Which Vaccines Use CRISPR Technology?

Gene editing has always been under the limelight of medical research. From creating effective vaccines to finding cures for the previously incurable, genetic engineering has always lent a hand to the boggled scientists.

This haven which we call heaven is full of monsters ready to pounce on us. There are numerous invisible attackers that can throw us down and even kill us. Amongst these seasoned veterans are viruses. 

These micro-organisms are so strong that even after years of medical breakthroughs, doctors are unable to completely defeat them. We rely on our immune systems to keep us safe from these lethal micro-organisms.

What Is A Vaccine?

A vaccine is a biological preparation that is designed to activate the body’s immune response against disease. It may contain attenuated micro-organisms (viruses mostly) or parts of the virus (DNA, a protein coat, etc.).

The most common method of vaccine administration is via needle injections, however, oral route and nasal sprays are also utilized for certain vaccines.

How Does A Vaccine Protect You Against Viral Attack?

Your immune system is an efficient system that works according to the load put on it. The immune cells (white blood cells) become active only after they have been exposed to the harmful micro-organism (i.e. a virus). The viral DNA, protein coating, or even toxic chemicals released by the virus can trigger an immune response from the body. 

Once identified, the immune system fills the body with specific lymphocytes (killer cells) to combat the infectious agent. After a due battle, the virus succumbs to the lymphocytes and your body becomes free of this particular harm-causing agent. 

In addition to making replicas of the specific blood cells, the immune system also produces memory B cells. These cells continue to circulate your body lifelong and will quickly identify and destroy if the same virus enters again. 

This normal process of immunity development is painstaking as the person suffers from the course of infection before the body takes complete control. However, scientists identified that the introduction of parts/segments of the virus body can trigger an immune response without causing infection. Thus, vaccines were created to keep mankind safe from infections.

CRISPR/Cas 9 System: The Magical World Of Gene Editing

CRISPR is the name of a new era in the field of gene editing. The bacterial defence sequence found inside their DNA (i.e. Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR) is paired with a CRISPR-associated enzyme Cas9 to bring the unbelievable to the table. 

It is a modern, efficient, time-saving and cost-saving procedure that has a wide variety of applications ranging from agriculture to diagnosing and treating medical conditions. 

What’s amazing about this system is that this particular gene-editing tool can be used to prepare vaccines too. Scientists started testing the CRISPR/Cas9 system aggressively in the year 2020. Thanks to these uncountable clinical trials, CRISPR has become the buzz of the town.

Leishmania Vaccine

Leishmaniasis is a parasitic infection that is common in southern Europe and subtropics. Every year the disease affects millions of people worldwide. (1)

It is a complex disease that has two major types:

• Visceral leishmaniasis (VL)
• Cutaneous leishmaniasis (CL)

Visceral leishmaniasis is a fatal disease that didn’t have improved control tools (diagnostic tests, drugs, and vaccines) as of 2012. (2)

The disease manifests itself in the following ways:

• Breathing issues 
• Slow healing skin ulcers/sores
• Difficulty in swallowing 
• Nasal bleeds 
• Stuffy or runny nose 

Different strategies to develop vaccines for Leishmania infection were brought under the light. (3)

Amongst all CRISPR came out as the true saviour. The process of protecting against leishmaniasis is known as leishmanization. In the study carried out on mice, a second-generation leishmanization vaccine prepared using CRISPR worked efficaciously against the tropical infection. It induced robust host protection and was found to be completely safe. (4)

With the CRISPR/Cas9 technique, geneticists can easily target the specific gene of interest by designing specific RNAs. Therefore, the method is highly efficient and easy, thereby, opening ways for the rapid adoption of a vaccine prepared this way. (5)

Avian Virus Vaccine

Avian influenza caused by the avian viruses refers to infection found in the birds. Avian viruses are also known as poultry viruses. Type A of these viruses infects wild aquatic birds and domestic poultry birds. 

The silent-killer infection causes the death of millions of poultry animals worldwide leading to financial and food losses. To overcome this hurdle, CRISPR/Cas9 is being employed at a rapid pace. 

This modern method of gene editing is utilized well in genome-wide screening for viral restriction factors. It helps in the quick identification of Pan-avian influenza virus inhibitory host. (6)

Research by Vilela and colleagues suggests that CRISPR/Cas system has opened a new avenue in the development of vaccines against avian viruses. (7) 

The insertion of a vaccine developed using CRISPR/Cas9 leads to significant protection against three major avian diseases. Therefore, this very technique saves time, money, and is more efficient(8)

Malaria Vaccine

The gene drive technology brought to light by CRISPR/Cas9 can help in the research and development of vaccines against malaria and leishmaniasis. (9)

CRISPR/Cas9 is being put to work to change the genetic makeup of malarial parasites i.e. Plasmodium falciparum. This way malaria can be eradicated. (10)

COVID-19 Vaccine

The hottest topic nowadays (since the end of 2019) is “coronavirus”. The killer virus is unstoppable and has baffled health experts for quite a good time. Developing vaccines against the coronavirus isn’t easy. The efficacy of the ones available in the market is still questionable.

CRISPR might play a role here too. The CRISPR treatment can be utilized as an anti-viral therapy in the management of COVID-19. (11)

Keeping in mind the unlimited power of the CRISPR/Cas9 system, it is expected that this method will potentially aid in developing efficient vaccines for COVID-19 infection. (12)

The CRISPR/Cas13 system can be used to produce targeted RNAs to speed up the process of vaccine development. (13)

The CRISPR system has opened up a world of opportunities for geneticists and biologists. This technique can rightfully help in the development of vaccines and also enhance treatment strategies in near future.

Works Cited:

1. Alvar, Jorge, et al. “Leishmaniasis worldwide and global estimates of its incidence.” PloS one 7.5 (2012): e35671.
2. Desjeux, Philippe. “Leishmaniasis: current situation and new perspectives.” Comparative immunology, microbiology and infectious diseases 27.5 (2004): 305-318.
3. Iborra, Salvador, et al. “Vaccine candidates against leishmania under current research.” Expert review of vaccines 17.4 (2018): 323-334.
4. Zhang, Wen-Wei, et al. “A second generation leishmanization vaccine with a markerless attenuated Leishmania major strain using CRISPR gene editing.” Nature communications 11.1 (2020): 1-14.
5. Sangani, Ghodratollah Salehi, et al. “Generation of a CRISPR/Cas9-Based Vector Specific for Gene Manipulation in Leishmania major.” Iranian journal of parasitology 14.1 (2019): 78.
6. Heaton, Brook E., et al. “A CRISPR activation screen identifies a pan-avian influenza virus inhibitory host factor.” Cell reports 20.7 (2017): 1503-1512.
7. Vilela, Julianne, Mohammed A. Rohaim, and Muhammad Munir. “Application of CRISPR/Cas9 in Understanding Avian Viruses and Developing Poultry Vaccines.” Frontiers in cellular and infection microbiology 10 (2020).
8. Tang, Na, et al. “Generation of a triple insert live avian herpesvirus vectored vaccine using crispr/cas9-based gene editing.” Vaccines 8.1 (2020): 97.
9. Nateghi Rostami, Mahmoud. “CRISPR/Cas9 gene drive technology to control transmission of vector‐borne parasitic infections.” Parasite Immunology 42.9 (2020): e12762.
10. Mogollon, Catherin Yizet Marin. “CRISPR/CAS9 GENETIC MODIFICATION OF PLASMODIUM FALCIPARUM AND TRANSGENIC PARASITES IN MALARIA VACCINE RESEARCH.”
11. Nalawansha, Dhanusha A., and Kusal TG Samarasinghe. “Double-barreled CRISPR technology as a novel treatment strategy for COVID-19.” ACS Pharmacology & Translational Science 3.5 (2020): 790-800.
12. Ding, Ronghua, et al. “CRISPR/Cas System: A Potential Technology for the Prevention and Control of COVID-19 and Emerging Infectious Diseases.” Frontiers in cellular and infection microbiology 11 (2021).
13. Kumar, Prashant, et al. “CRISPR-Cas system: an approach with potentials for COVID-19 diagnosis and therapeutics.” Frontiers in cellular and infection microbiology 10 (2020): 639.