Modulation of HLA-G expression in human thymic and amniotic epithelial cells

Area of Science:

• Immunology
• Cell Biology
• Molecular Biology

Background:

• Nonclassical Human Leukocyte Antigen-G (HLA-G) expression is tightly regulated and primarily restricted to specific placental and thymic cells.
• In vitro expression of HLA-G is limited, and cytokine-induced expression is rarely observed and cell-lineage dependent.

Purpose of the Study:

• To investigate the expression and cytokine regulation of HLA-G in primary human thymus and amnion epithelial cells.
• To determine if Interferon-gamma (IFN-γ) can modulate HLA-G expression and classical class I gene expression in these primary cultures and a thymus-derived cell line.

Main Methods:

• Primary cultures of human thymus epithelial cells (TECs) and amnion epithelial cells were established.
• Cell surface expression of HLA-G was assessed over time.
• The effect of IFN-γ on HLA-G expression, classical class I gene expression, and HLA-G transcript levels was evaluated.

Main Results:

• Primary cultures of human thymus and amnion epithelial cells maintained HLA-G cell surface expression, though it gradually decreased.
• IFN-γ re-induced HLA-G cell surface expression and upregulated classical class I gene expression in both primary cultures and a thymus-derived cell line.
• IFN-γ also increased HLA-G transcript levels in primary TEC cultures, indicating transcriptional regulation.

Conclusions:

• IFN-γ can induce HLA-G expression in human amnion and thymus tissues.
• The induction of HLA-G by IFN-γ in these tissues is mediated at the transcriptional level.
• These findings suggest that the microenvironment plays a role in regulating in vivo gene expression of HLA-G in the thymus and amnion membrane.