Immunogen sequence: YNKLKTKDEP QRETLKAIHY ALNCCGLAGG VEQFISDICP KKDVLETFTV KSCPDAIKEV FDNKFHIIGA VGIGIAVVMI FGMIFSMILC CAIRRNREMV. CD9 antigen is a glycoprotein expressed on the surface of developing B lymphocytes, platelets, monocytes, eosinophils, baso