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1.
JCI Insight ; 7(12)2022 06 22.
Article in English | MEDLINE | ID: covidwho-1902171

ABSTRACT

Immunosuppressed patients with inflammatory bowel disease (IBD) generate lower amounts of SARS-CoV-2 spike antibodies after mRNA vaccination than healthy controls. We assessed SARS-CoV-2 spike S1 receptor binding domain-specific (S1-RBD-specific) B lymphocytes to identify the underlying cellular defects. Patients with IBD produced fewer anti-S1-RBD antibody-secreting B cells than controls after the first mRNA vaccination and lower amounts of total and neutralizing antibodies after the second. S1-RBD-specific memory B cells were generated to the same degree in IBD and control groups and were numerically stable for 5 months. However, the memory B cells in patients with IBD had a lower S1-RBD-binding capacity than those in controls, which is indicative of a defect in antibody affinity maturation. Administration of a third shot to patients with IBD elevated serum antibodies and generated memory B cells with a normal antigen-binding capacity. These results show that patients with IBD have defects in the formation of antibody-secreting B cells and affinity-matured memory B cells that are corrected by a third vaccination.


Subject(s)
COVID-19 , Inflammatory Bowel Diseases , Antibodies, Viral , COVID-19/prevention & control , Humans , Memory B Cells , RNA, Messenger , SARS-CoV-2 , Spike Glycoprotein, Coronavirus
2.
Nat Commun ; 12(1): 7325, 2021 12 16.
Article in English | MEDLINE | ID: covidwho-1585854

ABSTRACT

Single-domain Variable New Antigen Receptors (VNARs) from the immune system of sharks are the smallest naturally occurring binding domains found in nature. Possessing flexible paratopes that can recognize protein motifs inaccessible to classical antibodies, VNARs have yet to be exploited for the development of SARS-CoV-2 therapeutics. Here, we detail the identification of a series of VNARs from a VNAR phage display library screened against the SARS-CoV-2 receptor binding domain (RBD). The ability of the VNARs to neutralize pseudotype and authentic live SARS-CoV-2 virus rivalled or exceeded that of full-length immunoglobulins and other single-domain antibodies. Crystallographic analysis of two VNARs found that they recognized separate epitopes on the RBD and had distinctly different mechanisms of virus neutralization unique to VNARs. Structural and biochemical data suggest that VNARs would be effective therapeutic agents against emerging SARS-CoV-2 mutants, including the Delta variant, and coronaviruses across multiple phylogenetic lineages. This study highlights the utility of VNARs as effective therapeutics against coronaviruses and may serve as a critical milestone for nearing a paradigm shift of the greater biologic landscape.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Crystallography, X-Ray , Receptors, Antigen/chemistry , Receptors, Antigen/immunology , Sharks/immunology , Angiotensin-Converting Enzyme 2 , Animals , COVID-19 , Epitopes , Mutation , Phylogeny , Protein Binding , SARS-CoV-2 , Sequence Alignment , Single-Domain Antibodies , Spike Glycoprotein, Coronavirus/immunology
3.
Transfusion ; 61(1): 17-23, 2021 01.
Article in English | MEDLINE | ID: covidwho-1388418

ABSTRACT

BACKGROUND: The transfer of passive immunity with convalescent plasma is a promising strategy for treatment and prevention of COVID-19, but donors with a history of nonsevere disease are serologically heterogenous. The relationship between SARS-Cov-2 antigen-binding activity and neutralization activity in this population of donors has not been defined. STUDY DESIGN AND METHODS: Convalescent plasma units from 47 individuals with a history of nonsevere COVID-19 were assessed for antigen-binding activity of using three clinical diagnostic serology assays (Beckman, DiaSorin, and Roche) with different SARS-CoV-2 targets. These results were compared with functional neutralization activity using a fluorescent reporter strain of SARS-CoV-2 in a microwell assay. RESULTS: Positive correlations of varying strength (Spearman r = 0.37-0.52) between antigen binding and viral neutralization were identified. Donors age 48 to 75 years had the highest neutralization activity. Units in the highest tertile of binding activity for each assay were enriched (75%-82%) for those with the highest levels of neutralization. CONCLUSION: The strength of the relationship between antigen-binding activity and neutralization varies depending on the clinical assay used. Units in the highest tertile of binding activity for each assay are predominantly comprised of those with the greatest neutralization activity.


Subject(s)
SARS-CoV-2/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , COVID-19/therapy , COVID-19 Serological Testing , Enzyme-Linked Immunosorbent Assay , Humans , Immunization, Passive , Immunoglobulin G/immunology , SARS-CoV-2/pathogenicity , Serologic Tests
4.
J Immunol ; 207(2): 376-379, 2021 07 15.
Article in English | MEDLINE | ID: covidwho-1341797

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing Abs target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with a human adenovirus type 5 vector expressing the SARS-CoV-2 nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and K18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral Ags in SARS-CoV-2 vaccines, even if they are not a target of neutralizing Abs, to broaden epitope coverage and immune effector mechanisms.


Subject(s)
Antibodies, Viral/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19/immunology , Cell Line , Chlorocebus aethiops , Cricetinae , Female , Immunologic Memory/immunology , Lymphocyte Count , Male , Mice , Mice, Inbred C57BL , Phosphoproteins/immunology , Vaccination , Vero Cells
5.
J Immunol ; 207(2): 376-379, 2021 07 15.
Article in English | MEDLINE | ID: covidwho-1291114

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the COVID-19 pandemic. Neutralizing Abs target the receptor binding domain of the spike (S) protein, a focus of successful vaccine efforts. Concerns have arisen that S-specific vaccine immunity may fail to neutralize emerging variants. We show that vaccination with a human adenovirus type 5 vector expressing the SARS-CoV-2 nucleocapsid (N) protein can establish protective immunity, defined by reduced weight loss and viral load, in both Syrian hamsters and K18-hACE2 mice. Challenge of vaccinated mice was associated with rapid N-specific T cell recall responses in the respiratory mucosa. This study supports the rationale for including additional viral Ags in SARS-CoV-2 vaccines, even if they are not a target of neutralizing Abs, to broaden epitope coverage and immune effector mechanisms.


Subject(s)
Antibodies, Viral/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Neutralizing/immunology , COVID-19/immunology , Cell Line , Chlorocebus aethiops , Cricetinae , Female , Immunologic Memory/immunology , Lymphocyte Count , Male , Mice , Mice, Inbred C57BL , Phosphoproteins/immunology , Vaccination , Vero Cells
6.
J Infect Dis ; 223(8): 1339-1344, 2021 04 23.
Article in English | MEDLINE | ID: covidwho-1203701

ABSTRACT

Coronavirus disease 2019 (COVID-19) outcomes are linked to host immune responses and may be affected by antiviral therapy. We investigated antibody and cytokine responses in ACTT-1 study participants enrolled at our center. We studied serum specimens from 19 hospitalized adults with COVID-19 randomized to treatment with remdesivir or placebo. We assessed severe acute respiratory syndrome coronavirus 2 antibody responses and identified cytokine signatures, using hierarchical clustering. We identified no clear immunologic trends attributable to remdesivir treatment. Seven participants were initially seronegative at study enrollment, and all 4 deaths occurred in this group with more recent symptom onset. We identified 3 dominant cytokine signatures, demonstrating different disease trajectories.


Subject(s)
COVID-19/immunology , COVID-19/mortality , Immunity/immunology , Adenosine Monophosphate/analogs & derivatives , Adenosine Monophosphate/immunology , Adenosine Monophosphate/therapeutic use , Adult , Alanine/analogs & derivatives , Alanine/immunology , Alanine/therapeutic use , Antibodies, Viral/immunology , Antiviral Agents/immunology , Antiviral Agents/therapeutic use , COVID-19/drug therapy , COVID-19/virology , Cytokines/immunology , Female , Humans , Immunity/drug effects , Male , SARS-CoV-2/drug effects , SARS-CoV-2/immunology
7.
J Immunol ; 206(5): 931-935, 2021 03 01.
Article in English | MEDLINE | ID: covidwho-1028951

ABSTRACT

The magnitude of SARS-CoV-2-specific T cell responses correlates inversely with human disease severity, suggesting T cell involvement in primary control. Whereas many COVID-19 vaccines focus on establishing humoral immunity to viral spike protein, vaccine-elicited T cell immunity may bolster durable protection or cross-reactivity with viral variants. To better enable mechanistic and vaccination studies in mice, we identified a dominant CD8 T cell SARS-CoV-2 nucleoprotein epitope. Infection of human ACE2 transgenic mice with SARS-CoV-2 elicited robust responses to H2-Db/N219-227, and 40% of HLA-A*02+ COVID-19 PBMC samples isolated from hospitalized patients responded to this peptide in culture. In mice, i.m. prime-boost nucleoprotein vaccination with heterologous vectors favored systemic CD8 T cell responses, whereas intranasal boosting favored respiratory immunity. In contrast, a single i.v. immunization with recombinant adenovirus established robust CD8 T cell memory both systemically and in the respiratory mucosa.


Subject(s)
CD8-Positive T-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/prevention & control , Epitopes, T-Lymphocyte/immunology , SARS-CoV-2/immunology , Vaccination/methods , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/virology , Cells, Cultured , Coronavirus Nucleocapsid Proteins/immunology , Disease Models, Animal , Female , Genetic Vectors/immunology , HLA-A2 Antigen/immunology , Humans , Mice , Mice, Inbred C57BL , Mice, Transgenic
8.
bioRxiv ; 2020 Oct 19.
Article in English | MEDLINE | ID: covidwho-900763

ABSTRACT

The human airway epithelium is the initial site of SARS-CoV-2 infection. We used flow cytometry and single cell RNA-sequencing to understand how the heterogeneity of this diverse cell population contributes to elements of viral tropism and pathogenesis, antiviral immunity, and treatment response to remdesivir. We found that, while a variety of epithelial cell types are susceptible to infection, ciliated cells are the predominant cell target of SARS-CoV-2. The host protease TMPRSS2 was required for infection of these cells. Importantly, remdesivir treatment effectively inhibited viral replication across cell types, and blunted hyperinflammatory responses. Induction of interferon responses within infected cells was rare and there was significant heterogeneity in the antiviral gene signatures, varying with the burden of infection in each cell. We also found that heavily infected secretory cells expressed abundant IL-6, a potential mediator of COVID-19 pathogenesis.

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