Response of memory CD8+ T cells to severe acute respiratory syndrome (SARS) coronavirus in recovered SARS patients and healthy individuals

J Immunol. 2005 Jul 1;175(1):591-8. doi: 10.4049/jimmunol.175.1.591.


To date, the pathogenesis of severe acute respiratory syndrome (SARS) in humans is still not well understood. SARS coronavirus (SARS-CoV)-specific CTL responses, in particular their magnitude and duration of postinfection immunity, have not been extensively studied. In this study, we found that heat-inactivated SARS-CoV elicited recall CTL responses to newly identified spike protein-derived epitopes (SSp-1, S978, and S1202) in peripheral blood of all HLA-A*0201(+) recovered SARS patients over 1 year postinfection. Intriguingly, heat-inactivated SARS-CoV elicited recall-like CTL responses to SSp-1 but not to S978, S1202, or dominant epitopes from several other human viruses in 5 of 36 (13.8%) HLA-A*0201(+) healthy donors without any contact history with SARS-CoV. SSp-1-specific CTLs expanded from memory T cells of both recovered SARS patients, and the five exceptional healthy donors shared a differentiated effector CTL phenotype, CD45RA(+)CCR7(-)CD62L(-), and expressed CCR5 and CD44. However, compared with the high avidity of SSp-1-specific CTLs derived from memory T cells of recovered SARS patients, SSp-1-specific CTLs from the five exceptional healthy donors were of low avidity, as determined by their rapid tetramer dissociation kinetics and reduced cytotoxic reactivity, IFN-gamma secretion, and intracellular production of IFN-gamma, TNF-alpha, perforin, and granzyme A. These results indicate that SARS-CoV infection induces strong and long-lasting CTL-mediated immunity in surviving SARS patients, and that cross-reactive memory T cells to SARS-CoV may exist in the T cell repertoire of a small subset of healthy individuals and can be reactivated by SARS-CoV infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antigens, Viral
  • CD8-Positive T-Lymphocytes / immunology*
  • Case-Control Studies
  • Cytokines / metabolism
  • Cytotoxicity, Immunologic
  • Epitopes
  • Female
  • Humans
  • Immunologic Memory*
  • In Vitro Techniques
  • Male
  • Membrane Glycoproteins / immunology
  • Middle Aged
  • SARS Virus / immunology*
  • Severe Acute Respiratory Syndrome / immunology*
  • Spike Glycoprotein, Coronavirus
  • T-Lymphocytes, Cytotoxic / immunology
  • Viral Envelope Proteins / immunology


  • Antigens, Viral
  • Cytokines
  • Epitopes
  • Membrane Glycoproteins
  • Spike Glycoprotein, Coronavirus
  • Viral Envelope Proteins
  • spike glycoprotein, SARS-CoV