Hybrid Adjuvant-Allergen H1sD2 Proteoforms Enhance Innate Immunity Activation via Distinct N-Glycosylation Profiles.

Novel adjuvants are key to making allergen-specific immunotherapy (AIT) safer and more effective. Their development is crucial for moving AIT into a new generation of precision medicine. N-glycosylation of protein antigens plays a pivotal role in modulating innate immune responses through enhanced recognition by pattern recognition receptors. New AIT vaccine strategies aim to exploit this by using innate-targeting adjuvants, modifying allergen structures, and routing early responses toward tolerance. Thus, we engineered five distinct N-glycosylated adjuvant configurations, composed of the receptor-binding domain of hemagglutinin (H1s) and Der p 2 (D2) allergen, to explore how glycan profile affects innate immune response for the application in therapeutic strategies for Type 1 hypersensitivity. Glycoengineered proteoforms produced in Pichia pastoris were structurally verified by mass spectrometry. Using M0 and M2 THP-1-derived macrophages, binding of all H1sD2 proteoforms to DC-SIGN was confirmed via confocal microscopy and flow cytometry. Stimulation of PBMCs with these proteoforms led to increased IL-10 and IFN-γ levels, indicating a shift toward regulatory immune responses. Notably, the M2 glycovariant elicited the strongest immunomodulatory signature, suggesting significant promise as a therapeutic candidate. These findings support the potential of glycoengineered allergen-adjuvant proteoforms to fine-tune innate immunity and improve the safety and efficacy of AIT.