Lyophilized powder may be stored at -20 degree C. Stable for 12 months at -20 degree C. Reconstitute with PBS. Aliquot to avoid repeated freezing and thawing. Store at -20 degree C. Reconstituted product is stable for 12 months at -20 degree C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.