Abstract
Purpose: :
To determine whether human iris pigment epithelial (h–IPE) cells inhibit T cell activation in vitro.
Methods: :
Primary cultured h–IPE cells were established from fresh iris tissues obtained from glaucoma patients after informed consent was obtained from each patient. Four weeks primary cultures were used in vitro assay. Target activated T cells were established from autogeneic or allogeneic T cells from peripheral blood mononuclear cells (PBMC). As another targets, T cell clones of patients with uveitis were established from ocular fluid by the limiting dilution. T–cell activation was assessed for proliferation by [3H]–thymidine incorporation or IFN–gamma production by the target T cells. Expression of TGF–beta on h–IPE cells was evaluated with semi–quantitative RT–PCR.
Results: :
Primary cultured h–IPE significantly inhibited T cell proliferation and IFN–gamma production by T cells when the target T cells from both autogeneic and allogeneic PBMC were stimulated with anti–human CD3 antibody for 72 hr. The h–IPE significantly also inhibited the activation of CD4+ T cells from patients with uveitis. Anti–TGF–bata abs–treated h–IPE failed to inhibit the activation of T cells. In addition, the h–IPE cells constitutively expressed TGF–beta transcripts.
Conclusions: :
Cultured h–IPE are capable of inhibiting T cell activation in vitro, suggesting a possible therapeutic strategy using h–IPE in uveitis.
Keywords: immune tolerance/privilege • immunomodulation/immunoregulation • cytokines/chemokines