The role of inflammatory cells in the pathogenesis of hemolytic-uremic syndrome induced by Shiga toxin (Stx)-producing Escherichia coli remains unclear. The hypothesis that Stx has direct effects on polymorphonuclear cell (PMN) viability and function was examined by measuring apoptosis, necrosis, phagocytosis, and spontaneous and phorbol myristate acetate (PMA)-stimulated production of reactive oxygen intermediates. PMN from 6 healthy persons were exposed to medium, Stx1 (0.01-100 ng/mL), or heat-inactivated Stx1 or Stx1 B subunit (100 ng/mL). Stx1 induced a prominent dose-dependent respiratory burst from PMN at doses as low as 0.01 ng/mL; they were less responsive to PMA stimulation and had reduced ability for phagocytosis. This dysfunction was not due to cell death, as the magnitude of apoptosis and necrosis of PMN treated with Stx1 (100 ng/mL) for 20 h was identical to that of medium control. These results suggest that Stx has direct effects on PMN that could contribute to tissue injury early in the disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.