Abstract
Purpose:
T cell activation and monocytes have been reported to contribute to uveitis pathogenesis. Peripheral monocytes can be categorized into 3 groups: CD14dimCD16+; CD14highCD16-; and CD14highCD16+. Our previous results indicated that CD14highCD16+ monocytes are enriched in uveitis patients. The goal of this study is to investigate the effect of subsets of peripheral monocytes on T cell activation.
Methods:
Human peripheral blood mononuclear cells (PBMCs) were isolated from the blood of healthy donors using a Ficoll gradient centrifugation protocol. Monocyte and T cell phenotyping was assessed by 4-color flow cytometry. T cell proliferation was evaluated by CFSE staining and detected by flow cytometry. ConA treated T cells were co-cultured separately with monocyte subsets, irradiated, and then subsequently co-culture with untreated PBMCs in the presence of ConA. Suppressive capacity was measured through detecting the proliferation of PBMCs.
Results:
T-cells co-cultured with CD14dimCD16+ and CD14highCD16+ monocytes in the presence of ConA delivered a more suppressive effect to untreated PBMCs when compared with T-cells co-cultured with CD14highCD16- monocytes. Furthermore, the CD14highCD16- subset of peripheral monocytes presented the most vigorous effect in assisting T cells proliferation and the expression of CD40L, a T cell co-stimulator, compared to CD14dimCD16+ and CD14highCD16+ monocytes.
Conclusions:
CD14highCD16+ and CD14dimCD16+ monocytes presented less of a T cell activation effect but more of a suppressive function on T cell proliferation. These results suggest that CD14highCD16+ monocytes, which are enriched in uveitis patients, have an immune regulatory role. Understanding the influence of subsets of human monocytes may be useful in understanding the mechanisms of uveitis pathogenesis.
Keywords: 557 inflammation