Proteomics and leukocytes: an approach to understanding potential molecular mechanisms of inflammatory responses

Leukocytes play an important role in the progression of disease and leukocyte-derived proteins are associated with the pathogenesis of the disease. Leukocyte activation causes production of inflammatory mediators, over-expression of cell surface adhesion molecules, and an increase in migration and infiltration, phagocytosis, and degranulation, as well as receptor phosphorylation and signal transduction. An increasing number of studies on the application of leukocyte proteomics have appeared in mapping protein profiles of inflammatory cells, contributing to the understanding of potential mechanisms involved in leukocyte function. Together with improvements in proteomic technology in leukocyte research, leukocyte proteomic analysis becomes more simple, rapid, flexible, sensitive, and specific. This enables proteomic investigation of activated or non-activated leukocytes to be highly focused on defined suborgans or specific signaling pathways. Research in leukocyte proteomics is progressing from fingerprinting to functioning, human cell lines to primary leukocytes, non-activated cells to inflammatory mediator-stimulated cells, in vitro culture to in vivo challenge, and animal models to human disease. A number of newly identified proteins from leukocyte proteomics may offer new mechanism-orientated targets for drug discovery and development.