H2 Class I molecules are trimeric complexes assembled in the ER and formed by the association of a 42-kDa heavy chain b2 microglobulin and a short (8-11 amino acids) peptide. The complex is assembled in the cytosol and transported into the ER by the transporter TAP. Although TAP targeted mutation and b2m targeted mutation mice exhibit greatly reduced numbers of CTL, some functional class Ia molecules (e.g.Db) from these mice can reach the cell surface. In contrast, the homozygous H-2Kb
double targeted mutation mice are virtually devoid of Class Ia cell surface molecules and exhibit a 90% reduction in the total number of CD8ab+ peripheral lymphocytes in spite of increased expression of specific Class Ib lymphocytes. These mice are useful for studying cytolytic T lymphocyte education and mobilization against pathogens, NK cell education and mobilization and humanization of the cytolytic T lymphocyte repertoire by combination with HLA class I transgenesis. Some restrictions apply to the use of these mice for the latter purpose.
Origin: C57BL/6 mice deficient in Db or Kb and were generated by gene targeting in the laboratory of Dr. Francois Lemonnier of The Institut Pasteur, Paris France. Generation of H2-Db knockout mice: The H2-Db gene was disrupted using an insert containing LacZ and a neo cassette flanked by a 4-kb HindIII-XbaI 5' and 1-kb KpnI-SpeI 3' fragment of the D gene resulting in the loss of the first three exons. The targeting construct was introduced into a CGR-8 embryonic stem cell of 129/OLA origin. Clones that were confirmed for homologous recombination were injected into B6 blastocysts and germline chimeras were identified. The founders were crossed twice with C57BL/6Ji females and heterozygous N2 offspring were intercrossed to generate the H2-Db homozygous strain. Inactivation of the H2-Db gene was confirmed by Southern blot analysis on tail DNA and immunofluorescence assay. Generation of H2-Db knockout mice: the H2-Db gene was disrupted by replacing the 2nd and 3rd exons with an HPRT minigene inserted in the opposite transcriptional orientation.The disrupted gene was introduced into an E14TGa(H-2b and b2m) HPRT deficient embryonic stem cell of 129/OLA origin. After injection into B6 blastocysts, the resultant germline chimeras were backcrossed twice to C57BL/6Ji mice and offspring heterozygous for the H2-Kb knockout allele were crossed to generate H2-Kb deficient mice (Kb -/-). Inactivation of the H2-Kb gene was confirmed by Southern blot analysis on tail DNA and by FACS analysis. Generation of H2-Kb H2-Db double knockout mice: N2 Kb -/- and Db -/ - mice were intercrossed and the H2-Kb and H2-Db targeted mutations were genetically linked by crossing-over between the two mutated loci. The double targeted mutation mice were subsequently backcrossed to C57BL/6Ji mice another 10 times
Availability: This model is no longer available.
Initial Publication: Pascolo S, Bervas N, Ure JM, Smith AG, Lemmonier FA and Pérarnau B. HLA-A2.1-restricted education and cytolytic activity of CD8+ T lymphocytes from β2-microglobulin(β2m) HLA-2.1 monochain trangenic H2Dbβ2m double knockout mice. J. Exp. Med. 1997. 185: 2043-2051
Pérarnau B, Saron MF, San Martin BR, Bervas N, Ong H, Soloski MJ, Smith AG, Ure JM, Gairin JE and Lemonnier FA. Single H-2Kb, H-2Db and double H-2KbDb knockout mice: peripheral CD8+ T cell repertoire and antilymphocytic choriomeningitis virus cytolytic responses. Eur. J. Immunol. 1999. 29: 1243-1252