New insights into the crosstalk between Shigella and T lymphocytes

• Shigella invades activated but not unactivated T lymphocytes in vitro.
• T lymphocyte invasion by Shigella also occurs upon in vivo infection.
• Shigella via its type III secretion system (T3SS) effector IpgD inhibits T cell migration in vitro.
• Bacterial invasion and induction of inflammation impair T cell dynamics in vivo.

Subversion of host immune responses is the key infection strategy employed by most, if not all, human pathogens. Modulation of the host innate response by pathogens has been vastly documented. Yet, especially for bacterial infections, it was only recently that cells of the adaptive immune response were recognized as targets of bacterial weapons such as the type III secretion system (T3SS) and its effector proteins. In this review, we focus on the recent advances made in the understanding of how the enteroinvasive bacterium Shigella flexneri interferes with the host adaptive response by targeting T lymphocytes, especially their migration capacities.