Combination gene therapy for HIV using a conditional suicidal gene with CCR5 knockout.

Area of Science:

• Immunology
• Gene Therapy
• Virology

Background:

• Hematopoietic stem cell gene therapy shows promise for HIV resistance.
• CCR5 knockout is a viable strategy, but CXCR4 co-receptor switching is a challenge.
• A dual gene therapy strategy was developed to address CCR5 knockout limitations.

Purpose of the Study:

• To design and evaluate a dual gene therapy for HIV resistance.
• To overcome the limitations of CCR5 knockout alone.
• To incorporate a conditional suicide gene for enhanced safety and efficacy.

Main Methods:

• A two-vector system was designed using lentiviral vectors.
• One vector expressed a conditional suicide gene (TK-SR39) and GFP reporter.
• The second vector delivered a CCR5 knockout (KO) via CRISPR/Cas9 and HIV Tat protein.

Main Results:

• Sequential transduction enabled suicide gene insertion, CCR5 KO, and GFP enrichment.
• Modified TZM cells showed resistance to CCR5-tropic viruses.
• Infection by CXCR4-tropic viruses was manageable with Ganciclovir treatment.

Conclusions:

• The combination gene therapy is a viable strategy for HIV resistance.
• This approach successfully overcomes limitations associated with CCR5 gene editing alone.