title: Globotriaosylceramide (Gb(3)/CD77) is synthesized and surface expressed by bovine lymphocytes upon activation in vitro.
abstract: Neutral glycosphingolipids (GSLs) are considered activation markers on human lymphocytes, which are fundamental for studying the immune system. For cattle, only a limited number of activation markers has yet been identified. We recently showed that Shiga toxin 1, known to use globotriaosylceramide (Gb(3) syn. CD77) as a cellular receptor, depresses proliferation of activated bovine lymphocytes [Infect. Immunol. 67 (1999b) 2209]. In order to confirm the expression of Gb(3)/CD77 on bovine lymphocytes, we flowcytometrically examined a bovine B-lymphoma cell line (BL-3) and bovine peripheral blood mononuclear cells (PBMC) before and after mitogenic stimulation and biochemically characterized neutral GSLs extracted from PBMC. CD77 was detected on the surface of BL-3 cells and cultured PBMC essentially after mitogenic stimulation. Although expressed by all PBMC subpopulations identified, the portion of CD7+ cells was highest for BoCD8+ cells, followed by B-cells and BoCD4+ cells at day 4 of cultivation. Ceramide trihexoside of stimulated PBMC was structurally determined as Gal(alpha1-4)Gal(1-4)Glc(1-1)ceramide (Gb(3)). Biochemically, Gb(3) was also detected within unstimulated PBMC which contained ceramide monohexoside (CMH) and Gb(3) in a ratio of about 4:1. However, stimulation induced an increase of CMH and Gb(3) by a factor of 2.5 and 10, respectively, implicating that bovine lymphocytes regulate surface expression of Gb(3)/CD77 predominantly by quantitative changes in the Gb(3) metabolism. This report presents Gb(3)/CD77 as the first GSL identified on bovine immune cells and highly recommends this activation dependent antigen as a useful tool to investigate lymphocyte activation within the bovine immune system.
authors.affiliation: Faculty of Veterinary Medicine, Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-University, Frankfurter Str. 89-91, D-35392 Giessen, Germany. christian.menge@vetmed.uni-giessen.de
authors.forename: C
authors.initials: C
authors.lastname: Menge
authors.forename: I
authors.initials: I
authors.lastname: Stamm
authors.forename: M
authors.initials: M
authors.lastname: Wuhrer
authors.forename: R
authors.initials: R
authors.lastname: Geyer
authors.forename: L H
authors.initials: LH
authors.lastname: Wieler
authors.forename: G
authors.initials: G
authors.lastname: Baljer
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005434:Flow Cytometry / Q000662:veterinary; D008401:Gas Chromatography-Mass Spectrometry / Q000662:veterinary; D005786:Gene Expression Regulation; D007150:Immunohistochemistry / Q000662:veterinary; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation / Q000502:physiology; D014281:Trihexosylceramides / Q000096:biosynthesis* / Q000737:chemistry; D014407:Tumor Cells, Cultured
chemical_list: D014281:Trihexosylceramides; C018549:globotriaosylceramide