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Background: Notch signaling is involved in cell fate determination along with the development of the immune system. However, very little is known about the role for Notch signaling in mast cells. Objective: We investigated the role of Notch signaling in mast cell functions. Methods: After mouse bone marrow–derived mast cells (BMMCs) or peritoneal mast cells (PMCs) were cocultured with mouse Notch ligand-expressing chinese hamster ovary cells for 5 days, we examined the mast cell surface expressions of MHC-II molecules and OX40 ligand (OX40L), FcɛRI-mediated cytokine production, and the effects of the mast cells on proliferation and differentiation of naive CD4+ T cells in vitro. Results: We showed that BMMCs and PMCs constitutively expressed Notch1 and Notch2 proteins on the cell surface. We also found that Delta-like 1 (Dll1)/Notch signaling induced the expression of MHC-II and upregulated the expression level of OX40L on the surface of the mast cells. Dll1/Notch signaling augmented FcɛRI-mediated IL-4, IL-6, IL-13, and TNF production by BMMCs. Dll1-stimulated MHC-II+OX40Lhigh BMMCs promoted proliferation of naive CD4+ T cells and their differentiation into TH2 cells producing IL-4, IL-5, IL-10, and IL-13. Conclusion: Dll1/Notch signaling confers the functions as an antigen-presenting cell on mast cells, which preferentially induce the differentiation of TH2. [Copyright &y& Elsevier]

Background: Trichophyton rubrum is the most common pathogen causing dermatophytosis worldwide. Recent genetic investigations showed that the microorganism originated in Africa and then spread to Europe and North America via Asia., Objects: We investigated the intraspecific diversity of T. rubrum isolated from two closely located Asian countries, Japan and China., Methods: A total of 150 clinical isolates of T. rubrum obtained from Japanese and Chinese patients were analyzed by randomly amplified polymorphic DNA (RAPD) and DNA sequence analysis of the non-transcribed spacer (NTS) region in the rRNA gene., Results: RAPD analysis divided the 150 strains into two major clusters, A and B. Of the Japanese isolates, 30% belonged to cluster A and 70% belonged to cluster B, whereas 91% of the Chinese isolates were in cluster A. The NTS region of the rRNA gene was divided into four major groups (I-IV) based on DNA sequencing. The majority of Japanese isolates were type IV (51%), and the majority of Chinese isolates were type III (75%)., Conclusions: These results suggest that although Japan and China are neighboring countries, the origins of T. rubrum isolates from these countries may not be identical. These findings provide information useful for tracing the global transmission routes of T. rubrum.