[The effects of B7H4 on human bone marrow mesenchymal stem cell inhibiting proliferation of PHA activated T cells].

OBJECTIVE

To investigate the effects of B7H4 on human bone marrow mesenchymal stem cells (HBMSC) mediating immune suppression.

METHODS

The expression of the negative immunoregulatory factor B7H4 on HBMSC were analyzed by RT-PCR and flow cytometry (FCM), respectively. The blocking experiment was used to detect the effects of B7H4 on HBMSC mediating suppression on PHA induced T cell activation, proliferation and cell cycle. HBMSC inhibiting T cell proliferation was examined by transwell cell culture system.

RESULTS

B7H4 was highly expressed on HBMSC. Blocking the B7H4 expression by B7H4mAb significantly attenuated the inhibitory effects of HBMSC on T cell proliferation. Compared with that of the unblocking group, T cell stimulator index (SI) of the B7H4 blocked group was significantly increased (53 +/- 5 vs 15 +/- 8, P < 0.01) and the inhibitory effects of HBMSC on T cell cycle were weakened significantly through down-regulating the cell number in G(0)/G(1) phase [(85.6 +/- 9.9)% vs (95.8 +/- 9.9)%] and up-regulating those in S phase[(5.8 +/- 3.2)% vs (2.3 +/- 2.2)%, P < 0.05]. The suppressive effects of HBMSC on T cell proliferation were significantly weakened after separating HBMSC from T cells by transwell cell culture system. Compared with the cell to cell contact group, T cell SI was significantly increased (27 +/- 17 vs 15 +/- 3, P < 0.01).

CONCLUSION

HBMSC highly express B7H4, which plays an important role in the suppressive effects of HBMSC on T cell proliferation.