Detection, identification and characterization of posttranslationally modified CXC chemokines involved in auto-immune diseases.

During pathological processes including acute and auto-immune inflammation, microbial infection and tumor growth, white blood cells migrate from blood to tissues and vice versa. Directional leukocyte migration is regulated by adhesion molecules, cytokines, chemokines and proteases. Chemokines are proteins that attract leukocytes along a chemokine concentration gradient. Posttranslational modifications (PTM) such as limited truncation and alterations of amino acid side chains have been identified on natural chemokines. Although for some modified chemokines, increased or decreased in vitro activity has been reported, information is limited for other chemokine forms. Knowledge on the overall effect of PTM of chemokines in a complex in vivo situation is almost non-existing due to (1) currently available detection methods which do not discriminate between naturally modified forms of a single chemokine and (2) insufficient quantities of pure protein of the specific chemokine forms necessary for in vivo evaluation. Therefore, it is not known whether a chemokine detected by such non-discriminating technique in patient samples promotes or inhibits the pathology. With this project we wish (1) to discover novel naturally occurring chemokine PTMs, (2) to produce modified chemokines in sufficient amounts to be able to analyze the biological effects of PTMs, and (3) to develop detection methods that discriminate between specifically modified chemokines in complex body fluids.