Harris, N. L.McCoy, K. D.Diener, P.Hatak, S.Odermatt, B.Hangartner, L.Senn, B. M.Marsland, B. J.Geuking, M. B.Hengartner, H.Macpherson, A. J.Zinkernagel, R. M.2010-01-062010-01-062010-01-06200610.1016/j.immuni.2006.01.013https://infoscience.epfl.ch/handle/20.500.14299/45075IgE induction by parasites and allergens is antigen driven and cognate T cell help dependent. We demonstrate that spontaneously produced IgE in T cell-deficient and germ-free wild-type (wt) mice is composed of natural specificities and induced by a mechanism independent of MHC class II (MHC II) cognate help. This does not require secondary lymphoid structures or germinal center formation, although some bystander T cell-derived IL-4 is necessary. The pathway of spontaneous IgE production is not inhibited by regulatory T cells and increases with age to constitute significant serum concentrations, even in naive animals.AnimalsAntibodies, Helminth/biosynthesisB-Lymphocytes/physiologyHistocompatibility Antigens Class II/*physiologyImmunoglobulin E/*biosynthesisInterleukin-4/physiologyMast Cells/physiologyMiceMice, Inbred BALB CMice, Inbred C57BLMice, Inbred ICRT-Lymphocytes/physiologyT-Lymphocytes, Regulatory/physiologytext::journal::journal article::research article