A new method for detecting TNF-alpha-secreting cells using direct-immunofluorescence surface membrane stainings

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Tumor Necrosis Factor-alpha (TNF-alpha) is a key cytokine in inflammatory responses.
• Accurate quantification of TNF-alpha-secreting cells is crucial for understanding immune status.
• Existing methods for detecting TNF-alpha production often require cell fixation and permeabilization, which can be time-consuming and may affect cell integrity.

Purpose of the Study:

• To develop and validate a novel, simplified flow cytometric method for identifying TNF-alpha-secreting cells.
• To evaluate the efficacy of a TNF-alpha converting enzyme (TACE) inhibitor, BB3103, in detecting surface TNF-alpha.
• To compare the new method with traditional secretion blocking agents like brefeldin A.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) were stimulated to induce TNF-alpha production.
• Cells were treated with either BB3103 (TACE inhibitor) or brefeldin A as secretion blocking agents.
• Surface expression of TNF-alpha and CD62L was analyzed using flow cytometry.

Main Results:

• The BB3103 method demonstrated slightly higher percentages and mean fluorescence intensity (MFI) of TNF-alpha positive CD4+ and CD8+ T-cells compared to brefeldin A.
• Detectable surface TNF-alpha expression was observed on T-cells and monocytes as early as 30 minutes post-stimulation.
• BB3103 effectively stabilized CD62L expression on leukocytes, indicating its broader utility for other surface markers.

Conclusions:

• The described flow cytometric method using BB3103 offers a simple, rapid, and effective way to identify intact TNF-alpha producing cells without fixation or permeabilization.
• This TACE inhibitor-based approach provides a valuable tool for immunological studies and diagnostics.
• The method's ability to stabilize other surface molecules like CD62L suggests its potential application in analyzing various cell surface markers.