[Role of nerve growth factor in differentiation of 
dendritic cells]

To explore the effect of nerve growth factor (NGF) on the  differentiation of murine bone marrow-derived dendritic cells (DCs) in vitro.

The bone marrow cells of femur and tibia from healthy C57B -L/6 mice were isolated and divided into 4 groups: a phosphate buffered saline (PBS) group (PBS group), a NGF group, a granulocyte monocyte colony stimulating factor (GM-CSF) plus interleukin 4 (IL-4) group (GM-CSF+IL-4 group), and a GM-CSF plus IL-4 and NGF group (n=6 in each group). The positive rate of CD11c+ and the proportion of CD8a- were compared at the 7th day among the different groups by flow cytometry. The immature DCs were acquired by classic methods with GM-CSF and IL-4. The purified DCs were obtained by magnetic bead positive selection for CD11c+ cells. The immature DCs were divided into 4 groups: a PBS group, a NGF group, a LPS group, and a NGF+LPS group (n=6 in each group), which were incubated with PBS, NGF, LPS and NGF+LPS, respectively. Cytokine levels of IL-6, IL-10 and IL-12 were detected by ELISA after 24 hours..

1) the percentage of CD11c+ DCs in the NGF group were more than that in the PBS group, and lower than that in the the GM- CSF+IL-4 group (both P<0.05). There was no difference between the GM-CSF + IL-4 group and the NGF+GM-CSF+IL-4 group (P>0.05). CD8a- DCs were dominant in these four groups; 2) NGF could further up-regulate the LPS-induced cytokine secretion from DCs, such as IL-6, IL-10, and IL-12 (all P<0.05), but NGF alone had no such effect (all P<0.05).

NGF can promote the murine bone-marrow cells differentiation into CD11c+ DCs, with CD8a-subset; NGF could enhance LPS-induced cytokine secretion from DCs (IL-6, IL-10 and IL-12).