Activation of resin with controllable ligand density via catalytic oxa-Michael addition and application in antibody purification.

This article reported a new strategy for resin activation with divinyl sulfone using catalytic oxa-Michael addition in a controllable manner. By screening a variety of organocatalysts, PPh3 and DMAP stand out with high catalytic efficiency in aprotic solutions. X-ray photoelectron spectroscopy (XPS) analysis indicates high reaction efficiency and less side reactions than traditional aqueous reactions, resulting in high activation density. A maximum activation density of 157.5 ±â€¯1.2 µmol/g resin was achieved in 12 h using PPh3 as catalyst, which is 1.5 times higher than the traditional aqueous reactions. Followed by conjugation with a chromatographic ligand, i.e., 4-mercaptoethyl pyridine (MEP), the resin is capable of antibody purification. Using IgG and BSA as model proteins, adsorption isotherms and dynamic binding behavior of the resin samples were investigated. A higher affinity and dynamic binding capacity of IgG was observed on resins with higher ligand density. Finally, the resin samples were applied to the purification of a therapeutic monoclonal antibody from cell culture supernatant. The recovery of the resin samples with high ligand density are 70% higher than those of the commercial resin (MEP HyperCel). Moreover, our method achieves a controllable chromatographic ligand density by varying reaction times, which is useful to clarify the density-affinity relationship and improve process-scale antibody purification.

Pharmacological Therapy of Bronchial Asthma: The Role of Biologicals.

Bronchial asthma is a heterogeneous, complex, chronic inflammatory and obstructive pulmonary disease driven by various pathways to present with different phenotypes. A small proportion of asthmatics (5-10%) suffer from severe asthma with symptoms that cannot be controlled by guideline therapy with high doses of inhaled steroids plus a second controller, such as long-acting ß2 agonists (LABA) or leukotriene receptor antagonists, or even systemic steroids. The discovery and characterization of the pathways that drive different asthma phenotypes have opened up new therapeutic avenues for asthma treatment. The approval of the humanized anti-IgE antibody omalizumab for the treatment of severe allergic asthma has paved the way for other cytokine-targeting therapies, particularly those targeting interleukin (IL)-4, IL-5, IL-9, IL-13, IL-17, and IL-23 and the epithelium-derived cytokines IL-25, IL-33, and thymic stromal lymphopoietin. Knowledge of the molecular basis of asthma phenotypes has helped, and continues to help, the development of novel biologicals that target a diverse array of phenotype-specific molecular targets in patients suffering from severe asthma. This review summarizes potential therapeutic approaches that are likely to show clinical efficacy in the near future, focusing on biologicals as promising novel therapies for severe asthma.