What Is Immunogenicity? - Definition & Role in Blood Transfusions

Instructor: Dan Washmuth

Dan has taught college Nutrition and Anatomy courses for over 5 years. He has a B.S. in Exercise Physiology from Furman University and a M.S. in Dietetics & Nutrition from Florida International University. He is a Registered Dietitian (RD) and a Certified Exercise Physiologist (EP-C)

Immunogenicity is a very important part of a person's immune response to infectious viruses and bacteria. Learn more about immunogenicity and how it plays a role in blood transfusions.

He Needs a Blood Transfusion

Dave is a 43-year-old factory worker. Recently, Dave had an accident at work that caused a very deep and long laceration to his chest and abdomen. This wound resulted in Dave losing a massive amount of blood.

In the hospital, doctors decided that Dave needed a blood transfusion to replace the blood he had lost. How would the healthcare staff know what type of blood he should receive? What could happen if Dave received the wrong type of blood? The answer to these questions revolves around immunogenicity.

What Is Immunogenicity?

Immunogenicity is the ability of a foreign substance to enter a person's body and cause an immune response. A great example of immunogenicity is a vaccination. When a person gets vaccinated, they are injected with a very tiny amount of a specific disease. Once a person receives the injection, their immune system will begin to create antibodies, which are special proteins created by the body that help protect us against infectious viruses and bacteria.

Another great example of immunogenicity is when a person gets a viral infection. When a virus enters a body and makes that person sick, the immune system will react by creating antibodies designed to destroy the virus. As the immune system creates more antibodies, the body is able to destroy all the viruses and the person will eventually get better.

When a virus enters the body and causes the flu, the immune system responds by producing antibodies that work to destroy the virus.

Immunogenicity & Blood Group Antigens

An antigen is a foreign molecule that can cause an immune response. For example, the virus that caused the sickness in the example above contains antigens, and these antigens caused the person's immune system to respond and create antibodies. The substance injected into a person's body for a vaccine also contains antigens.

Antigens & ABO Blood Types

Do you know what blood type you are? There are four main blood types (A, B, AB, and O), and these are based on antigens found on red blood cells. There are two main blood antigens, and the following list describes how these two blood antigens determine a person's blood type:

  • A: blood only contains the A antigen
  • B: blood only contains the B antigen
  • AB: blood contains both the A and B antigens
  • O: blood does not contain A or B antigens

Blood type depends on which antigens are found in the blood.

Immunogenicity & Blood Transfusions

A person who is receiving a blood transfusion should only be given blood that is compatible with their own blood, and compatibility depends on which antigens are found in the donor blood. Think about the how antigens cause an immune response. If a foreign antigen gets into the body, the body will response by creating antibodies to fight this foreign substance. This same concept applies to blood transfusions. If a person receives a blood transfusion that does not contain the same antigens as their own blood, their body will start an immune response and try to kill and destroy this new blood and its antigens.

During a blood transfusion, a person can only receive blood that contains the same antigens as their own blood.
blood transfusion

Let's use Dave from the beginning of the lesson as an example. Pretend that Dave has type A blood, meaning that his blood contains only the A antigen. If Dave was given type B blood, his body would treat these B antigens as a foreign invader and try to destroy and reject this blood. However, if Dave was given type A blood (just like his own), his body would recognize the A antigens and would accept the newly transfused blood.

Two interesting points about blood types and blood transfusions:

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