Proteinase 3-processed form of the recombinant IL-32 separate domain.

Interleukin-32 (IL-32) induces a variety of proinflammatory cytokines and chemokines. The IL-32 transcript was reported originally in activated T cells; subsequently, it was demonstrated to be abundantly expressed in epithelial and endothelial cells upon stimulation with inflammatory cytokines. IL-32 is regulated robustly by other major proinflammatory cytokines, thereby suggesting that IL-32 is crucial to inflammation and immune responses. Recently, an IL-32alpha-affinity column was employed in order to isolate an IL-32 binding protein, neutrophil proteinase 3 (PR3). Proteinase 3 processes a variety of inflammatory cytokines, including TNFalpha, IL-1beta, IL-8, and IL-32, thereby enhancing their biological activities. In the current study, we designed four PR3-cleaved IL-32 separate domains, identified by potential PR3 cleavage sites in the IL-32alpha and gamma polypeptides. The separate domains of the IL-32 isoforms alpha and gamma were more active than the intrinsic alpha and gamma isoforms. Interestingly, the N-terminal IL-32 isoform gamma separate domain evidenced the highest levels of biological activity among the IL-32 separate domains.