Validation and implementation of a method for microarray gene expression profiling of minor B-cell subpopulations in...

Area of Science:

• Immunology
• Molecular Biology
• Genomics

Background:

• Generating global gene expression profiles from low-frequency B-cell subsets presents challenges due to limited cell numbers.
• Optimization and validation of each procedural step are crucial for reliable results.

Purpose of the Study:

• To describe and validate a method for generating gene expression profiles from low-frequency B-cell subsets.
• To optimize cell sorting, RNA amplification, and microarray analysis for rare cell populations.

Main Methods:

• Multiparametric flow cytometry (8-colour Euroflow panel) was used to immunophenotype normal lymphoid tissues.
• B-cell subsets (800-33,000 cells) were sorted, subjected to mRNA purification and amplification (NuGEN protocol), and analyzed by Affymetrix arrays.
• Validation involved comparing RNA amplification protocols, cell storage conditions, and concordance between cell surface markers and gene expression.

Main Results:

• The NuGEN amplification protocol showed significant correlation with standard protocols (r ≥ 0.9) and preserved relative gene expression differences (r ≥ 0.9).
• Storage in lysis/binding buffer yielded higher purified mRNA compared to other methods (p < 0.001).
• Transcriptional gene expression strongly correlated with B-cell subset identity (p < 0.001) and lymphopoiesis biology (p < 0.001).

Conclusions:

• A validated workflow for generating microarray data from minor sorted B-cell subsets has been established.
• The described method integrates cell sorting, lysis/stabilization, RNA isolation, and amplification using commercially available kits.
• This workflow facilitates the creation of gene-specific B-cell atlases.