Characterization of fusion vaccines used in this study. (A) Schematic structure of a homodimeric vaccine fusion protein (Vaccibody, VB). Targeting, dimerization and antigenic units are indicated, as are the different moieties expressed in the various units. MHC class II targeted (I-Ed-specific) and non-targeted (NIP-specific) constructs are denoted (FvI-EFvPn)2 and (FvNIPFvPn)2, respectively, whereas LD78β VB are denoted (LD78βFvPn)2. where Pn indicates patient number. (B) Detection of VB proteins in supernatants of transfected HEK 293E cells in an ELISA specific for hγCH3. (C) Binding of MHC class II-targeted VB to I-Ed+ A20 cells. (D) LD78β VB displays dose-dependent chemotactic activity on lymphocytic Esb/MP cells. Recombinant LD78β was used as positive control.