A versatile bifunctional dendritic cell targeting vaccine vector.

Wang, Welson W; Das, Dipankar; Suresh, Mavanur R

We have developed an efficient versatile in vivo dendritic cell (DC) targeting vector for delivering different classes of antigens such as proteins, peptide, glycolipids and naked DNA for vaccine applications. A single chain antibody (scFv) that recognizes DEC-205 receptor of DC was fused with a core-streptavidin domain and expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed as a periplasmic soluble protein and affinity-purified in its monomeric form. The bifunctional activity against DEC-205 and biotin was characterized by ELISA and Western blot. In vivo DC targeting of a diverse group of biotinylated antigens such as viral and bacterial proteins, a cancer peptide, gangliosides and DNA of certain infectious diseases was conducted in mice. Results show that in the presence of bfFp and costimulatory anti-CD40 mAb, both humoral and cell-mediated responses were augmented in either the single antigen or multiple antigen targeting strategy. Lastly, bfFp based DC targeting of antigens in low doses may be a useful strategy for the design of monovalent or polyvalent vaccines for the masses.