A Hybrid Soluble gp130/Spike-Nanobody Fusion Protein Simultaneously Blocks Interleukin-6 trans -Signaling and Cellular Infection with SARS-CoV-2

• Published in: Journal of virology Vol. 96; no. 4; p. e0162221
• Main Authors: Ettich, Julia, Werner, Julia, Weitz, Hendrik T, Mueller, Eva, Schwarzer, Roland, Lang, Philipp A, Scheller, Jürgen, Moll, Jens M
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 23.02.2022
• Subjects: Animals; Biotechnology; Cellular Response to Infection; Chlorocebus aethiops; COVID-19 - drug therapy; COVID-19 - metabolism; Cytokine Receptor gp130 - chemistry; Cytokine Receptor gp130 - genetics; Humans; Interleukin-6 - metabolism; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - pharmacology; Signal Transduction - drug effects; Single-Domain Antibodies - chemistry; Single-Domain Antibodies - genetics; Single-Domain Antibodies - pharmacology; Spike Glycoprotein, Coronavirus - metabolism; Vero Cells; SARS-CoV-2; trans-signaling; IL-6; sgp130
• ISSN: 0022-538X; 1098-5514
• DOI: 10.1128/jvi.01622-21

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can induce mild to life-threatening symptoms. Especially individuals over 60 years of age or with underlying comorbidities, including heart or lung disease and diabetes, or immunocompromised patients are at a higher risk. Fatal multiorgan damage in coronavirus disease 2019 (COVID-19) patients can be attributed to an interleukin-6 (IL-6)-dominated cytokine storm. Consequently, IL-6 receptor (IL-6R) monoclonal antibody treatment for severe COVID-19 cases has been approved for therapy. High concentrations of soluble IL-6R (sIL-6R) were found in COVID-19 intensive care unit patients, suggesting the involvement of IL-6 -signaling in disease pathology. Here, in analogy to bispecific antibodies (bsAbs), we developed the first bispecific IL-6 -signaling inhibitor, c19s130Fc, which blocks viral infection and IL-6 -signaling. c19s130Fc is a designer protein of the IL-6 -signaling inhibitor cs130 fused to a single-domain nanobody directed against the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. c19s130Fc binds with high affinity to IL-6:sIL-6R complexes as well as the spike protein of SARS-CoV-2, as shown by surface plasmon resonance. Using cell-based assays, we demonstrate that c19s130Fc blocks IL-6 -signaling-induced proliferation and STAT3 phosphorylation in Ba/F3-gp130 cells as well as SARS-CoV-2 infection and STAT3 phosphorylation in Vero cells. Taken together, c19s130Fc represents a new class of bispecific inhibitors consisting of a soluble cytokine receptor fused to antiviral nanobodies and principally demonstrates the multifunctionalization of signaling inhibitors. The availability of effective SARS-CoV-2 vaccines is a large step forward in managing the pandemic situation. In addition, therapeutic options, e.g., monoclonal antibodies to prevent viral cell entry and anti-inflammatory therapies, including glucocorticoid treatment, are currently developed or in clinical use to treat already infected patients. Here, we report a novel dual-specificity inhibitor to simultaneously target SARS-CoV-2 infection and virus-induced hyperinflammation. This was achieved by fusing an inhibitor of viral cell entry with a molecule blocking IL-6, a key mediator of SARS-CoV-2-induced hyperinflammation. Through this dual action, this molecule may have the potential to efficiently ameliorate symptoms of COVID-19 in infected individuals.