Smooth and rough lipopolysaccharide phenotypes of Brucella induce different intracellular trafficking and cytokine/chemokine release in human monocytes.

Virulence of the intracellular pathogen Brucella for humans is mainly associated with its lipopolysaccharide (LPS) phenotype, with smooth LPS phenotypes generally being virulent and rough ones not. The reason for this association is not quite understood. We now demonstrate by flow cytometry, electron microscopy, and ELISA that human peripheral blood monocytes interact both quantitatively and qualitatively different with smooth and rough Brucella organisms in vitro.

Chemokine receptor expression and chemotactic responsiveness of human monocytes after influenza A virus infection.

Chemokines and their receptors play an important role in site-directed migration and activation of leukocytes. To understand how viral infections may impair this function, we analyzed chemokine receptor expression and responsiveness of human monocytes after infection with influenza A virus. Whereas treatment with infectious virus induced a rapid down-regulation of the CCL2/monocyte chemoattractant protein-1 (MCP-1)-specific receptor CCR2, inactivated virus did not significantly alter CCR2 surface expression.