Objective To explore the effects of intracellular calcium concentration ([Ca2 + ]i )and signal transducers and activators of transcription 3 (STAT3 )signaling pathway on the invasion of Vibrio vuknificus (Vv )clinical isolates B2 into dendritic cells (DC).Methods The co-culture model of Vv B2 and DC 2.4 was constructed.Apoptosis and necrosis rates in different invasion phases were detected by flow cytometry.The calcium fluorescence probe Fluo-8-AM was used to detect the change of [Ca2 + ]i ,and Western blot and immunofluorescent techniques were used to explore the relative molecular expressions and intracellular distributions of STAT3 and phosphorylation STAT3 [p-STAT3 (705 )].Data were analyzed by t-test.Results After co-culture ofVv B2 and DC 2.4,the apoptosis rates of 1 ,2,3 and 4 h were (13.10±4.72)%,(30.10±3.52)%,(46.20±15 .61)% and(31 .00 ±19.10)%,respectively.The differences were statistical significant between Vv standard strain (1 .1758)and Vv B2 (t=4.30,22.33, 4.30 and 4.30,respectively;P =0.040,0.002,0.040 and 0.040,respectively).The necrosis rates of 1 , 2,3 and 4 h in co-culture of Vv B2 and DC 2.4 were(19.70 ±3.50 )%,(39.20±4.60 )%,(40.90 ± 13.80)% and (62.10 ± 8.20 )%,respectively.The differences were statistical significant between Vv 1 .1758 andVv B2 (t=9.93,14.09,4.30 and 14.09,respectively;P =0.010,0.005 ,0.049 and 0.005 , respectively).Compared to Vv 1 .1758,Vv B2 induced more apparent cell apoptosis and necrosis within the same time.By fluorescence microscope,intensity of calcium was enhanced with the rising of apoptosis. Although the total expression of STAT3 increased,the relative molecular expression of p-STAT3 (705 ) decreased.There was no significant difference in its distribution in cells compared to the blank group. Conclusion The rapid apoptosis and necrosis of DC during Vv B2 invasion into DC may be caused by increasing [Ca2 + ]i and inhibiting phosphorylation of p-STAT3 (705)simultaneously.