Frontiers in Cellular and Infection Microbiology (May 2022)

Humoral, Cellular and Cytokine Immune Responses Against SARS-CoV-2 Variants in COVID-19 Convalescent and Confirmed Patients With Different Disease Severities

  • Chun-Hsiang Chiu,
  • Yu-Hsiu Chang,
  • Feng-Yee Chang,
  • Yi-Jen Hung,
  • Ching-Len Liao,
  • Ching-Len Liao,
  • Kuo-Chou Chiu,
  • Kuo-Chou Chiu,
  • Pei-Ling Tsai,
  • Tien-Wei Chang,
  • Li-Chen Yen

DOI
https://doi.org/10.3389/fcimb.2022.862656
Journal volume & issue
Vol. 12

Abstract

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ObjectivesTo assess humoral and cellular immune responses against SARS-CoV-2 variants in COVID-19 convalescent and confirmed patients, to explore the correlation between disease severity, humoral immunity, and cytokines/chemokines in confirmed patients, and to evaluate the ADE risk of SARS-CoV-2.MethodsAnti-RBD IgG were quantified using an ELISA. Neutralization potency was measured using pseudovirus and real virus. Cellular immunity was measured using ELISpot. Cytokine/chemokine levels were detected using multiplex immunoassays. In vitro ADE assays were performed using Raji cells.ResultsOne-month alpha convalescents exhibited spike-specific antibodies and T cells for alpha and delta variants. Notably, the RBD-specific IgG towards the delta variant decreased by 2.5-fold compared to the alpha variant. Besides, serum from individuals recently experienced COVID-19 showed suboptimal neutralizing activity against the delta and omicron variants. Humoral immune response, IL-6, IP-10 and MCP-1 levels were greater in patients with severe disease. Moreover, neither SARS-CoV-1 nor SARS-CoV-2 convalescent sera significantly enhanced SARS-CoV-2 pseudovirus infection.ConclusionsSignificant resistance of the delta and omicron variants to the humoral immune response generated by individuals who recently experienced COVID-19. Furthermore, there was a significant correlation among disease severity, humoral immune response, and specific cytokines/chemokine levels. No evident ADE was observed for SARS-CoV-2.

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