Suppression of human T-cell responses to beta-cells by activation of B7-H4 pathway

Cell Transplant. 2006;15(5):399-410.


B7-H4, a recently described member of the B7 family of cosignal molecules, is thought to be involved in the regulation of cellular and humoral immune responses through receptors on activated T and B cells. Human islet cells express positive B7-H4 mRNA in RT-PCR assays, but not B7-H4 protein on cell surface in flow cytometric analyses. To investigate the regulatory effects of activation of the B7-H4 pathway on the function of activated T cells of patients with type 1 diabetes (T1D), we have used our in vitro human experimental system, including human beta-cell antigen-specific T-cell clones and human beta-cell lines CM and HP62, as well as primary islet cells. B7-H4.Ig protein was purified from the culture supernatant of 293T cells transfected by a B7-H4.Ig plasmid (pMIgV, containing a human B7-H4 cDNA and a mouse IgG2a Fc cDNA). Our preliminary studies showed that immobilized fusion protein human B7-H4.Ig (coated with 5 microg/ml for 2 h at 37 degrees C), but not control Ig, clearly inhibited the proliferation of activated CD4+ and CD8+ T cells of patients induced by anti-CD3 antibody in CFSE assays. B7-H4.Ig also arrested cell cycle progression of T cells in G0/G1 phase and induced T-cell apoptosis as measured by BrdU-7-AAD flow cytometric analysis. To determine the cytoprotective effects of B7-H4, we developed transfectants of human beta-cell lines CM and HP62 and islet cells transfected with the B7-H4.Ig plasmid, using empty vector transfectants as controls. The results demonstrate that cell-associated B7-H4.Ig expressed on human beta-cells clearly inhibits the cytotoxicity of the T-cell clones to targeted human beta-cells in 51Cr release cytotoxicity assays. Activation of the B7-H4 pathway may represent a novel immunotherapeutic approach to inhibit T-cell responses for the prevention of beta-cell destruction in T1D.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Monoclonal / pharmacology
  • Apoptosis / drug effects
  • B7-1 Antigen / genetics
  • B7-1 Antigen / immunology
  • B7-1 Antigen / metabolism*
  • CD3 Complex / immunology
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / cytology
  • CD8-Positive T-Lymphocytes / drug effects
  • Cell Cycle / drug effects
  • Cell Division / drug effects
  • Cell Line
  • Cells, Cultured
  • Cytotoxicity, Immunologic / drug effects
  • Female
  • Humans
  • Immunoglobulins / metabolism
  • Immunoglobulins / physiology
  • Insulin-Secreting Cells / cytology
  • Insulin-Secreting Cells / immunology*
  • Insulin-Secreting Cells / metabolism
  • Interferon-gamma / metabolism
  • Male
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Recombinant Fusion Proteins / pharmacology
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • V-Set Domain-Containing T-Cell Activation Inhibitor 1


  • Antibodies, Monoclonal
  • B7-1 Antigen
  • CD3 Complex
  • Immunoglobulins
  • RNA, Messenger
  • Recombinant Fusion Proteins
  • V-Set Domain-Containing T-Cell Activation Inhibitor 1
  • VTCN1 protein, human
  • Interferon-gamma