Adenoviral targeting using genetically incorporated camelid single variable domains.

Area of Science:

• Gene Therapy
• Virology
• Immunology

Background:

• Human adenovirus serotype 5 (Ad5) vectors are widely used in gene therapy due to efficient transduction.
• Modifying Ad5 vector tropism is crucial for cell-specific gene delivery.
• Targeting motifs are genetically incorporated into Ad5 fibers to alter tropism.

Purpose of the Study:

• To explore the use of novel anti-human carcinoembryonic antigen (hCEA) single variable domains (VHHs) for targeted gene transfer.
• To assess the feasibility of using VHHs to retarget Ad5-based gene transfer vectors.

Main Methods:

• Produced a VHH-display library from alpaca peripheral blood lymphocytes RNA immunized against hCEA.
• Genetically incorporated an anti-hCEA VHH into a de-knobbed Ad5 fiber-fibritin chimera.
• Demonstrated selective targeting to hCEA on target cell membranes.

Main Results:

• The anti-hCEA VHH retained antigen recognition functionality.
• The VHH provided specificity for gene transfer with capsid-modified Ad5 vectors.
• Selective targeting to cells expressing the hCEA epitope was achieved.

Conclusions:

• Novel anti-hCEA VHHs can be effectively used to retarget Ad5-based gene transfer.
• This strategy demonstrates the feasibility of VHH-mediated retargeting for Ad5 gene therapy applications.
• VHHs offer a promising approach for achieving specific gene delivery in Ad5 vectors.