AIM

To observe the effect of rapamycin (Rap) and dexamethasone (Dex) on differentiation and development of murine bone marrow-derived dendritic cells (DC) in vitro.

METHODS

DC cells generated from C57BL/6 murine bone marrow cells were induced by GM-CSF and IL-4. During the course, Rap or Dex was added to the culture and the cells were then stimulated by LPS. (1)Morphology development of DCs was observed by inverted microscope and scanning electron microscope.(2)The cells were analyzed by flow cytometry (FCM) to determine the proportion of CD11c(+) cells and the change of CD86 and MHC class II molecule.(3)The influence of DCs treated by Rap or Dex on the allogeneic T cell proliferation was studied by one-way MLR.

RESULTS

(1)The morphology of DCs maintained in a durable state of immaturity after Rap or Dex pretreatment.(2)The expression of CD11c and MHC-II slightly decreased but CD86 dramatically reduced on Rap-treated DC cells. There was close relationship between the expression of CD11c on Dex-treated cells and the dosage of Dex. The surface expression of CD86 and MHC-II dramatically reduced on Dex-treated DCs. Moreover, DCs treated by Rap or Dex were both able to resist the maturation triggered by LPS.(3)Bone marrow-derived DCs cultured with Dex or Rap had a lower stimulatory effect on allogeneic T cells compared with that of mature DCs.

CONCLUSION

Rap and Dex could keep DCs in durable immaturity. Compared with Dex, which inhibited the expression of co-stimulatory molecules, Rap hardly influenced the differentiation of DCs and the expression of MHC class II molecules.