Viral vectors refer to genetically engineered viruses that are used in gene therapy, a therapeutic approach aimed at treating genetic disorders and certain diseases caused by genetic mutations. These vectors are designed to carry a specific gene into a patient's cells so that the gene can be properly expressed, leading to the desired therapeutic effect.
Viral vectors derived from naturally occurring viruses are modified in the laboratory to remove their disease-causing capabilities while retaining their ability to deliver genetic material into target cells. Commonly used viral vectors include retroviruses, lentiviruses, adenoviruses, and adeno-associated viruses.
Retroviruses, for example, are RNA viruses that can convert their RNA genome into DNA and integrate it into the host cell's genome. This feature makes them suitable for delivering genes to non-dividing cells. Lentiviruses, a subtype of retroviruses, can infect both dividing and non-dividing cells, making them useful for long-term gene expression.
Adenoviruses are double-stranded DNA viruses that efficiently infect a wide range of cells, although their gene expression is often transient. Adeno-associated viruses are small, single-stranded DNA viruses that can infect both dividing and non-dividing cells, and they are known for their relatively low immunogenicity.
Using viral vectors in gene therapy allows for the efficient delivery of therapeutic genes to target cells, enhancing gene expression and potentially correcting genetic defects. They hold great promise in the development and implementation of various gene-based therapies, including treatment for genetic disorders, cancer, and certain acquired diseases.
The etymology of the term "viral vectors" is a combination of the words "viral" and "vectors".
- "Viral" refers to something related to viruses. The word "virus" dates back to the late 14th century and originates from the Latin word "virus", meaning a poisonous substance or venom. In modern usage, it refers to small infectious agents that can replicate inside living cells and cause various diseases.
- "Vectors" have a different etymology. The word comes from the Latin term "vector", meaning a carrier or something that conveys. It entered the English language in the mid-17th century and initially referred to a quantity that has both magnitude and direction in mathematics. Over time, "vector" expanded its usage to indicate carriers of diseases or agents that transmit genetic material in biological science.