ABSTRACT
Monoclonal antibodies are an increasingly important tool for prophylaxis and treatment of acute virus infections like those with SARS-CoV-2. However, their use is largely limited by the length of development, yield and high production costs, as well as the need for continuous adaptation to newly emerging virus variants. Here we have used the filamentous fungus expression system Thermothelomyces heterothallica(C1), which has a natural high biosynthesis capacity for secretory enzymes and other proteins further enhanced by genetic engineering of the wild-type fungus, to produce a human monoclonal IgG1 antibody (HuMab 87G7) that neutralises SARS-CoV-2 variants of concern (VOCs) Alpha, Beta, Gamma, Delta, and Omicron. Like its mammalian cell produced equivalent, C1 produced HuMab 87G7 broadly neutralised SARS-CoV-2 VOCs in vitro and it also provided protection against Omicron and Delta VOCs in both hamsters and non-human primates, respectively. The only notable difference between the two versions was their N-linked glycosylation patterns detected by glyoproteomic analysis. Taken together, these findings demonstrate potential of the C1 expression system as a promising technology platform for the development of HuMabs in preventive and therapeutic medicine.
Subject(s)
Acute Disease , Severe Acute Respiratory SyndromeABSTRACT
A relevant number of coronavirus disease 2019 (COVID-19) survivors suffers from post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PASC). Current evidence suggests a dysregulated alveolar regeneration in COVID-19 as a possible explanation for respiratory PASC symptoms, a phenomenon which deserves further investigation in a suitable animal model. This study investigates morphologic and transcriptomic features of alveolar regeneration in SARS-CoV-2 infected Syrian golden hamsters. We demonstrate that CK8+ alveolar differentiation intermediate (ADI) cells accumulate following SARS-CoV-2-induced diffuse alveolar damage. A subset of ADI cells shows nuclear accumulation of p53 at 6- and 14-days post infection (dpi), indicating a prolonged block in the ADI state. Transcriptome data shows the expression of gene signatures driving ADI cell senescence, epithelial-mesenchymal transition, and angiogenesis. Moreover, we show that multipotent CK14+ airway basal cell progenitors migrate out of terminal bronchioles, aiding alveolar regeneration. At 14 dpi, persistence of ADI cells, peribronchiolar proliferates, M2-type macrophages, and sub-pleural fibrosis is observed, indicating incomplete alveolar restoration. The results demonstrate that the hamster model reliably phenocopies indicators of a dysregulated alveolar regeneration of COVID-19 patients. The study provides a suitable translational model for future research on the pathomechanims of PASC and testing of prophylactic and therapeutical approaches.
Subject(s)
Coronavirus Infections , Fibrosis , Adenocarcinoma, Bronchiolo-Alveolar , Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
The ongoing evolution of SARS-CoV-2 has resulted in the emergence of Omicron, which displays striking immune escape potential. Many of its mutations localize to the spike protein ACE2 receptor-binding domain, annulling the neutralizing activity of most therapeutic monoclonal antibodies. Here we describe a receptor-blocking human monoclonal antibody, 87G7, that retains ultrapotent neutralization against SARS-CoV-2 variants including the Alpha, Beta, Gamma, Delta and Omicron (BA.1/BA.2) Variants-of-Concern (VOCs). Structural analysis reveals that 87G7 targets a patch of hydrophobic residues in the ACE2-binding site that are highly conserved in SARS-CoV-2 variants, explaining its broad neutralization capacity. 87G7 protects mice and/or hamsters against challenge with all current SARS-CoV-2 VOCs. Our findings may aid the development of sustainable antibody-based strategies against COVID-19 that are more resilient to SARS-CoV-2 antigenic diversity.
Subject(s)
Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
Since its discovery in 2019, multiple variants of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have been identified worldwide. The present study investigates virus spread and associated pathology in the upper and lower respiratory tracts in the early phase of SARS-CoV-2 Omicron infection in the Syrian golden hamster (Mesocricetus auratus) in comparison to previous identified variants of concern (VOCs). Syrian golden hamsters were infected intranasally with SARS-CoV-2 614G or with VOCs Gamma, Delta and Omicron. Pathological changes both in the upper and lower respiratory tract of VOC Omicron infected hamsters were milder than those caused by the other investigated strains. VOC Omicron infection caused only a mild rhinitis with mild involvement of the olfactory epithelium and minimal lesions in the lung with frequent sparing of the alveolar compartment. Similarly, viral antigen detection as well as infectious SARS-CoV-2 titers were lower in upper and lower respiratory tract of VOC Omicron infected hamsters. These findings demonstrate that the SARS-CoV-2 VOC Omicron variant has a decreased pathogenicity for both the upper and lower respiratory tract of Syrian golden hamsters.