In situ quantitative immunoprofiling of regulatory T cells using laser scanning cytometry

Area of Science:

• Immunology
• Biotechnology
• Transplantation Science

Background:

• Regulatory T cells (T regs) are crucial for immune tolerance in transplantation.
• Accurate quantification of T regs in biopsy samples is essential for monitoring graft health.
• Current methods for T reg analysis in formalin-fixed/paraffin-embedded (FFPE) tissues can be subjective.

Purpose of the Study:

• To develop and validate an objective, quantitative immunoprofiling method for T regs in FFPE allograft biopsy samples.
• To evaluate the utility of laser scanning cytometry (iCys) for single-cell analysis of T regs.
• To assess the population of CD4(+) Foxp3(+) T regs within CD4(+) T cells and the total T-cell population.

Main Methods:

• Utilized laser scanning cytometry (iCys) for quantitative measurements at the single-cell level.
• Employed dual-color immunofluorescence staining with Alexa Fluor 488 and 647 conjugated antibodies (Foxp3, CD4, CD8) on FFPE sections.
• Applied signal amplification techniques for enhanced detection and analysis.

Main Results:

• Achieved sufficient signal intensity for quantitative analysis of T reg populations using iCys.
• Successfully calculated the proportion of T regs among CD4(+) T cells, CD4(+) T cells among total T cells, and T regs among total T cells.
• Demonstrated objective, quantitative immunoprofiling of in situ T reg populations at a single-cell level.

Conclusions:

• Laser scanning cytometry enables precise, quantitative, and objective immunoprofiling of regulatory T cells in FFPE biopsy samples.
• This method provides a robust tool for analyzing T reg populations in transplanted allografts.
• The developed technique has potential applications for various transplanted organs, aiding in graft monitoring and management.