SDF-1-alpha and SDF-1-beta are small cytokines belonging to the CXC- Chemokines. SDF-1 is identical with a chemokine reported to function as a pre-B-cell growth factor in the presence of IL-7 and isolated originally from a murine bone marrow stromal cell line. Human SDF-1-alpha and SDF-1-beta are encoded by a single gene and arise by alternative splicing. SDF-1 acts on lymphocytes and monocytes but not neutrophils in vitro and is a highly potent chemoattractant for mononuclear cells in vivo. In addition. SDF-1 also induces intracellular actin polymerization in lymphocytes. SDF acts as a chemoattractant for human hematopoietic progenitor cells expressing CD34 giving rise to mixed types of progenitors, and more primitive types. The chemotactic response is inhibited by pertussis toxin. Chemotaxis of CD34(+) cells in response to SDF is increased by IL-3 in vitro. SDF has been shown also to induce a transient elevation of cytoplasmic calcium in these cells.
<1.0 EU/μg of recombinant protein as determined by the LAL method.
Biological Activity Comment
Determined by its ability to chemoattract human peripheral T cells activated with PHA and IL-2 using a concentration range of 5.0-40 ng/mL.
Weight
8.0 kDa
Description
A quick spin of the vial followed by reconstitution in distilled water to a concentration not less than 0.1 mg/mL. This solution can then be diluted into other buffers.
Format
Lyophilized PowderLyophilized from a 0.2 μm filtered solution in 2.5% glycine, 0.5% sucrose, 0.01% Tween80, 5 mM Glutamic acid, pH 4.5.
Purity
>95% as determined by SDS-PAGE
Storage
The lyophilized protein is stable for at least one year from date of receipt at -70°C. Upon reconstitution, this cytokine can be stored in working aliquots at 2° - 8°C for one month, or at -20°C for six months, with a carrier protein without detectable loss of activity. Avoid repeated freeze/thaw cycles.