Recombinant Human CX3CL1/Fractalkine

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.

Recombinant human CX3CL1 is a single, non-glycosylated poly-peptide chain containing 76 amino acids. Fractalkine, also named neurotactin, is a novel chemokine recently identified through bioinformatics. Fractalkine has a unique CX3-C cysteine motif near the amino-terminus and is the first member of a fourth branch of the chemokine superfamily. Unlike other known chemokines, fractalkine is a type 1 membrane protein containing a chemokine domain tethered on a long mucin-like stalk. Human fractalkine cDNA encodes a 397 amino acid (a.a.) residue membrane protein with a 24 aa residue predicted signal peptide, a 76 aa residue chemokine domain, a 241 aa residue stalk region containing 17 degenerate mucin-like repeats, a 19 aa residue transmembrane segment and a 37 aa residue cytoplasmic domain. The extracellular domain of human fractalkine can be released, possibly by proteolysis at the dibasic cleavage site proximal to the membrane, to generate soluble fractalkine. The soluble chemokine domain of human fractalkine was reported to be chemotactic for T cells and monocytes while the soluble chemokine domain of mouse fractalkine was reported to chemoattract neutrophils and T-lympho-cytes but not monocytes.

Centrifuge vial prior to opening. Add sterile distilled water or aqueous buffer to a concentration of 0.1-1.0 mg/mL. Further dilutions should be made in appropriate buffered solutions.

Fully biologically active when compared to standard. The ED50 determined by a chemotaxis bioassay using human T-lymphocytes is less than 10 ng/ml.