Human T cell receptor and human leukocyte antigen class II transgenic mouse as a new model for multiple sclerosis.

摘要

Multiple sclerosis (MS) is an inflammatory demyelinating disease that affects the myelin sheath of the central nervous system (CNS). Although the etiology of MS is unknown, studies from both experimental autoimmune encephalomyelitis (EAE), animal model for MS, and observations from MS patients support the concept that MS is an autoimmune disease mediated by myelin-specific CD4 + T cells. Patients with MS shove the strongest association to certain HLA class II haplotypes, especially HLA-DR2 (DRB5 *0101 and DRB1* I501).; To study the genetic contribution of HLA-DR2a (DRB5*0101) in disease susceptibility, identify immunodominant epitopes, and delineate mechanisms by which HLA-DR2a could influence immune responsiveness, a human-mouse chimeric HLA-DR2a-IE transgenic mouse was generated. Mice expressing human-mouse chimeric MHC class II molecule, with the antigen-binding domain of human class II (HLA-DR) and the CD4-binding domain of mouse MHC class II (I-E) molecule were generated and characterized.; HLA-DR-IEα and HLA-DR2a-IEβ transgene-vectors were microinjected into oocytes of C57BL/6 mice. Transgene-positive mice were crossed with MHC class II-deficient (I-Aβ−/−) mice and MHC class II expression, thymic selection and antigenic specificity were analyzed. The HLA-DR2a transgenic mouse expressed HLA-DR in a tissue-specific manner and was co-expressed with mouse MHC class II molecules. Three different surface expression levels of low, intermediate, and high DR expression were observed among different founder transgenic lines.; Additionally, in order to study how myelin basic protein (MPB)-specific T cells are able to escape central tolerance and their role in disease pathogenesis we generated double transgenic mice expressing human-mouse chimeric HLA-DRB1*0401-IE MHC class II molecule and human-mouse chimeric T cell receptor (TCR). The transgenic TCR (Tg+) composed of human V(D)J region of MS-patient-derived CD4+ T-cell clone and mouse C region with specificity for amino acids 111–129 of MBP and HLA-DRB1*0401 restriction. The Tg+ T cells were positively selected by HLA-DRB1*0401-IE in the thymus, were skewed to CD4+ T cell lineage and showed appropriate specificity and restriction. Tg+ T cells activated in vitro induced EAE in irradiated HLA-DRB1*0401-IE transgenic mice and not in naive HLA-DRB1*0401-IE transgenic mice. The presence of endogenous T cells appears to reduced disease susceptibility and severity. Disease course was clinically heterogeneous, similar to MS patients. Histological analysis showed preferential localization of inflammatory lesions in the spinal cord and brain stem.