title: Chitin particles induce size-dependent but carbohydrate-independent innate eosinophilia.
abstract: Murine Mϕ that phagocytose CMP develop into M1; this response depends on the size and the chemical composition of the particles. In contrast, recent studies concluded that chitin particles induce M2 and eosinophil migration, promoting acquired Th2 immune responses against chitin-containing microbes or allergens. This study examined whether these apparently inconsistent responses to chitin could be induced by variation in the size and chemical composition of the chitin particles. We compared the responses of Mϕ with CMP, LCB, and Sephadex G-100 beads (>40 μm). Beads were given i.p. to WT mice and to mice deficient in a CRTH2, a receptor for the eosinophil chemoattractant PGD(2). In contrast to the M1 activation induced by CMP, i.p. administration of LCB or Sephadex beads induced within 24 h a CRTH2-dependent peritoneal eosinophilia, as well as CRTH2-independent activation of peritoneal Mϕ that expressed Arg I, an M2 phenotype. LCB-induced Mϕ exhibited elevated Arg I and a surface MR, reduced surface TLR2 levels, and no change in the levels of CHI3L1 or IL-10 production. Our results indicate that the effects of chitin in vivo are highly dependent on particle size and that large, nonphagocytosable beads, independent of their chemical composition, induce innate eosinophilia and activate Mϕ expressing several M2, but not M1, phenotypes.
authors: Florida Atlantic University, 777 Glades Rd., Boca Raton, FL 33431-0991, USA.
authors: Mari
authors: M
authors: Kogiso
authors: Akihito
authors: A
authors: Nishiyama
authors: Tsutomu
authors: T
authors: Shinohara
authors: Masataka
authors: M
authors: Nakamura
authors: Emiko
authors: E
authors: Mizoguchi
authors: Yoshinori
authors: Y
authors: Misawa
authors: Elisabeth
authors: E
authors: Guinet
authors: Mahyar
authors: M
authors: Nouri-Shirazi
authors: C Kathleen
authors: CK
authors: Dorey
authors: Ruth Ann
authors: RA
authors: Henriksen
authors: Yoshimi
authors: Y
authors: Shibata
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002469:Cell Separation; D002634:Chemotaxis, Leukocyte; D002686:Chitin / Q000737:chemistry* / Q000276:immunology*; D004802:Eosinophilia / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D007113:Immunity, Innate; D016753:Interleukin-10 / Q000096:biosynthesis; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018613:Microscopy, Confocal; D010587:Phagocytosis / Q000187:drug effects / Q000276:immunology; D011971:Receptors, Immunologic / Q000172:deficiency; D011982:Receptors, Prostaglandin / Q000172:deficiency; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; D016753:Interleukin-10; D002686:Chitin; C036293:prostaglandin D2 receptor