Viral and Non-Viral Vectors: Tools of Gene Delivery

In therapies related to genes, genetic materials are needed to get into the cell nucleus from outside of the body. Currently, it can happen only via a system of delivery known as a vector.

Gene therapy holds a huge potential for the management and treatment of diseases. Viral vectors are one of the most commonly used agents for therapy-related genes because of their ability to deliver several therapeutic gene copies for host cells.

In the vector family, Adeno-associated vectors (AAVs) are the most promising. It is because of their nature to transcode non-driving and driving cells and their lower immunogenic dispositions. Let’s understand vector in depth.

Vector and its types:

Gene therapy is performed with the help of genetic materials like the nucleus and transgene into the cell nucleus. The system that is used for delivering the genetic materials is known as a vector.

In simple words, vectors act as a delivery truck responsible for transporting the packages (genetic materials) to particular locations (the targeted cells).

Vector types:

There are mainly two kinds of vectors, namely, viral vectors and non-viral vectors. Each of these vectors offers a different way to deliver genetic materials inside the cells.

• Viral vectors:

This type of vector is made using the virus blueprints, not the real virus itself. Scientists only take help from the part of the virus blueprints to deliver the genetic materials. Nowadays, viral vectors are commonly used carriers in approved gene therapies.

• Non-viral vectors:

Non-viral vectors rely on chemical or physical methods to deliver the genetic materials. They can either use a physical technique like entering a needle into the cell or the chemical technique made inside the labs. Most studies about the non-viral vectors include electroporation, polymer, and chemical disruption. The techniques related to non-viral vectors are constantly being researched for their efficiency and safety.

Why are viruses used for delivering gene therapy?

Viruses help in providing an ideal way to deliver the gene therapy to cells in the specific areas where researchers want genetic mutation to be treated using gene therapy.

The natural design of the virus is highly effective and helps them to enter the cells with ease. This process is similar to a truck that delivers, knows the neighbourhood location well, and can navigate to specific areas for delivering packages without any problems.

Scientists have made blueprints for the complete group of organism cells. They isolate the virus genome parts, which can enter inside the cell, and remove those virus genome parts that have the potential of causing disease.

Since there are several blueprints for the virus, the choice for choosing the types of the vector depends on different characteristics. It includes genetic material size, targeted cells, immunogenicity, and gene expressions.

What is the role of the vector after reaching the target?

Once this vector reaches the specific area, it does the following things:

• It passes through several cell membranes, enters inside the cell, and reaches the targeted nucleus.
• At the nucleus, the vector starts disabling itself (packages are taken out).
• Once these packages are out, genetic materials are delivered inside the special nucleus.

Now, inside the nucleus, genetic materials start instructing the cells to provide the required treatment. The vector is broken down naturally by the cell and later discarded.

Example of viral vector method for gene therapy:

Several vectors are being used for gene therapy nowadays. Following is one example of the viral vector method:

• Lentiviral vectors (LVVs)

Lentiviral vectors (LVVs) are said to be a group of retrovirus species. The most researched lentivirus is said to be the human immunodeficiency virus (HIV), as the blueprints of HIV are used to make lentiviral vectors for the therapy related to genes.

Lentiviral vectors have the capability to enter inside the cell for adding genetic materials in dividing cells like non-dividing and dividing cells.

This type of vector came in research using the cells of mammals in the 1980s. Since then, it has been getting more advanced and improving the stability and safety of gene therapy. It is commonly used in cancer treatments and blood diseases.

Example of non-viral vector method for gene therapy:

Non-viral vectors are those vectors whose delivery mechanisms do not use blueprints of the viruses. Following is an example of non-viral vector method.

Electroporation:

It is a type of non-viral vector method for delivering genetic materials. With electroporation, an electric pulse is used by the scientist for making temporary pores in the membrane of the cell. These pores help in delivering gene therapy inside the cell, where it can create the desired impact.

The additional factors that are promoting the growth of the viral and non-viral vector market are the increasing incidents of cancers, infectious diseases, and genetic disorders.

Market Insight:

The promising result is being displayed by the vector-based gene therapies, which is fueling the global market of vectors.

In 2020, the global viral and non-viral vector manufacturing market was valued at $1.50 billion. However, as per the BIS Research market report, the market is projected to reach $27.03 billion by 2031, at a CAGR of 18.54% during 2021–2031.

Conclusion:

Although several systems for viral vector and non-viral vectors have been developed over the last few years, all these vector types have got some advantages and disadvantages and are being constantly researched for delivering effective and safe gene therapies.