Neuroimmune circuits involved in β-lactoglobulin-induced food allergy

Cow’s milk allergy is the most prevalent food allergy that usually begins early in life and β- lactoglobulin (BLG) is the milk component with the highest allergenicity. It has been described that ovalbumin (OVA)-induced food allergy in mice is associated with anxiety and aversive behavior. However, it is yet to be determined whether altered behavior is a general component of food allergy or whether it is specific for some types of allergens. Thus, we investigated behavioral and neuroimmune circuits triggered by allergic sensitization to BLG. We found a neuroimmune conflict between aversion and reward in a model of food allergy induced to BLG. Mice sensitized to BLG did not present aversive behavior when the allergen was used for sensitization and oral challenge. Mice allergic to BLG preferred to drink the allergen-containing solution over water even though they presented high levels of specific IgE, inflammatory cells in the intestinal mucosa and significant weight loss. When sensitized to OVA and orally challenged with the same antigen, mice had display neuron activation in the amygdala suggesting an anxiety-related sensation. On the other hand, OVA-sensitized mice showed preference to consume a mixture of BLG and OVA during oral challenge in spite of their aversion to OVA. Consumption of OVA-BLG solution was associated with neuron activation in the nucleus accumbens, suggesting a reward sensation. Thus, the aversive behavior observed in food allergy to OVA does not apply to all antigens and some allergens may induce preference rather than aversion. Our study provides new insights into the neuroimmune conflicts regarding preference and avoidance to a common antigen associated with food allergy.