SlyA regulates function of Salmonella pathogenicity island 2 (SPI-2) and expression of SPI-2-associated genes.

During the systemic phase of murine infection with Salmonella enterica serovar Typhimurium, bacterial virulence is correlated with the ability to grow and survive within host macrophages. Salmonella pathogenicity island 2 (SPI-2), encoding a type three secretion system, has emerged as an important contributor to Salmonella intracellular growth. SPI-2 mutants have been proposed to be more accessible than wild-type Salmonella to oxyradicals generated by the NADPH phagocyte oxidase.

Enhanced expression of the mannose receptor by endothelial cells of the liver and spleen microvascular beds in the macrophage-deficient PU.1 null mouse.

Mice null for the haematopoietic lineage-specific transcription factor PU.1 lack mature Mphi and are compromised in their ability to clear cellular debris from the blood circulation. We investigated the possibility that non-professional phagocytes may partially compensate for the lack of Mphi in clearance functions.

The mannose receptor is expressed by subsets of APC in non-lymphoid organs.

Background: The mannose receptor (MR) is an endocytic receptor of Mphi and endothelial cell subsets whose natural ligands include both self glycoproteins and microbial glycans. It is also expressed by immature cultured dendritic cells (DC), where it mediates high efficiency uptake of glycosylated antigens, yet its role in antigen handling in vivo is unknown. Knowledge of which APC subsets express MR will assist the design of experiments to address its immunological functions.

IL-4 receptor signaling is required for mannose receptor expression by macrophages recruited to granulomata but not resident cells in mice infected with Schistosoma mansoni.

High levels of mannose receptor (MR) expression and pinocytic activity are a hallmark of Th2 cytokine-driven alternative MPhi activation in vitro. We examined expression of MR in situ and its regulation by Th1/Th2 cytokines in IL-4Ralpha -/- and wild-type (WT) mice challenged with Schistosoma mansoni. Parasite eggs induce a vigorous granulomatous response, driven by Th2 cytokines in WT mice, but by Th1 cytokines in IL-4Ralpha -/- mice.

The interplay between Salmonella typhimurium and its macrophage host--what can it teach us about innate immunity?

Salmonella enterica sv. Typhimurium (S. typhimurium) is a genetically tractable, facultative intracellular pathogen, whose capacity to cause systemic disease in mice depends upon its ability to survive and replicate within macrophages.