Robust and Functional Immune Memory Up to 9 Months After SARS-CoV-2 Infection: A Southeast Asian Longitudinal Cohort

Front Immunol. 2022 Feb 3:13:817905. doi: 10.3389/fimmu.2022.817905. eCollection 2022.

Abstract

The duration of humoral and cellular immune memory following SARS-CoV-2 infection in populations in least developed countries remains understudied but is key to overcome the current SARS-CoV-2 pandemic. Sixty-four Cambodian individuals with laboratory-confirmed infection with asymptomatic or mild/moderate clinical presentation were evaluated for Spike (S)-binding and neutralizing antibodies and antibody effector functions during acute phase of infection and at 6-9 months follow-up. Antigen-specific B cells, CD4+ and CD8+ T cells were characterized, and T cells were interrogated for functionality at late convalescence. Anti-S antibody titers decreased over time, but effector functions mediated by S-specific antibodies remained stable. S- and nucleocapsid (N)-specific B cells could be detected in late convalescence in the activated memory B cell compartment and are mostly IgG+. CD4+ and CD8+ T cell immune memory was maintained to S and membrane (M) protein. Asymptomatic infection resulted in decreased antibody-dependent cellular cytotoxicity (ADCC) and frequency of SARS-CoV-2-specific CD4+ T cells at late convalescence. Whereas anti-S antibodies correlated with S-specific B cells, there was no correlation between T cell response and humoral immune memory. Hence, all aspects of a protective immune response are maintained up to nine months after SARS-CoV-2 infection and in the absence of re-infection.

Keywords: B cell immunity; SARS-CoV-2; T cell immunity; antibody effector function; long term immune response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Neutralizing / blood*
  • Antibodies, Viral / blood*
  • B-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / immunology*
  • CD8-Positive T-Lymphocytes / immunology*
  • COVID-19 / pathology
  • Cambodia
  • Coronavirus Nucleocapsid Proteins / immunology
  • Humans
  • Immunity, Cellular / immunology
  • Immunity, Humoral / immunology
  • Immunologic Memory / immunology*
  • Phosphoproteins / immunology
  • SARS-CoV-2 / immunology*
  • Spike Glycoprotein, Coronavirus / immunology

Substances

  • Antibodies, Neutralizing
  • Antibodies, Viral
  • Coronavirus Nucleocapsid Proteins
  • Phosphoproteins
  • Spike Glycoprotein, Coronavirus
  • nucleocapsid phosphoprotein, SARS-CoV-2
  • spike protein, SARS-CoV-2