using the protocol described above, Tregs can be successfully isolated and expanded from HIV-1-infected individuals in vitro. Expanded Tregs express high levels of FOXP3, CTLA4 and HELIOS, are highly suppressive and display a highly demethylated Treg-Specific Demethylation Region (TSDR) locus of the FOXP3 gene (data not shown) 15, suggesting true origin from the regulatory T cell lineage, as opposed to activation-induced transient FOXP3 upregulation. Deep sequencing demonstrated that the TCR repertoir.......
This work was supported in part by research funding from the Elisabeth Glaser Pediatric AIDS Foundation (Pediatric HIV Vaccine Program Award MV-00-9-900-1429-0-00 to MMA), MGH/ECOR (Physician Scientist Development Award to MMA), NIH NIAID (KO8219 AI074405 and AI074405-03S1 to MMA), and the Harvard University Center for AIDS Research (CFAR), an NIH funded program (P30 AI060354) which is supported by the following NIH Co-Funding and Participating Institutes and Centers: NIAID, NCI, NICHD, NHLBI, NIDA, NIMH, NIA, FIC, and OAR. These studies were furthermore supported by the Bill & Melinda Gates Foundation and the Terry and Susan Ragon Foundation.....
|RosetteSep Human CD4+ T Cell Enrichment Cocktail
|Round-Bottom tube with 35 μm a nylon mesh
|Human T-activator CD3/CD28
|NIH Aids Research & Reference Reagent Program
|LIVE/DEAD Fixable Violet Dead Cell Stain Kit
|Foxp3 / Transcription Factor Staining Buffer Set
|CellTrace Violet Cell Proliferation Kit
|Vybrant CFDA SE Cell Tracer Kit
|Treg Suppression inspector
|BD Vacutainer Blood Collection Tube w/ ACID CITRATE DEXTROSE (ACD)
|Becton, Dickinson and Company (BD)
|FACSAria IIu Cell Sorter
|LSR II Flow Cytometer
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