Biology subjects

Sedeyn, K.

Publications and source records attributed to Sedeyn, K..

5 recordsLinked to original sources

bioRxiv2026

The breadth of protection mediated by anti-N2 neuraminidase antibody responses relies on cross-reactive and not cross-inhibiting antibodies

Neuraminidase (NA) inhibition (NAI) titers have been identified as an independent correlation of protection against influenza. Few studies, however, have investigated the breadth of NA-based immune protection. Previously, we have reported that N2 NAs derived from human H3N2 viruses that circulated between 2009 and 2017 can be subdivided into four antigenic groups. Here, we immunized mice with recombinant soluble tetrameric NA from H3N2 strains representing those four antigenic groups or passively transferred N2 NA immune serum into naive mice to evaluate the breadth of protection against a heterologous HxN2 influenza virus challenge. We show that the breadth of protection goes beyond the breadth of NAI but still requires the presence of cross-reactive antibodies. Interestingly, in the absence of cross-reactive antibodies, the immunization of DBA/2J mice with heterologous NA was associated with an early onset of disease upon challenge with the reassortant HxNind11 or H2N2 A/Singapore/1/1957.

immunology↗

bioRxiv2024

Yeast-based production platform for potent and stable heavy chain-only antibodies

Monoclonal antibodies are the leading drug of the biopharmaceutical market because of their high specificity and tolerability, but the current CHO-based manufacturing platform remains expensive and time-consuming leading to limited accessibility, especially in the case of diseases with high incidence and pandemics. Therefore, there is an urgent need for an alternative production system. In this study, we present a rapid and cost-effective microbial platform for heavy chain-only antibodies (VHH-Fc) in the methylotrophic yeast Komagataella phaffii (aka Pichia pastoris). We demonstrate the potential of this platform using a simplified single-gene VHH-Fc fusion construct instead of the conventional monoclonal antibody format, as this is more easily expressed in Pichia pastoris. We demonstrate that the Pichia-produced VHH-Fc fusion construct is stable and that a Pichia-produced VHH-Fc directed against the SARS-CoV-2 spike has potent SARS-CoV-2 neutralizing activity in vitro and in vivo. We expect that this platform will pave the way towards faster and cheaper development and production of broadly neutralizing single-chain antibodies in yeast.

microbiology↗

bioRxiv2023

Ultrapotent SARS coronavirus-neutralizing single-domain antibodies that bind a conserved membrane proximal epitope of the spike

Currently circulating SARS-CoV-2 variants have gained complete or significant resistance to all SARS-CoV-2-neutralizing antibodies that have been used in the clinic. Such antibodies can prevent severe disease in SARS-CoV-2 exposed patients for whom vaccines may not provide optimal protection. Here, we describe single-domain antibodies (VHHs), also known as nanobodies, that can broadly neutralize SARS-CoV-2 with unusually high potency. Structural analysis revealed their binding to a unique, highly conserved, membrane proximal, quaternary epitope in the S2 subunit of the spike. Furthermore, a VHH-human IgG1 Fc fusion, efficiently expressed in Chinese hamster ovary cells as a stable antibody construct, protected hamsters against SARS-CoV-2 replication in a therapeutic setting when administered systemically at low dose. This VHH-based antibody represents a new candidate anti-COVID-19 biologic that targets the Achilles heel of the viral spike.

microbiology↗

bioRxiv2021

Ring Finger Protein 213 Assembles into a Sensor for ISGylated Proteins with Antimicrobial Activity

ISG15 is an interferon-stimulated, ubiquitin-like protein that can conjugate to substrate proteins (ISGylation) to counteract microbial infection, but the underlying mechanisms remain elusive. Here, we used a viral-like particle trapping technology to identify ISG15-binding proteins and discovered Ring Finger Protein 213 (RNF213) as an ISG15 interactor and cellular sensor of ISGylated proteins. RNF213 is a poorly-characterized, interferon-induced megaprotein that is frequently mutated in Moyamoya disease, a rare cerebrovascular disorder. We found that interferon induces ISGylation and oligomerization of RNF213 on lipid droplets, where it acts as a sensor for ISGylated proteins. We showed that RNF213 has broad antimicrobial activity in vitro and in vivo, counteracting infection with Listeria monocytogenes, herpes simplex virus 1 (HSV-1), human respiratory syncytial virus (RSV) and coxsackievirus B3 (CVB3), and we observed a striking co-localization of RNF213 with intracellular bacteria. Together, our findings provide novel molecular insights into the ISGylation pathway and reveal RNF213 as a key antimicrobial effector.

cell biology↗

bioRxiv2021

Drug development of an affinity enhanced, broadly neutralizing heavy chain only antibody that restricts SARS-CoV-2 in hamsters

We have identified camelid single-domain antibodies (VHHs) that cross-neutralize SARS-CoV-1 and -2, such as VHH72, which binds to a unique highly conserved epitope in the viral receptor-binding domain (RBD) that is difficult to access for human antibodies. Here, we establish a protein engineering path for how a stable, long-acting drug candidate can be generated out of such a VHH building block. When fused to human IgG1-Fc, the prototype VHH72 molecule prophylactically protects hamsters from SARS-CoV-2. In addition, we demonstrate that both systemic and intranasal application protects hACE-2-transgenic mice from SARS-CoV-2 induced lethal disease progression. To boost potency of the lead, we used structure-guided molecular modeling combined with rapid yeast-based Fc-fusion prototyping, resulting in the affinity-matured VHH72_S56A-Fc, with subnanomolar SARS-CoV-1 and -2 neutralizing potency. Upon humanization, VHH72_S56A was fused to a human IgG1 Fc with optimized manufacturing homogeneity and silenced effector functions for enhanced safety, and its stability as well as lack of off-target binding was extensively characterized. Therapeutic systemic administration of a low dose of VHH72_S56A-Fc antibodies strongly restricted replication of both original and D614G mutant variants of SARS-CoV-2 virus in hamsters, and minimized the development of lung damage. This work led to the selection of XVR011 for clinical development, a highly stable anti-COVID-19 biologic with excellent manufacturability. Additionally, we show that XVR011 is unaffected in its neutralizing capacity of currently rapidly spreading SARS-CoV-2 variants, and demonstrate its unique, wide scope of binding across the Sarbecovirus clades.

molecular biology↗