Binding to chondroitin sulfate chains protects CCL2 from protease-mediated degradation. (A) CCL2 was pre-incubated with chondroitin sulfate (CS) or vehicle, and treated with a series of proteases including elastase, cathepsin G, and trypsin. A representative immunoblot from three different experiments shows a band corresponding to intact CCL2 (10 kDa). (B) Amount of intact CCL2 in individual wells precoated with CS or vehicle, and subsequently treated with a series of proteases. Mean and standard deviation of three independent measurements is shown. The quantity of intact CCL2 in individual samples was expressed as a percentage of the quantity of CCL2 on wells precoated with CS and not treated with protease.