Syphilitic infection impairs immunity by inducing both apoptosis and pyroptosis of CD4 <sup>+</sup> and CD8 <sup>+</sup> T lymphocytes
Wei Xia, Jinxue Zhao, Bin Su, Yan‐Mei Jiao, Wenjia Weng, Ming Zhang, Xiaodan Wang, Caiping Guo, Hao Wu, Tong Zhang, Yanqing Gao, Zaicun Li
Abstract
Syphilis is an important health problem worldwide; however, few studies have probed the impact of syphilitic infection on T cell turnover. The mechanisms behind the frequency of T cell subset changes and the associations between these subsets during syphilitic infection remain unclear. Herein, we used a cell-staining method and flow cytometry to explore changes in T cell subpopulations and potential contribution of apoptosis and pyroptosis that triggered therein. We investigated caspase-1-mediated pyroptosis and caspase-3-mediated apoptosis of CD4 + and CD8 + T cells, the major effector lymphocytes with pivotal roles in the pathogenesis of infectious diseases. We found that the levels of caspase-1 and caspase-3 increased in both the circulation and intracellularly in CD4 + and CD8 + T cells. Caspase-1 showed a continual increase from early latent stage infection through to phase 2 disease, whereas caspase-3 increased through to phase 1 disease but declined during phase 2. In addition, serum levels and intracellular expression of caspase-1 and caspase-3 were positively correlated. Overall, this study increases our understanding of how syphilitic infection influences CD4 + and CD8 + T-cell turnover, which may help with designing novel and effective strategies to control syphilis infection and prevent its transmission.