Beta-galactoside-binding protein secreted by activated T cells inhibits antigen-induced proliferation of T cells.
We have used mRNA differential display PCR to search for genes induced in activated T cells and have found the LGALS1 (lectin, galactoside-binding, soluble) gene to be strongly up-regulated in effector T cells. The protein coded by the LGALS1 gene is a beta-galactoside-binding protein (betaGBP), which is released by cells as a monomeric negative growth factor but which can also associate into homodimers (galectin-1) with lectin properties. Northern blot analysis revealed that ex vivo isolated CD8+ effector T cells induced by a viral infection expressed high amounts of LGALS1 mRNA, whereas LGALS1 expression was almost absent in resting CD8+ T cells. LGALS1 expression could be induced in CD4+ and CD8+ T cells upon activation with the cognate peptide antigen and high levels of LGALS1 expression were found in concanavalin A-activated T cells but not in lipopolysaccharide-activated B cells. Gel filtration and Western blot analysis revealed that only monomeric betaGBP was released by activated CD8+ T cells and in vitro experiments further showed that recombinant betaGBP was able to inhibit antigen-induced proliferation of naive and antigen-experienced CD8+ T cells. Thus, these data indicate a role of betaGBP as an autocrine negative growth factor for CD8+ T cells.
Blaser
C
C
Institute for Medical Microbiology and Hygiene, Department of Immunology, University of Freiburg, Germany.
Kaufmann
M
M
Müller
C
C
Zimmermann
C
C
Wells
V
V
Mallucci
L
L
Pircher
H
H
D000818:Animals; D000941:Antigens; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D005697:Galactosides / Q000378:metabolism*; D037161:Galectins; D006131:Growth Inhibitors / Q000235:genetics / Q000378:metabolism; D006388:Hemagglutinins / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D015854:Up-Regulation
D000941:Antigens; D002352:Carrier Proteins; D017931:DNA Primers; D005697:Galactosides; D037161:Galectins; D006131:Growth Inhibitors; D006388:Hemagglutinins; D012333:RNA, Messenger; D011994:Recombinant Proteins