IgE 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. ©2006 Elsevier Inc.
McCoy, K. D., Harris, N. L., Diener, P., Hatak, S., Odermatt, B., Hangartner, L., … Zinkernagel, R. M. (2006). Natural IgE production in the absence of MHC class II cognate help. Immunity, 24(3), 329–339. https://doi.org/10.1016/j.immuni.2006.01.013