Mature human SDF-1α shares 100% amino acid sequence homology with rhesus macaque and feline SDF-1α.

SDF-1α/PBSF, a member of the α (CXC) chemokine family, is a chemoattractant for T lymphocytes and monocytes, but not neutrophils. SDF-1α/PBSF is highly conserved between species, with only one amino acid substitution between the human and mouse proteins. SDF-1α and SDF-1β are encoded by a single gene and arise by alternative splicing. The two proteins are identical except for the four amino acid residues that are present in the C-terminal of SDF-1β and absent from SDF-1α.. SDF-1/PBSF is a ligand for CXCR4 receptor that functions as a coreceptor for lymphocyte-tropic HIV-1 strains. SDF-1/PBSF is a powerful inhibitor of infection by lymphocyte-tropic HIV-1 strains.

Lyophilized from a 0.2 μm filtered solution in 30% acetonitrile and 0.1% trifluoracetic acid containing 0.5 mg bovine serum albumin.

The biological activity can be measured by its ability to chemoattract 5-10 day cultured human T lymphocytes or chemoattract BaF/3 human CXCR4 cells.