Immunogen sequence: LDKIEDERNL HEDFVFMKTI QRCNTGERSL SLLNCEEIKS QFEGFVKDIM LNKEETKKEN SFEMQKGDQN PQIAAHVISE ASSKTTSVLQ WAEKGYYTMS N. CD40 Ligand (CD40-L), or CD154, is a membrane glycoprotein and differentiation antigen expressed on the surface of T cell