Abstract

Background There are remarkable genetic differences between animal major histocompatibility complex (MHC) systems and the human leukocyte antigen (HLA) system. HLA transgenic humanized mouse model systems offer a much better method to study the HLA-A-related principal mechanisms for vaccine development and HLA-A-restricted responses against infection in human. Methods A recombinant gene encoding the chimeric HLA-A30 monochain was constructed. This HHD molecule contains the following: α1-α2 domains of HLA-A30, α3 and cytoplasmic domains of H-2D b , linked at its N-terminus to the C-terminus of human β2m by a 15-amino-acid peptide linker. The recombinant gene encoding the chimeric HLA-A30 monochain cassette was introduced into bacterial artificial chromosome (BAC) CH502-67J3 containing the HLA-A01 gene locus by Red-mediated homologous recombination. Modified BAC CH502-67J3 was microinjected into the pronuclei of wild-type mouse oocytes. This humanized mouse model was further used to assess the immune responses against influenza A virus (H1N1) pdm09 clinically isolated from human patients. Immune cell population, cytokine production, and histopathology in the lung were analyzed. Results We describe a novel human β2m-HLA-A30 (α1α2)-H-2D b (α3 transmembrane cytoplasmic) (HHD) monochain transgenic mouse strain, which contains the intact HLA-A01 gene locus including 49 kb 5′-UTR and 74 kb 3′-UTR of HLA-A01*01. Five transgenic lines integrated into the large genomic region of HLA-A gene locus were obtained, and the robust expression of exogenous transgene was detected in various tissues from A30-18# and A30-19# lines encompassing the intact flanking sequences. Flow cytometry revealed that the introduction of a large genomic region in HLA-A gene locus can influence the immune cell constitution in humanized mice. Pdm09 infection caused a similar immune response among HLA-A30 Tg