Accelerating Antibody Discovery
Struggling to analyze and screen all the cells in your repertoire due to inefficient methods that rely on multiple instruments? Our single cell isolation technology combines selective cell screening, cell isolation, imaging, and sensitive single cell assays into a single platform designed to help you remove common bottlenecks and find rare variants faster.
Single cell analysis allows detection of those very rare antibodies or potential drugs with unique properties that are exceptionally hard to find. My experience in drug discovery since the early 1990s all points to the importance of diversity and Cyto-Mine® is well placed to explore this effectively. This technology takes screening capability, traditionally conducted through plate-based analysis, to a whole new level via continuous flow. There is huge potential for the instrument in discovering the rarest cells and best antibodies.
Dr Tristan Vaughan, Vice-President of Research and Development, Antibody Discovery and Protein Engineering, AstraZeneca
How Does Cyto-Mine® Accelerate Antibody Discovery?
The core assay that enables the detection of cells secreting proteins of interest is based around a technique called FRET (Fӧster Resonance Energy Transfer). Two molecular probes, that bind to different sites on the protein that you are trying to measure, are each labelled with an appropriate fluorophore. In the case of secreted antibody detection, the two molecular probes bind to either the Fc region on the target antibody or the antigen-specific region. As these regions are physically close, laser excitation of the donor fluorophore results in resonance energy to excite the acceptor probe. The resulting emission is detected by Cyto-Mine® and used to identify picodroplets containing the secreted antibody of interest. This assay format can be adapted and tailored to many different antigen targets providing a flexible assay format for the detection of specific targets.
Cyto-Mine® provides a high-throughput, fully integrated platform for accelerating antibody discovery. Using Cyto-Mine®, you can analyze up to 40 million cells (B-cells) in a two-day process (each picodroplet will contain approximately 30 cells). Or you can analyze up to 200,000 cells individually (B-cells or hybridomas) for Antigen (Ag)-specific antibody-secreting cells, isolate those cells of interest and dispense directly into the wells of a microtiter plate, in a single day.
Highly sensitive and specific assays
Leveraging our proprietary picodroplet technology and assay design flexibility, Cyto-Mine® provides a powerful tool to measure antibody secretion at a single cell level accurately. This highly sensitive method enables you to assay and select antigen-specific antibody-secreting cells in ways that conventional methods cannot. We offer flexible assay design, including the ability to develop tailored assays to suit your specific application needs including:
- Antigen-specific assays: Hybridoma fusion screen, B cell screening
- IgG secretion assay: Productivity screen
- Customized assays: Functional, Post-translational modifications, Reporter assays
Improved efficiency to screen hybridomas
To demonstrate how effective picodroplets are for screening hybridomas and isolating antibodies, we measured monoclonal antibody secretion by single cell hybridomas in picodroplets. The cells were incubated at 37°C over three hours and antibody secretion measured using a FRET-based ELISA (i.e. a homogenous assay). As can be seen in the graph, cells grown in picodroplets performed as well as cells grown in bulk culture over the period analyzed. This allows users to screen a vast number of hybridomas in a short time frame with minimal use of reagents, all without compromising on assay performance.
Picodroplets provide a uniquely protective environment to support cell viability and integrity during incubation and to shield cells against shear stress as they flow through the microfluidic channels. Additionally, the biocompatible surfactants used in picodroplet formation promote high levels of gas exchange and oxygen availability to improve cell outgrowth.
Improved cell viability for B-cell analysis
Cyto-Mine® ensures that the viability of primary B-cells remains high when encapsulated and analyzed in picodroplets. Cells incubated in 450 pL picodroplets remain viable over the four-hour incubation period that is standard for most of the workflows carried out using our systems. This viability is crucial in primary B-cell analysis, as the cells need to be happy and healthy after screening and sorting, so they are ready for use in downstream applications.
Cyto-Mine® incorporates multiple machines into one automated and easy-to-use platform. That simplifies the screening, sorting, isolation and verification of antigen-specific clones into a one-day workflow. This fully integrated platform eliminates the need for multiple instruments to improve productivity and reduce screening costs by over 10-fold compared to conventional techniques.
Hybridoma Screening Workflow
Unlike clone pickers, which are only able to screen 10,000 hybridomas in 3 to 6 weeks, Cyto-Mine® can screen hundreds of thousands of single hybridoma cells one day. The unique speed of Cyto-Mine® allows you to screen and selectively isolate rare hybridomas that secret the Ag-specific antibodies of interest from a whole hybridoma population.
Detecting Rare Antigen-specific Antibody-secreting Cells in Large Populations
An antigen specific FRET assay was used to demonstrate Cyto-Mine®’s capability of detecting rare positive hits from a large cell population. As a proof of concept, a hybridoma cell line secreting antigen specific IgG was spike into a non-specific hybridoma cell line, resulting in model samples consisting A) 5%, B) 1% and C) 0.1 % of antigen-specific cells. These model cell samples were encapsulated in picodroplets together with the antigen-specific FRET assay, incubated for 1 hour, then sorted based on fluorescent signal. From all three model samples, specific FRET-positive populations were detected where proportion of detected positives matched with the expected positive rate.
Primary B Cell Analysis Workflow
Cyto-Mine® is designed to overcome bottlenecks in traditional screening methods, such as sensitivity, accurate quantification of secreted antibodies and workflow efficiency. Our approach lets you analyze whole B-cell repertoires in a single run, then isolate and dispense all positively secreting B-cells by total IgG production or antigen-specific assays. Once these cells have been identified, isolated and dispensed, they can be subject to further downstream processing.
To screen 40,000,000 B-cells, you need to adopt a two-stage approach. The first run (Day 1) you will screen every picodroplet for IgG secretion and collect ‘hit’ picodroplets – picodroplets that contain at least one B-cell that is secreting an IgG – as a combined pool. Once this pool of picodroplets has been collected, they are ‘broken’ open to release the cells into a recovery medium and incubated overnight. The second day, the remaining cells are re-encapsulated with Ag-specific assay reagents on the Cyto-Mine®. Each picodroplet will contain a single B-cell. You then select the hit picodroplets again and dispense each hit cell directly into a microtitere plate. You have then found, selected and cloned all Ag-specific antibody-secreting cells from the total B-cell repertoire. The whole workflow is completed in two days!
Application Note: High-Throughput Method for Mining B Cell Repertoires and Hybridoma Fusions to Find Rare Cells Secreting Antigen-Specific Antibodies
Discover how Cyto-Mine® screens complex populations of primary B cells and hybridomas using a miniaturised, high-throughput, homogeneous secretion assay to analyse and identify antigen-specific clones for subsequent sorting and collection to microplates.