Rat RT1.B-transfected fibroblast lines process and present myelin antigensand activate T cells to induce experimental autoimmune encephalomyelitis

The genes encoding the Lewis rat RT1.B molecule (MHC Class II I-A equivalen t) were transfected and expressed in mouse DAP.3 fibroblast cells together with the gene encoding the mouse ICAM-1 molecule. Both molecules were stabl y expressed on the cell surface of DAP.3 cells under longterm culture condi tions. The RT1.B/mICAM-1 transfectants presented antigen in a specific mann er to a RT1.B-restricted rat T cell hybridoma specific for the 69-89 peptid e of myelin basic protein (BP). In addition, the transfectants were able to present antigen to a BP69-89-specific rat T cell line. Presentation to a R T1.D (MHC Class II I-E equivalent)-restricted BP87-99-specific T cell line was minimal. Production of the Th1 cytokine IFN-gamma by BP69-89-specific T cells when stimulated by RT1.B/mICAM-1 transfectants correlated very well with proliferation to specific antigen. Moreover, RT1.B-transfected DAP.3 c ells sufficiently stimulated BP69-89-specific T cells such that they were a ble to transfer experimental autoimmune encephalomyelitis (EAE) to Lewis ra t recipients. Thus, the RT1.B molecule is functionally expressed on the sur face of transfected Dap.3 fibroblasts and is capable of MHC Class II-restri cted. antigen-specific presentation to rat T cells. (C) 2001 Elsevier Scien ce B.V. All rights reserved.