Antibody Screening Methods Accelerating Lead Development

Antibody screening is a crucial step in selecting the most promising antibodies for research, diagnostic, and clinical applications. This article explores some of the methods being used to identify and characterize antibodies with desired properties, which can accelerate lead development.

Desired antibody attributes vary with the intended application

When developing antibodies, identifying candidates with high specificity for the target antigen is critically important. However, depending on how the antibody will be used, many other properties should also be considered. For research use only (RUO) antibodies, key attributes include reproducibility across batches, versatility for different assays, and stability under various experimental conditions. For clinical antibodies, the criteria are much stricter.

“Compared to research and diagnostic antibodies, clinical antibodies face significant added constraints,” reports Claes Gustafsson, Co-Founder of ATUM. “These include purity, high solubility, and stability, as well as low immunogenicity risks, controlled Fc receptor binding, and predictable pharmacokinetics influenced by glycosylation or non-specific binding. Optimizing for developability also involves minimizing self-association to prevent viscosity issues in high-concentration formulations and minimizing charge heterogeneity to ensure consistent efficacy and safety. This is in addition to cell-based assays that mimic the clinical efficacy of the antibody. The exact developability issues for each antibody will of course vary depending on the clinical application and commercial context.”

Desired properties of antibodies

• Research use only (RUO)

• High specificity and affinity
• Minimal cross-reactivity
• Stability under various experimental conditions and for long-term studies
• Reproducibility across batches and experiments
• Versatility for different assay formats

• Clinical applications

• High specificity with required affinity
• Low immunogenicity and minimal off-target effects
• Stability in physiological conditions (resistance to thermal, chemical, or proteolytic degradation)
• High purity (free from contaminants and ensuring clean co-purification of all chains)
• High solubility (to reduce aggregation and enhance formulation options)
• Extended serum half-life (for sustained efficacy)
• Balanced isoelectric points (pI)
• Controlled Fc receptor binding
• Predictable pharmacokinetics
• Scalability and manufacturability for clinical-grade production

Technologies for identifying and characterizing potential antibody candidates

To accelerate the discovery of lead antibody candidates, advanced technologies have been developed, including:

• Function-first, live single-cell screening with the Beacon^® Optofluidic Platform

The Beacon Optofluidic Platform integrates rapid single-cell screening, deep functional characterization, and direct sequence recovery, enabling researchers to efficiently isolate high-value antibody-secreting B cells. Unlike traditional methods, Beacon directly screens primary B cells from immunized animals or human donors—eliminating the need for cell immortalization—and accommodates B cells from diverse species, organ sources, and subsets. This significantly enhances the probability of discovering rare, high-quality antibodies, even against challenging targets.

“The Beacon platform performs up to 16 sequential functional assays—including antigen specificity, affinity, cross-reactivity, ligand blocking, and cell-based functions—on every individual B cell,” explains Vikram Devgan, Ph.D., VP of Global Marketing at Bruker Cellular Analysis. “This is made possible by a combination of NanoPen^® chambers—100,000x smaller than traditional microwells—and advanced microfluidics, which sustain live single B cell cultures and enable rapid fluidic exchange. As a result, up to 80,000 B cells can be screened per run, generating over 1 million data points to drive confident lead selection.”

• Comprehensive in silico prediction from ATUM

Based on its production of more than 100,000 antibodies, ATUM has established a rigorous in silico prediction package to instantly identify sequence liabilities, calculate N-glycans, and evaluate parameters such as antibody size and pI. “No antibody is ever picture perfect, but instead a compromise between multiple competing constraints,” says Gustafsson. “Our in silico report not only calculates different measures, but it also shows where a specific measure for an antibody falls across the distribution of all antibodies. This helps the user to balance the quality needs.”

To ensure analytic measures suit the type of antibody and its clinical application, ATUM offers a diverse range of functional and biophysical assays. “Recent years have seen growing demand for liquid formulations for self-administered subcutaneous administration,” reports Gustafsson. “An increasingly requested assay is AC-SINS (Affinity Capture - Self Interaction Nanoparticle Spectroscopy), which quantifies antibody self-association using gold nanoparticles. Our AC-SINS data correlate well with other antibody self-aggregation tests such as Dynamic Light Scattering (DLS), and with formulation tolerance, thus helping guide the development of these types of products.”

• Label-free, real-time kinetics with Octet^® biolayer interferometry (BLI)

Octet^® BLI is a technique offering real-time kinetic data, high-throughput screening, and label-free detection that preserves native antibody-antigen interactions. It also supports direct measurement in crude samples, making it valuable for early-stage discovery techniques like phage display. “Real-time kinetic data allows scientists to make decisions based not only on the affinity of the antibody-antigen interaction but also on how quickly or slowly the target complex is formed and its subsequent lifetime —a resolution that traditional end-point methodologies such as ELISAs cannot provide,” says Nilshad Salim, Ph.D., Product Manager, Label-Free Technologies at Sartorius.

“In terms of antibody characterization, Octet BLI is an indispensable tool, capable of analyzing multiple samples simultaneously to significantly speed up the characterization process. Its versatility allows applications such as affinity measurement, epitope binning, and quantitation of the active analyte, all with minimal sample requirements. Other critical quality attributes (CQAs), such as sample purity, process residual analysis, or glycosylation profiling, can also be accomplished.”

• Cyto-Mine^® Chroma high-throughput single-cell analysis and isolation

Cyto-Mine Chroma is a platform based on microfluidic picodroplet technology, which enables high-throughput screening of plasma cells, activated B cells, and mammalian display libraries. “By encapsulating single cells in picodroplets containing growth media, each of which serves as a bioreactor that can trap secreted antibody molecules, Cyto-Mine Chroma allows for screening millions of antibody-producing cells in a day,” explains Xin Liu, Ph.D., Senior Global Product Manager at Sphere Bio. “This significantly improves efficiency, diversity, and scalability in candidate selection compared with traditional antibody discovery workflows.”

Key features of Cyto-Mine Chroma include its flexibility in assay implementation, which enables screening of antibody productivity, binding specificity, and functional activity at the single-cell level. “Cyto-Mine Chroma also includes built-in imaging and image analysis software, which provides documented proof of monoclonality for each selected cell,” says Liu. “Furthermore, with four lasers as excitation sources and four detection channels, Cyto-Mine Chroma enables multiplexed assays, allowing for in-depth repertoire mining to identify antibodies with the desired function and properties. In combination, these attributes make Cyto-Mine a powerful and integrated solution for early antibody discovery.”

Future perspectives

Technologies that can streamline antibody development are in high demand. “As antibody research evolves, leveraging advanced screening and characterization methods will accelerate drug discovery and improve therapeutic outcomes,” says Salim. “Technologies like Octet BLI combined with AI and automation will play a pivotal role in in shaping the future of therapeutics and diagnostics.”

“Ultimately, technologies that eliminate low-quality candidates early reduce costs and shorten development timelines,” adds Devgan. “The Beacon platform doesn’t just streamline antibody discovery—it maximizes campaign success by ensuring only the most promising candidates move forward, whether for therapeutics, diagnostics, or research applications.”