Schematic representation of DNA vaccines. All DNA vaccines encode the leader sequence of the V_H heavy chain gene from the BCL₁ lymphoma upstream of sequence encoding the first domain of fragment C (FrC) of tetanus toxin (TT_865-1120), which contains a promiscuous MHC II-binding sequence, p30. The control vaccine p.DOM contains no additional sequence, whereas p.DOM-WT1.37 additionally encodes VLDFAPPGA (WT1_37-45), p.DOM-WT1.126 additionally encodes RMFPNAPYL (WT1_126-134), and p.DOM-WT1.235 encodes CMTWNQMNL (WT1_235-243) downstream of the FrC sequence.