Memory Th-17 cells specific for C. albicans are persistent in human peripheral blood

Area of Science:

• Immunology
• Cell Biology
• T-cell differentiation

Background:

• T-helper 17 (Th-17) cells are a recently identified subset of effector CD4(+) T cells.
• Their role in human immune responses, particularly in defense against pathogens, is an active area of research.

Purpose of the Study:

• To characterize the phenotype and function of IL-17-producing CD4(+) T cells in human peripheral blood mononuclear cells (PBMCs).
• To investigate the potential role of Th-17 cells in response to fungal infections, specifically Candida albicans.

Main Methods:

• Human PBMCs were stimulated with anti-CD3 and anti-CD28 antibodies.
• ELISA and ELISPOT assays were used to detect IL-17 production.
• Flow cytometry was employed for phenotypic analysis of IL-17-producing cells.
• Purified CD4(+) T cells were used to confirm direct IL-17 induction.
• PBMCs were stimulated with Candida albicans (yeast and hyphae) to assess IL-17 response.

Main Results:

• High levels of IL-17 and IL-17-producing cells were detected upon stimulation.
• CD4(+) T cells were identified as the primary source of IL-17 production.
• IL-17-producing CD4(+) T cells were predominantly memory cells expressing CD45RO, CD69, CCR6, CCR4, and CCR7.
• Th-17 cells were phenotypically distinct from Th1, Th2, and regulatory T (Treg) cells.
• Stimulation with Candida albicans induced IL-17 production at both protein and transcriptional levels.

Conclusions:

• Memory Th-17 cells are present in PBMCs of healthy individuals.
• These memory Th-17 cells may contribute to the immune defense against fungal pathogens like Candida albicans.