Abstract: Objective 1) To investigate the apoptotic gene expression profile in T lymphocytes after aggregatibacter actinomycetemcomitans (A.actinomycetemcomitans) cytolethal distending toxin (CDT) infection,and to find out the molecules involved in this process.2) To explore mechanisms of the development and progression of aggressive periodontitis (AgP),and to provide potential biomarkers for diagnosis and therapy.Methods After human Jurkat cells were treated by A.actinomycetemcomitans CDT for 24 hours,annexin V/PI detection andelectron microscopy technology was employed to detect the apoptosis.Apoptotic gene expression was examined by quantitative real-time PCR.Results By flow cytometry,the proportion of apoptotic cells was 29.1% in treatment groups,and that in the control group was 6.3%.The typical features of apoptosis were observed under transmission electron microscopy in treatment groups,such as cell shrinkage,chromatin condensation,and marginalization.Five pro-apoptotic genes were upregulated,including GADD45A、TNFSF8、TRADD、TNFRSF10B and TP53.Conclusions A.actinomycetemcomitans CDT could promote apoptosis of human T lymphocytes,and the expression of related pro-apoptotic genes increases during this process.

Key words: Aggregatibacter actinomycetemcomitans, cytolethal distending toxin, human Jurkat cells, apoptosis