Qa-1, a Nonclassical Class I Histocompatibility Molecule With Roles in Innate and Adaptive Immunity
| Autor: | Peter E. Jensen, Dominique A. Weber, Lisa M. Reed-Loisel, Barbara A. Sullivan |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
T-Lymphocytes
Immunology Antigen presentation Major histocompatibility complex Natural killer cell Mice Interleukin 21 Antigens CD HLA Antigens medicine Animals Insulin Lectins C-Type Receptors Immunologic Antigen-presenting cell biology ZAP70 Histocompatibility Antigens Class I Acquired immune system Natural killer T cell Immunity Innate Cell biology Killer Cells Natural Immunity Active medicine.anatomical_structure biology.protein Receptors Natural Killer Cell NK Cell Lectin-Like Receptor Subfamily C NK Cell Lectin-Like Receptor Subfamily D |
| Zdroj: | Immunologic Research. 29:081-092 |
| ISSN: | 0257-277X |
| Popis: | Qa-1, a nonclassical class I histocompatibility molecule expressed in mice, predominantly assembles with a single nonameric peptide, Qdm, derived from the signal sequence of certain class Ia molecules. The Qa-1/Qdm complex is the primary ligand for CD94/NKG2A inhibitory receptors expressed on a major fraction of natural killer (NK) cells. Cells become susceptible to killing by NK cells under conditions where surface expression of the Qa-1/Qdm inhibitory ligand is reduced. The CD94/NKG2 "missing-self" recognition system serves as mechanism for removing cells that have abnormalities in the intracellular machinery required for assembly and expression of class I-peptides complexes, as a consequence of viral infection, for example. Despite its highly focused peptide-binding specificity, Qa-1 also has a capacity to act as an antigen-presentation molecule for CD8+ T cells. It appears that a small subpopulation of these T cells undergoes positive selection by interaction with Qa-1 in the thymus, and they maintain their specificity for Qa-1 after maturation. The role of these unusual T cells in adaptive immune responses remains to be defined. |
| Databáze: | OpenAIRE |
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