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Hum Vaccin Immunother ; 18(5): 2048622, 2022 11 30.
Article in English | MEDLINE | ID: covidwho-1900981


We report a Human Immune System (HIS)-humanized mouse model ("DRAGA": HLA-A2.HLA-DR4.Rag1KO.IL-2 RγcKO.NOD) for COVID-19 research. DRAGA mice express transgenically HLA-class I and class-II molecules in the mouse thymus to promote human T cell development and human B cell Ig-class switching. When infused with human hematopoietic stem cells from cord blood reconstitute a functional human immune system, as well as human epi/endothelial cells in lung and upper respiratory airways expressing the human ACE2 receptor for SARS-CoV-2. The DRAGA mice were able to sustain SARS-CoV-2 infection for at least 25 days. Infected mice showed replicating virus in the lungs, deteriorating clinical condition, and human-like lung immunopathology including human lymphocyte infiltrates, microthrombi and pulmonary sequelae. Among the intra-alveolar and peri-bronchiolar lymphocyte infiltrates, human lung-resident (CD103+) CD8+ and CD4+ T cells were sequestered in epithelial (CD326+) lung niches and secreted granzyme B and perforin, suggesting anti-viral cytotoxic activity. Infected mice also mounted human IgG antibody responses to SARS-CoV-2 viral proteins. Hence, HIS-DRAGA mice showed unique advantages as a surrogate in vivo human model for studying SARS-CoV-2 immunopathological mechanisms and testing the safety and efficacy of candidate vaccines and therapeutics.

COVID-19 , HLA-DR4 Antigen , Animals , B-Lymphocytes , CD8-Positive T-Lymphocytes , Disease Models, Animal , Endothelial Cells , HLA-A2 Antigen/genetics , Humans , Mice , Mice, Inbred NOD , Mice, Transgenic , SARS-CoV-2
J Immunol ; 208(8): 1851-1856, 2022 04 15.
Article in English | MEDLINE | ID: covidwho-1855934


Unconventional HLA class I-restricted CD8+ T cell epitopes, longer than 10 aa, have been implicated to play a role in human immunity against viruses and cancer. T cell recognition of long peptides, centrally bulging from the HLA cleft, has been described previously. Alternatively, long peptides can contain a linear HLA-bound core peptide, with a N- or C-terminal peptide "tail" extending from the HLA peptide binding groove. The role of such a peptide "tail" in CD8+ T cell recognition remains unclear. In this study, we identified a 20mer peptide (FLPTPEELGLLGPPRPQVLA [FLP]) derived from the IL-27R subunit α gene restricted to HLA-A*02:01, for which we solved the crystal structure and demonstrated a long C-terminal "tail" extension. FLP-specific T cell clones demonstrated various recognition modes, some T cells recognized the FLP core peptide, while for other T cells the peptide tail was essential for recognition. These results demonstrate a crucial role for a C-terminal peptide tail in immunogenicity.

CD8-Positive T-Lymphocytes , Epitopes, T-Lymphocyte , HLA-A2 Antigen , CD8-Positive T-Lymphocytes/immunology , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , Genes, MHC Class I/genetics , Genes, MHC Class I/immunology , HLA-A Antigens/genetics , HLA-A Antigens/immunology , HLA-A2 Antigen/genetics , HLA-A2 Antigen/immunology , Humans , Peptides/genetics , Peptides/immunology
Cell Rep ; 37(13): 110167, 2021 12 28.
Article in English | MEDLINE | ID: covidwho-1596401


Cross-reactivity and direct killing of target cells remain underexplored for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific CD8+ T cells. Isolation of T cell receptors (TCRs) and overexpression in allogeneic cells allows for extensive T cell reactivity profiling. We identify SARS-CoV-2 RNA-dependent RNA polymerase (RdRp/NSP12) as highly conserved, likely due to its critical role in the virus life cycle. We perform single-cell TCRαß sequencing in human leukocyte antigen (HLA)-A∗02:01-restricted, RdRp-specific T cells from SARS-CoV-2-unexposed individuals. Human T cells expressing these TCRαß constructs kill target cell lines engineered to express full-length RdRp. Three TCR constructs recognize homologous epitopes from common cold coronaviruses, indicating CD8+ T cells can recognize evolutionarily diverse coronaviruses. Analysis of individual TCR clones may help define vaccine epitopes that can induce long-term immunity against SARS-CoV-2 and other coronaviruses.

Coronavirus RNA-Dependent RNA Polymerase/immunology , HLA-A2 Antigen/immunology , SARS-CoV-2/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , COVID-19/therapy , Cell Culture Techniques , Cross Reactions/immunology , Epitopes, T-Lymphocyte/immunology , HLA-A Antigens/immunology , HLA-A2 Antigen/genetics , Humans , Immunodominant Epitopes/immunology , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/metabolism , Leukocytes, Mononuclear/virology , RNA, Viral/genetics , Receptors, Antigen, T-Cell/immunology , Receptors, Antigen, T-Cell, alpha-beta/genetics , Receptors, Antigen, T-Cell, alpha-beta/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/immunology