Lymphocytes in Peyer patches regulate clinical tolerance in a murine model of food allergy

Background: Food allergy can lead to severe, potentially life-threatening anaphylactic reactions. To generate efficient strategies aimed at an active cure, a better understanding of the pathogenic mechanisms is strongly needed. Objective: To investigate T-cell-related mechanisms of food allergy and tolerance to beta-lactoglobulin (BLG) in gut-associated lymphoid structures. Methods: beta-Lactoglobulin-specific IgG1, IgG2a, and IgE in serum from mice anaphylactic to BLG were analyzed by ELISA and compared with those obtained in mice actively tolerized to BLG. The number of Ab-secreting cells in the spleen and in Peyer patches was determined by ELISPOT. The numbers of cytokine-producing cells after antigen-specific activation were measured by the same method. Furthermore, mesenteric lymph node cells and Peyer patches cells were transferred to naive mice, and Ab production as well as Ab-secreting cells were measured. Results: Serum IgG1 and IgE Ab titers as well as IL-4-producing cell numbers were strongly increased in anaphylactic mice. IL-10 was found in Peyer patch cells from tolerant mice after BLG activation but not in anaphylactic mice. Peyer patch cells, in contrast to mesenteric lymph node cells, proliferated weakly in anaphylactic mice after antigen activation, and activation of Peyer patches was partially inhibited by tolerization. Conclusions: Our data suggest a specific role for lymphocytes in Peyer patches in tolerance to BLG. Low IL-10 production in Peyer patches may favor symptoms of food allergy.