Immunogen sequence: FAIEIAAAIW GYSHKDEVIK EVQEFYKDTY NKLKTKDEPQ RETLKAIHYA LNCCGLAGGV EQFISDICPK KDVLETFTVK SCPDAIKEVF DNKFHIIGAV GIGIAVVMI. CD9 antigen is a glycoprotein expressed on the surface of developing B lymphocytes, platelets, monocytes, eosinop