关键词: 脐血, 间充质干细胞, T淋巴细胞, 抑制

Abstract: Objective To study the influences of human umbilical cord blood derived mesenchymal stem cells (HUCB-MSCs) on allogeneic peripheral blood T lymphocytes. Methods HUCB-MSCs were isolated from normal human umbilical cord blood, isolated and cultured in vitro, and then surface marker were determinate with FCM. After isolating CD3＋T cells from normal human peripheral blood, CD3＋T cells were mixed with HUCB-MSCs stimulated with PHA or not. Five days later, the effects of HUCB-MSCs on T-cell proliferation was detected by 3H-TdR. Cytokines production of PHA-stimulated T cells in co-culture were investigated with ELISA. T-cell apoptosis affected by HUCB-MSCs were also observed by FCM. Results HUCB-MSCs showed a spindle-shaped fibroblastic morphology in culture. The populations appeared as a homogenous population and were uniformly positive for the expression of CD29, CD44, and HLA-ABC, but negative for the expression of CD14, CD34, CD45, and HLA-DR. In co-culture, MSCs failed to elicit positive responses of T cells (3760 ± 730 counts/min versus 3600 ± 800 counts/min，p=0.85), whereas significantly suppressed PHA-stimulated T-cell proliferation(5230 ± 550 counts/min versus 10500 ± 800 counts/min，p<0.001). Both pro-inflammatory cytokines IFN-γ（510 ± 60 pg/ml versus 1580 ± 100 pg/ml, p<0.001）and TNF-α（590 ± 20 pg/ml versus 1180 ± 30 pg/ml, p<0.001）secreted by T cells were inhibited by HUCB-MSCs while anti-inflammatory cytokines IL-10（105 ± 5 pg/ml versus 17 ± 2 pg/ml, p<0.001）and IL-4 (16.3 ± 8.2 pg/ml versus 4.1 ± 1.8 pg/ml, p<0.001) were up-regulated. In addition, MSCs-inhibited T cells were not apoptotic during 5 days’ culture. Conclusion HUCB-MSCs possessed could inhibit the activity of allogeneic peripheral blood T lymphocytes.

Key words: umbilical cord blood, mesenchymal stem cells, T lymphocytes, inhibition