Evaluation of antiviral T cell responses and TSCM cells in volunteers enrolled in a phase I HIV-1 subtype C prophylactic vaccine trial in India

PLoS One. 2020 Feb 25;15(2):e0229461. doi: 10.1371/journal.pone.0229461. eCollection 2020.


T cells play an important role in controlling viral replication during HIV infection. An effective vaccine should, therefore, lead to the induction of a strong and early viral-specific CD8+ T cell response. While polyfunctional T cell responses are thought to be important contributors to the antiviral response, there is evidence to show that polyfunctional HIV- specific CD8+ T cells are just a small fraction of the total HIV-specific CD8+ T cells and may be absent in many individuals who control HIV replication, suggesting that other HIV-1 specific CD8+ effector T cell subsets may be key players in HIV control. Stem cell-like memory T cells (TSCM) are a subset of T cells with a long half-life and self-renewal capacity. They serve as key reservoirs for HIV and contribute a significant barrier to HIV eradication. The present study evaluated vaccine-induced antiviral responses and TSCM cells in volunteers vaccinated with a subtype C prophylactic HIV-1 vaccine candidate administered in a prime-boost regimen. We found that ADVAX DNA prime followed by MVA boost induced significantly more peripheral CD8+ TSCM cells and higher levels of CD8+ T cell-mediated inhibition of replication of different HIV-1 clades as compared to MVA alone and placebo. These findings are novel and provide encouraging evidence to demonstrate the induction of TSCM and cytotoxic immune responses by a subtype C HIV-1 prophylactic vaccine administered using a prime-boost strategy.

Publication types

  • Clinical Trial, Phase I
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • AIDS Vaccines / administration & dosage
  • AIDS Vaccines / immunology*
  • Antiviral Agents / administration & dosage
  • Female
  • HIV Infections / immunology*
  • HIV Infections / prevention & control
  • HIV Infections / virology
  • HIV-1 / classification
  • HIV-1 / immunology*
  • Humans
  • Immunologic Memory / drug effects
  • Immunologic Memory / immunology*
  • Male
  • Stem Cells / drug effects
  • Stem Cells / immunology*
  • T-Lymphocyte Subsets / drug effects
  • T-Lymphocyte Subsets / immunology*
  • Vaccination
  • Virus Replication / drug effects
  • Virus Replication / immunology*
  • Volunteers


  • AIDS Vaccines
  • Antiviral Agents

Grants and funding

The vaccine trial and the present study were supported and coordinated by the International AIDS Vaccine Initiative (IAVI). IAVI’s work is made possible by generous support from many donors including the Bill & Melinda Gates Foundation, the Ministry of Foreign Affairs of Denmark, Irish Aid, the Ministry of Finance of Japan in partnership with The World Bank, the Ministry of Foreign Affairs of the Netherlands, the Norwegian Agency for Development Cooperation (NORAD), the United Kingdom Department for International Development (DFID), and the USAID. The full list of IAVI donors is available at www.iavi.org. This study was possible through the generous support of the American people through funding from the United States Agency for International Development (USAID; Grant ID: 2233). The contents are the responsibility of the authors and do not necessarily reflect the views of USAID or the United States Government.