title: VLA-4 mediates CD3-dependent CD4+ T cell activation via the CS1 alternatively spliced domain of fibronectin.
abstract: We previously showed that fibronectin (FN) synergized with anti-CD3 in induction of CD4+ T cell proliferation, and that VLA-5 acted as a functional FN receptor in a serum-free culture system. In the present study, we showed that VLA-4 is also involved in this CD3-dependent CD4 cell activation through its interaction with the alternatively spliced CS1 domain of FN. When highly purified CD4 cells were cultured on plates coated with anti-CD3 plus synthetic CS1 peptide-IgG conjugate, significant proliferation could be observed. Neither CS1 alone nor anti-CD3 alone induced this activation. This proliferation was completely blocked by anti-VLA beta 1 (4B4) and anti-VLA-4 (8F2), while anti-VLA-5 (monoclonal antibody [mAb] 16 and 2H6) had no effect. These data indicate that VLA-4 mediates CD3-dependent CD4 cell proliferation via the CS1 domain of FN. Anti-VLA-4 also partially (10-40%) inhibited CD4 cell proliferation induced by native FN plus anti-CD3, implying that the CS1 domain is active in the native plasma FN. However, this native FN-dependent proliferation was entirely abolished by addition of anti-VLA-5 alone. Moreover, when native FN-coated plates were pretreated with anti-FN (mAb 333), which blocks RGDS sites but not CS1 sites, no CD4 cell activation could be observed. These results strongly suggest that CD4 cell activation induced by plasma FN/anti-CD3 may be dependent on both VLA4/CS1 and VLA5/RGDS interactions, although the latter interaction may be required for function of the former.
authors.affiliation: Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
authors.forename: Y
authors.initials: Y
authors.lastname: Nojima
authors.forename: M J
authors.initials: MJ
authors.lastname: Humphries
authors.forename: A P
authors.initials: AP
authors.lastname: Mould
authors.forename: A
authors.initials: A
authors.lastname: Komoriya
authors.forename: K M
authors.initials: KM
authors.lastname: Yamada
authors.forename: S F
authors.initials: SF
authors.lastname: Schlossman
authors.forename: C
authors.initials: C
authors.lastname: Morimoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology*; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002448:Cell Adhesion; D005353:Fibronectins / Q000502:physiology*; D006801:Humans; D016023:Integrins / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000502:physiology; D010446:Peptide Fragments / Q000502:physiology*; D012326:RNA Splicing; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D015398:Signal Transduction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D005353:Fibronectins; D016023:Integrins; D009842:Oligopeptides; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; C046617:arginyl-glycyl-aspartyl-serine