A versatile bifunctional dendritic cell targeting vaccine vector.

Area of Science:

• Immunology
• Vaccinology
• Molecular Biology

Background:

• Dendritic cells (DCs) are crucial for initiating adaptive immune responses.
• Targeting DCs can enhance vaccine efficacy.
• Efficient delivery of diverse antigens to DCs is needed for novel vaccine development.

Purpose of the Study:

• To develop and characterize an efficient, versatile in vivo dendritic cell (DC) targeting vector.
• To evaluate the vector's ability to deliver various antigen classes for vaccine applications.
• To assess the impact of DC-targeted antigens on humoral and cell-mediated immune responses.

Main Methods:

• A bifunctional fusion protein (bfFp) was engineered, combining a single-chain antibody (scFv) targeting the DC receptor DEC-205 with a core-streptavidin domain.
• The bfFp was expressed in Escherichia coli and purified.
• Bifunctional activity was confirmed via ELISA and Western blot.
• In vivo studies in mice involved targeting biotinylated antigens (proteins, peptides, glycolipids, DNA) to DCs using the bfFp, often in conjunction with anti-CD40 mAb.

Main Results:

• The bfFp demonstrated bifunctional activity against DEC-205 and biotin.
• In vivo DC targeting with bfFp successfully delivered diverse antigens.
• Co-administration with anti-CD40 mAb significantly augmented both humoral and cell-mediated immune responses.
• Both single and multiple antigen targeting strategies were effective.

Conclusions:

• The developed bfFp is an efficient and versatile tool for in vivo DC targeting.
• This strategy effectively enhances immune responses against various antigen types.
• bfFp-mediated DC targeting holds potential for designing effective monovalent or polyvalent vaccines, even at low antigen doses.