An anti-major histocompatibility complex class I intrabody protects endothelial cells from an attack by immune mediators

• Published in: Cardiovascular research 2006-11, Vol.72 (2), p.331-338
• Main Authors: DOEBIS, Cornelia, SCHU, Sabine, LADHOFF, Juliane, BUSCH, Annette, BEYER, Florian, REISER, Jakob, NICOSIA, Roberto F, BROESEL, Sabine, VOLK, Hans-Dieter, SEIFERT, Martina
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - genetics; Biological and medical sciences; Cardiology. Vascular system; Cytotoxicity, Immunologic; Down-Regulation; Endothelial Cells - immunology; Flow Cytometry; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; Immunoglobulin Fragments - genetics; Immunologic Factors - immunology; Intracellular Fluid - immunology; Isoantibodies - immunology; Medical sciences; Rats; Statistics, Nonparametric; T-Lymphocytes, Cytotoxic - immunology; Transduction, Genetic - methods; Transplantation, Homologous
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1016/j.cardiores.2006.08.005

In vitro endothelialization has significantly improved the overall outcome of artificial prostheses in cardiovascular bypass surgery. A drawback of this tissue-engineering method remains the limited availability of suitable autologous endothelial cells (EC), especially in aged patients. Allogeneic EC with high proliferative capacity represent a potentially valuable alternative to a patient-specific vascular transplant. However, such cells carry the risk of being rejected due to Major Histocompatibility Complex (MHC) mismatches. We investigated the effects of a very potent, intracellularly expressed antibody directed against MHC class I molecules, referred to as alpha-rat MHC I single chain variable fragment (sFv) intrabody. The intrabody was stably expressed in rat aortic EC (RAEC) following lentiviral vector-mediated gene transfer. The functional consequence of the MHC I down-regulation was tested in an allogeneic setting in two different in vitro assays. Stable expression of the alpha-rat MHC I sFv intrabody resulted in a highly efficient depletion of surface MHC I. Thereby those RAEC which displayed low MHC I levels over extended periods of time were protected against killing by allo-specific, cytotoxic T cells (CTL) and by allo-antibody/complement-mediated lysis. These results demonstrate that intrabody-mediated down-regulation of MHC I reduces the immunogenicity of RAEC which may provide a suitable alternative supply for the lining of vascular prostheses.