CD100/Sema4D Atsushi Kumanogoh and Hitoshi Kikutani* Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan * corresponding author tel: +81-6-6879-8363, fax: +81-6-6875-4465, e-mail:
[email protected] DOI: 10.1006/rwcy.2002.0329. SUMMARY Alternative names CD100 is a 150 kDa transmembrane protein that belongs to the semaphorin family. Many members of the semaphorin family have been identified as axonal guidance factors during neuronal development. CD100 is the first semaphorin member shown to have physiological roles and expression in the immune system. CD100 utilizes two types of receptors in different tissues. Plexin-B1 has been shown to be the receptor of CD100 in nonlymphoid tissues, while CD72 has been identified to be a lymphocyte receptor of CD100 in lymphoid tissues. CD100 functions as a ligand in the immune system through CD72 to augment the proliferation and antibody production of activated B cells and to promote the activation and maturation of antigen-presenting dendritic cells. Sema4D/SEMA4D, M-Sema G (mouse), and C-Coll-4 (chick). BACKGROUND Discovery CD100 was originally identified as a 150 kDa surface antigen recognized by monoclonal antibodies (mAb) raised against human T cells (Herold et al., 1995). In 1996, molecular cloning revealed that CD100 is a transmembrane-type semaphorin member, which provided the first evidence that semaphorins are expressed in the immune system (Hall et al., 1996). Mouse CD100 was independently cloned from the brain and has been shown to be expressed in lymphoid tissues as well (Furuyama et al., 1996). Mouse CD100 was also cloned as one of molecules induced in