Immunogenetics: Definition & Examples

Instructor: Betsy Chesnutt

Betsy teaches college physics, biology, and engineering and has a Ph.D. in Biomedical Engineering

By studying immunogenetics, we have been able to safely perform blood transfusions and organ transplants, as well as treat autoimmune diseases like diabetes. In this lesson, learn more about the fascinating science of immunogenetics!

What Makes a Blood Transfusion Work?

In the late 1800s, receiving a blood transfusion was extremely dangerous. Even though some people got better after receiving donated blood, many others suddenly died as their veins filled with clots. What was happening?

At the University of Vienna, a scientist named Karl Landsteiner decided to find out why some people were able to survive a blood transfusion while others were not. He collected blood samples from all of the people in his lab and separated the cellular components in the blood from the liquid part, which is called plasma. He found that when he mixed the plasma from one person with the red blood cells of another, sometimes the blood cells would stick together. By analyzing the blood of many people, he was able to identify three of the four main blood types that we now know as A, B, and O. The fourth, AB, was discovered about a year later.

Although Landsteiner did not understand exactly WHY this happened, we now know that each blood cell is marked with a specific protein, called an antigen. In people with type A blood, each red blood cell is marked with a Type A antigen, and in people with type B blood, each red blood cell is marked with a Type B antigen. Blood cells in people with type O blood do not have A or B antigens, and type AB blood cells have both. The plasma contains molecules called antibodies that bind to specific antigens and cause the blood cells to stick together, forming clots.

These antibodies are part of the immune system and they help to protect your body from being invaded by cells that are not supposed to be there. So, type A blood contains red blood cells that display the A antigen, and in the plasma, there are antibodies that can bind to B antigens.

Immunogenetics helps us to understand how to perform successful blood transfusions.
Blood Types

So, if a person with type A blood receives a transfusion of type B blood cells, all those anti-B antibodies in the plasma will immediately bind to the B antigens because they recognize that this blood is NOT supposed to be there. This results in the B blood cells sticking together and forming blood clots, which can cause lots of problems for the person who just received the blood transfusion!

What is Immunogenetics?

By figuring out how blood groups affect the success of a transfusion, Karl Landsteiner was one of the founders of a new science which we now call immunogenetics. Immunogenetics is the scientific field that studies the complex relationships between the immune system, genetics, and disease.

These different blood types evolved in humans in different parts of the world, and the type of blood that you have is determined by the genes that you inherited from your parents. The study of blood types and their interactions is just one small part of the scientific field of immunogenetics, which also helps us to understand why some people are more susceptible to certain diseases than others, and how to successfully perform organ transplants.

Immunogenetics and Organ Transplantation

Transplanting entire organs from one person to another is even more difficult than performing a blood transfusion. Without a thorough understanding of immunogenetics, it wouldn't even be possible!

Every single cell in your body is covered with antigens that act like flashing signs saying, ''Ignore me! This cell is supposed to be here!'' to your immune system. These antigens are determined by your genes, just like the antigens on your blood cells.

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