Removing the limitations of ELISA and flow cytometry within antibody discovery
An alternative immunoassay screening approach that delivers data driven decisions faster, within budget and with confidence.
Flexibility to work the way you want to
ELISA is an essential tool within antibody discovery, but this approach can generate bottlenecks due to their limited throughput, restricted capability and lengthy error-prone protocols.
Newer approaches offering multiplexing or homogeneous assays can lead to significantly increased reagent and consumable costs. Many of these are unsuitable for membrane associated proteins campaigns, as they require intact whole cells, or a phenotypic approach to screening.
Flow cytometers remain a commonly used alternative for suspension cells and beads, but their propensity to clog and inability to perform adherent cell phenotypic screens limits reliability and versatility.
Accelerating the pace to meet project deadlines
Screen smarter. Choose the most convenient, or physiologically relevant model for your therapeutic target (adherent cells analysed in-situ, suspension cells, and/or sol-R beads) and multiplex for accelerated decision making.
- combine hit identification with species cross-reactivity and non-specific binding counter-screens
- discover more from screens: include titre determination and uncover the effects of antibody affinity versus quantity
- include a dead cell marker to reduce false hit reporting for cell-based immunoassays
- combine immunoassay and phenotypic outcomes
Featured applications are highlighted below.
Simultaneous determination of binding, specificity and titre
Cell culture supernatants in HTS screens are usually tested at a fixed volume or dilution without normalisation for protein concentration. A screening method that enables the determination of antibody concentration (titre) and binding affinity is desirable for primary screens. This approach is also useful for verifying the expression of binders following reformatting into mammalian expression vectors and to select the best secreting cell lines after expression optimisation.
We have developed a simple homogenous (no-wash) assay to screen antibody samples for binding to a target cell line, non-specific binding to a control cell line and antibody titre by binding to a sol-R bead.
Improved safety and robustness for virus neutralisation assays
Homogenous assay formats are particularly advantageous for two reasons. Assay components are contained within the lidded (or sealed) microplate at all times minimising safety concerns. No-wash conditions mean that infected, poorly attached cells remain on the plate at all times leading to better quality data.
mirrorball's no-wash immunoassay workflow combined with whole well imaging provides the ideal solution, permiting the normalisation of assay readout to total well cell count for improved assay robustness.
Providing reliability for cell-surface receptor screening
To improve the reliability of hits against cell surface receptors, it is beneficial to screen against cell lines expressing the antigen of interest rather than immobilised purified antigen. Antigen epitopes are more likely to be preserved in their natural confirmation and therefore the incidence of false positive, or negative binding events should decrease.
Screening adherent cells in-situ decreases the risk of compromised antigens due to trypsinisation. Additionally, when cells die their membranes can become ruptured and expose a large range of proteins, which can lead to significant off-target antibody binding. By simply eliminating dead cells from analysis, the quality of screening data can be further enhanced.
Ensuring equilibrium for competition assays
Competition assay screens are used routinely to determine the relative binding affinities of lead candidate variants during the characterisation and optimisation phase of drug discovery.
Our workflow permits use of a cell, or bead-based approach (sol-R toolbox reagents), the former of which preserves the integrity of membrane associated targets for improved data quality. In addition, no-wash assay formats ensure that binding is at equilibrium when plates are read. Preceeding competition assay screens, mirrorball may also be used for Kd/Bmax determination (note this assay requires a wash-step).
Rapid hit profiling using multiplexed sandwich immunoassays
Whether you are confirming the efficacy of hits derived from target-based immunoassay screens, or looking to establish early indications of off-target effects using multi-analyte panels, you can step up the pace of discovery without obliterating your budget.
No specialist services are required to custom build your own assay panel using sol-R toolbox reagents.
Choose one to five analytes to multiplex into one productive, no-wash immunoassay and save up to 90% of sample and costs versus ELISA.
The no-wash workflow
Accurate determination of hits from screening campaigns requires a workflow that provides gold standard data and better utilises the skills of laboratory scientists.
Our mix and read automation-friendly protocols couldn’t be simpler, freeing operators of mundane multi-step, multi-wash ELISAs and reducing the opportunity for error.
Simply choose your model, add, mix and read!
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