Antibody Discovery from a Chicken Polyclonal Mixture

Identify novel and functional antibodies directly from the polyclonal population in chicken with a de novo protein sequencing platform that is truly species agnostic.

Background

• Our client is a biotechnology company developing therapeutics that target cancer-specific carbohydrate antigens on the surface of tumour cells.
• Their diverse portfolio includes the generation and development of antibodies as immunotherapeutic agents against chemically synthesized carbohydrate antigens.

Challenge

• Working with a carbohydrate antigen of interest, they sought to generate monoclonal antibodies (mAbs) using a chicken (Gallus gallus domesticus) as the host species.
• Our clients faced uncertainty regarding the approach to antibody discovery and generation from chicken.
• More traditional approaches were not accessible as hybridoma generation was not a viable option and procedures for B cell screening were under-established for their host of interest.

Approach

• With the elimination of the more traditional methods, our clients had two viable technologies to focus their efforts on – the first being Rapid Novor’s REpAb® Polyclonal Antibody Sequencing Platform and the second being phage display.
• The outcome of their phage display campaign did not provide substantial leads for their antibody discovery efforts.
• Our clients approached their challenge with our REpAb® Polyclonal Antibody Sequencing Platform to initiate their antibody discovery and generation campaign.

*For a detailed description of polyclonal antibody sequencing and its applications, please refer to our reference materials on our website:

1. What is Polyclonal Antibody Sequencing?
2. Polyclonal Antibody Sequencing in Therapeutics Development Pipelines
3. Sequencing and Recombinant Expression of Goat Antibodies from a Polyclonal Mixture

Polyclonal Antibody Sequencing

• We met with our clients to outline the project and challenges, as well as discuss the REpAb® workflow, experimental requirements, timelines, and deliverables (Figure 1).
• A key part of the process is a direct consultation with our antibody discovery and mass spectrometry scientists to ensure alignment on the immunization, purification, and selection strategies, in order to produce optimal pAbs and useful resulting sequences.
• Once the project details were established, our logistics team ensured the safe arrival of the protein samples to initiate the REpAb® workflow. Upon completion of the REpAb® workflow, our clients received a Project Report outlining the protein sequence analyses.

*For more information on our REpAb® polyclonal antibody sequencing platform, please refer to our antibody discovery services page.

Figure 1. Species agnostic mAb discovery and characterization with REpAb®.

Outcome

• From the REpAb® polyclonal sequencing data, our clients discovered seven chicken mAb candidates that they then expressed recombinantly in-house.
• Out of the seven, six of the recombinant mAbs demonstrated optimal binding activity and were subsequently evaluated through their established cell-based assays. 
• One lead candidate was selected for downstream characterization and development for oncology therapeutic applications.
• In addition to identifying their lead candidate, our clients were able to develop a standard operating protocol for the purification of antibodies from a polyclonal mixture using a carbohydrate antigen – a process that was not established prior to their antibody discovery and generation efforts with Rapid Novor.

Key Takeaways

• REpAb® enables novel antibody discovery in a wide array of host species that otherwise would be inaccessible through traditional approaches by directly sequencing from the pool of native circulating antibodies.
• REpAb® successfully delivered the protein sequence data for 7 functional mAb candidates within 11 weeks for recombinant expression.
• By advancing their early discovery and development efforts with REpAb®, our client selected one lead candidate that demonstrated optimal therapeutic characteristics for pre-clinical development.