Grant: Operating Grant

Polymorphonuclear neutrophils (PMNs) are the most abundant human blood leucocytes, and are considered the first non-specific defence line against infectious agents. Severe recurrent bacterial infections associated with inherited disorders have contributed to our understanding of the essential role of PMNs in bacterial killing and our innate immunity. The inability of PMNs to mount an appropriate immune response is associated with defective adherence, migration from the vascular bed to tissues, or release of various antimicrobial products. PMNs express on their cell surface various markers, of which many are receptors specific for endogenous molecules or components of bacterial cells. These receptors are only activated when they sense bacteria or cellular debris in their environment. In chronic inflammatory diseases inappropriate activation of PMNs causes tissue injuries and destruction. By delineating the processes regulating directed movement and activation of PMNs we may be better positioned to develop new therapeutic approaches to boost our immune system or to control excessive activation of these cells in chronic inflammatory diseases such as rheumatoid arthritis.