title: Expression of lymphocyte activation gene 3 (LAG-3) on B cells is induced by T cells.
abstract: Lymphocyte activation gene 3 (LAG-3/CD223) is a CD4 homolog known to be selectively expressed in activated T and NK cells. It is thought to have a negative regulatory function in T cells. With the help of new monoclonal antibodies against mouse LAG-3, we show that LAG-3 surface expression is not limited to activated T and NK cells but is also found on activated B cells. Induction of B cell surface expression is T cell dependent and mediated by a soluble factor. The majority of LAG-3 on B cell surface is endogenously produced, even though soluble LAG-3 is present in the culture supernatants and can be passively absorbed. As B cells express LAG-3 in a T cell dependent manner and not when activated by Toll-like-receptor agonists alone, we propose LAG-3 as a new marker of T cell induced B cell activation.
authors.affiliation: Institute for Research in Biomedicine, Bellinzona, Switzerland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Kisielow
authors.forename: Jan
authors.initials: J
authors.lastname: Kisielow
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Capoferri-Sollami
authors.forename: Klaus
authors.initials: K
authors.lastname: Karjalainen
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D015703:Antigens, CD / Q000235:genetics* / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000276:immunology*; D006825:Hybridomas; D008213:Lymphocyte Activation / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051381:Rats; D011917:Rats, Inbred Lew; D015398:Signal Transduction / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D000093322:Lymphocyte Activation Gene 3 Protein
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000093322:Lymphocyte Activation Gene 3 Protein