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CD1
CD1 (cluster of differentiation 1) is a family of glycoproteins expressed on the surface of various human antigen-presenting cells. CD1 glycoproteins are structurally related to the class I MHC molecules, however, in contrast to MHC class 1 proteins, they present lipids, glycolipids and small molecules antigens, from both endogenous and pathogenic proteins, to T cells and activate an immune response.
T cells recognise CD1 using TCR αβ, γδ, or CD36 family members. T cells that are activated by CD1-antigen complexes are called CD1-restricted T cells. 10% of all αβ T lymphocytes in human peripheral blood are Cd1-restricted, out of which, the most abundant are the T cells specific for CD1c.
The human CD1 gene cluster is located on chromosome 1. Genes of the CD1 family were first cloned in 1986, by Franco Calabi and C. Milstein, whereas the first known lipid antigen for CD1 was discovered in 1994, during studies of Mycobacterium tuberculosis. The first antigen that was discovered to be able to bind CD1 and then be recognised by TCR is C80 mycolic acid. Even though their precise function is unknown, The CD1 system of lipid antigen recognition by TCR offers the prospect of discovering new approaches to therapy and developing immunomodulatory agents.
CD1 glycoproteins can be classified primarily into two groups of CD1 isoforms which differ in their lipid anchoring, as well as their expression patterns of the CD1 genes (CD1d is constitutively expressed, whereas the group 1 CD1 genes are inducible and coordinately regulated by myeloid cells).
CD1e is an intermediate form, a soluble lipid transfer protein that is expressed intracellularly. It does not present lipid antigens to T cells, rather plays a role in the processing of lipid antigens and loading them onto other CD1 molecules.
Group 1 CD1 molecules have been shown to present foreign lipid antigens to CD1-specific T cells. Human CD1 cells can recognise and bind a large number of lipids, from monoacylated lipids or lipopeptides to tetra-acylated lipids. However, not all of the lipid ligands can be considered antigens for T-cells. Free fatty acids sphingolipids, phospholipids, sulfolipids, lysophospholipids, amphipathic small molecules and some oils function as natural antigens for T cells.
The natural antigens of group 2 CD1 are not well characterized, but a synthetic glycolipid, alpha-galactosylceramide (α-GalCer), originally isolated from a compound found in a marine sponge, has strong biologic activity.
Group 2 CD1 molecules activate a group of T cells, known as natural killer T cells because of their expression of NK surface markers such as CD161. Natural Killer T (NKT) cells are activated by CD1d-presented antigens, and rapidly produce Th1 and Th2 cytokines, typically represented by interferon-gamma and IL-4 production. The group 2 (CD1d) ligand α-GalCer is currently in phase I clinical trials for the treatment of advanced non-hematologic cancers.
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CD1 AI simulator
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CD1
CD1 (cluster of differentiation 1) is a family of glycoproteins expressed on the surface of various human antigen-presenting cells. CD1 glycoproteins are structurally related to the class I MHC molecules, however, in contrast to MHC class 1 proteins, they present lipids, glycolipids and small molecules antigens, from both endogenous and pathogenic proteins, to T cells and activate an immune response.
T cells recognise CD1 using TCR αβ, γδ, or CD36 family members. T cells that are activated by CD1-antigen complexes are called CD1-restricted T cells. 10% of all αβ T lymphocytes in human peripheral blood are Cd1-restricted, out of which, the most abundant are the T cells specific for CD1c.
The human CD1 gene cluster is located on chromosome 1. Genes of the CD1 family were first cloned in 1986, by Franco Calabi and C. Milstein, whereas the first known lipid antigen for CD1 was discovered in 1994, during studies of Mycobacterium tuberculosis. The first antigen that was discovered to be able to bind CD1 and then be recognised by TCR is C80 mycolic acid. Even though their precise function is unknown, The CD1 system of lipid antigen recognition by TCR offers the prospect of discovering new approaches to therapy and developing immunomodulatory agents.
CD1 glycoproteins can be classified primarily into two groups of CD1 isoforms which differ in their lipid anchoring, as well as their expression patterns of the CD1 genes (CD1d is constitutively expressed, whereas the group 1 CD1 genes are inducible and coordinately regulated by myeloid cells).
CD1e is an intermediate form, a soluble lipid transfer protein that is expressed intracellularly. It does not present lipid antigens to T cells, rather plays a role in the processing of lipid antigens and loading them onto other CD1 molecules.
Group 1 CD1 molecules have been shown to present foreign lipid antigens to CD1-specific T cells. Human CD1 cells can recognise and bind a large number of lipids, from monoacylated lipids or lipopeptides to tetra-acylated lipids. However, not all of the lipid ligands can be considered antigens for T-cells. Free fatty acids sphingolipids, phospholipids, sulfolipids, lysophospholipids, amphipathic small molecules and some oils function as natural antigens for T cells.
The natural antigens of group 2 CD1 are not well characterized, but a synthetic glycolipid, alpha-galactosylceramide (α-GalCer), originally isolated from a compound found in a marine sponge, has strong biologic activity.
Group 2 CD1 molecules activate a group of T cells, known as natural killer T cells because of their expression of NK surface markers such as CD161. Natural Killer T (NKT) cells are activated by CD1d-presented antigens, and rapidly produce Th1 and Th2 cytokines, typically represented by interferon-gamma and IL-4 production. The group 2 (CD1d) ligand α-GalCer is currently in phase I clinical trials for the treatment of advanced non-hematologic cancers.