CD1

CD1 (cluster of differentiation 1) is a family of glycoproteins expressed on the surface of various human antigen-presenting cells. They are related to the class I MHC molecules, and are involved in the presentation of lipid antigens to T cells. However their precise function is unknown.

Types

CD1 glycoproteins can be classified primarily into two groups which differ in their lipid anchoring.

CD1e is an intermediate form, expressed intracellularly, the role of which is currently unclear.

In humans

Group 1

Group 1 CD1 molecules have been shown to present foreign lipid antigens, and specifically a number of mycobacterial cell wall components, to CD1-specific T cells.

Group 2

The natural antigens of group 2 CD1 are not well-characterized, but a synthetic glycolipid, alpha-galactosylceramide, originally isolated from a compound found in a marine sponge, has strong biologic activity.

CD1A

CD1a (Cluster of Differentiation 1a) is a human protein encoded by the CD1A gene.

This gene encodes a member of the CD1 family of transmembrane glycoproteins, which are structurally related to the major histocompatibility complex (MHC) proteins and form heterodimers with beta-2-microglobulin. The CD1 proteins mediate the presentation of primarily lipid and glycolipid antigens of self or microbial origin to T cells. The human genome contains five CD1 family genes organized in a cluster on chromosome 1. The CD1 family members are thought to differ in their cellular localization and specificity for particular lipid ligands. The protein encoded by this gene localizes to the plasma membrane and to recycling vesicles of the early endocytic system. Alternatively spliced transcript variants have been observed, but their biological validity has not been determined.

See also

References

Further reading

This article incorporates text from the United States National Library of Medicine, which is in the public domain.