About antibody at a glance
1. What is an antibody?
Multiple invaders: bacteria, fungi and their toxins can make people sick by producing infections like meningitis, candidiasis, or flu.
However, you or your friend are usually not sick, but healthy and happy.
So, how can we survive and enjoy life in such a dangerous environment?
Fortunately, you have a powerful protective supersystem in your body, called the immune system.
This system includes two large teams: the immune cells and the immune molecules.
Antibodies belong to the immune molecules produced by immune cells of this supersystem in your body.
Together with other players of the immune system, antibodies can protect you from multiple infections.
Of course, there are other interesting immune molecules, but today we will talk about antibodies.
So, what are antibodies?
The antibodies are made of proteins.
Like a chain made of chain links, any protein is made of amino acids.
Any protein in antibody is just a sequence of amino acids.
So, it is like a long-long word, where instead of single letters, we have amino acids that are bonded together.
Due to chemical links between amino acids in proteins, the body of antibodies are folded many times and have a very beautiful globular shape.
This is why another name of antibodies are immunoglobulins.
There are 5 types of antibodies or immunoglobulins: A, G, M, D and E.
They are abbreviated by IgA, IgG, IgM, Ig D, and Ig E.
2. Why is it “anti”?
Why do these magic molecules have such an intriguing name?
Why is antibody “anti”?
Roots of this word are, of course, in Latin language.
In Latin language, “Anti” means “against”.
Against what?
Your immune system produces antibodies against molecules called the antigens.
Any molecule which is recognized by antibodies is antigen.
Antibody which can recognise this antigen is specific to this antigen.
Many of the antigens are proteins or their pieces.
However, there are also antigens like polysaccharides, lipids, nucleic acids etc.
Ii is interesting; the antibody can be an antigen for another antibody!
And the next antibody could be the antigen for the next antibody
And the 3rd antibody is the antigen for the antibody number 4th and so on!
3. Beauty of antibodies and why the antibodies are specific.
Despite a great variety of antibodies, they have very similar structure.
Any antibody has 4 chains made of proteins: two light chains and two heavy chains.
Antibody has two special places where it can bind to antigen.
Scientists call these places hypervariable regions.
Why do antibodies need those regions?
They are responsible for specificity of antibodies.
The shape of this piece of surface of antibody can fit or not fit to the shape of antigen’s surface.
It is pretty similar to how some key fits or does not fit to a lock.
The key is antigen, the lock is antibody.
Coincidence of surfaces of antibody and antigen makes them specific to each other!
4. Your antibodies protect you (or what is immunity).
Antibodies are just a part of your body’s defense, created by the immune system.
This defence is called “immunity”.
Again, this word comes from the Latin “immunis”, which means “exempt from public service.”
As you can see, there is no public service here, but there are a lot of microbes!
In our case, “immunity” just means resistance or being protected to various infections.
So, if any bacteria or virus cannot make you sick and unhappy, you have got immunity against this intruder.
How can we get this magic advantage so far?
There are two ways to get immunity.
You can get sick due to infection.
Of course, nobody wants to be sick even if you need antibodies!
So, get vaccinated and your immune system can make specific antibodies for you.
Due to disease or due to getting a vaccine, you can receive antibodies against bacteria, fungi, viruses etc.
Antibodies can bind to these enemies of your body and make it recognizable by immune cells.
The immune cells can destroy or eat the pathogen with attached antibodies on it and make them harmless.
Like we said before, antibodies are just immune molecules, produced by the immune system.
There are other kinds of immune molecules.
The antibodies should work together with immune cells and other systems of your body to protect you and survive.
Scientists named the immunity created by antibodies humoral immunity.
Again, it comes from Latin word: “humor”, which means “liquid” or “fluid”. This is because antibodies are present in fluids of your body: blood, mucus, saliva.
5. Where and how are your antibodies produced?
Antibodies are made in a special kind of immune cells, plasma cells.
The plasma cells originate from other cells, white blood cells called B cells.
Both plasma cells and B cells live and work in your bone marrow.
Bone marrow is the most important organ of your immune system and immunity.
However, for the first time, scientists discovered the B cells in the organ of birds, called Bursa of Fabricius, not in the bone marrow.
There is no such an organ in the human or cat’s body, only the birds have Bursa of Fabricius.
So, our B cells are located in bone marrow.
6. Provocation by vaccines makes antibodies in your body to protect you.
Your own antibodies can be helpful against multiple bacteria, fungi and viruses.
Some infections are so dead dangerous or at least unpleasant to you, that you should protect yourself before getting sick.
You do not need to get sick with the flu to get antibodies against the flu virus infection!
Instead, you just need to receive a flu shot, and your antibodies will be produced by your immune system without severe disease!
No struggling with real influenza!
7. Antibodies can tell you why you are sick.
When you are sick, your immune system produces a lot of antibodies against bacteria or viruses which makes you sick.
This means that people in the laboratory can take your blood and make a test.
The blood test can confirm or reject the doctor's suggestion that you feel bad because of an invasion of this or that pathogen.
If the doctor was right, you should have plenty of antibodies against the suggested intruder in your blood.
Moreover, many non-infectious diseases are characterized by the appearance of disease-specific proteins in the body.
These proteins are antigens.
And it is possible to get specific antibodies for those antigens.
It is also not a big deal to determine the presence of those antigens in the body.
They can be found with help of antibodies that are specific to these antigens.
How is it possible to do?
Just remember, the specific antibody can bind to its antigen.
Moreover, it is possible to attach some molecule to the antibody.
This molecule is a molecule-witness or marker.
It could be a radioactive or fluorescent molecule.
Or it could be the enzyme which makes a color reaction in the media.
So, if there is the antigen in the body, it should be binded by the specific antibody.
This binding will be confirmed by radioactivity, fluorescence or color reaction.
Moreover, the more antigen we have, the more radioactivity, fluorescence or more intensive color reaction we have.
Thus, we can say not just about presenting the antigen but how much the antigen we have.
8. How scientists make antibodies.
In the middle and the end of the XX century, antibodies were made in our furry friends: goats, sheeps, cows, horses, bunnies, rats, mice, monkeys.
Poor animals, they were infected many times with antigens, and felt really bad.
Multiple injections of antigen induced production of a lot of specific antibodies by immune systems of fury creatures.
Those antibodies were used to determine the presence of dangerous pathogens in the blood and tissues of humans and animals.
Many people were saved, and many epidemia of dead infections were prevented because of those tests...
Thank you, little brothers, you have made a great job for saving humankind.
9. What are monoclonal antibodies.
Since the mid-70s of the XX century, scientists learned how to receive antibodies without animal struggling.
Now people do not need to immunize many animals to get antibodies for their own purposes.
Basically, for making antibodies without a live organism, one should take two cells; one from the spleen, which is an immune organ, and the second, a myeloma cell, which is a cancer B cell.
And make a fusion cell which is called hybridoma.
Hybridoma is capable of producing a lot of antibodies.
These antibodies are called monoclonal antibodies, because they received only from one clone of cells.
Monoclonal antibodies were obtained for tons of various proteins and their pieces!
There are a kind of libraries of millions of monoclonal antibodies!
Like to antibodies, made in real organisms, the scientists can attach radioactive or fluorescent or other markers to monoclonal antibodies.
Even gold, real gold, is used as a witnessing marker by attaching to monoclonal antibodies!
Such monoclonal antibodies are still able to recognize antigen, but additionally report about this event to scientists or lab technicians.
Monoclonal antibodies with markers and without are successfully used in science, diagnostics and treatment of patients.
For example, fluorescence staining of cells and tissues in biology, laboratory diagnosis of infectious and non-infectious diseases, and treatment of patients with cancer and autoimmune diseases
10. Antibody against you: allergies and autoimmune diseases
Surprisingly, your own antibodies can be harmful for you!
For example, allergies.
In case of allergy, antigen is called allergen.
It is usually a protein.
Allergic antigens or allergens induce production of specific allergic antibodies called immunoglobulins E in the body.
They participate in allergic reactions on the skin, in the nose, throat, or lungs.
Doctors should determine what allergen or allergens are responsible for the allergic disease.
Then they recommend patients to stay away from allergens.
Unfortunately, sometimes it is not possible.
The doctors prescribe drugs which decrease or block immune reactions which in this case bring to allergic disease.
Autoimmune diseases are another problem of bad antibodies.
This happens when the immune system ubnormally produces antibodies, called autoantibodies, against one or more of the patient's own proteins.
Own proteins in this case are technically antigens for production of specific autoantibodies.
Thus, the immune system attacks the person's own tissues and organs like proteins of intruders: bacteria, fungi or viruses.
The famous examples of autoimmune diseases are rheumatoid arthritis, Crohn's disease, ulcerative colitis, ankylosing spondylitis and lupus.
Unfortunately, autoimmune diseases affect many different systems of the patient: brain, heart, lungs, joints, skin, kidneys etc.
Fortunately, people learned to use monoclonal antibodies to treat autoimmune diseases!
11. Conclusion
Thus, as you can see, antibodies can be great friends or dangerous foes!
Antibodies may protect you against multiple infections after vaccination and survive the diseases.
The antibodies could be bad in allergic and autoimmune diseases; they attack the own cells and tissues of patients.
Fortunately, millions of multiple tests with the use of monoclonal antibodies are running in the biological and medical labs every day.
Various monoclonal antibodies are used in treatment of cancer and autoimmune diseases, making the lives of patients better.
Many important vaccines are created to prevent humankind from dangerous infections.
Of course, it is difficult to stay away from bacteria and viruses in our world.
However, you can get vaccinated and protect yourself from infections!
References
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2. Roitt's Essential Immunology (Essentials) 13th Edition by Peter J. Delves, Seamus J. Martin, Dennis R. Burton, and Ivan M. Roitt
3. Kuby Immunology – Jan 15, 2000 by Richard A. Goldsby, Thomas J. Kindt, Barbara A. Osborne, Janis Kuby.
5. Fundamental Immunology, 7th Ed by William E. Paul
6. Stedman's Medical Dictionary for the Health Professions and Nursing. Philadelphia :Lippincott Williams & Wilkins, 2005.
7. Merriam-Webster.com. Merriam-Webster, 2011 Web. 8 May 2011.
8. genome.gov/genetics-glossary/Antibody
9. Lodish, H. F. (2000). Molecular cell biology (4th ed.). New York: W.H. Freeman.
10. Antibody Engineering: Methods and Protocols (Methods in Molecular Biology (1827)) 3rd ed. 2018 Ed. by Damien Nevoltris & Patrick Chames
11.www.aaaai.org/conditions-and-treatments/conditions-dictionary/immunoglobulin-e-(ige).