Engineeredtargets the IgT-pIgR axis to confer mucosal protection againstin snakehead ().

Abstract

INTRODUCTION: remains a pervasive aquatic pathogen precipitating catastrophic economic depletion and threats to global food security. Conventional therapeutic modalities are constrained by inadequate stability, prohibitive costs, and biosafety risks. METHODS: To address such challenges, an engineeredstrain was developed to constitutively express theouter membrane protein OmpAI through a tandem promoter system to ensure optimized antigen delivery. RESULTS: Anal intubation with engineeredinstimulated compartmentalized mucosal immunity, evidenced by a six-fold elevation in hindgut IgT transcripts, significant infiltration of IgTB cells, and pIgR mediated transcytosis, synchronized with systemic IgM activation. The probiotic treament accelerated pathogen clearance, improved survival rates to 42.9% compared to 12.5% in control group, and reorganized the commensal microbiome through a specific enrichment of beneficial. DISCUSSION: This study elucidated a novel engineered-probiotic mucosal vaccination strategy for teleosts, providing a noninvasive, mucosal targeted immunoprophylactic strategy to decrease antibiotic dependency in aquaculture.