Identification and Enumeration of Immune Cells in Bronchoalveolar Lavage Fluid by Flow Cytometry
JoVE Encyclopedia of Experiments
Immunology
0 views • 3:03 min • July 8th, 2025
Begin with a multi-well plate containing mouse bronchoalveolar lavage fluid comprising an immune cell population stained with a green fluorescent viability dye.
Introduce Fc-antibodies to block immune cells' Fc-receptors.
Add a cocktail of distinct fluorophore-labeled antibodies targeting specific cell markers. Remove unbound antibodies and resuspend the cells in a buffer.
Using flow cytometry, identify dim fluorescence singlets, indicating live cells.
Illuminate cells at 488 nanometers, causing cells to emit red fluorescence correlating with CD11c-expressing cells.
Within the high CD11c population, with appropriate wavelength filters, identify cell marker proteins MHC-II on dendritic cells and SiglecF on macrophages.
In the CD11c low population, expression of CD3 on T cells and CD19 on B cells enable their identification.
Illuminate cells at 405 nanometers, emitting blue fluorescence, signifying the CD11b-expressing neutrophils.
Illuminating cells at 633 nanometers excites far-red fluorophores on Ly-6G-expressing eosinophils.
Using flow cytometry data, enumerate the abundance of each type of immune cell in the bronchoalveolar lavage fluid.
After the third bronchoalveolar lavage collection, centrifuge the pooled aspirate, and store the supernatant at negative 80 degrees Celsius. Resuspend the pellet in 200 microliters of ACK lysis buffer. After no more than two minutes at room temperature, dilute the lysis buffer with one milliliter of cold PBS and collect the cells by centrifugation.
Resuspend the pellet in the appropriate volume of PBS for the number of samples to be analyzed and aliquot the cells into the appropriate number of wells of a 96-well plate for the analysis. Collect the cells by another centrifugation, and resuspend the pellets in 50 microliters of FC block in PBS.
After 10 minutes at room temperature, add 50 microliters of the appropriate antibody cocktail of interest to each well, and incubate the cells for 30 minutes at four degrees Celsius protected from light. At the end of the incubation, centrifuge the plate and discard the supernatant, resuspending the pellets to a final volume of 200 microliters of FACS buffer per well for flow cytometric analysis.
Overview
This article details a method for analyzing immune cell populations in mouse bronchoalveolar lavage fluid using flow cytometry. The protocol includes staining cells with fluorescent antibodies to identify specific immune cell markers.
Key Study Components
Area of Science
- Immunology
- Flow Cytometry
- Cell Biology
Background
- Understanding immune cell populations is crucial for studying respiratory diseases.
- Flow cytometry allows for the detailed analysis of cell types based on surface markers.
- Mouse models are commonly used to investigate immune responses.
- Fluorescent labeling enhances the detection of specific cell populations.
Purpose of Study
- To develop a protocol for identifying and enumerating immune cells in bronchoalveolar lavage fluid.
- To utilize flow cytometry for detailed immune profiling.
- To enhance understanding of immune cell dynamics in respiratory health and disease.
Methods Used
- Collection of bronchoalveolar lavage fluid from mice.
- Staining of immune cells with viability dyes and fluorophore-labeled antibodies.
- Flow cytometric analysis to identify and quantify specific immune cell populations.
- Use of centrifugation and lysis buffers for cell preparation.
Main Results
- Successful identification of CD11c-expressing dendritic cells and SiglecF-expressing macrophages.
- Enumeration of T cells and B cells based on CD3 and CD19 expression, respectively.
- Detection of neutrophils and eosinophils using specific fluorescent markers.
- Establishment of a reliable method for analyzing immune cell populations in respiratory samples.
Conclusions
- The protocol provides a robust framework for immune cell analysis in bronchoalveolar lavage fluid.
- Flow cytometry is an effective tool for characterizing immune responses.
- This method can be applied to further studies on respiratory diseases and immune function.
Frequently Asked Questions
Executive Industry Relevance
Flow cytometry-based immune cell profiling in bronchoalveolar lavage fluid enables precise quantification of inflammatory infiltrates, supporting target validation in respiratory disease models. This approach provides quantitative, marker-specific data that enhances mechanistic de-risking by linking immune phenotypes to pathophysiological processes. The method supports early discovery decisions by delivering reproducible, high-content immune profiling data critical for portfolio triage in immunology and inflammation research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses through precise identification and enumeration of immune cell subsets in disease-relevant lung microenvironment.
- Operational Value: Supports biological de-risking by clarifying the functional contribution of dendritic cells, macrophages, T cells, B cells, neutrophils, and eosinophils to inflammatory pathways.
- Predictive Value: Generates quantitative immune profiling data that improves target confidence and informs go/no-go decisions in preclinical immunology programs.
Screening & Assay Development
- Assay Readiness: Produces standardized, reproducible single-cell suspensions from bronchoalveolar lavage fluid suitable for high-parameter flow cytometric analysis.
- Quantitative Output: Delivers precise cell counts and frequencies of immune populations, enabling reliable comparison across experimental conditions and treatment groups.
- Scalability: Compatible with 96-well plate formats, supporting medium-throughput screening of immunomodulatory compounds or genetic perturbations.
Translational & Preclinical Research
- Disease Relevance: Directly models immune cell infiltration in murine lung inflammation, providing a translationally relevant system for studying respiratory disease mechanisms.
- Translational Continuity: Bridges discovery and preclinical validation by delivering consistent immune phenotyping data across study stages.
- Risk-Adjusted Advancement: Enables data-driven decisions on candidate progression by correlating immune modulation with phenotypic outcomes.
Pipeline & Workflow Integration
The method fits within the discovery-to-preclinical continuum, supporting immune profiling from hypothesis testing through lead optimization and preclinical validation in respiratory inflammation models.
- Discovery Biology: Facilitates hypothesis testing and pathway clarification by quantifying immune cell responses to experimental interventions in lung tissue.
- Screening: Delivers assay-ready, reproducible immune cell data with standardized staining and gating strategies for compound or target evaluation.
- Analytics: Generates multiparametric flow cytometry readouts that enable comparative analysis of immune cell abundance and activation states.
- Translational Research: Supports preclinical continuity by providing quantifiable immune biomarkers aligned with disease pathology in murine models.
- Enterprise Reuse: Establishes a reusable immunoprofiling platform applicable across multiple respiratory disease models and therapeutic modalities.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence in target validation through precise, marker-based immune cell identification and enumeration.
- Operational Value: Ensures standardization and reproducibility via defined antibody panels, viability gating, and standardized sample preparation.
- Strategic Value: Improves capital efficiency by reducing late-stage biological risk through early immune mechanism de-risking.
- Portfolio Impact: Enables risk-adjusted prioritization of candidates based on immune modulation profiles in disease-relevant systems.
Implementation Considerations
- Requires expertise in flow cytometry panel design, compensation, and gating strategy for multicolor immunophenotyping.
- Dependent on access to flow cytometers with appropriate laser configurations (405 nm, 488 nm, 633 nm) and filter sets for detecting fluorophores.
- Necessitates standardized SOPs for bronchoalveolar lavage collection, cell preparation, antibody staining, and data analysis to ensure cross-lab consistency.
- Requires adaptation of antibody panels when translating across species or disease models with differing immune cell markers.
- Limited by sample quality and cell yield from bronchoalveolar lavage, which can affect sensitivity for rare population detection.
Biopharma FAQs
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Last updated: 22 August 2026