Improved gene delivery to B lymphocytes using a modified adenovirus vector targeting CD21

Area of Science:

• Molecular Biology
• Virology
• Gene Therapy

Background:

• Adenoviruses are common vectors for gene therapy, particularly for hematopoietic malignancies.
• Adenovirus serotype 5 (HAdV5) vectors exhibit natural tropism for the hCAR receptor, limiting their specificity.
• Tissue-specific viral vectors are needed to improve the efficacy of adenoviral gene therapy.

Purpose of the Study:

• To develop a modified adenovirus vector for targeted gene delivery to CD21-positive cells.
• To enhance transgene expression in target cells while minimizing off-target transduction.
• To investigate the impact of receptor-specific targeting on viral intracellular trafficking and nuclear transfer.

Main Methods:

• Engineered HAdV5 fiber protein by inserting a CD21 binding sequence from EBV GP350/220 into the HI loop.
• Created a novel vector, HAdV5-CD21HIloop, for specific binding to CD21 receptors.
• Assessed viral binding, transduction efficiency, and transgene expression in CD21-positive and CD21-negative cells.

Main Results:

• The HAdV5-CD21HIloop vector specifically bound to CD21-positive cells.
• Transduction and transgene expression were significantly enhanced in CD21-positive cells.
• Infection and expression were reduced in CD21-negative cells, indicating improved specificity.
• The modified vector maintained efficient intracellular trafficking and nuclear transfer without vesicular retention.

Conclusions:

• The HAdV5-CD21HIloop vector demonstrates specific gene transfer to CD21-positive cells.
• This targeted approach improves transgene expression in desired cells and reduces off-target effects.
• The engineered vector holds promise for enhancing gene therapy strategies in hematopoietic malignancies.