SDF-1α cleavage by crude and lysine Sepharose-purified serum fractions. Recombinant SDF-1α (25 ng in 18 μL PBS) was incubated at room temperature for 10 minutes with serum, plasma or serum components, and subsequently immunoblotted with rabbit and goat anti-SDF-1α antibodies (10%). Lanes 1-3: SDF-1α incubated with 10% serum (100 μg), 1% serum (10 μg), or 0.1% (1 μg) serum, respectively. Lanes 4-6: SDF-1α incubated with 1 μg, 0.1 μg, or 0.01 μg lysine Sepharose fraction from purification of stored serum. Lane 7: SDF-1α incubated with 1 μg of the flow-through fraction from lysine Sepharose column. Lane 8: SDF-1α incubated with PBS.