CX3CL1 recently identified through bioinformatics is the only known member of the CX3C chemokine family and it is also commonly known under the names fractalkine (in humans) and neurotactin (in mice). Unlike other known chemokines, CX3CL1 is a type 1 membrane protein containing a chemokine domain tethered on a long mucinlike talk. The soluble form of CX3CL1 is chemotactic for T-cells and monocytes, but not for neutrophils. In addition, it may play a role in regulating leukocyte adhesion and migration processes at the endothelium. Recombinant Rat CX3CL1 contains 76 amino acids and it shares approximately 86 % and 83 % amino acid sequence homology with the murine and human protein.

> 95% as determined by SDS-PAGE; > 95% as determined by HPLC