title: Selective depletion of immature thymocytes by oral administration of ethylene glycol monomethyl ether.
abstract: Although immunotoxicity of ethylene glycol monomethyl ether (EGME) has been strongly suspected, functional evaluation of the immune response in EGME-treated animals was negative in previous studies. We observed a decrease in thymic cellularity and increases in the various ex vivo immunological assays in mice, orally administered with EGME 0.5 or 1.0 mg/g body weight daily for 5 or 10 days: ex vivo lymphoproliferative responses to concanavalin A, in vitro induction of trinitrophenyl (TNP)-specific cytotoxic T-cell activity of thymocytes and splenocytes. Histopathological examination of the thymus of the treated mice disclosed a markedly atrophic cortex and almost intact thymic medulla. Study of thymocyte surface markers revealed that CD4+/CD8+, Thy-1+, PNA+ immature thymocytes were relatively decreased in EGME-gavaged mice and that, thus, ratios of CD4-/CD8+, H2+ mature thymocytes were enriched. These findings indicate that oral administrations of EGME selectively deplete immature thymocytes in mice. Although the mechanism of action remains unknown, the EGME-induced immature thymocyte depletion is not considered to be due to lymphocidal action of corticosteroids.
authors.affiliation: Department of Environmental Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Kayama
authors.forename: U
authors.initials: U
authors.lastname: Yamashita
authors.forename: T
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Kodama
mesh_terms: D000284:Administration, Oral; D000818:Animals; D015703:Antigens, CD / Q000187:drug effects; D000943:Antigens, Differentiation; D003208:Concanavalin A / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic; D005026:Ethylene Glycols / Q000494:pharmacology*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D013154:Spleen / Q000187:drug effects; D013601:T-Lymphocytes / Q000187:drug effects*; D013950:Thymus Gland / Q000166:cytology / Q000187:drug effects*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D005026:Ethylene Glycols; D003208:Concanavalin A; C005219:methyl cellosolve