3. Production Process
3.1. DNA Engineering
Recombinant DNA technology is used to engineer the corrected copy of the gene in the laboratory. This could be part of a gene, or the whole gene. This process involves sticking together different sequences of DNA to make a functional gene. Researchers use bacteria to produce large amounts of this engineered DNA because they are highly efficient at making DNA. Generally, smaller genes are easier to deliver to cells than large genes. The DNA of the corrected gene is inserted into the vector, which will protect the DNA during its journey into the body and to the affected cells (Figure 1.1). Gene therapy agents are produced on a very small scale as the process is extremely labour-intensive.
Figure 1.1. Overview of gene therapy . Normal DNA sequences are engineered in the laboratory and multiple copies are made by bacterial cells. The DNA is then inserted into a gene therapy vector, either viral or non-viral. Liposomes are an example of non-viral vectors and are small membranes made of fatty acids, which can easily encapsulate the DNA. The gene therapy vector is then introduced to cells, either, directly into the body via injection or inhalation, or cells are modified in the laboratory before implantation into the body.