Immunogen sequence: VFPEVLLSEN QLAPGEFQVS TDGRLFSLKP TSGPVLTVTL FGRLYEKDWA SNASSGLTAQ ARIIMLIVIA PIVCSLSW Antigen sequence identity: Mouse 73%; Rat 76%. Hematopoietic precursor cells migrate to the thymus, where they differentiate into mature T lymphocyt