Targeting with scFv: immune modulation by complement receptor specific constructs

The fate of a microbe in the host is determined by various molecules of the innate immune system, which recognize the microbe and enhance its interaction with antigen presenting cells. This 'natural targeting' phenomenon, however, does not function when antigens with limited immunogenicity enter the host. Peptide vaccines, for instance, require adjuvants to induce immune responses. As a surrogate for the natural targeting mechanisms, antibodies against selected receptors of antigen presenting cells, conjugated with the peptides, could be used as targeting devices. Here we review various antibody-mediated antigen-targeting strategies, paying special attention to complement receptor-mediated targeting. We also describe and summarize our method of single-chain antibody-mediated targeting of viral epitopes to complement receptor type two and discuss the perspectives of single-chain antibody-mediated antigen targeting.