The future prospects of cell
and gene therapy

Role of Cell and Gene Therapy in Infectious Disease

1. HIV/AIDS

• • Gene Therapy:
    • CCR5 Gene Editing: The CCR5 receptor on CD4+ T cells is a critical entry point for HIV. Gene editing technologies, such as CRISPR-Cas9 and zinc finger nucleases, are being used to knock out the CCR5 gene in T cells, making them resistant to HIV infection. Clinical trials have shown that this approach can lead to a significant reduction in viral load and an increase in HIV-resistant immune cells.
    • Long-acting Antiviral Genes: Gene therapy can deliver genes encoding for broadly neutralizing antibodies or antiviral proteins that provide long-term protection against HIV. For example, AAV vectors have been used to deliver genes that produce antibodies targeting multiple HIV strains.

• • Cell Therapy: Chimeric antigen receptor (CAR) T cells are engineered to specifically target and kill HIV-infected cells. This approach has shown promise in preclinical studies and early-phase clinical trials, leading to a reduction in the viral reservoir and improved immune function.

2. Hepatitis B and C

• • Gene Therapy:
  • RNA Interference (RNAi): RNAi can be used to silence viral genes necessary for hepatitis B virus (HBV) and hepatitis C virus (HCV) replication. Delivering small interfering RNA (siRNA) molecules to liver cells can effectively reduce viral load and improve liver function in infected patients.
  • Gene Editing: CRISPR-Cas9 technology is being explored to directly target and cleave HBV DNA within infected liver cells, potentially eliminating the virus. Preclinical studies have shown that this approach can significantly reduce viral DNA levels and restore liver function.

• • Cell Therapy: Transplanting healthy hepatocytes can help restore liver function in patients with severe liver damage due to chronic hepatitis infection. This approach can also provide a new source of liver cells resistant to viral infection through genetic modification.

3. Cytomegalovirus (CMV)

• • Gene Therapy: Gene therapy can deliver genes encoding antiviral proteins that inhibit CMV replication. For example, AAV vectors have been used to deliver genes that produce antiviral cytokines, reducing CMV replication and improving immune control of the virus.
  • Cell Therapy: Adoptive T Cell Therapy approach involves infusing patients with CMV-specific T cells that have been expanded in the laboratory. These T cells can specifically target and eliminate CMV-infected cells, providing effective control of the virus, particularly in immunocompromised patients such as those undergoing hematopoietic stem cell transplantation.

4. COVID-19

• • Gene Therapy:
    • Antibody Genes: Gene therapy using AAV vectors can deliver genes encoding neutralizing antibodies against SARS-CoV-2, the virus causing COVID-19. This approach aims to provide long-term protection by enabling the body to continuously produce the antibodies.
    • mRNA Vaccines: While not traditional gene therapy, mRNA vaccines deliver genetic instructions to cells to produce viral antigens, eliciting a robust immune response. The Pfizer-BioNTech and Moderna COVID-19 vaccines are based on this technology and have shown high efficacy in preventing infection.

• • Cell Therapy: Mesenchymal Stem Cells (MSCs) have immunomodulatory and anti-inflammatory properties that can help treat severe COVID-19 by reducing lung inflammation and promoting tissue repair. Clinical trials are investigating the efficacy of MSC therapy in improving outcomes for patients with severe respiratory symptoms.