Objective    To construct melanoma B16 cells which can stably express mouse β defensin 2 (B16-mBD2)

and to investigate the effect of mBD2 on the biological characteristics of B16 cells.     Methods    After constructing the eukaryotic expression plasmid of mBD2

we transfected B16 cells with the plasmid using Liposome 2000 and screened transfected B16 cells with 400 mg/L G418 for 8 weeks to obtain stably expressed B16-mBD2 cells. Identification of the sta

ble expression of mBD2 cells was confirmed by RT-PCR and Western blot. MTT assay was used to determine the growth curve of B16-mBD2 cells. Flow cytometry was used to detect the cell cycle distribution

apoptosis and expression of cell membrane surface molecules such as CD80

CD86

MHCⅠ(H-2K

d

) and MHCⅡ (I-A

d

).     Results    B16-mBD2 cells were constructed. The stable expression of mBD2 was confirmed by RT-PCR and Western blot at the mRNA and protein levels. Compared with that of empty-vector-transfected B16 cells (B16-p) or wild-type B16 cells

the proliferation of B16-mBD2 cells decreased significantly (P0.05). Flow cytometry analysis showed that compared with that of B16-p or B16 cells

the proportion of B16-mBD2 cells in S phase increased significantly (P0.05). The apoptosis and expression of cell membrane surface molecules

such as CD80

CD86

MHCⅠ(H-2K

d

) and MHCⅡ(I-A

d

) in the three cells were not significantly different (P0.05).     Conclusion    mBD2 significantly inhibits the proliferation of B16 cells

and the mechanism seems to be related to its capacity in inducing S phase blocking. mBD2 has no effect on the apoptosis and expression of cell membrane surface molecules in B16 cells.