Cell-Based Assays

Fit-for-purpose in vitro assays to confirm activity and support candidate selection

Mosaic delivers biologically relevant, data-rich functional insights through custom cell-based assay development for biologics discovery programs, including in-house generation of cell lines and assays.

We combine commercial and engineered cell systems with flow cytometry, fluorescence microscopy, and plate-based functional readouts to reveal mechanism of action and guide lead selection.

Our functional assays are built around program-specific biology, ensuring relevance and interpretability.

These functional assays are frequently paired with Antibody Discovery & Optimization programs to evaluate candidate binding and downstream cellular signaling.

Cell-Based Assay Capabilities

Cellular Response Readouts

Effector function (ADCC, ADCP, CDC, TDCC)

Receptor internalization (fluorescence microscopy–based)

Proliferation

Signaling (phospho-flow, reporter activity, and downstream functional readouts)

Cell death (apoptosis, necrosis)

Cytokine release

Receptor & Cell Engagement

Bispecific engagement

Binding and EC50 determination

Receptor occupancy

Competitive binding

Epitope-specific function

Stable Cell Line Generation

Knockout / Knockdown: CRISPR-based gene editing and RNAi approaches generated in house for target validation and specificity assessment

Overexpression & Stable Line Generation: Tunable expression systems for challenging or low-abundance targets

Immune Cell Models: Primary PBMCs, T cells, NK cells, and immortalized engineered effector cell lines

Reporter Cell Lines: Luciferase and pathway-specific reporters, commercially sourced or generated in house as needed

Cell-Based Assay Technologies

Plate-based Functional Readouts

Luminescence (ATP, luciferase, cytotoxicity)
MSD electrochemiluminescence (multiplex cytokine and phosphoprotein detection)
ELISA and immunoassays
Absorbance and colorimetric assays

Flow Cytometry

Multi-parameter immunophenotyping
Intracellular cytokine staining and signaling analysis
Cell cycle, apoptosis, and proliferation measurements
High-throughput analysis

Fluorescence Microscopy

• Qualitative and semi-quantitative imaging

Cell-Based Assay Workflow

1. Assay design and endpoint selection

2. Cell model development or sourcing

3. Assay execution with rigorous controls

4. Analysis and reporting with MoA insight

For later-stage evaluation, Mosaic supports pharmacology studies through our Pharmacology capabilities.

Translational Readiness

Functional profiling routinely includes binding capacity, signaling activation or inhibition, proliferation, survival, and secretion.

This characterization informs dose selection, biomarker strategy, and preclinical study design, bridging in vitro discovery with in vivo proof of concept.

Downstream characterization may include Protein Sciences & Analytics to assess stability, aggregation, and developability.

Discover Mosaic’s complete biologics discovery solutions supporting antibody discovery, protein engineering, and pharmacology studies.

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Start a conversation with our scientific team about your biologic discovery program.

Explore Other Discovery Solutions

Complementary capabilities supporting biologics discovery, engineering, and characterization.