Summary: Mast cells are key elements of the immune system. These cells release a wide variety of pro-inflammatory mediators which are responsible for the pathophysiology of many allergic diseases. Recent studies, however, have shown that mast cells have the capacity to modulate the host's innate immune response to gram negative bacteria by their ability to phagocytose bacteria, process and present bacterial antigens to T cells and recruit phagocytic help through the release of physiological amounts of pro-inflammatory mediators. Here, current knowledge of mast cell responses to gram negative bacteria and molecular mechanisms associated with mast cell bacteria interaction is reviewed.

This work was supported in part by NIH research grant AI45013. We are grateful to Ms. Tamara Paul for critical review of the manuscript.