Summary
Antibody discovery is rarely one-size-fits-all. In this webinar, Dr. Kathryn Hastie of the La Jolla Institute for Immunology and Vincent Pai of Bruker Cellular Analysis explored how live single-cell functional biology can support single B cell discovery workflows across therapeutic development, vaccine development, diagnostics, and structural biology research. Through HERV-K and measles case studies, they showed how functional profiling of live single cells can help researchers identify, characterize, and prioritize antibodies based on more than binding alone.
Top Takeaways
1. Beyond Standard Screening: Expanding Antigen-Specificity Assessment with Functional Assays
Many antibody discovery workflows begin with a simple question: does the antibody bind the target? The challenge is that binding alone often does not predict whether a candidate will succeed in a therapeutic, diagnostic, or research application.
As Vincent Pai explained, the Beacon® Optofluidic platform enables multimodal, functional profiling of live single cells, including primary antibody-secreting B cells, allowing researchers to measure antibody secretion, antigen binding, internalization, cytokine secretion, cell-cell interactions, and other functional characteristics from the same individual live cell over time.
A key theme of the presentation was flexibility. Beyond traditional antigen-specificity assessment, the webinar highlighted several advanced assay approaches:
- pH-dependent binding assays
- Competition assays for cross-reactivity detection
- Screening against membrane-expressed antigens
- Relative binding affinity assessment
- Ligand-receptor blocking assays
One example demonstrated how researchers evaluated antibody binding under different pH conditions to identify pH-sensitive candidates. Another showcased competition assays used to detect cross-reactive antibodies against unlabeled small-molecule antibiotics, a challenging application for many conventional screening methods.
Definition: Antigen-specificity assessment is the process of determining whether an antibody recognizes its intended target and distinguishing desired binders from off-target interactions.
For researchers working in therapeutic development or diagnostics, these additional functional readouts can provide valuable screening information before investing in downstream characterization.
2. Single B Cell Discovery Enables Functional Profiling of Live Single Cells
The webinar reinforced a simple but important idea: studying the live single-cell biology layer provides information that may be difficult to capture through bulk or endpoint workflows.
According to Pai, the Beacon platform combines high-parameter, on-chip control with the ability to isolate, culture, assay, and recover individual live antibody-secreting cells. Researchers can then connect cellular function with downstream sequencing and molecular analysis.
This workflow is particularly useful in antibody discovery because researchers can evaluate:
- Antibody secretion
- Target specificity
- Relative affinity
- Functional activity
before selecting which cells to carry forward.
As Pai noted during the webinar, the goal is not simply to discover binders. It is to identify antibodies with characteristics that align with the intended end application, whether that application is therapeutic development, diagnostics, or structural biology research.
3. From Discovery to Structure: How Antibody Discovery Supports Structural Biology Research
One of the most compelling examples came from Dr. Kathryn Hastie's work on HERV-K, a human endogenous retrovirus associated with several disease areas, including cancer and autoimmune disorders.
Hastie's laboratory needed antibodies capable of distinguishing different forms of the HERV-K envelope protein. Existing commercial reagents were limited, making it difficult to understand which protein conformations might be biologically relevant.
Using single B cell discovery workflows, the team discovered a panel of new antibodies that enabled structural characterization of the metastable pre- and post-fusion confirmations of HERV-K envelope protein by cryo-EM.
Importantly, one antibody helped stabilize a difficult protein conformation, allowing the team to resolve high-resolution structural information that otherwise would have been challenging to obtain.
As Hastie explained, antibody discovery serves multiple purposes in her laboratory. The resulting antibodies support therapeutics, diagnostics, basic research, and structural biology studies that improve our understanding of viral proteins and immune responses.
4. Measles Research Shows the Connection Between Antibody Discovery and Vaccine Development
The webinar’s second major case study examined immune responses generated by the measles component of the MMR vaccine.
Although measles vaccination has dramatically reduced disease burden worldwide, Hastie noted that surprisingly little structural information has been available regarding human antibody responses against measles viral proteins.
To address this gap, the La Jolla Institute for Immunology (LJI) team isolated memory B cells from vaccinated donors and screened them using the Beacon platform. The campaign identified approximately:
| Antibody population | Candidates identified |
|---|---|
| Fusion protein (F) specific | ~200 |
| Hemagglutinin (H) specific | ~90 |
The team then performed epitope mapping, neutralization studies, and structural characterization to understand how these antibodies recognize the virus and which epitopes are associated with stronger neutralization responses.
This work revealed multiple protective antibody communities and generated several therapeutic candidates for further study.
Beyond therapeutic development, these findings contribute to a broader understanding of vaccine-induced immunity and may help researchers identify antigen conformations and epitopes that can inform future vaccine development efforts.
5. A Flexible Platform for Therapeutic Development, Diagnostics, and Structural Biology
A recurring theme throughout the webinar was flexibility.
Different research programs require different functional readouts. Structural biology projects may require antibodies that stabilize specific conformational states or require campaigns to maximize epitopic and genetic diversity. Diagnostics development programs may prioritize broad recognition or cross-reactivity. Therapeutic programs often focus on neutralization or receptor blocking, especially against targets with native or physiologically relevant conformations.
The examples presented by Bruker Cellular Analysis and LJI demonstrated how a single platform can support antibody discovery workflows spanning:
- Therapeutic development
- Vaccine development
- Diagnostic development
- Structural biology research
- Research reagent generation
These applications all draw on multi-faceted functional profiling of live single cells.
Your Questions Answered: Antibody Discovery Workflow Best Practices and Considerations
How were antigen-reactive cells enriched before using the Beacon system?
For the measles study, LJI first identified donors with measurable immune responses and then used flow cytometry to identify and enrich H- and F-reactive memory B cells. These populations were activated before being loaded onto OptoSelect® chips for live single-cell screening.
Is antigen-specific enrichment always required?
Not necessarily. The optimal approach depends on the frequency of target-reactive cells and the goals of the discovery program. Enrichment can improve efficiency when target-specific populations are rare, while broader B-cell populations may be appropriate in other workflows.
How can antibody discovery support future vaccine development?
The measles project illustrated how epitope mapping, functional characterization, and neutralization studies can reveal which antibody responses are most protective. These insights can help researchers better understand immune responses and guide future vaccine research efforts.
How has LJI accelerated research across multiple infectious disease programs?
Hastie's presentation highlighted an integrated approach combining antibody discovery, functional characterization, epitope mapping, structural biology, and downstream validation. This strategy has helped the team investigate diverse pathogens while generating both biological insights and potential therapeutic candidates.
Does a pH-dependent binding assay affect B-cell viability or BCR sequence recovery?
The transcript did not include the live answer to this audience question. The webinar showed that pH-dependent binding can be assessed within a workflow designed to recover selected live cells for downstream BCR sequencing, but project-specific effects on viability and recovery should be confirmed with Bruker.
Can the Beacon platform support modalities such as bispecific antibodies?
The transcript did not include the live answer to this question. The Beacon platform supports functional profiling of live antibody-secreting cells co-cultured with other reporter and/or assay cells, including T cells and antigen-presenting target cells, so deeper single-cell resolution functional characterization of bispecific molecules can be performed. However, depending on the suitability of screening scale, depth and breadth of characterization, and the specific downstream modality, especially considering the full diversity of bispecific formats, depends on the assay design and should be discussed with Bruker.
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