Fractalkine Human, His

Fractalkine, also known as CX3CL1, is a unique chemokine that plays a significant role in the immune system. It is characterized by a distinctive cysteine motif, -Cys-X-X-X-Cys-, at the N-terminal end, making it the only known member of the δ-chemokine family . Initially discovered in 1997, it was named neurotactin and fractalkine, with the latter name currently in use .

Fractalkine is synthesized as a membrane-bound molecule that mediates cell migration and adhesion . It signals through interaction with a single receptor, CX3CR1, which is expressed on various cell types, including monocytes, natural killer cells, T cells, microglia, and smooth muscle cells . The protein is upregulated in endothelial cells by inflammatory signals, highlighting its role in immune response and inflammation .

Recombinant human fractalkine (CX3CL1) with a His tag is produced using human embryonic kidney cells (HEK293) or mouse myeloma cell lines (NS0) . The His tag facilitates purification and detection of the protein. The recombinant protein is typically lyophilized from a filtered solution and can be reconstituted in phosphate-buffered saline (PBS) for use in various applications .

Recombinant fractalkine is used in research to study its role in immune cell signaling, migration, and adhesion. It is also utilized in functional assays to measure its chemoattractant activity. For instance, it has been shown to chemoattract BaF3 mouse pro-B cells transfected with mouse or human CX3CR1 . Additionally, it is used in binding assays to study its interaction with specific antibodies .

The recombinant protein is stable for up to 12 months when stored at -20 to -70°C. After reconstitution, it should be stored under sterile conditions at 2 to 8°C for up to one month or at -20 to -70°C for up to three months . It is essential to avoid repeated freeze-thaw cycles to maintain protein integrity .