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

Dawei Ou, Xiaojie Wang, Daniel L. Metzger, Ziliang Ao, Paolo Pozzilli, Roger F L James, Lieping Chen, Garth L. Warnock

Research output: Contribution to journalArticle

Abstract

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 β-cell antigen-specific T-cell clones and human β-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 μg/ml for 2 h at 37°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 β-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 β-cells clearly inhibits the cytotoxicity of the T-cell clones to targeted human β-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 β-cell destruction in T1D.

Original languageEnglish (US)
Pages (from-to)399-410
Number of pages12
JournalCell Transplantation
Volume15
Issue number5
DOIs
StatePublished - 2006

Keywords

  • β-Cell destruction
  • B7-H4
  • Costimulatory molecules
  • Islet cell transplantation
  • Suppression of T-cell responses
  • Type 1 diabetes

ASJC Scopus subject areas

  • Cell Biology
  • Transplantation

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    Ou, D., Wang, X., Metzger, D. L., Ao, Z., Pozzilli, P., James, R. F. L., Chen, L., & Warnock, G. L. (2006). Suppression of human T-cell responses to β-cells by activation of B7-H4 pathway. Cell Transplantation, 15(5), 399-410. https://doi.org/10.3727/000000006783981837