Protective Pathogen Infection Against Tick-Induced Allergy in Zebrafish.

The α-Gal syndrome (AGS) links tick bites with delayed anaphylaxis to mammalian meat consumption. Recent work in zebrafish shows that the Ixodes ricinus salivary metalloprotease (MET) and allergen-like p23 trigger AGS-like responses, whereas subsequent infection with the mycobacterial fish pathogen, Mycobacterium marinum, skews immunity towards a protective Th1 profile. Here we provide a step-by-step protocol to: (i) reproduce tick-induced allergy in adult zebrafish, (ii) superimpose water-borne mycobacterial infection, and (iii) quantify clinical, serological, and molecular outcomes. The method allows exploration of host-pathogen-allergen interactions and evaluation of prophylactic interventions in a validated vertebrate animal model.