Fig. 1

Experiment 1 Experimental design to characterize the role of tick salivary proteins in allergic reactions to mammalian meat consumption in the zebrafish model of the α-Gal syndrome (AGS). Saliva from semi-engorged Ixodes ricinus female ticks was collected and used in this experiment. Wild type adult AB strain zebrafish (20 animals/group) were treated with PBS, saliva, saliva non-protein fraction (NPF) alone and combined with recombinant tick proteins metalloprotease (MET), allergen-like p23 (p23) and, as control, Subolesin (SUB). Zebrafish were kept on fish feed during pre-treatment and until Day 2. Zebrafish were injected with each treatment at Days 0 and 3, and from Day 2 and until the end of the experiment at Day 8 fish were fed with dog food containing mammalian meat. Zebrafish local hemorrhagic type allergic reactions, abnormal behavior patterns and feeding and accumulated mortality were examined from Day 1 and followed daily until the end of the experiment at Day 8. After fish euthanasia, serum was collected individually to determine IgM antibody titers against tick salivary glands (SG) protein extract, α-Gal and tick proteins. Intestine samples were collected for expression analysis of selected immune response and allergy gene markers by RT-qPCR.