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1.
Nat Immunol ; 23(4): 543-555, 2022 04.
Article in English | MEDLINE | ID: covidwho-1738613

ABSTRACT

Despite the success of the BNT162b2 mRNA vaccine, the immunological mechanisms that underlie its efficacy are poorly understood. Here we analyzed the innate and adaptive responses to BNT162b2 in mice, and show that immunization stimulated potent antibody and antigen-specific T cell responses, as well as strikingly enhanced innate responses after secondary immunization, which was concurrent with enhanced serum interferon (IFN)-γ levels 1 d following secondary immunization. Notably, we found that natural killer cells and CD8+ T cells in the draining lymph nodes are the major producers of this circulating IFN-γ. Analysis of knockout mice revealed that induction of antibody and T cell responses to BNT162b2 was not dependent on signaling via Toll-like receptors 2, 3, 4, 5 and 7 nor inflammasome activation, nor the necroptosis or pyroptosis cell death pathways. Rather, the CD8+ T cell response induced by BNT162b2 was dependent on type I interferon-dependent MDA5 signaling. These results provide insights into the molecular mechanisms by which the BNT162b2 vaccine stimulates immune responses.


Subject(s)
CD8-Positive T-Lymphocytes , Vaccines , Adaptive Immunity , Animals , Humans , Immunity, Innate , Mice , Vaccines, Synthetic
2.
Nature ; 596(7872): 410-416, 2021 08.
Article in English | MEDLINE | ID: covidwho-1305364

ABSTRACT

The emergency use authorization of two mRNA vaccines in less than a year from the emergence of SARS-CoV-2 represents a landmark in vaccinology1,2. Yet, how mRNA vaccines stimulate the immune system to elicit protective immune responses is unknown. Here we used a systems vaccinology approach to comprehensively profile the innate and adaptive immune responses of 56 healthy volunteers who were vaccinated with the Pfizer-BioNTech mRNA vaccine (BNT162b2). Vaccination resulted in the robust production of neutralizing antibodies against the wild-type SARS-CoV-2 (derived from 2019-nCOV/USA_WA1/2020) and, to a lesser extent, the B.1.351 strain, as well as significant increases in antigen-specific polyfunctional CD4 and CD8 T cells after the second dose. Booster vaccination stimulated a notably enhanced innate immune response as compared to primary vaccination, evidenced by (1) a greater frequency of CD14+CD16+ inflammatory monocytes; (2) a higher concentration of plasma IFNγ; and (3) a transcriptional signature of innate antiviral immunity. Consistent with these observations, our single-cell transcriptomics analysis demonstrated an approximately 100-fold increase in the frequency of a myeloid cell cluster enriched in interferon-response transcription factors and reduced in AP-1 transcription factors, after secondary immunization. Finally, we identified distinct innate pathways associated with CD8 T cell and neutralizing antibody responses, and show that a monocyte-related signature correlates with the neutralizing antibody response against the B.1.351 variant. Collectively, these data provide insights into the immune responses induced by mRNA vaccination and demonstrate its capacity to prime the innate immune system to mount a more potent response after booster immunization.


Subject(s)
Adaptive Immunity , Antibodies, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Immunity, Innate , T-Lymphocytes/immunology , Vaccinology , Adult , Aged , Antibodies, Neutralizing/immunology , Autoantibodies/immunology , COVID-19 Vaccines/administration & dosage , Female , Humans , Immunization, Secondary , Male , Middle Aged , Single-Cell Analysis , Spike Glycoprotein, Coronavirus/immunology , Transcription, Genetic , Transcriptome/genetics , Young Adult
3.
Science ; 369(6508): 1210-1220, 2020 09 04.
Article in English | MEDLINE | ID: covidwho-704393

ABSTRACT

Coronavirus disease 2019 (COVID-19) represents a global crisis, yet major knowledge gaps remain about human immunity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We analyzed immune responses in 76 COVID-19 patients and 69 healthy individuals from Hong Kong and Atlanta, Georgia, United States. In the peripheral blood mononuclear cells (PBMCs) of COVID-19 patients, we observed reduced expression of human leukocyte antigen class DR (HLA-DR) and proinflammatory cytokines by myeloid cells as well as impaired mammalian target of rapamycin (mTOR) signaling and interferon-α (IFN-α) production by plasmacytoid dendritic cells. By contrast, we detected enhanced plasma levels of inflammatory mediators-including EN-RAGE, TNFSF14, and oncostatin M-which correlated with disease severity and increased bacterial products in plasma. Single-cell transcriptomics revealed a lack of type I IFNs, reduced HLA-DR in the myeloid cells of patients with severe COVID-19, and transient expression of IFN-stimulated genes. This was consistent with bulk PBMC transcriptomics and transient, low IFN-α levels in plasma during infection. These results reveal mechanisms and potential therapeutic targets for COVID-19.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Pneumonia, Viral/immunology , COVID-19 , Cytokines/blood , DNA, Bacterial/blood , Dendritic Cells/immunology , Dendritic Cells/metabolism , Female , Flow Cytometry , HLA-DR Antigens/analysis , Humans , Immunity , Immunity, Innate , Immunoglobulins/blood , Immunoglobulins/immunology , Inflammation Mediators/blood , Interferon Type I/metabolism , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/metabolism , Lipopolysaccharides/blood , Male , Myeloid Cells/immunology , Myeloid Cells/metabolism , Pandemics , SARS-CoV-2 , Signal Transduction , Single-Cell Analysis , Systems Biology , TOR Serine-Threonine Kinases/metabolism , Transcription, Genetic , Transcriptome
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