Figure 2.

The expression of four recombinant interleukin-32 (rIL-32) isoform proteins and verification of their specificity by neutrophil proteinase 3 (PR3). (a) Four rIL-32 isoform proteins, indicated by letter at the top of the lane, were purified by a multi-step purification procedure and then each rIL-32 protein (50 ng/lane) was applied for sodium dodecyl sulphate–polyacrylamide gel electrophoresis/silver stain to evaluate their purity. (b) The verification of rIL-32 isoform protein by PR3, which is a specific binding protein for IL-32 and has the ability to digest IL-32 in a very specific manner.