Gene Therapy Vectors & Tools
What is Gene Therapy?
Gene therapy is focused on the treatment of diseases by directly altering the genetic material within a patient's cells. This can involve replacing a faulty gene with a functional one, inactivating a malfunctioning gene, or introducing a new gene to help fight a disease.
Depending on the treatment, the target of gene therapy may differ. On one hand, germ or stem cells as a target (GGT – germline cell therapy) introduce heritable changes to the genome, which could find their use in hereditary disease. However, germline gene therapy is subject to many ethical debates due to unforeseeable risks and technical difficulties. On the other hand, somatic cells (SCGT – somatic cell gene therapy) are often used for genetic disorders such as immunodeficiency, hematological disorders such as hemophilia, and thalassemia, or cystic fibrosis, with great number of clinical trials currently underway.
Check our peptide tools for gene therapy!
Different Types of Gene Therapy
1. Gene Replacement Therapy
Replaces a defective or missing gene with a functional copy to restore normal cellular function. Gene replacement therapy is used in genetic disorders with a specific protein missing or malfunctioning. By introducing a functional copy of a defective gene into bone marrow cells of patients, researchers were able to restore immune function in some cases of SCID.
2. Gene Silencing Therapy
Involves silencing or knocking down a malfunctioning gene to prevent it from producing harmful proteins. Gene silencing makes use of the body’s natural processes to control disease by temporally suppressing genes that are associated with certain diseases. RNAi, CRISPR, or siRNA are common methods of gene silencing.
3. Gene Addition Therapy
Adds a new gene into the patient's genome to bypass the problem. The added gene allows the body to make proteins that potentially manage or treat a genetic disease.
4. Gene Editing Therapy
In gene editing therapy, technologies like CRISPR-Cas9 are used to edit specific DNA sequences in vivo. With CRISPR/Cas9 you can edit genes by precisely cutting the DNA and let the natural DNA repair processes modify the gene according to your specifications. The CRISPR/Cas9 is packed and targeted to specific organs.
Modes of Gene Transfer
Gene therapy distinguishes between several modes of transfer:
Naked DNA
Gene delivery may occur by inserting DNA in a naked or complex-loaded form into the host cell. Though the transfer of naked DNA, e.g. by complexing it with Calcium ions or complexes is probably one of the oldest technique to transfect, it is hampered by some limitations such as low in vivo availability. However, with the advent of the genome editing tool CRISPR-Cas9 a novel approach with great potential was established. It makes use of the bacterial nuclease Cas9 to modify the host genome at any desired location. However, since Cas9 is of non-human origin it has the potential to trigger an immune response. To monitor immune responses against this endonuclease we developed a PepMix S. pyrogenes (CAS9) peptide pool covering Cas9 antigens.
Vector Based Gene Transfer
Second, vector-based gene transfer, also known as viral-based gene transfer makes use of recombinant viruses to deliver and replicate DNA in the host cell. Different viruses e.g. lentivirus, herpes simplex, vaccinia, adenovirus and adeno-associated virus are used as gene delivery vehicles.
Adenovirus - AdV
Adenoviridae (AdV) are the most commonly researched vectors for anti-cancer therapy or for vaccine development against infectious diseases such as Ebola, HIV or SARS-CoV-2. Adenovirus can modify a cell's genetic expression with genetic material that is not integrated into the host cell's DNA. For example, human AdV types 5 & 26 and chimpanzee AdVs are commonly used artificial vectors whose replication machinery is inhibited, and thus exclusively allowing gene transfer while preventing replication.
The most immunogenic adenovirus proteins are
- Hexon protein - a major coat protein synthesized during late infection
- Penton protein - forms the base of the fibers that attach to the host cells
There are 88 known human adenovirus types that are associated with various diseases. JPT offers hexon and penton proteins as peptide pools for several human and chimpanzee adenovirus types.
Adeno associated virus - AAV
Adeno-associated viruses (AAV) can infect both dividing and quiescent cells and exist in an extrachromosomal, thus not integrating state, making them also state-of-the-art candidates for gene therapy. AAV cannot be transmitted between cells unless a helper virus, such as adenovirus or herpesvirus, also infects the cell.
The most immunogenic protein of AAV is the capsid protein, which is present in each AAV serotype with different sequences. JPT offers capsid proteins of different AAV serotypes as PepMixTM peptide pools and antigen peptides for immunogenicity testing of unwanted immune responses (immunotoxicity) against the capsid protein.
Role of Peptide Pools in Gene Therapy
PepMix™ Peptide Pools play a significant role in gene therapy, particularly in the areas of immune monitoring, vaccine development, and the optimization of gene delivery systems.
Immune Monitoring
During gene therapy, you need to monitor the patient's immune response, to measure therapeutic success. Overlapping peptide pools representing a whole protein are used to stimulate and measure antigen-specific T-cell responses. Common T cell assays used for immune monitoring are ELISpot, ICS or multimer staining.
Immunogenicity
Before clinical application, gene therapies undergo rigorous testing to ensure safety and efficacy. Immunogenicity testing of unwanted immune reaction is important, especially when using viral vectors or CRISPR/Cas9. It ensures that the therapy does not trigger adverse immune reactions or unwanted immunogenicity to the viral vector itself. Peptide pools are used in preclinical and clinical studies to assess the immunogenicity of the therapy. We have developed multiple peptide tools in the form of PepMix peptide pools, or Antigen Peptides, which cover antigens from many different viral vectors.
Vaccine Development
Somatic mutations in tumor cells give rise to tumor-specific MHC I restricted epitopes that can be recognized by the immune system to differentiate cancer from normal cells. Thus, generally occurring shared tumor antigens (e.g. KRAS) are candidates for cancer vaccines. A tumor antigen vaccine made of tumor antigens (peptides) stimulates the host's immune system to neutralize cancer cells. Our Clinical Peptides and Pools meet the need for high quality yet fast and affordable peptides for development of vaccines.
Gene Therapy in a Nutshell
Gene therapy holds great promise for treating a wide range of genetic disorders and diseases. The use of peptide pools in gene therapy is essential for monitoring immune responses, developing effective vaccines, and ensuring the safety and efficacy of new treatments. With advancements in peptide synthesis and gene editing, the synergy between these fields continues to push the boundaries of modern medicine.
For more information, please contact our team of experts.
Peptides for Gene Therapy Development
Cellular Immune Response
- Antigen specific stimulation of T-cells
- Immune monitoring of high-risk patients
- Qualification of immunodominant antigens
- Validating clinical T-cell assays
- AAV5 (Capsid protein)
- AAV6 (Capsid Protein VP1)
- AAV8 (Capsid Protein)
- Human AdV3 (Hexon Protein)
- Human AdV5 (Penton Protein)
- Human AdV5 (Hexon Protein)
- Human AdV26 (Penton Protein)
- Human AdV26 (Hexon Protein)
- Chimpanzee AdV Y25 (Penton Protein)
- Chimpanzee AdV Y25 (Hexon Protein)
- S. pyogenes (CAS9)
Humoral Immune Response
- Immune Monitoring of humoral responses
- Evaluation of co-infection
- Detection of epitopes and epitope spreading
