Immunogen sequence: NAESYENEDE ELTQPVARTM DFLSPHGSAW DPSREATSLG SQSYEDMRGI LYAAPQLRSI RGQPGPNHEE DADSYENMDN PDGPDPAWGG GGRMGTWSTR. CD19 is a member of the immunoglobulin superfamily, characterized by two Ig-like domains, and is expressed on B cells throu