Involvement of CD2 and CD3 in galectin-1 induced signaling in human Jurkat T-cells.
Galectin-1 (gal-1) a member of the mammalian beta-galactoside-binding proteins recognizes preferentially Galbeta1-4GlcNAc sequences of oligosaccharides associated with several cell surface glycoconjugates. In the present work, gal-1 has been identified to be a ligand for the CD3-complex as well as for CD2 as detected by affinity chromatography of Jurkat T-cell lysates on gal-1 agarose and by binding of the biotinylated lectin to CD3 and CD2 immunoprecipitates on blots. In CD45(+)Jurkat E6.1 cells, the lectin stimulates a sustained increase in the intracytoplasmic calcium concentration ([Ca(2+)](i)) consisting of both the release of calcium from intracellular stores and the calcium influx from the extracellular space. This effect of gal-1 on [Ca(2+)](i)is completely inhibited by lactose at 10 mM and was absent in CD45(-)Jurkat J45.01 cells. Preincubation of Jurkat E6.1 cells with cholera toxin or with the protein tyrosine kinase inhibitor herbimycin A reduced the gal-1 induced calcium response whereas the increase in [Ca(2+)](i)stimulated by CD2 or CD3 monoclonal antibodies (mAbs) was completely inhibited. Depolarization of E6.1 cells in a high-potassium buffer, a standard method to activate voltage-operated calcium channels, was without effect on [Ca(2+)](i). Membrane depolarization with gramicidin or by a high-potassium buffer was without effects on the lectin-mediated calcium release from intracellular stores but inhibited the gal-1 induced receptor-operated calcium influx. In Jurkat E6.1 cells the lectin stimulates the transient generation of inositol-1,4,5-trisphosphate and the tyrosine phosphorylation of phospholipase Cgamma1. The results suggest that the ligation of CD2 and CD3 by gal-1 induces early events in T-cell activation comparable with that elicited by CD2 or CD3 mAbs.
Walzel
H
H
Institute of Medical Biochemistry and Molecular Biology, Schillingallee 70, University of Rostock, D-18057 Rostock, Germany
Blach
M
M
Hirabayashi
J
J
Kasai
K I
KI
Brock
J
J
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D016227:Benzoquinones; D018801:CD2 Antigens / Q000276:immunology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D037483:Galectin 1; D006388:Hemagglutinins / Q000494:pharmacology*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D019169:Jurkat Cells; D007700:Kinetics; D047029:Lactams, Macrocyclic; D037102:Lectins / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000276:immunology / Q000502:physiology*; D011994:Recombinant Proteins / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013347:Subcellular Fractions / Q000276:immunology; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D016227:Benzoquinones; D018801:CD2 Antigens; D004791:Enzyme Inhibitors; D037483:Galectin 1; D006388:Hemagglutinins; D047029:Lactams, Macrocyclic; D037102:Lectins; D011809:Quinones; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011994:Recombinant Proteins; D017828:Rifabutin; C020754:herbimycin; D015544:Inositol 1,4,5-Trisphosphate; D011505:Protein-Tyrosine Kinases; D002118:Calcium