Enhanced Effect of β -Lactoglobulin Immunization in Mice with Mild Intestinal Deterioration Caused by Low-Dose Dextran Sulphate Sodium: A New Experimental Approach to Allergy Studies.

Background/Objectives: Cow's milk allergy is one of the most common food allergies in children, and its pathomechanism is still under investigation. Recently, an increasing number of studies have linked food allergy to intestinal barrier dysfunction. The present study aimed to investigate changes in the intestinal microenvironment during the development of β-lactoglobulin (β-lg) allergy under conditions of early intestinal dysfunction. Methods: BALB/c mice received intraperitoneal β-lg with Freund's adjuvant, followed by oral β-lg while receiving dextran sulphate sodium salt (DSS) in their drinking water (0.2% w/v). The immunized group without DSS and the groups receiving saline, oral β-lg, or DSS served as controls. Results: The study showed that the immunization effect was greater in mice with mild intestinal barrier dysfunction. Although DSS did not affect the mice's humoral response to β-lg, in combination with β-lg, it significantly altered their cellular response, affecting the induction and distribution of T cells in the inductive and peripheral tissues and the activation of immune mediators. Administration of β-lg to sensitized mice receiving DSS increased disease activity index (DAI) scores and pro-inflammatory cytokine activity, altered the distribution of claudins and zonulin 1 (ZO-1) in the colonic tissue, and negatively affected the balance and activity of the gut microbiota. Conclusions: The research model used appears attractive for studying food allergen sensitization, particularly in relation to the initial events leading to mucosal inflammation and the development of food hypersensitivity. [ABSTRACT FROM AUTHOR]