Recombinant Human PF-4/CXCL4

This lyophilized preparation is stable at 2-4C, but should be kept desiccated at -20C for long term storage. Upon reconstitution, the preparation is stable for up to one week at 2-4C. For maximal stability, apportion the reconstituted preparation into working aliquots and store at -20C to -80C. Avoid repeated freeze/thaw cycles.

Platelet Factor 4, is a member of the CXC chemokine family, CXCL4. CXCL4 has homology with IL8 and athromboglobulin. The active protein consists of a tetramer composed of individual CXCL4 subunits. Megakaryocytes synthesize CXCL4 and store it as tetramers in a-granules. The CXCL4 tetramers are secreted by activated platelets and can be measured at micromolar levels in serum. In contrast to other CXC chemokines, CXCL4 lacks chemotactic activity for polymorphonuclear granulocytes. CXCL4 does not contain an ELR motif. However, many other functions have been observed for CXCL4. CXCL4 is involved in monocyte survivial and differentiation into macrophages, and it has antiangiogenic activity. CXCL4 has been demonstrated to inhibit the binding of FGF2 to highaffinity receptors and its subsequent internalization. Cell surface neutrophil chondroitin sulfate chains serve as CXCL4 binding sites;, affinity is controlled by the degree of sulfation of these chains.

We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1% BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at <-20C. Further dilutions should be made in appropriate buffered solutions.

Less than 1EU/ug of rHuPF-4/CXCL4 as determined by LAL method.