Cell-Surface Expression and Alloantigenic Function of a Human Nonclassical Class I Molecule (HLA-E) in Transgenic Mice

• Published in: The Journal of immunology (1950) Vol. 162; no. 9; pp. 5190 - 5196
• Main Authors: Pacasova, Rita, Martinozzi, Silvia, Boulouis, Henri-Jean, Ulbrecht, Matthias, Vieville, Jean-Claude, Sigaux, Francois, Weiss, Elisabeth H, Pla, Marika
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 01.05.1999
• Subjects: Animals; beta 2-Microglobulin - physiology; Cell Membrane - immunology; Cell Membrane - metabolism; Cells, Cultured; Cytotoxicity Tests, Immunologic; Cytotoxicity, Immunologic - genetics; Female; Flow Cytometry; Genetic Vectors - chemical synthesis; Genetic Vectors - immunology; Histocompatibility Antigens Class I - biosynthesis; Histocompatibility Antigens Class I - genetics; Histocompatibility Antigens Class I - immunology; HLA Antigens - biosynthesis; HLA Antigens - genetics; HLA Antigens - immunology; HLA-B27 Antigen - genetics; HLA-E Antigens; Humans; Isoantigens - genetics; Isoantigens - physiology; Lymph Nodes - cytology; Lymph Nodes - immunology; Lymphocyte Activation - genetics; Mice; Mice, Inbred C57BL; Mice, Transgenic - immunology; Skin Transplantation - immunology; T-Lymphocytes, Cytotoxic - immunology; Transgenes - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.162.9.5190

We have introduced the gene (E*01033) encoding the heavy chain of the human nonclassical MHC class I Ag, HLA-E, into the mouse genome. Two founder mice carry a 21-kb fragment, the others bear an 8-kb fragment. Each of the founder mice was mated to mice of an already established C57BL/10 transgenic line expressing human beta2-microglobulin (beta2m). Cell surface HLA-E was detected on lymph node cells by flow cytometry only in the presence of endogenous human beta2m. However, HLA-E-reactive mouse CTL (H-2-unrestricted) lysed efficiently the target cells originating from HLA-E transgenic mice without human beta2m, showing that the HLA-E protein can be transported to the cell surface in the absence of human beta2m, presumably by association with murine beta2m. Rejection of skin grafts from HLA-E transgenic mice demonstrates that HLA-E behaves as a transplantation Ag in mice. HLA-E transgenic spleen cells are effective in stimulating an allogeneic CTL response in normal and human classical class I (HLA-B27) transgenic mice. Furthermore, results from split-well analysis indicate that the majority of the primary in vivo-induced CTL recognizes HLA-E as an intact molecule (H-2-unrestricted recognition) and not as an HLA-E-derived peptide presented by a mouse MHC molecule, although a small fraction (ranging from 4 to 21%) of the primary in vivo-induced CTL is able to recognize HLA-E in an H-2-restricted manner. Based on these observations, we conclude that HLA-E exhibits alloantigenic properties that are indistinguishable from classical HLA class I molecules when expressed in transgenic mice.