The CD6-ALCAM Pathway Plays a Central Role in Autoimmunity
CD6 is a co-stimulatory receptor that uniquely modulates T cell activity and
trafficking and is a key checkpoint in regulating Teff cells that are central to autoimmune
responses. Activated leukocyte cell adhesion molecule (ALCAM) is a ligand of CD6 that is expressed
on hematopoietic tissues such as antigen-presenting cells, where it is important for immune synapse
formation and optimal co-stimulation. Binding of ALCAM to CD6 leads to the downstream activation of
several mitogen activated protein kinase (MAPK) pathways related to T cell activation,
proliferation, differentiation and survival. Preclinical and clinical studies have shown that
blockade of the CD6-ALCAM pathway leads to selective inhibition of pathogenic Teff cell activity and
trafficking, while preserving the important regulatory function of Treg cells, which provide ongoing
immune surveillance.