Attenuated asthma phenotype in mice with a fetal-like antigen receptor repertoire

Abstract

We hypothesized that the scarcity of N-nucleotides might contribute to the inability of the neonate to mount a robust allergic immune response. To test this, we used terminal deoxyribunucleotidyl Transferase defcient (TdT−/−) mice, which express “fetal-like” T cell receptor and immunoglobulin repertoires with largely germline-encoded CDR3 regions. Intraperitoneal sensitization was followed by aerosol provocation with either PBS or the allergen OVA in both TdT−/− mice and wild-type mice to develop allergic respiratory infammation. The efects of this procedure were investigated by lung function test, immunological analysis of serum and brochoalveolar lavage. The local TH2 cytokine milieu was signifcantly attenuated in TdT−/− mice. Within this group, the induction of total IgE levels was also signifcantly reduced after sensitization. TdT−/− mice showed a tendency toward reduced eosinophilic infow into the bronchial tubes, which was associated with the elimination of respiratory hyperreactivity. In conclusion, in a murine model of allergic airway infammation, the expression of fetal-like antigen receptors was associated with potent indications of a reduced ability to mount an asthma phenotype. This underlines the importance of somatically-generated antigen-receptor repertoire diversity in type one allergic immune responses and suggests that the fetus may be protected from allergic responses, at least in part, by controlling N addition.