Functions of CD 1 to CD 10:

•CD 1: Present nonpeptide antigens including lipids and glycolipids to T cells (group 1 = CD1a,b,c to conventional T cells; group2 = CD1d to NK T cells only). Members have various secondary roles. •CD 2: Adhesion molecule, binding LFA-3 (CD58). Binding to sheep CD58 is the basis of the sheep rosette reaction, used to identify and purify T cells. Other ligands (of lower affinity) are CD48 and possibly CD59, CD15. CD2 binding by ligands induces T cell activation. KO mice have apparently healthy immune systems. •CD3: Required for cell surface expression of T cell receptor and signal transduction. •CD 4: Coreceptor for MHC class II antigen restricted T cell activation, involved in thymic differentiation, primary receptor for HIV infection. •CD 5: Putative ligand is CD72. CD5 participates in a membrane complex with CD3 or Ig. Cytoplasmic sequence binds PTK p56lck through SH2 domain. • CD6: Binds CD166 and possibly other ligands, suggesting adhesion function. Antibody ligation costimulates with signals through CD3 •CD7: Essential role in T cell interactions and T cell/B cell interactions, and may aid in prevention of autoimmune disease. May modulate cell adhesion. •CD8: Coreceptor for MHC class I restricted T cell activation. •CD9: Forms complexes with integrins and other tetraspanin members. Modulates cell adhesion and migration. Can trigger platelet activation and aggregation. • CD10: Peptidase activity may limit action of physiologically active peptides. Inhibition in vivo enhances B cell maturation.