Processing and Presentation of the Islet Autoantigen GAD by Vascular Endothelial Cells Promotes Transmigration of Autoreactive T-Cells
- James E. Greening12,
- Timothy I.M. Tree1,
- Karolena T. Kotowicz2,
- Astrid G. van Halteren3,
- Bart O. Roep3,
- Nigel J. Klein2 and
- Mark Peakman1
- 1Department of Immunology, Guy’s, King’s and St. Thomas’ School of Medicine, London, U.K.
- 2Infectious Diseases and Microbiology Unit, Institute of Child Health, University College London, London, U.K.
- 3Department of Immunohematology and Blood Transfusion, Leiden University Medical Centre, Leiden, the Netherlands
Type 1 diabetes is characterized by T-cell infiltration of the islets of Langerhans and abundant HLA class II molecule expression on islet endothelial cells (ECs). The specificity of infiltrating T-cells for islet autoantigens has been amply demonstrated in animal models, and is implicit in human diabetes, but the processes regulating endothelial transmigration of islet autoantigen-specific T-cells into islets are not known. We examined the ability of ECs expressing HLA class II molecules to process and present the islet autoantigen GAD65 and examined the effects of presentation on transmigration of GAD65-specific T-cells. Primary cultures of human vascular ECs expressing the DRB1*0401 (VEC1) and DRB1*0301 (VEC2) genotypes were established and de novo expression of HLA class II molecules induced with interferon-γ. Under these conditions, VEC1 efficiently processed and presented whole GAD65 to the HLA-DR4–restricted murine T-cell hybridoma T33.1 that recognizes the 274-286 epitope of GAD65. Using a transwell system, we examined the effect of GAD65 presentation on migration of GAD65-specific T-cells across EC monolayers. Migration of T33.1 hybridoma cells and of the human T-cell clone, PM1#11 (recognizes GAD65 epitope 339-352 presented by HLA-DR3) across VEC1 and VEC2, respectively, were greatly enhanced in the presence of GAD65, commencing more rapidly and achieving a higher peak migration at 3 h. Migrated PM1#11 cells retained full proliferative capacity. These results support the hypothesis that presentation of autoantigens by islet endothelium in vivo could promote transmigration of circulating islet autoantigen-specific T-cells primed in regional lymph nodes against islet autoantigens.
Address correspondence and reprint requests to Dr. Mark Peakman, Department of Immunology, Guy’s, King’s and St. Thomas’ School of Medicine, Rayne Institute, 123 Coldharbour Ln., London SE5 9NU, U.K. E-mail:.
Received for publication 12 April 2002 and accepted in revised form 17 December 2002.
J.E.G. and T.I.M.T. contributed equally to this work.
APC, antigen-presenting cell; CFDA-SE, carboxyfluorescein diacetate succinimidyl ester; EC, endothelial cell; EPV, Epstein Barr virus; CFDA-SE, carboxyfluorescein diacetate succinimidyl ester; HBSS, Hank’s balanced salt solution; ICAM, intercellular adhesion molecule; IFN, interferon; LFA-1, leukocyte function-associated antigen-1; mAb, monoclonal antibody; MHC, major hisocompatiblity complex; PE, phycoerythrin; PHA, phytohemagglutinin; TBST, Tris-buffered saline with Tween; TCR, T-cell receptor; TNF, tumor necrosis factor; VCAM, vascular cell adhesion molecule.