
<ArticleTitle>Valve interstitial cells induce donor-specific T-cell anergy.</ArticleTitle>
<AbstractText>OBJECTIVES: Valve allografts produce an immune response, which can influence their performance. The exact role of the interaction between recipient T cells and the different cellular components of the donor valve in stimulating an immune response is not known. Therefore the T-cell response to valve endothelial and interstitial cells was investigated in vitro. METHODS: Valve endothelial and interstitial cells were characterized for cell-surface molecules before and after <prot>interferon gamma</prot> treatment by means of a panel of specific monoclonal antibodies and flow cytometry. The proliferative response of highly purified T lymphocytes was used to assess the immunogenicity of cultured valve endothelial and interstitial cells. This was further investigated by using a 2-step tolerance-induction protocol. RESULTS: Valve endothelial and interstitial cells express similar levels of human leukocyte antigens and adhesion and costimulatory molecules, which are either induced or upregulated after <prot>interferon gamma</prot> treatment. T-cell responses to endothelial cells were detected after <prot>interferon gamma</prot> treatment, but responses to <prot>interferon gamma</prot>-treated interstitial cells were not detected. This lack of response resulted in the induction of T-cell anergy, which was reversed by the presence of the costimulatory molecule B7-1. CONCLUSIONS: Although valve endothelial and interstitial cells express a similar range of cell-surface molecules, it is only the endothelial cells that are immunogenic. In addition, we have shown that these 2 cell types interact in a donor-specific manner to orchestrate the immune response and therefore may have clinical relevance in the allogeneic response of the heart valve recipients.</AbstractText>
