CD6 (Cluster of Differentiation 6) is a human protein encoded by the CD6 gene.

This gene encodes a protein found on the outer membrane of T-lymphocytes as well as some other immune cells. The encoded protein contains three scavenger receptor cysteine-rich (SRCR) domains and a binding site for an activated leukocyte cell adhesion molecule. The gene product is important for continuation of T cell activation.

Certain alleles of this gene may be associated with susceptibility to multiple sclerosis.

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