Maternal allergen stimulation suppressed respiratory allergy in offspring: with special reference to allergy related cells in the tonsil.

Pregnant mice and Hartley guinea pigs were immunized with T dependent antigen, heterologous erythrocyte and ovalbumin (OVA), and the active immune responsiveness as well as the allergic symptoms of the offspring were investigated. Guinea pigs were also sensitized to OVA intraperitoneally and subcutaneously with a 100 mg/ml solution of saline containing 5 mg of AI(OH)(3) as an adjuvant. Six weeks after the initial allergen stimulation, systemic and local anaphylaxis as elicited by 1-min aerosol administration of a nebulizer and monitored by macroscopic vision accompanied by a time trial for respiratory and cardiac arrest. Serum antibody levels were tested by passive hemagglutination as well as passive cutaneous anaphylaxis especially for the estimation of IgE levels. Nasal, tonsillar and bronchial tissues were also prepared and fixed, followed by hematoxylin and eosin staining for histological observation. In the offspring of mothers who had been stimulated with optimal amounts of the allergen and had fully developed specific antibodies against the allergen, there was a clear-cut suppression in the development of a specific respiratory allergy over a significant period after delivery. The effect was confirmed by systemic and local anaphylaxis, eosinophil infiltration, ciliary deformation in nasal mucosae and the tonsillar site in the complex interaction of various cell types and mediators eliciting the clinical respiratory symptoms, in particular nasal hypersensitivity. In a different experimental model, the mouse model, these biological findings were not regulated by maternal transferable antibody or antigen fragments from the mother. The induction of suppressor T cell (CD(4+)) in offspring depends on the recognition of the antigens presented in association with the same MHC haplotype as that utilized in the maternal T cell response during pregnancy. These results suggest the presence of suppression mechanisms in the offspring of mothers stimulated during pregnancy. From these results, we discuss the mechanisms for suppression and protective efficacy for respiratory allergy as well as possible side effects in the young of mothers stimulated during pregnancy.