Unit: Antiviral Cell Immunology

Director: François Lemonnier

The work of the laboratory aims, using different approaches, especially the production of genetically modified strains of mice (knock-out mice lacking selectively or globally H-2 class I or class II molecules, HLA class I or class II transgenic mice) at a) the analysis of the mechanisms involved in the education, the peripheral mobilization and the long term maintenance of cytolytic CD8+, helper CD4+ T lymphocytes and Natural Killer (NK) cells, b) the identification of viral or tumoral peptides presented to cytolytic and helper T lymphocytes, c) the evaluation and optimization of their vaccine potential and d) finally, the evaluation of the auto agressive potential.

Introduction of cytolytic T lymphocytes recognizing a histocompatibility class Ib molecule deprived of bound peptide : HFE (P. Rohrlich, H. Firat)

Immunizing mice expressing a single type of HLA class I molecule (HLA-A0201), with transfected cells expressing also a single species of HLA class Ib molecule (the human HFE molecule implicated in the control of iron metabolism), CD8+, TcRß+ cytolytic T lymphocytes recognizing specifically HFE through their T cell receptor for the antigen, were induced despite the fact that HFE molecules, as documented crystographically, are totally deprived of bound peptide. Similar CTL responses have been induced in DBA/2 HFE KO mice against the mouse HFE molecule. In view of the structural polymorphism in humans of the HFE molecule, these results support the possibility that HFE could be a significant histocompatibility antigen worth to consider in certain tissue transplantations.

Vaccine potential of HLA-A0201- and HLA-B702-restricted epitopic peptides of HIV 1 origin (P. Langlade-Demoyen, S. Cardinaud, P. Rohrlich)

The vaccine potentials of HIV 1-derived epitopic peptides reported in the literature or identified in the laboratory have been compared using transgenic mice expressing HLA-A0201 molecules in the complete absence of H-2 class I molecules or the HLA-B0702 molecules in a H-2Kb, H-2Db double KO context. Following these studies, it was possible to establish a hierarchy in terms of immunogenicity of these peptides, to optimize the immunogenicity of those which were poorly immunogenic in their native configuration, to compare vaccine strategies and to demonstrate that a polyepitope construct could induce multiepitopic, long-lasting cytolytic responses in a single mouse. Two polyepitopes (HLA-A02.01, -B07.02) have been constructed. A third one will be realized in the coming year corresponding to the HLA-A3.01 molecule, using a new transgenic strain of mice.

Creation of HLA-class I transgenic, H-2 class I KO and HLA class II transgenic, H-2 class II KO mice (A. Pajot, Y.C. Lone)

HLA class II transgenic (DPß401, DPα 103) H-2 class II KO mice have been created and used to identify HBV-derived epitopic peptides presented by HLA- DPß401.α 103 molecules which are expressed by > than 50% of individuals in human populations. Similar studies will be extended to HIV 1. Similarly, transgenic (HLA-A0201, HLA-DR) H-2 class I class II KO mice have been derived. These animals will be used to evaluate preclinically and simultaneously all components of the immune adaptative responses (CD8+ cytolytic, CD4+ helper and antibody) to vaccine formulations of potential interest in humans and the protection confered.

Genes controlling NK cell differentiation (C. Roth)

Using stable NK cell lines and clones derived from P53 deficient mice, two complementary approaches have been used to identify new receptors and co-receptors potentially involved in NK cell maturation. A differential expression library was prepared from clones either highly or poorly cytotoxic. Among the different cDNA isolated, we are focusing on one corresponding to a receptor. Strains of mice deficient in this receptor exhibit a profound defect in bone-marrow maturation of NK cells.

Keywords: HLA Transgenic, H-2 KO mice, HIV 1, NK

Activity Reports 2003 - Institut Pasteur

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