Host responses to secreted Shigella virulence factors

Shigella and related enteropathogens deliver effector molecules into the cy toplasm of epithelial cells and macrophages via a type III secretion system . Epithelial cells respond to contact with Shigella by rearranging the cyto skeleton, which leads to uptake of the bacterium. Apart from several cytosk eletal proteins, this process involves the recruitment and activation of ki nases, and the small GTPase rho, Macrophages infected with Shigella undergo apoptosis and release mature IL-1 beta, a pro-inflammatory cytokine. This apoptotic pathway requires caspase-1 (IL-1 beta-converting enzyme). Pro-inf lammatory macrophage apoptosis triggers acute shigellosis and might be rele vant in other infectious diseases. Curr Opin Infect Dis 12:221-228. (C) 199 9 Lippincott Williams & Wilkins.