Development of a human respiratory tract effector cell-mediated antiviral assay using blood and airway immune cells from individuals previously hospitalised with COVID-19
Abstract
Serum antibody–based neutralisation assays correlate with protective immunity to SARS-CoV-2, but cell-mediated in vitro cytotoxicity assays are lacking. Data on virus-specific respiratory tract immune responses in humans remain limited. Fifteen healthy participants who had previously been hospitalised with severe COVID-19 pneumonia were recruited. Peripheral blood mononuclear cells (PBMCs), bronchoalveolar lavage (BAL), and nasal lavage (NL) cells were phenotyped by flow cytometry. Cells were stimulated with SARS-CoV-2 S1 receptor-binding domain and nucleocapsid antigens using 15-mer peptide pools or recombinant proteins. Compartment-specific effector cell-mediated cytotoxicity of SARS-CoV-2 Delta pseudovirus by antigen-stimulated effector cells was assessed using a luciferase assay. Cytokine expression was measured by Luminex. Distinct immune profiles were observed across compartments. Macrophages and dendritic cells predominated in BAL, B cells in NL, and T cells and natural killer cells in PBMCs. BAL cells expressed significantly higher IL-1β, while PBMCs showed higher TNF-α, IL-2 and IL-6 expression. Responses did not differ between peptide and protein antigens. Antigen-stimulated PBMC, BAL, and NL cells demonstrated significantly greater pseudovirus cytotoxicity than unstimulated controls ( p < 0.05). This proof-of-concept study establishes a functional human T-cell–mediated SARS-CoV-2 cytotoxic assay in blood and alveolar compartments, providing a platform to study antiviral mucosal immunity relevant to future pandemics.
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BibTeX
@article{tomasicchio2026development,
title = {{Development of a human respiratory tract effector cell-mediated antiviral assay using blood and airway immune cells from individuals previously hospitalised with COVID-19}},
author = {Michele Tomasicchio and Lynn Semple and Rolanda Londt and Aliasgar Esmail and Lance Lucas and Suzette Oelofse and Anil Pooran and Shameem Jaumdally and Penny Moore and Keertan Dheda},
journal = {Scientific Reports},
year = {2026},
month = oct,
doi = {10.1038/s41598-026-74636-8},
url = {https://www.nature.com/articles/s41598-026-74636-8},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Development of a human respiratory tract effector cell-mediated antiviral assay using blood and airway immune cells from individuals previously hospitalised with COVID-19
AU - Michele Tomasicchio
AU - Lynn Semple
AU - Rolanda Londt
AU - Aliasgar Esmail
AU - Lance Lucas
AU - Suzette Oelofse
AU - Anil Pooran
AU - Shameem Jaumdally
AU - Penny Moore
AU - Keertan Dheda
PY - 2026
DA - 2026/10/17
JO - Scientific Reports
DO - 10.1038/s41598-026-74636-8
UR - https://www.nature.com/articles/s41598-026-74636-8
AB - Serum antibody–based neutralisation assays correlate with protective immunity to SARS-CoV-2, but cell-mediated in vitro cytotoxicity assays are lacking. Data on virus-specific respiratory tract immune responses in humans remain limited. Fifteen healthy participants who had previously been hospitalised with severe COVID-19 pneumonia were recruited. Peripheral blood mononuclear cells (PBMCs), bronchoalveolar lavage (BAL), and nasal lavage (NL) cells were phenotyped by flow cytometry. Cells were stimulated with SARS-CoV-2 S1 receptor-binding domain and nucleocapsid antigens using 15-mer peptide pools or recombinant proteins. Compartment-specific effector cell-mediated cytotoxicity of SARS-CoV-2 Delta pseudovirus by antigen-stimulated effector cells was assessed using a luciferase assay. Cytokine expression was measured by Luminex. Distinct immune profiles were observed across compartments. Macrophages and dendritic cells predominated in BAL, B cells in NL, and T cells and natural killer cells in PBMCs. BAL cells expressed significantly higher IL-1β, while PBMCs showed higher TNF-α, IL-2 and IL-6 expression. Responses did not differ between peptide and protein antigens. Antigen-stimulated PBMC, BAL, and NL cells demonstrated significantly greater pseudovirus cytotoxicity than unstimulated controls ( p < 0.05). This proof-of-concept study establishes a functional human T-cell–mediated SARS-CoV-2 cytotoxic assay in blood and alveolar compartments, providing a platform to study antiviral mucosal immunity relevant to future pandemics.
SN - 2045-2322
ER -