Neutrophil extracellular traps are involved in enhanced contact hypersensitivity response in IL-36 receptor antagonist-deficient mice.

Loss-of-function homozygous or compound heterozygous mutations in IL36RN, which encodes interleukin-36 receptor antagonist (IL-36Ra), have been implicated in the pathogenesis of skin disorders. We previously reported that Il36rn-/- mice exhibit an enhanced contact hypersensitivity (CHS) response through increased neutrophil recruitment. In addition, Il36rn-/- mice show severe imiquimod-induced psoriatic skin lesions and enhanced neutrophil extracellular trap (NET) formation. We hypothesized that NETs may play an important role in the CHS response. To confirm this, we examined the CHS response and NET formation in Il36rn-/- mice. Il36rn-/- mice showed enhanced CHS responses, increased infiltration of inflammatory cells, including neutrophils, CD4+ T cells, and CD8+ T cells, NET formation, and enhanced mRNA expression of cytokines and chemokines, including IL-1ß, C-X-C motif chemokine ligand (CXCL)1, CXCL2, and IL-36γ. Furthermore, NET formation blockade improved the CHS response, which consequently decreased inflammatory cell infiltration and NET formation. Consistently, we observed decreased expression of these cytokines and chemokines. These findings indicate that IL-36Ra deficiency aggravates the CHS response caused by excessive inflammatory cell recruitment, NET formation, and cytokine and chemokine production, and that NET formation blockade alleviates the CHS response. Thus, NET formation may play a prominent role in the CHS response.

A Novel Surface Modification and Immobilization Method of Anti-CD25 Antibody on Nonwoven Fabric Filter Removing Regulatory T Cells Selectively.

Anti-CD25 antibodies were immobilized on polypropylene (PP) nonwoven fabrics to specifically remove mouse regulatory T cells (Tregs) from mouse spleen cells. PP fibers were coated with peptide nanosheets, which were prepared by self-assembling of a mixture of X-poly(sarcosine)-b-(l-Leu-Aib)6 (X: glycolic acid or a phenylboronic acid) and Y-poly(sarcosine)-b-(d-Leu-Aib)6 (Y: glycolic acid or diazirine derivative). Anti-CD25 antibodies were immobilized by covalent linking between the sugar moiety of the antibody and the phenylboronic acid group on the peptide nanosheet. The removal rate of mouse Tregs from the mouse spleen cells was more than 95% only by passing the filters, while the nonspecific removal rates of other cells were less than 15%. The coating of peptide nanosheets on PP fibers was very effective to provide a suitable environment for the immobilized antibody to interact with the counterpart cells while the coating suppressed nonspecific adsorption of other cells.