Interaction of Burkholderia pseudomallei and Burkholderia thailandensis with human monocyte-derived dendritic cells.

Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic in areas of South-East Asia and northern Australia, and is classed as a category B select agent by the Centers for Disease Control and Prevention (CDC). Factors that determine whether host infection is achieved or if disease is chronic or acute are unknown but the type of host immune response that is mounted is important. B. pseudomallei can replicate within macrophages, causing them to multinucleate. In light of the common lineage of macrophages with dendritic cells (DCs), and the role played by DCs in orchestration of the immune response, we investigated the interactions of a variety of B. pseudomallei and B. thailandensis strains with DCs. This study demonstrates that, in the majority of cases, infection of human monocyte-derived dendritic cells is dramatically decreased or cleared by 12 h post-infection, showing a lack of ability to replicate and survive within DCs. Additionally we have shown that B. pseudomallei activates DCs, as measured by cytokine secretion, and live bacteria are not required for activation.