A Human Leucocyte Antigen‐DR1 Transgene Confers Susceptibility to Experimental Allergic Encephalomyelitis Elicited by an Epitope of Myelin Basic Protein

Much evidence now indicates that human leucocyte antigen (HLA) class I and class II transgenic (Tg) mice can be of value in analysing HLA‐restricted presentation of T‐cell epitopes relevant to experimental models of autoimmune diseases. One area where this has been applied is the characterization of myelin epitopes presented by HLA class II molecules in experimental model of multiple sclerosis (experimental allergic encephalomyelitis (EAE)). As a first step towards humanized disease models in HLA Tg mice, we have analysed immune response of lymph node cells of HLA‐DR1 Tg mice immunized with the human myelin basic protein (MBP) peptides 13–33, 87–106 and 139–154 bound by HLA‐DR1. We report here that HLA‐DR1 Tg mice display a hierarchy of response in vivo and in vitro to MBP epitopes depending on the binding affinity to DRB*0101 molecule. In fact, the 13–33 epitope induced a strong T helper 1 (Th1) response accompanied by high T‐cell precursor frequency and caused mild EAE, while the two other epitopes gave poor (139–154) or no disease (87–106), and these data correlate with in vitro Th1 response. These data could prove a useful tool in understanding the role played by different MBP epitopes in EAE.