Abstract
In all human cells, human leukocyte antigen (HLA) class I glycoproteins assemble with a peptide and take it to the cell surface for surveillance by lymphocytes. These include natural killer (NK) cells and γδ T cells of innate immunity and αβ T cells of adaptive immunity. In healthy cells, the presented peptides derive from human proteins, to which lymphocytes are tolerant. In pathogen-infected cells, HLA class I expression is perturbed. Reduced HLA class I expression is detected by KIR and CD94:NKG2A receptors of NK cells. Almost any change in peptide presentation can be detected by αβ CD8+ T cells. In responding to extracellular pathogens, HLA class II glycoproteins, expressed by specialized antigen-presenting cells, present peptides to αβ CD4+ T cells. In comparison to the families of major histocompatibility complex (MHC) class I, MHC class II and αβ T cell receptors, the antigenic specificity of the γδ T cell receptors is incompletely understood.
Keywords:
HLA; KIR; TCR; haplotype; lymphocyte; polymorphism.
MeSH terms
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Antigen Presentation
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CD8-Positive T-Lymphocytes / cytology
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CD8-Positive T-Lymphocytes / immunology
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Evolution, Molecular
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Gene Expression Regulation
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Haplotypes
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Histocompatibility Antigens Class I / chemistry*
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Histocompatibility Antigens Class I / classification
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Histocompatibility Antigens Class I / genetics
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Histocompatibility Antigens Class I / immunology
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Histocompatibility Antigens Class II / chemistry*
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Histocompatibility Antigens Class II / classification
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Histocompatibility Antigens Class II / genetics
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Histocompatibility Antigens Class II / immunology
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Humans
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Immunity, Cellular*
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Immunity, Innate
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Killer Cells, Natural / cytology
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Killer Cells, Natural / immunology
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Models, Molecular
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NK Cell Lectin-Like Receptor Subfamily D / chemistry*
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NK Cell Lectin-Like Receptor Subfamily D / genetics
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NK Cell Lectin-Like Receptor Subfamily D / immunology
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Protein Interaction Domains and Motifs
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Protein Structure, Secondary
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Receptors, Antigen, T-Cell, alpha-beta / chemistry*
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Receptors, Antigen, T-Cell, alpha-beta / genetics
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Receptors, Antigen, T-Cell, alpha-beta / immunology
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Receptors, Antigen, T-Cell, gamma-delta / chemistry*
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Receptors, Antigen, T-Cell, gamma-delta / genetics
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Receptors, Antigen, T-Cell, gamma-delta / immunology
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Receptors, KIR / chemistry*
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Receptors, KIR / classification
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Receptors, KIR / genetics
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Receptors, KIR / immunology
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Signal Transduction
Substances
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Histocompatibility Antigens Class I
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Histocompatibility Antigens Class II
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KLRD1 protein, human
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NK Cell Lectin-Like Receptor Subfamily D
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Receptors, Antigen, T-Cell, alpha-beta
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Receptors, Antigen, T-Cell, gamma-delta
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Receptors, KIR