Frontiers in Immunology (Oct 2022)

Evidence for the heterologous benefits of prior BCG vaccination on COVISHIELD™ vaccine-induced immune responses in SARS-CoV-2 seronegative young Indian adults

  • Srabanti Rakshit,
  • Srabanti Rakshit,
  • Vasista Adiga,
  • Vasista Adiga,
  • Vasista Adiga,
  • Asma Ahmed,
  • Asma Ahmed,
  • Chaitra Parthiban,
  • Chaitra Parthiban,
  • Nirutha Chetan Kumar,
  • Nirutha Chetan Kumar,
  • Pratibha Dwarkanath,
  • Sudarshan Shivalingaiah,
  • Srishti Rao,
  • George D’Souza,
  • Mary Dias,
  • Thomas J. A. Maguire,
  • Katie J. Doores,
  • Martijn Zoodsma,
  • Martijn Zoodsma,
  • Busranur Geckin,
  • Prokar Dasgupta,
  • Sudhir Babji,
  • Krista E. van Meijgaarden,
  • Simone A. Joosten,
  • Tom H. M. Ottenhoff,
  • Yang Li,
  • Yang Li,
  • Mihai G. Netea,
  • Kenneth D. Stuart,
  • Stephen C. De Rosa,
  • M. Juliana McElrath,
  • M. Juliana McElrath,
  • Annapurna Vyakarnam,
  • Annapurna Vyakarnam,
  • Annapurna Vyakarnam

DOI
https://doi.org/10.3389/fimmu.2022.985938
Journal volume & issue
Vol. 13

Abstract

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This proof-of-concept study tested if prior BCG revaccination can qualitatively and quantitively enhance antibody and T-cell responses induced by Oxford/AstraZeneca ChAdOx1nCoV-19 or COVISHIELD™, an efficacious and the most widely distributed vaccine in India. We compared COVISHIELD™ induced longitudinal immune responses in 21 BCG re-vaccinees (BCG-RV) and 13 BCG-non-revaccinees (BCG-NRV), all of whom were BCG vaccinated at birth; latent tuberculosis negative and SARS-CoV-2 seronegative prior to COVISHIELD™ vaccination. Compared to BCG-NRV, BCG-RV displayed significantly higher and persistent spike-specific neutralizing (n) Ab titers and polyfunctional CD4+ and CD8+ T-cells for eight months post COVISHIELD™ booster, including distinct CD4+IFN-γ+ and CD4+IFN-γ- effector memory (EM) subsets co-expressing IL-2, TNF-α and activation induced markers (AIM) CD154/CD137 as well as CD8+IFN-γ+ EM,TEMRA (T cell EM expressing RA) subset combinations co-expressing TNF-α and AIM CD137/CD69. Additionally, elevated nAb and T-cell responses to the Delta mutant in BCG-RV highlighted greater immune response breadth. Mechanistically, these BCG adjuvant effects were associated with elevated markers of trained immunity, including higher IL-1β and TNF-α expression in CD14+HLA-DR+monocytes and changes in chromatin accessibility highlighting BCG-induced epigenetic changes. This study provides first in-depth analysis of both antibody and memory T-cell responses induced by COVISHIELD™ in SARS-CoV-2 seronegative young adults in India with strong evidence of a BCG-induced booster effect and therefore a rational basis to validate BCG, a low-cost and globally available vaccine, as an adjuvant to enhance heterologous adaptive immune responses to current and emerging COVID-19 vaccines.

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