Human treg cells are characterized by low/negative CD6 expression

Area of Science:

• Immunology
• Cell Biology

Background:

• Natural regulatory T cells (nTreg) are vital for immune homeostasis, defined by CD4+, CD25hi, and FOXP3+ expression.
• Existing markers like CD25 and FOXP3 have limitations due to expression on other T cell subsets and activated cells.
• Improved identification and isolation of nTreg cells and their subsets are necessary for deeper understanding and therapeutic applications.

Purpose of the Study:

• To identify novel surface markers for more precise identification and isolation of natural regulatory T cells (nTreg).
• To evaluate the utility of CD6 expression in combination with other markers for nTreg characterization.
• To develop improved methods for nTreg purification without the need for intracellular staining.

Main Methods:

• Flow cytometry analysis of CD4+ T cells using combinations of surface markers including CD6, CD127, CD49d, and CD26.
• Assessment of FOXP3 expression in conjunction with surface marker profiles.
• Evaluation of in vitro suppressive activity of identified nTreg populations on CD8+ T cell proliferation.

Main Results:

• CD4+ CD25hi CD6(lo/-) nTreg cells exhibit high FOXP3 expression and potent in vitro suppressive activity.
• Combined CD6(lo/-) and CD127(lo/-) expression enriches for CD25hi FOXP3+ cells.
• CD6(lo/-) expression serves as a reliable indicator for FOXP3+ nTreg cells.

Conclusions:

• CD6(lo/-) expression is a novel characteristic of FOXP3+ nTreg cells, enabling identification without intracellular staining.
• The CD6(lo/-) marker offers a new tool for the efficient purification of nTreg cells via negative selection.
• This finding advances the ability to isolate and study specific nTreg subsets for immunological research.