Optimization of human Th17 cell differentiation in vitro: evaluating different polarizing factors

Area of Science:

• Immunology
• Cell Biology

Background:

• Human Th17 cell differentiation protocols vary, leading to discrepancies in research findings.
• Understanding optimal conditions and the role of specific cytokines like TGF-β is crucial for reliable Th17 cell studies.

Purpose of the Study:

• To determine the optimal cytokine combination for human Th17 cell differentiation.
• To elucidate the specific role of TGF-β in this differentiation process.

Main Methods:

• Naïve CD4(+) T cells were isolated from human cord blood.
• Cells were cultured in serum-free X-VIVO 15 or RPMI 1640 with FBS.
• Cells were treated with various combinations of TGF-β, IL-1β, IL-6, IL-23, and IL-21.
• Gene and cytokine expression analyzed via real-time quantitative RT-PCR and ELISA.

Main Results:

• A combination of TGF-β, IL-6, and IL-23 in X-VIVO 15 medium yielded the best human Th17 cell differentiation.
• TGF-β acts as a positive regulator of Th17 differentiation at average concentrations.
• Absence of TGF-β led to double-secreting Th17 cells (IL-17 and IFN-γ), while its presence induced single-secreting (IL-17) cells.

Conclusions:

• X-VIVO 15 medium with TGF-β, IL-6, and IL-23 represents an optimal condition for human Th17 differentiation.
• TGF-β concentration critically influences Th17 cell polarization and cytokine production, specifically IL-17 and IFN-γ co-expression.