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This article is part of the supplement: AIDS Vaccine 2012

Open Access Poster presentation

Chronic progressive HIV-1 infection is associated with elevated levels of myeloid-derived suppressor cells

T Vollbrecht1, J Roider1, R Stirner1, A Tufman1, RM Huber1, JR Bogner1, A Lechner1, C Bourquin2 and R Draenert1*

  • * Corresponding author: R Draenert

Author Affiliations

1 Ludwig-Maximilians-University, Munich, Germany

2 University of Fribourg, Fribourg, Switzerland

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Retrovirology 2012, 9(Suppl 2):P283  doi:10.1186/1742-4690-9-S2-P283


The electronic version of this article is the complete one and can be found online at: http://www.retrovirology.com/content/9/S2/P283


Published:13 September 2012

© 2012 Vollbrecht et al; licensee BioMed Central Ltd.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background

Myeloid-derived suppressor cells (MDSC) have been described as suppressors of T cell functions in many tumor models. However MDSC in HIV-1 infection have not been studied to date. As impaired T cell function is a hallmark of chronic progressive HIV-1 infection, we hypothesized that MDSC also play a role here.

Methods

Surface staining and FACS analysis were performed on freshly isolated PBMC of HIV-infected individuals and compared to healthy controls and individuals with lung carcinoma. MDSC of late-stage HIV-infected subjects were isolated using magnetic beads and co-cultured with the respective CD8 T cells for evaluation of proliferative capacity.

Results

We found that chronically HIV-infected HAART-naïve individuals had significantly higher CD11b+CD14-CD33+CD15+ MDSC levels than healthy controls (p=0.01). MDSC frequencies showed a positive correlation with viral load (r2=0.24, p=0.0002) and a negative correlation with CD4 count (r2=0.29, p<0.0001). Initiation of HAART led to a rapid drop in MDSC levels. MDSC from HIV-infected progressors restricted the proliferative capacity of CD8 T cells from healthy donors and of Gag/Nef-specific CD8 T cells from HIV-controllers in vitro. Furthermore CD11b+CD14-CD33+CD15+ MDSC induced the expansion of CD4+CD25+FoxP3+ regulatory T cells when co-incubated with PBMC from controllers in vitro.

Conclusion

We conclude that chronic uncontrolled HIV-infection is associated with elevated levels of MDSC which potentially contribute to the impaired T cell responses characteristic for the progressive disease stage.