Monoclonal antibodies neutralizing snake venom long & short chain three finger neurotoxins – Biophysics Workshops in South Africa

Monoclonal antibodies neutralizing snake venom long & short chain three finger neurotoxins

Topic

Date: 29 May 2024, 4:00 pm

Snakebite envenomation is a neglected tropical disease killing >135,000 people annually, predominantly in developing countries. Polyvalent antivenom is the only treatment, but it’s made through outdated technology. Monoclonal antibodies (mAbs) are the logical alternative for developing next-generation antivenom medicines.

Here, we isolated a pair of antivenom mAbs that broadly cross-neutralized long and short chain three finger neurotoxins from elapids. Stored peripheral blood mononuclear cells from a hyperimmunised horse were fluorescently stained with long and short chain neurotoxins from Dendroaspis polylepis to select toxin binding memory B cells. Antibody variable genes were identified by RT-PCR and Sanger sequencing, then cloned and expressed in expiCHO. Binding was measured by ELISA and neutralization was assessed with a TE671 cell assay.

Data for two crystal structures of Fab-Toxin complexes were collected at Diamond Light Source. Eight of the isolated antibodies bound snake neurotoxins and were 5%-14% mutated with human-like complementarity determining region 3 (CDR3) lengths.

Two somatically related mAbs (Eq4.Dp46-3A/-3D) completely neutralized long and short chain α-neurotoxins and broadly bound neurotoxins from Africa, Asia, and the Americas.

Crystal structures revealed an epitope between Fingers II and III that overlapped with the n-acetylcholine receptor (nAChR) F loop, explaining broad binding activity. Indels in heavy chain CDR1/2 were shown to determine monomeric or dimeric toxin binding, while the angle of approach completely occluded nAChR, providing a neutralization mechanism.

Our data is the first to describe broadly cross-reactive mAbs with the ability to neutralise long and short chain α-neurotoxins, identifying a lead candidate for next-generation antivenom in the developing world.

Speaker

Dr. Constantinos Kurt Wibmer

Venom & Vaccine Immunotherapeutics & Immunogens Protein Engineering Research, Wits University

About

He has since solved dozens of unique protein structures, characterising at atomic resolution the interactions between antibodies and their antigens. His SARS-CoV-2 research was the first to describe neutralization resistance by variants of concern (VoC) and was instrumental in reshaping the global vaccine response.

As an independent researcher Dr. Wibmer has focused his attention on developing novel antivenom biologics to treat snakebite envenoming. He developed a rapid, high-throughput pipeline for isolating native mAbs from horses (funded through The Royal Society and Wellcome, UK) which he is currently employing to discover novel lead candidates for next-generation mAb-based antivenom.

This mAb discovery is coupled with structural biology to design extremely broad, potent, and thermostable biologics for use in Africa and the developing world.


RSVP to this event

Sorry, this event was held on 29 May 2024, and registration is now closed.

About

The Biophysics in Africa Monthly Colloquium Series is a joint project of the African Light Source Foundation (AfLS), African Physical Society (AfPS), and the South African Institute of Physics (SAIP). SAIP is an adhering body of the International Union of Pure and Applied Biophysics (IUPAB). The colloquia are always on the last Wednesday of every month. In addition to participation by students and colleagues worldwide, we invite speakers from around the globe as well. For more information please feel free to contact us at colloquium.series@africanbiophysics.org