TABLE 9-3 SELECTED T-CELL ACCESSORY MOLECULES Function Signal Member of Name Ligand Adhesion transduction Ig superfamily CD4 Class II MHC + CD8 Class I MHC X + CD2 (LFA-2) CD58(LFA-3) + LFA-1 (CDI1a/CD18) ICAM-1 (CD54) +(-） CD28 B7 CTLA-4 B7 一 CD45R CD22 CD5 CD72 CD28 is expressed by both resting and activated T cells CD28 B7 TH cell APC 参与第二信号途 径的主要分子对 B> CTLA-4 CTLA-4 is expressed Both B7 molecules are on activated T cells expressed on dendritic cells activated macrophages,and activated B cells参与第二信号途 径的主要分子对