Antigen Vs Antibody Diffrence


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Ever since COVID-19 has taken over the world by storm, we have been hearing a lot about antigens and antibodies. But have you ever stopped to wonder what they are and how they differ from each other? If you have and are looking for answers, then you have come to the right place!

In this article, we will discuss in details the definition of antigens and antibodies, how they are different from one another, how they are used in vaccines and COVID-19 testing. So let’s get started!

What Is Antigen?

Antigens, also known as immunogens, are toxins or compounds in our blood that cause our body to resist them for being foreign substances. Antigens are mainly bacteria or viruses, but they can also be foreign substances that pose a health risk.

Antigens activate our body’s disease-fighting white blood cells, known as lymphocytes. They stimulate white blood cells to produce cells called antibodies that try to protect our body by attacking these antigens.

Heteroantigens and autoantigens are the two primary categories of antigens. Heteroantigens are compounds that are not manufactured by or found naturally in our body, and they include substances such as protozoa, bacteria, viruses, snake venom, and other elements.

Autoantigens, also known as self-antigens, are proteins produced naturally by our body to combat our cells and usually indicate an autoimmune disease. These mostly help to strengthen immune system by helping our body generate antibodies before any external antigens can even enter the body.

What Is Antibody?

Antibodies Y-shaped proteins produced by B lymphocytes or B cells in our immune system. These B lymphocytes assault and remove viruses and other poisons. They accomplish this by developing antibodies that are specific to a single antigen.

These antigen-specific antibodies bind to their antigens and mark them for any attack. Thus, they ensure our bodies and all our healthy cells remain safe from any antigen attack. Antibodies (Immunoglobulins) come in a variety of forms. These are the antibodies that are found in the highest concentration in our plasma. They cleanse the body of harmful toxins while also providing long-term protection.


These are the earliest antibodies produced by B cells in response to antigens.


These antibodies bind to antigens and transport them out of your body through mucus or other bodily fluids.


Allergies are triggered by these antibodies, which also guard against parasites. Skin, lungs, and mucosal membranes contain trace quantities of such antibodies.


These antibodies attach to B cells and trigger the production of IgM antibodies.

What Are The Differences Between Antigen And Antibody?

Here are the critical differences between antigens and antibodies-

  • Antibodies, also known as Immunoglobulins, have protein, a molecule type, while antigens have a lipid molecular type. However, antigens can also nave nucleic acids, carbohydrates, and proteins as their molecular type.
  • While antigens cause illnesses and allergic reactions, antibodies help the body protect itself against these antigens effects.
  • Lastly, antigens originate outside the body, while antibodies form inside the body. Antibodies are formed in response to antigens – they help immobilize antigens to protect the body from allergies or illnesses.

How Are They Used In Vaccines?

Vaccines operate by injecting infection-causing antigens in our bodies beforehand without actually causing any sickness. This is done so that if the infection imitated by the vaccination ever resurfaces in our body, our body already has the tools it needs to protect us.

Traditional Vaccines

Vaccines contain antigens from viral illnesses that have been attenuated or rendered inert. These dormant antigens cause your B cells to produce specific antibodies to combat the illness. Nowadays, instead of employing essential antigen components, vaccinations use genetic blueprints for creating antigens, which work similarly.

Vaccines increase the number of antibodies against a particular antigen in your body. As a result, your B-cells react to vaccines as if they were a naturally occurring antigen attacking your body. These B-cells multiply, forming an army of cells primed to respond to infection antigens in the vaccine.

The vaccine’s triggered antibodies remain dormant in your body until you catch an Infection caused by that specific antigen, at which point they are activated. When you get an infection, memory B cells, or the antibodies, multiply quickly and create the exact antibodies you need to eliminate the antigen. The response of the memory B-cells is known as a secondary immune response. It is considerably faster and more effective than your body’s reaction to the illness if you hadn’t been vaccinated.

How Are They Used In COVID-19 Testing? 

Antibody Test

Antibodies in the blood are measured in these tests. A blood test, which involves extracting blood from your arm or sticking your finger, is used to collect material for testing. These tests can reveal if your body has started fighting a COVID-19 infection or if you’ve had an infection for several days. Thus, they help establish whether you’ve had COVID- 19 for a long time. However, they may not be a reliable means to determine whether you are currently infected. To rule out a current infection, more testing may be required.

Antigen Test

Antigen proteins from the virus are measured in these procedures. A swab is used to gather material for testing from your nose or throat. This antigen testing or PCR testing is the most common COVID-19 test. COVID-19 can be diagnosed using these tests, although they may not rule out an active infection. If an antigen test comes out negative, a molecular test will be required to establish that you do not currently have COVID-19.

Molecular Test

These tests look for genetic material in your body from a virus. If you get a negative test result, it means you didn’t get infected with the COVID-19 virus during the testing period. However, the test may be inaccurate if you have a meager amount of the virus.

• Also Read: Covid-19 Testing


Thus, to summarize, we can say that both antigens and antibodies are very different from each other. While antigens are responsible for initiating illnesses or allergies in our body, Urgent care suggest antibodies help the body fight against these effects. We hope this article provided you with a comprehensive look into the world of antigens, antibodies, their differences, and how they are used in vaccines.

Also Read: What Do You Need To Know About Delta Variant


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