Fig. 3.

Immunoblot analysis of HDL stored with and without cryoprotectants. HDL was isolated from serum by density gradient ultracentrifugation. HDL was stored at −20°C or −70°C in the presence or absence of 25% glycerol or 5% sucrose for 25 weeks. Three samples for each condition (control, glycerol, or sucrose) from three individual donors are shown. Proteins were separated by native gel electrophoresis and blotted onto PVDF membranes. Blots were probed using antibodies for apoA-I, apoA-II, apoC-I, and SAA. Total protein was visualized after blotting by Ponceau red staining. The dashed line indicates the typical size range of HDL₂ and HDL₃ ranging from about 8 to 12 nm.