How does the UK Approved COVID-19 vaccine work?

Synthetic Biology Technology has brought us to the point today that the UK has accepted one of the COVID-19 vaccines for distribution, with the promise that distribution will begin soon. This result has taken just 10 months, how have the pharmaceutical researchers managed to do this? Through advances in technology.

In reality, there are different types of COVID-19 vaccine currently in trials:

1: Live attenuated vaccines

Some well-known vaccines for other infectious diseases are based on weakened versions of a virus.  These are known as live attenuated vaccines.
The viruses are weakened to reduce virulence by culturing cells in a laboratory, and then processed into a vaccine. After people come into contact with these attenuated viruses through vaccination, the virus will not be able to replicate easily in humans. As a result, our immune system has enough time to learn how to fight against this weaker form of the virus. This approach enables us to become immune without getting sick.

2: Inactivated vaccines

Inactivated vaccines contain viruses or bacteria that have been killed, which are either whole or in pieces. When our immune system detects these dead viruses or bacteria or their fragments, it can learn to recognise the fragments. After this, we are protected. If we are infected by the live version of the virus or bacteria in the future, our immune system will recognise the virus or bacteria and respond more quickly to protect us from infection – so we will not become ill.

3: Subunit vaccines

If the vaccine only contains particular pieces of a virus or bacteria, it is known as a subunit vaccine. When that subunit can be recognised by the immune system, it is referred to as an antigen.
Extensive research is being carried out on subunit vaccines for protection against COVID-19. An important subunit of SARS-CoV-2 is the spike protein or S protein, which is attached to the exterior of the virus. The virus uses the S protein to make contact with another protein which is located on the exterior of the cells in our lung vesicles. If the virus attaches itself to a human cell via the S protein, the virus can penetrate the exterior and enter the cell. Then the cell is infected.  Because the S protein plays such an essential role in the infection process, it is targeted by many vaccine developers. If we are infected by the live version of the virus in the future, our immune system will immediately recognise the virus and we will not become ill.
 

4: mDNA and mRNA vaccines (m stands for messenger)

DNA and RNA vaccines add a new piece of genetic material – deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) – to specific immune cells in our body. The targeted cells are often a particular type, which absorb and break down a virus or bacteria. The immune cells that have broken down a virus or bacteria then show a piece of the virus or bacteria (a subunit known as an antigen) to other immune cells so they learn to recognize the antigen. That is why these immune cells are also referred to as antigen-presenting cells. The cells that learn to recognize the antigen are called lymphocytes. DNA and RNA vaccines allow the antigen-presenting cells to detect a piece of the pathogen without the cell first having to absorb and break down the live version of the virus or bacteria. If we are then infected by the live version of the virus or bacteria in the future, the lymphocytes will recognize the antigen for the pathogen, neutralize the virus or bacteria, and we will not become ill.

There are also DNA and RNA vaccines that use ‘normal’ body cells instead of immune cells. These cells also present the antigen to our immune system, which ensures that we will not become ill if we do get infected. 
These DNA and RNA techniques are new, and a DNA or RNA vaccine has not yet been approved for any human disease. A number of DNA vaccines have already been used successfully for animals.
 

5: Vector vaccines

Researchers can modify existing viruses to act as vaccines. Once that happens, they are no longer viruses, but vectors. The viruses have been adapted in such a way that they do not display exactly the same behaviour as unmodified viruses. The difference compared to the real viruses is that vector viruses:

  • can no longer make someone ill;
  • (often) cannot replicate themselves, and;
  • not only contain their own RNA or DNA, but also have a piece of RNA or DNA from another virus within them. All pieces of RNA or DNA can work as an antigen, so the cells in our immune system will react to the vector virus as well as to part of the vaccine virus. This is how immunity is developed.

A category of viruses that are often adapted into a vector are the adenoviruses. Adenoviruses are a group of viruses to which people are often exposed, but which cause no or only mild illness. Because adenoviruses are so common, our immune system is very good at dealing with an adenovirus infection.

This article in Nature goes into further detail.

The vaccine approved today in the UK from Pfizer/BioNTech is an mRNA vaccine. This is cutting-edge technology, and the first time such a vaccine has been approved!

To produce an mRNA vaccine, scientists produce a synthetic version of the mRNA that a virus uses to build its infectious proteins. This mRNA is delivered into the human body, whose cells read it as instructions to build that viral protein, and therefore create some of the virus’s molecules themselves. These proteins are solitary, so they do not assemble to form a virus. The immune system then detects these viral proteins and starts to produce a defensive response to them.

Synthetic Biology!

What actually is GM Food?

Last week I gave some statistics about GM food production both in the USA and worldwide, and this week I wanted to consider what genetic modification actually is. It appears to me that confusion reigns when addressing issues surrounding GM, so I would like to try and clarify a few issues.

GM exists in plants but also in animals as the salmon link showed last week (not currently approved for consumption), but we tend to associate it mainly with crops, so what does it entail?

In relation to the biggest crops that I mentioned last week, soybean, cotton and corn, there are 2 distinctly different approaches. The first is herbicide tolerance (HT) and the second insect resistance (Bt). In other cases nutritional changes have been made, but the major cash crops are based around the following approaches.

Herbicide-tolerant (HT) crops are developed to survive application of specific herbicides that previously would have destroyed the crop along with the targeted weeds. So you can plant your seeds and spray a herbicide that kills everything apart from your desired crop.

Herbicides target key enzymes in the plant metabolic pathway, which disrupt plant food production and eventually kill it. Genetic modification creates a degree of tolerance to the broad-spectrum herbicides – in particular glyphosate and glufosinate – which will control most other green plants.

Industrial Herbicide Techniques

Industrial Herbicide spreading Techniques

1. Glyphosate-tolerant crops
Glyphosate herbicide kills plants by blocking the EPSPS enzyme, an enzyme involved in the biosynthesis of aromatic amino acids, vitamins and many secondary plant metabolites.  There are several ways by which crops can be modified to be glyphosate-tolerant. One strategy is to incorporate a soil bacterium gene that produces a glyphosate-tolerant form of EPSPS. Another way is to incorporate a different soil bacterium gene that produces a glyphosate degrading enzyme.

2. Glufosinate-tolerant crops
Glufosinate herbicides contain the active ingredient phosphinothricin, which kills plants by blocking the enzyme responsible for nitrogen metabolism and for detoxifying ammonia, a by-product of plant metabolism. Crops modified to tolerate glufosinate contain a bacterial gene that produces an enzyme that detoxifies phosphonothricin and prevents it from doing damage.

The developers argue that use of this type of seeds cuts fuel usage and tilling as there are fewer weeds, (tilling leads to top soil loss as it is blown in the wind). They also argue that GM production has led to less herbicide use, and this seems to currently be the case.

Unfortunately one effect of this mass usage seems to be the development of ‘superweeds’, that are becoming resistant to theses herbicides. Farmers have had to address this problem by using more and different types of herbicide, with the journal Nature recently reporting a Pennsylvania State University research article that claims that pesticide use will increase dramatically in the very near future as a result, questioning the sustainability of the process. Something similar to the present antibiotics resistance problem that we are seeing in the human population. It should also be noted that the use of broad spectrum herbicides has grown as GM usage has grown, as its ease of application using the new seeds has made it more widespread, even though it only needs to be applied once.

Insect-resistant crops containing the gene from the soil bacterium Bt (Bacillus thuringiensis) have been available for corn and cotton since 1996. These bacteria produce a protein that is toxic to specific insects. Instead of the insecticide being sprayed, the plants produce the bacteria so the insects eat the plant and die.

There are risks associated with this approach as well as the advantage that farm workers are not exposed to spraying insecticides.

Invasiveness – Genetic modifications, through traditional breeding or by genetic engineering can potentially change the organism to become invasive. Few introduced organisms become invasive, yet it’s a concern for the users.

Resistance to Bt – The biggest potential risk to using Bt-crops is resistance. Farmers have taken many steps to help prevent resistance but as in the previous case it is a potentially serious problem.

Cross-contamination of genes, genes from GM crops can potentially introduce the new genes to native species.

Now I am no scientist as we all know but I presume that the human must consume the bacteria too, although scientists assure me that the bacteria is not harmful to humans or other mammals.

Much of the recent dramatic growth in GM usage can be attributed to the development of plants that offer both of these systems.

Next week I will take a look at the regulation of GM foods.

Technology in Food Production

Over the coming weeks I am going to write a series of posts about technology and food production. Food is a topic that I have been interested in from a sociological perspective for several years, and I have a few topics that I would like to address, from GM, to regulation, sustainability and organic alternatives.

Technology plays a huge part in food production. If we just think about GM products, transport issues, industrial farming techniques and globalization in generic terms, it becomes immediately apparent that this sector is the largest in the world. According to these statistics agriculture accounts for between 14 and 24% of all global emissions of CO2, and 19 to 29% of total greenhouse pollutant emissions. An interesting point here is that in the so-called developed countries post-farm emissions are very high, so in the UK for example 50% of these emissions are produced after the food has left the farm, presumably through processing and transport techniques.

But it seems to me that processing is where the money is. According to Forbes, Pepsi for example made almost $45 billion in 2009 and Nestle’ made $110 billion, and these profits only refer to US sales. This year the sector is one of the very few that is still growing.

If you look at vegetables though they make less money. Dole is the largest producer of fruits and vegetables in the world, but in the same year made only $6.8 billion, leading me to conclude that the profit is in the processing and not in the actual foodstuffs themselves.

And this leads on to the question of what goes into these products. The answer is, largely, genetically modified (GM) organisms.

Genetic Modification

Genetic Modification

Yes if we look at the statistics that the US Department of Agriculture publish, we find the following:

93% of soybeans grown in the USA are GM

90% of all corn produced in the US is GM

95% of US sugar beat is GM

40% of all cropland in the US is used for Monsanto (the largest GM seed producer) production

40% of all global GM crops are produced in the US

35% of all the corn grown in the world is GM

81% of all the soybeans grown in the world are GM

I take some of my information from here, the Organic Consumers Association website and the rest from US government sources.

So as you can see it is big business. It is estimated that 70% of all the foods in our supermarkets contains GM organisms. 16.5 million people work in the industry in the US and it accounts for more than 10% of GDP.

And it is not just plants, there is a request for FDA approval for GM salmon. It grows at twice the speed of regular salmon.

The GM salmon, produced by AquaBounty Technologies contains a gene from a Chinook salmon that produces a growth hormone, and a genetic “on-switch” from an ocean pout (an eel-like fish) that keeps the growth hormone pumping out year round. The company state that GM salmon will consume 25 percent less feed, half of which can be plant protein.

Oh and in the US none of this is labeled, although currently 64 other countries do require labeling.

GM organisms have been found in many countries that do not allow their production however, Mexico comes to mind as the closest example to the USA. Seeds have blown across the borders from the US, over the mountains, across the seas, possibly even from Brazil and Argentina and landed and grown. Not to mention imports of contaminated produce. Read the scientific report here.

Corn is socially extremely important in Mexico, its cultivation all started there, and this contamination has caused some serious soul searching. In a related issue GM companies are currently trying to get permission for huge plantations in Mexico, as this Reuters article explains. We await the court’s decision.

For now I stop here, I think that is enough food for thought for this week (groan). Next week I shall delve once more into the murky waters of the global food industry however, and who knows what we might find. Comments please below.