Injection of T3SS effectors not resulting in invasion is the main targeting mechanism of Shigella toward human lymphocytes

Significance Invasion of human intestinal epithelial cells resulting from the delivery of bacterial effectors into the host cell cytoplasm via a type III secretion system (T3SS) is the hallmark of Shigella , the causal agent of bacillary dysentery. Here, we provide evidence that human lymphocytes are mainly targeted by injection of T3SS effectors not resulting in cell invasion. These findings highlight the diversity of mechanisms triggered by Shigella to enlarge the panel of targeted cells and thus counteract host immunity, including adaptive immune responses. The potential impact of these data on vaccine design, in particular for live-attenuated vaccine candidates, deserves further investigation.