Negative modulation of suppressive HIV-specific regulatory T cells by IL-2 adjuvanted therapeutic vaccine

PLoS Pathog. 2017 Jul 14;13(7):e1006489. doi: 10.1371/journal.ppat.1006489. eCollection 2017 Jul.

Abstract

The potential benefit in using IL-2 in immunotherapy for cancer and autoimmunity has been linked to the modulation of immune responses, which partly relies on a direct effect on Tregs populations. Here, we revisited the role of IL-2 in HIV infection and investigated whether its use as an adjuvant with therapeutic vaccination, impacts on HIV-specific responses. Antiretroviral therapy treated-patients were randomized to receive 4 boosts of vaccination (ALVACHIV/Lipo-6T, weeks 0/4/8/12) followed by 3 cycles of IL-2 (weeks 16/24/32) before treatment interruption (TI) at week40. IL-2 administration increased significantly HIV-specific CD4+CD25+CD134+ T-cell responses, which inversely correlated with viral load after TI (r = -0.7, p <0.007) in the vaccine/IL-2 group. IL-2 increased global CD25+CD127lowFoxP3+Tregs (p <0.05) while it decreased HIV- but not CMV- specific CD39+FoxP3+CD25+CD134+Tregs (p <0.05). HIV-specific Tregs were inversely correlated with IFN-γ producing specific-effectors (p = 0.03) and positively correlated with viral load (r = 0.7, p = 0.01), revealing their undesired presence during chronic infection. Global Tregs, but not HIV-specific Tregs, inversely correlated with a decrease in exhausted PD1+CD95+ T-cells (p = 0.001). Altogether, our results underline the negative impact of HIV-specific Tregs on HIV-specific effectors and reveal the beneficial use of IL-2 as an adjuvant as its administration increases global Tregs that impact on T-cell exhaustion and decreases HIV-specific CD39+Tregs by shifting the balance towards effectors.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • AIDS Vaccines / administration & dosage*
  • AIDS Vaccines / immunology
  • Adjuvants, Immunologic / administration & dosage*
  • Adult
  • Female
  • HIV Infections / immunology*
  • HIV Infections / therapy*
  • HIV Infections / virology
  • HIV-1 / physiology*
  • Humans
  • Immunotherapy
  • Interferon-gamma / immunology
  • Interleukin-2 / administration & dosage*
  • Interleukin-2 / immunology
  • Lymphocyte Activation
  • Male
  • Middle Aged
  • T-Lymphocytes, Regulatory
  • Vaccination

Substances

  • AIDS Vaccines
  • Adjuvants, Immunologic
  • Interleukin-2
  • Interferon-gamma

Grants and funding

This study was supported by the Investissement d’Avenir program managed by the ANR under reference ANR-10-LABX-77 and by the Agence Nationale pour la Recherche sur le SIDA et les hepatites virales (ANRS), the Vaccine Research Institute (VRI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.