Qi Sun,Guangqing Mu,Peng Sun,Qing Zhao,Xiaomeng Wu,Fanhua Kong
Casein (CN) is the primary factor leading to allergic reactions in infants to bovine milk, severely limiting the intake of bovine milk formula by allergic infants. This study investigates the conformational changes and regulation of linear epitopes during the hydrolysis of CN by five proteases derived from microbial and plant sources using multiple spectroscopic techniques combined with LC/MS-MS. The results showed that the IgE inhibition rates for SD (subtilisin hydrolysate), PD (papain hydrolysate), BD (bromelain hydrolysate), KD (proteinase K hydrolysate), and FD (ficin hydrolysate) were 43.19%, 41.99%, 35.45%, 48.15%, and 14.80%, respectively. The differences in antigenic residues remaining after hydrolysis by different proteases mainly result from the varying degrees of structural alteration of CN and the hydrolysis allergic epitope regions. This study provides theoretical basis for understanding the mechanism by which proteases reduce the allergenicity of CN. It also offers new insights into the development of multienzyme combinatorial hydrolysis strategies.
Epicutaneous immunotherapy (EPIT) is effective and safe to induce sustained protection against anaphylaxis with small doses of allergens. To penetrate the barrier of the stratum corneum, a coaxial nanofiber patch is designed that incorporates natural phase-change materials (PCM) for mild hyperthermia-assisted skin permeability, while minimizing the risk of systemic events during immunotherapy. For adaptive immune activation, Toll-like receptor 7/8 ligand of resiquimod (R848) is combined with ovalbumin (OVA) allergen, thereby stimulating the Th1 pathway and strengthening therapeutic efficacy. For sequential administration, coaxial electrospinning technology is utilized for multiple drug encapsulation and sequential release, where the shell layer consists of poly(vinyl alcohol) (PVA) with OVA dispersion, and the core region is a mixture of PCM and R848. Under mild hyperthermia irritation, the nanofiber patches perform an efficient immunomodulation by manipulating the skin immune system via allergen/adjuvant combinations, which inhibits the secretion of OVA-specific IgE, and improves lung functions sufficiently in a mouse model of allergic asthma. Mechanistically, the treatment favors IgG2a expression from a Th1-biased immune response and induces protective regulatory immunity against allergen exposure. Overall, the simplicity and potency of mild hyperthermia mediated EPIT qualifies as a translational strategy for IgE-mediated allergies with long-lasting curative effects.
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