Plague, one lymph node at a time

Abstract

Microbiology![Figure][1] The bacterium that causes plague, Yersinia pestis , in false color CREDIT: EYE OF SCIENCE/SCIENCE SOURCE Swollen lymph nodes, or buboes, are the hallmark of plague, which is caused by the pathogen Yersinia pestis . Buboes result from a massive influx of immune cells into draining lymph nodes (DLNs). Recently, Y. pestis was shown to disseminate by carriage within immune cells migrating from one DLN to the next. Arifuzzaman et al. investigated how Y. pestis exploits the features of buboes to promote pathogenesis. Infiltration of infected monocytic cells into tightly packed buboes coincided with cytolysis triggered by Yersinia outer protein J, resulting in the release of intracellular bacteria and extensive infection of neighboring cells. The dying monocytic cells released sphingosine 1-phosphate (S1P), which attracted yet more cells, and up-regulated expression of the S1P receptor promoted the exit of newly infected monocytic cells from buboes. Preventing necrotic cell death protected mice from otherwise lethal infection. Thus, Y. pestis commandeers cell-death and immune-cell trafficking programs to convert the host's DLNs into specialized hubs for dissemination. JCI Insight 3 , e122188 (2018). [1]: pending:yes