Human invariant chain isoform p35 restores thymic selection and antigen presentation in CD74-deficient mice
| Autor: | Jacques Thibodeau, Laetitia Genève, Magali Chemali, Michel Desjardins, Nathalie Labrecque |
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| Rok vydání: | 2012 |
| Předmět: |
Gene isoform
CD4-Positive T-Lymphocytes Male CD74 Ovalbumin Immunology Antigen presentation Receptors Antigen T-Cell Antigen-Presenting Cells Mice Transgenic Thymus Gland Biology Interferon-gamma Mice Deficient mouse Immunology and Allergy Animals Humans Protein Isoforms Selection (genetic algorithm) Cells Cultured Genetics Mice Knockout Antigen Presentation Thymocytes Macrophages fungi Histocompatibility Antigens Class II Cell Biology Flow Cytometry Cell biology Invariant chain Antigens Differentiation B-Lymphocyte Mice Inbred C57BL embryonic structures Natural Killer T-Cells Female |
| Zdroj: | Immunology and cell biology. 90(9) |
| ISSN: | 1440-1711 |
| Popis: | The invariant chain (Ii) has pleiotropic functions and is a key factor in antigen presentation. Ii associates with major histocompatibility complex class II molecules in the endoplasmic reticulum (ER) and targets the complex in the endocytic pathway to allow antigenic peptide loading. The human Iip35 isoform includes a cytoplasmic extension containing a di-arginine motif causing ER retention. This minor isoform does not exist in mice and its function in humans has not been thoroughly investigated. We have recently generated transgenic mice expressing Iip35 and these were crossed with Ii-deficient mice to generate animals (Tgp35/mIiKO) expressing exclusively the human isoform. In these mice, we show that Iip35 is expressed in antigen presenting cells and is inducible by interferon gamma (IFN-γ). Despite the low constitutive expression of the protein and some minor differences in the Vβ repertoire of Tgp35/mIiKO mice, Iip35 restored thymic selection of CD4(+) T cells and of invariant natural killer T cells. In vitro functional assays using purified primary macrophages treated with IFN-γ showed that Iip35 allows presentation of an Ii-dependent ovalbumin T-cell epitope. Altogether, our results suggest that Iip35 is functional and does not require co-expression of other isoforms for antigen presentation. |
| Databáze: | OpenAIRE |
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