Objective: To investigate the effects of human amniotic mesenchymal stem cells (hAMSCs) on the function of lymphocytes in vitro.
Methods: Enzymatic digestion method was used to isolate and culture hAMSCs. Fluorophore-labeled mouse anti-human monoclonal antibodies were used to identify cell surface antigens with flow cytometry. The expressions of vimentin and stage specific embryonic antigen-4 (SSEA-4) were detected by immunofluorescence staining. Isolated lymphocytes were stimulated by concanavalin (ConA), and then 1 × 10⁴, 5 × 10⁴, 1 × 10⁵ hAMSCs were co-cultured with the ConA-treated lymphocytes. Lymphocyte proliferation was measured by CCK-8 assay and the supernatant level of IFN-γ was determined by ELISA.
Results: ConA (5 μg/mL) could cause lymphocyte proliferation. hAMSCs inhibited lymphocyte proliferation induced by ConA in co-culture conditions, and with the increasing number of hAMSCs, the suppressing effect was more obvious. When the cells were cultured for 72 hours, CCK-8 assay showed that the number of lymphocytes treated with ConA alone was significantly higher than that of ConA-treated lymphocytes co-cultured with hAMSCs. The best inhibitory group 1 × 10(6) lymphocytes co-cultured with 1 × 10⁵ hAMSCs was selected to measure supernatant IFN-γ secretion by ELISA after 72 hours. The level of IFN-γ was significantly lower than that in the simple ConA-stimulated group.
Conclusion: HAMSCs could inhibit lymphocyte proliferation and reduce IFN-γ secretion induced by ConA in vitro.