In this webinar, the featured speaker will discuss the rapid single B-cell cloning workflow that ChemPartner is using to discover rabbit antibodies. After a quick primer on the technical equipment they are using (Beacon), they will use an internal anti-CD28 (cluster of differentiation 28) rabbit antibody discovery case study to go over the individual steps of the rabbit workflow. Attendees will get an understanding of the Beacon system, the scientific background of the workflow, as well as an overview of the characteristics of the antibodies discovered in this case study.

CD28 is a costimulatory receptor for T-cell activation, and CD28 binding antibodies are in clinical development to block or promote T-cell activation. CD28-specific binding domains are also used in bi- or tri-specific antibody formats to generate T-cell-engaging antibodies. They set out to generate CD28-specific monoclonal antibodies (mAbs) from rabbits using a single B-cell cloning workflow on the Beacon system.

The Beacon system enables rapid antibody discovery using a function-first approach. Antibody-secreting cells (ASCs) are isolated from immunized animals and placed individually into nanowells (pens) of a Beacon chip. Due to the small size of the pens, the secreted antibody concentration reaches µg/ml levels within minutes, and the functional properties of the antibodies can be tested in sequential or multiplexed bead-based assays with a fluorescent readout. Typical assay duration is 30-60 minutes.

Rabbits were immunized with Chinese hamster ovary cells (CHOK1) stably transfected to carry human CD28 (hCD28) on their surface. Serum samples showed clear, yet low specific titers for hCD28. At the end of the immunization schedule, memory B-cells were isolated from blood using Ficoll separation and magnetic sorting. B-cells were cultured in an activation media, and cells were analyzed after four and five days of activation. During the activation period, the average cell size increased and cells proliferated roughly 15-fold until day five, with cell numbers unchanged after that. Flow cytometry showed a reduction of surface immunoglobulin G (IgG) and a clear increase of intracellular IgG during activation, consistent with a shift from B-cells to antibody-secreting cells.

On days four and five, a total of 32,716 activated B-cells were screened on Beacon, first for overall IgG secretion and then for IgG specific for hCD28. 14,889 cells secreted IgG (76%) and 108 cells secreted IgG specific to hCD28 (0.43% of IgG secretors). cDNA from identified hits was individually exported from the chip and submitted for heavy chain variable and light chain variable (VH/VL) sequencing. Based on sequence diversity, 23 antibodies were expressed and further characterized among others for affinity, receptor-blocking efficiency, T-cell activation potency and epitope binning.

In summary, the rabbit antibody discovery workflow on the Beacon enabled rapid screening of a large number of ASCs and identification of antigen-specific antibodies within four days of obtaining peripheral blood mononuclear cells (PBMCs) from immunized rabbits. cDNA generation and export happened on the day of the Beacon run, and cDNA amplification added another day to the workflow. The generation of constructs and expression of antibodies for further characterization was completed in less than one month. Overall, the method was robust and substantially reduced the hands-on time for rabbit antibody discovery, especially compared to the traditional hybridoma approach.

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Join this webinar to gain insights into ChemPartner’s innovative single B-cell cloning workflow and the groundbreaking Beacon system.

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Speaker

Andreas Loos, PhD, Director Biologics Discovery ChemPartner

Dr. Andreas Loos joined ChemPartner in 2021 as the Director of Biologics Discovery and he leads the biologics discovery team at ChemPartner’s South San Francisco site. The team was one of the first adopters of Berkeley Lights’ (BLI) Beacon® technology and has successfully used the platform since 2019 to conduct antibody discovery projects.

Prior to joining ChemPartner, Dr. Loos led an antibody discovery and assay development group at Aridis Pharmaceuticals. During his PhD and post-doctoral training in Gent (Belgium), Heidelberg (Germany) and Vienna (Austria), he studied production and post-translational modifications of biologics in plants.

Message Presenter

Who Should Attend?

This webinar will appeal to:

Biologics Discovery Scientists
Upper management that will decide on the discovery modality for an antibody program
Scientists interested in antibody discovery

What You Will Learn

Attendees will gain insights into:

Rabbit antibody discovery using the Beacon single-cell cloning process
The scientific background of the workflow
An overview of the characteristics of the antibodies discovered in this case study

Xtalks Partner

Shanghai ChemPartner

Shanghai ChemPartner, which includes ChemPartner and ChemPartner Biologics, is a CRO/CDMO offering a broad range of drug discovery, development, and manufacturing services.

ChemPartner is a science-based, technology-driven global CRO and CDMO offering a broad range of services including discovery chemistry, biology, pharmacology, DMPK, and exploratory toxicology as well as biologics discovery, CMC development, and manufacturing.

ChemPartner serves a diverse global client base as more and more pharmaceutical and biotech companies look for alliance partners to provide intellectual contributions and exceptional technical expertise. With locations and representatives in China, Europe, and the US, ChemPartner is uniquely positioned to be a true biopharmaceutical alliance partner.