Structure-guided deimmunisation of Fel d 1 suppresses allergic effector functions ex vivo

Abstract Allergic responses to the major cat allergen Fel d 1 are primarily driven by immunoglobulin E (IgE) cross-linking on effector cells. While conventional allergen-specific immunotherapies often rely on whole-allergen extracts with inherent risks of systemic reactions, rationally engineered variants offer a safer path to desensitisation. We present a structure-guided strategy to deimmunise Fel d 1 by selectively disrupting crucial IgE-binding interfaces. Using a computational pipeline integrating structural mapping and immunoinformatics, we designed 30 single-point mutations targeting immunodominant regions. Ex vivo functional evaluation using sera from cat-allergic individuals demonstrated that specific variants, notably K29G in Chain 1, exhibited significantly diminished IgE reactivity and profoundly suppressed basophil activation. Furthermore, CRISPR/Cas9-mediated introduction of the K29G mutation into feline fibroblasts confirmed that the substitution preserves fundamental cellular proliferation. This work demonstrates that targeted computational design can not only yield superior candidates for safer immunotherapeutics but also establish a viable foundation for generating genetically edited, hypoallergenic cats.