Haley L. Dugan
Profile Url: haley-l--dugan
Researcher at University of Chicago
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently causing a global pandemic. The antigen specificity and kinetics of the antibody response mounted against this novel virus are not understood in detail. Here, we report that subjects with a more severe SARS-CoV-2 infection exhibit a larger antibody response against the spike and nucleocapsid protein and epitope spreading to subdominant viral antigens, such as open reading frame 8 and non-structural proteins. Subjects with a greater antibody response mounted a larger memory B cell response against the spike, but not the nucleocapsid protein. Additionally, we revealed that antibodies against the spike are still capable of binding the D614G spike mutant and cross-react with the SARS-CoV-1 receptor binding domain. Together, this study reveals that subjects with a more severe SARS-CoV-2 infection exhibit a greater overall antibody response to the spike and nucleocapsid protein and a larger memory B cell response against the spike. ### Competing Interest Statement The authors have declared no competing interest.
Artificial mutagenesis and chimeric/mosaic protein engineering have laid the foundation for antigenic characterization and universal vaccine design for influenza viruses. However, many methods used for influenza research and vaccine development require sequence editing and protein expression, limiting their applicability and the progress of related research to specialists. Rapid tools allowing even novice influenza researchers to properly analyze and visualize influenza protein sequences with accurate nomenclature are needed to expand the research field. To address this need, we developed Librator, a system for analyzing and designing protein sequences of influenza virus Hemagglutinin (HA) and Neuraminidase (NA). With the graphical user interface (GUI) and built-in sequence editing functions of Librator, biologists can easily analyze influenza sequences and phylogenies, automatically port sequences to visualize structures, then readily mutate target residues and design sequences for antigen probes and chimeric/mosaic proteins efficiently and accurately. This system provides optimized fragment design for Gibson Assembly of HA and NA expression constructs based on peptide conservation of all historical HA and NA sequences, ensuring fragments are reusable and compatible, allowing for significant reagent savings. Use of Librator will significantly facilitate influenza research and vaccine antigen design.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections can cause Coronavirus Disease 2019 (COVID-19), which manifests with a range of severities from mild illness to life threatening pneumonia and multi-organ failure. Severe COVID-19 is characterized by an inflammatory signature including high levels of inflammatory cytokines, alveolar inflammatory infiltrates and vascular microthrombi. Here we show that severe COVID-19 patients produced a unique serologic signature, including increased IgG1 with afucosylated Fc glycans. This Fc modification on SARS-CoV-2 IgGs enhanced interactions with the activating Fc{gamma}R, Fc{gamma}RIIIa; when incorporated into immune complexes, Fc afucosylation enhanced production of inflammatory cytokines by monocytes, including IL-6 and TNF. These results show that disease severity in COVID-19 correlates with the presence of afucosylated IgG1, a pro-inflammatory IgG Fc modification.
Background: Convalescent plasma therapy for COVID-19 relies on the transfer of anti-viral antibody from donors to recipients via plasma transfusion. The relationship between clinical characteristics and antibody response to COVID-19 is not well defined. We investigated predictors of convalescent antibody production and quantified recipient antibody response in a convalescent plasma therapy clinical trial. Methods: Multivariable analysis of clinical and serological parameters in 103 confirmed COVID-19 convalescent plasma donors 28 days or more following symptom resolution was performed. Mixed effects regression models with piecewise linear trends were used to characterize serial antibody responses in 10 convalescent plasma recipients with severe COVID-19. Results: Mean symptom duration of plasma donors was 11.9 and 7.8% (8/103) had been hospitalized. Antibody titers ranged from 0 to 1:3,892 (anti-receptor binding domain (RBD)) and 0 to 1:3,289 (anti-spike). Multivariable analysis demonstrated that higher anti-RBD and anti-spike titer were associated with increased age, hospitalization for COVID-19, fever, and absence of myalgia (all p<0.05). Fatigue was significantly associated with anti-RBD (p=0.03) but not anti-spike antibody titer (p=0.11). In pairwise comparison among ABO blood types, AB donors had higher anti-RBD titer than O negative donors (p=0.048) and higher anti-spike titer than O negative (p=0.015) or O positive (p=0.037) donors. Eight of the ten recipients were discharged, one remains on ECMO and one died on ECMO. No toxicity was associated with plasma transfusion. After excluding two ECMO patients and adjusting for donor antibody titer, recipient anti-RBD antibody titer increased on average 31% per day during the first three days post-transfusion (p=0.01) and anti-spike antibody titer by 40.3% (p=0.02). Conclusion: Advanced age, fever, absence of myalgia, fatigue, blood type and hospitalization were associated with higher convalescent antibody titer to COVID-19. Despite variability in donor titer, 80% of convalescent plasma recipients showed significant increase in antibody levels post-transfusion. A more complete understanding of the dose-response effect of plasma transfusion among COVID-19 patients is needed to determine the clinical efficacy of this therapy.
Broadly neutralizing antibodies against influenza virus hemagglutinin (HA) have the potential to provide universal protection against influenza virus infections. Here, we report a distinct class of broadly neutralizing antibodies targeting an epitope toward the bottom of the HA stalk domain where HA is "anchored" to the viral membrane. Antibodies targeting this membrane-proximal anchor epitope utilized a highly restricted repertoire, which encode for two conserved motifs responsible for HA binding. Anchor targeting B cells were common in the human memory B cell repertoire across subjects, indicating pre-existing immunity against this epitope. Antibodies against the anchor epitope at both the serological and monoclonal antibody levels were potently induced in humans by a chimeric HA vaccine, a potential universal influenza virus vaccine. Altogether, this study reveals an underappreciated class of broadly neutralizing antibodies against H1-expressing viruses that can be robustly recalled by a candidate universal influenza virus vaccine.