Peptide Vaccines — A Brief Overview Of How They Work
Peptide vaccines are a relatively new development in the world of vaccine technology. They are made up of short chains of amino acids — called peptides — which stimulate the immune system.
Researchers are currently studying the effectiveness of peptide vaccines against various diseases, including cancer and rheumatoid arthritis.
This blog post will give a brief overview of how peptide vaccines work and discuss some of the benefits they offer over traditional vaccines.
But before we can discuss peptide vaccines, it’s important to have a basic understanding of how vaccines work in general. So let’s do that now.
What Are Vaccines And How Do They Work?
A vaccine is a substance that helps the body build immunity against a particular disease. It works by exposing the immune system to a dead or weakened form of a disease-causing virus or bacteria. This allows the immune system to learn how to recognise and fight off that bug if it comes into contact later on.
Vaccines are part of something called “active immunisation,” which is the process of protecting someone from disease by exposing them to a pathogen. On the other hand, passive immunisation is the process of protecting someone from disease by giving them antibodies.
Antibodies are proteins produced by the immune system in response to a foreign invader. This invader can be anything from a virus to a transplanted organ.
Traditional vaccines are made up of viruses or bacteria that have been killed or weakened so they can’t cause disease. For example, the polio vaccine is made from a weakened form of the poliovirus. Similarly, the hepatitis A vaccine is made from a virus that has been killed.
But a vaccine doesn’t always have to contain the entire bacteria or virus. For example, toxoid vaccines contain a toxin produced by bacteria. The tetanus vaccine, for example, is made from a toxin produced by the bacterium Clostridium tetani.
Similarly, the diphtheria vaccine is made from a toxin produced by the bacterium Corynebacterium diphtheriae. There’s a reduced risk of the vaccine causing the disease it’s meant to protect against with toxoid vaccines.
We also have other types of vaccines, such as conjugate vaccines and subunit vaccines. Conjugate vaccines are made from a combination of a pathogen and a protein. The Hib vaccine, for example, is a conjugate vaccine. It’s made from the Haemophilus influenzae type b (Hib) bacteria and a protein carrier.
Subunit vaccines are made from just a few proteins from a pathogen. The hepatitis B vaccine, for example, is a subunit vaccine. It’s made from the hepatitis B surface antigen (HBsAg), a protein on the surface of the hepatitis B virus.
Peptide vaccines are a subtype of subunit vaccines because they’re made from peptides, which are fragments of proteins. Let’s discuss them now.
How Do Peptide Vaccines Work?
Peptide vaccines work by stimulating the immune system to produce antibodies against a particular disease. They expose the immune system to short chains of amino acids, called peptides.
For example, in our previous example of hepatitis B, the vaccine is made from the hepatitis B surface antigen (HBsAg), a protein on the surface of the hepatitis B virus. The vaccine contains just a few peptides from this protein.
When someone gets the hepatitis B vaccine, their immune system will produce antibodies against these peptides. If they later come into contact with the hepatitis B virus, these antibodies will help fight it off.
Another example of a subunit vaccine is the pertussis vaccine, made from a protein called the pertussis toxin (PT). The pertussis vaccine contains just a few peptides from this protein.
Peptide vaccines are less likely to cause side effects than traditional vaccines because they don’t contain any dead or weakened pathogens. When you inject a weakened virus or bacteria into someone, there’s a risk that it will gain strength and cause disease.
For example, when you give someone the polio vaccine, the weakened poliovirus might actually cause polio instead of protecting against it. This is one of the arguments used by anti-vaccine groups.
Peptide vaccines are being studied in relation to various diseases, including cancers like melanoma and Alzheimer’s disease. In clinical trials, they have been found to be reasonably effective at protecting people from disease.
Let’s discuss some of the novel uses of peptide vaccines, such as their use against autoimmune disease, cancer, and their application in personalised medicine.
Novel Peptide Vaccines For Broad Application
Peptide Vaccines For Autoimmune Disease
Autoimmune diseases are caused by the immune system attacking the body’s own tissues. There are many different autoimmune diseases, including rheumatoid arthritis, lupus, and Crohn’s disease.
There is no cure for autoimmune diseases, and current treatments only help manage the symptoms. However, peptide vaccines may offer a new way to treat these diseases. Peptide vaccines have been shown to be effective against a range of autoimmune diseases in clinical trials.
In one study on mice, researchers used a peptide vaccine to reduce the severity of psoriasis, an autoimmune skin disease. In another study, researchers significantly reduced kidney damage in mice with lupus.
When treating autoimmune diseases, peptide vaccines are directed against molecules like TNF-alpha, interferon-alpha, and IL-17. These molecules are called cytokines, and they play a key role in the immune system. Peptide vaccines lead to antibodies against these cytokines, suppressing the immune system and reducing inflammation.
Peptide Vaccines For COVID-19
The COVID-19 pandemic has shown the world the importance of having a vaccine for this virus. The current vaccines for COVID-19 are made from the virus’ genetic material (mRNA). However, there is a potential for a peptide vaccine against COVID-19.
A study published in 2022 showed that a peptide vaccine against COVID-19 successfully induced antibody production against the virus in human subjects. In addition, the study did not report any side effects from the vaccine.
This study is promising and suggests that a peptide vaccine against COVID-19 may be possible. Potential components of this vaccine include the S protein and the nucleocapsid protein. These help the virus attach to human cells and cause disease.
Peptide Vaccines For Cancer
Cancer is a disease that is caused by the abnormal growth of cells. There are many different types of cancer, including breast cancer, melanoma, and lung cancer.
Current cancer treatments include surgery, chemotherapy, and radiation therapy. However, these treatments can be expensive and cause side effects like nausea and hair loss.
Peptide vaccines offer a new way to treat cancer. They are made up of fragments of proteins that can trigger the immune system to attack cancer cells.
For example, researchers used a peptide vaccine in patients who recently had their melanoma (skin cancer) removed in this study. The vaccine successfully triggered the production of anti-melanoma white blood cells, which might prevent cancer from coming back.
We also have evidence that peptide vaccines are effective against brain tumours in mice. And their effectiveness in humans is currently being investigated.
Peptide vaccines are also being investigated as a way to personalise cancer treatment. Personalised cancer treatment involves using information about a person’s tumour to choose the best treatment. This information can include the genetic makeup of the tumour and the proteins it makes.
These peptide vaccines can then be tailored to redirect the immune system against these proteins, leading to the death of cancer cells.
Some companies combine two cancer treatments — oncolytic viruses and peptide vaccines — to fight cancer. ValoTx is one such company working on a treatment that delivers cancer-specific peptides to the body using the adenovirus.
The adenovirus has a negative charge, while cancer peptides are positively charged. This means they can be easily combined into an electrostatic complex, which might be able to treat cancer with very few side effects.
Peptide Vaccines For Influenza
The flu is a virus that causes fever, muscle aches, and respiratory problems. It is a common illness that affects millions of people each year.
The current vaccine for the flu is made from killed viruses. It is given as an injection and can cause side effects like pain and redness at the injection site. Plus, new strains of the influenza virus emerge every year. And current vaccines don’t offer reliable protection against every strain.
We have some evidence that suggests peptide vaccines might play an important role in curbing annual influenza epidemics in the future.
For example, in this study, participants who received a peptide vaccine had a significantly reduced risk of developing mild influenza disease than those who received a placebo. Still, more research is needed to determine whether we can routinely use these vaccines safely and effectively.
Advantages and Limitations Of Peptide Vaccines
A peptide vaccine is no different from any other treatment; it has its pros and cons. And although they offer an exciting avenue of cancer treatment, it’s important to be aware of the advantages and limitations of peptide vaccines so we can use them safely.
For starters, peptide vaccines can be used to deliver a specific treatment for a tumour. This is because the peptides can be tailored to match the proteins expressed by the tumour. This is a major advantage of peptide vaccines over traditional cancer treatments like chemo and radiation.
In addition to killing cancer cells, chemo and radiation also kill healthy body cells. And this leads to side effects like nausea, hair loss, fatigue, and a weakened immune system.
Another advantage of peptide vaccines is that they are easier to produce than traditional vaccines. Traditional vaccines are made from live organisms that have been weakened so they can’t cause disease. But peptide vaccines can be made from proteins that are extracted from a pathogen.
This means they don’t need to be grown in a lab, which reduces the cost and time it takes to produce them.
However, peptide vaccines do have some limitations. They haven’t been tested in as many people as traditional vaccines. So we don’t know yet how well they work or what their side effects might be.
Plus, peptide vaccines are not always good at eliciting a strong immune response. This means they might not be as effective at protecting people from disease as traditional vaccines.
For this reason, they are sometimes combined with proteins from other viruses or with adjuvants, which are substances that help boost the immune response. However, this combination increases the risk of allergic and autoimmune reactions to the vaccine.
Another limitation of peptide vaccines is their instability in the human body. Our bodies have large amounts of proteases, which are enzymes that can break down the peptides in these vaccines.
Final Thoughts
Peptide vaccines are a new and exciting avenue of cancer treatment. They offer many advantages over traditional treatments, including the ability to target tumours specifically. They are also less toxic than traditional cancer treatments like chemo and radiation.
However, more research is needed to determine their safety and effectiveness. So far, they appear to be safe, but we don’t yet know what the long-term side effects might be.
And it’s important to remember that peptide vaccines are still in development and can’t be used to replace traditional cancer treatments.
Even though we’re not sure how useful peptide vaccines are for treating cancer, they offer clear-cut benefits over traditional vaccines when it comes to infectious diseases. These include a more targeted immune response against viruses and bacteria, reduced risk of allergic reactions to the vaccine, and low production costs.
As medicine continues to advance, the role of peptide vaccines in the war against disease will definitely increase in the future.
