FIGURE 1.

Schematic representation of intermolecular help for the induction of cytokine-specific antibody responses. (A) Cytokines are conjugated to a carrier protein, resulting in cytokine-specific B cells receiving, however, carrier specific T-cell help. (B) Conjugation to virus-like particles (VLPs) further increases antibody responses, due to repetitive display of the antigen and packaged non-coding RNA, which is a ligand for toll-like receptor 7/8 (TLR7/8) and present in many RNA virus-derived VLPs. (C) Presence of a universal T cell epitope may further improve Th cell dependent IgG responses, in particular if the epitope is derived from tetanus toxin (TT), as essentially everybody harbors memory Th cells against TT.