Observation for the process of Vibrio vulnificus inducing dendritic cell apoptosis / 中华微生物学和免疫学杂志

ABSTRACT

Objective To observe the process of Vibrio vulnificus inducing dendritic cell strain apoptosis.Methods We established the mixed culture model of mouse dendritic cell ( DC 2.4 strain) and Vibrio vulnificus( Vv1.1758 strain ),analyzed morphological characteristics of cell apoptosis by DAPI fluorescence staining,detect DNA fragmentation level of apoptosis cells by DNA Ladder assay,analyze DC2.4 apoptosis rate by Annexin V FITC/PI staining,determine activities of caspase-3 and caspase-8 by means of spectrophotometric method and detect changes of mitochondrial transmembrane potential ( △ Ψm ) by JC-1 fluorescence labeling.Results After Vv1.1758 strain and DC2.4 cell were mixed and cultured for 4 h,DAPI fluorescence staining showed typical apoptosis characteristics-chromatin condensation and marginalization; DNA agarose gel electrophoresis showed apoptosis band; apoptosis rates at 2,4 and 6 h were respectively (37.8±9.8) ％,(54.3 ± 12.7 ) ％ and ( 68.2± 14.6 ) ％ ; Mitochondrial transmembrane potentials (△Ψm) at 1 h,2 h and 4 h reduced by 7.1％,16.1％ and 46.7％ respectively; caspase-8 activity increased at 1.5 h and reached the peak at 2 h [ (2.48±0.19) U/μg],while caspase-3 activity started to increase at 3h and reached the peak at 4 h [ ( 1.91 ±0.16) U/μg ].Conclusion Vibrio vulnificus could induce dendritic cells by two pathways: reducing mitochondrial transmembrane potential and activating caspase-8 promoter and finally activate effector caspase-3 to promote apoptosis.