Generation of functional human T-cell subsets with HLA-restricted immune responses in HLA class I expressing NOD/SCID/IL2rγnull humanized mice

Whereas humanized mouse models have contributed significantly to human immunology research, human T cells developing in mouse thymic environment fail to demonstrate HLA-restricted function. To achieve HLA-restricted human immune response, we created an immune-compromised non-obese diabetic/SCID/IL2rg(null) strain (NSG) with homozygous expression of HLA class I heavy chain and light chain (NSG-HLA-A2/HHD). Transplantation of purified Lin-CD34+ CD38- human hematopoietic stem cells into NSG-HLA-A2/HHD newborns resulted in the development of human CD4+ and CD8+ TCR alpha beta+ T cells and CD4-CD8- and CD8+ TCR gamma delta+ cells in recipient bone marrow and spleen. Human cytotoxic T lymphocytes (CTLs) become functionally mature, as evidenced by the production of granzyme corresponding to phenotypic transition from nave to effector memory CTLs. In these recipients, human Th17 cells developed along with Th1 and Th2 cells. Epstein-Barr virus (EBV) infection in the humanized NSG-HLA-A2/HHD recipients resulted in the formation of lymphoproliferative lesions consisting mainly of human B cells with scattered human T cells. Human CTLs developing in the recipients recognized EBV-derived peptides in an HLA-restricted manner and exerted HLA-restricted cytotoxicity against EBV-infected human B cells. The HLA-expressing humanized mouse with functional HLA-restricted T cells and consistent representation of rare T-cell subsets overcomes a major constraint in human immunology, and serves as a useful model for investigation of human immune responses against pathogens and for the development of therapeutic strategies against human diseases.