title: Long term maintenance of IgE-mediated memory in mast cells in the absence of detectable serum IgE.
abstract: Mast cells and basophils involved in allergic responses do not have clonotypic Ag receptors. However, they can acquire Ag specificity through binding of Ag-specific IgE to FcepsilonRI expressed on their surface. Previous studies demonstrated that IgE binding induced the stabilization and accumulation of FcepsilonRI on the cell surface and resulted in up-regulation of FcepsilonRI. In this study we have further analyzed the maintenance of IgE-mediated memory in mast cells and basophils in vivo by comparing kinetics of serum IgE levels, FcepsilonRI expression, and ability to induce systemic anaphylaxis. A single i.v. injection of trinitrophenyl-specific IgE induced 8-fold up-regulation of FcepsilonRI expression on peritoneal mast cells in B cell-deficient (micro m(-/-)) mice. Serum IgE levels became undetectable by day 6, but the treatment of mice with anti-IgE mAb induced a significant drop in body temperature on days 14, 28, and 42. The administration of trinitrophenyl -BSA, but not BSA, in place of anti-IgE mAb gave similar results, indicating the Ag specificity of the allergic response. This long term maintenance of Ag-specific reactivity in the allergic response was also observed in normal mice passively sensitized with IgE even though the duration was shorter than that in B cell-deficient mice. The appearance of IgE with a different specificity did not interfere with the maintenance of IgE-mediated memory of mast cells and basophils. These results suggest that IgE-mediated stabilization and up-regulation of FcepsilonRI enables mast cells and basophils not only to acquire Ag specificity, but also to maintain memory in vivo for lengthy periods of time.
authors.affiliation: Department of Laboratory Animal Science, Tokyo Metropolitan Organization for Medical Science, Tokyo Metropolitan Institute of Medical Science, Japan. skubo@rinshoken.or.jp
authors.forename: Shuichi
authors.initials: S
authors.lastname: Kubo
authors.forename: Toshinori
authors.initials: T
authors.lastname: Nakayama
authors.forename: Kunie
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Yonekawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Karasuyama
mesh_terms: D000707:Anaphylaxis / Q000097:blood / Q000235:genetics / Q000276:immunology; D000818:Animals; D004406:Dysgammaglobulinemia / Q000235:genetics / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D007116:Immunization, Passive; D007073:Immunoglobulin E / Q000008:administration & dosage / Q000097:blood / Q000172:deficiency* / Q000502:physiology*; D007156:Immunologic Memory / Q000235:genetics; D007275:Injections, Intravenous; D007700:Kinetics; D008231:Lymphopenia / Q000235:genetics / Q000276:immunology; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017455:Receptors, IgE / Q000096:biosynthesis; D013997:Time Factors; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D000939:Epitopes; D017455:Receptors, IgE; D014301:Trinitrobenzenes; D007073:Immunoglobulin E