In agreement with this lack of pathology, organoids derived from 2 AOM-treated C57BL/6 mice (designated A1DSS naive, A1DSSna; and A2DSS naive, A2DSSna) and cultured in 50% Wnt3a-conditioned medium (v/v), 10% R-spondin1–conditioned medium, 5% Noggin-conditioned medium, and recombinant EGF (hereafter termed WENR, as published by Clevers and colleagues, refs. 37, 38, 43) were phenotypically indistinguishable from untreated large intestinal organoids in terms of morphology, growth rate, conditions for subculturing, and maintenance requirements (data not shown) (38). This evidence concerns the gene EGF and infectious otitis media.