Regulation of decidual cell chemokine production by group B streptococci and purified bacterial cell wall components

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Objective: Our purpose was to determine whether cultured human decidual cells produce chemokines in response to different strains of group B streptococci and purified bacterial cell wall components. Study design: Human decidual cells were cultured from term placentas by standard techniques. Different strains of group B streptococci were isolated from neonates with early-onset group B streptococci sepsis. Confluent cell monolayers were incubated with these different strains of group B streptococci and various concentrations of purified bacterial cell wall components (including lipoteichoic acid, sialic acid, lipopolysaccharide, and lipid A) for 16 hours at 37° C. Culture supernatants were collected and assayed for macrophage inflammatory protein-1α and interleukin-8. Statistical analysis was by analysis of variance. Results: We found that cultured human decidual cells produced significant amounts of the two chemokines macrophage inflammatory protein-1α and interleukin-8 in a strain-specific fashion to the various different strains of group B streptococci tested, from 215% to 421% over baseline production ( p < 0.05 by analysis of variance). Also, we found that incubation of decidual cells with various concentrations of lipoteichoic acid, sialic acid, lipopolysaccharide, and lipid A resulted in significant concentration-dependent increases in decidual cell macrophage inflammatory protein-1α and interleukin-8 production ( p < 0.05.) CONCLUSIONS: Decidual cells produced significant amounts of the chemokines macrophage inflammatory protein-1α and interleukin-8 in response to intact group B streptococci in a strain-specific fashion and in response to various concentrations of different bacterial cell wall components. Because chemokines are important mediators signaling migration of different immune effector cells into areas of inflammation, we suggest that decidual cell chemokine production in response to bacteria and bacterial cell wall components may be a key early event in the pathogenesis of infection-associated preterm labor.