In this lesson, you’ll learn all about active immunity. We will discuss how active immunity works in the body, the different types of active immunity, as well as explore some examples.
Defining Active Immunity
You might think that active immunity is immunity that comes from being active. That’s not really the case though. Active immunity is immunity that develops from creating antibodies to a disease or illness. Immunity refers to having a resistance to a disease or illness.
Taking this into consideration, you could further break down active immunity by defining it as gaining resistance to a particular disease or illness by creating antibodies to the disease or illness. Now that you know what active immunity is, let’s look at the two different types of active immunity.
Natural Active Immunity
The first type of active immunity comes from being exposed to the pathogen that causes the disease. The term for this is natural active immunity. When an infectious organism, like a bacteria or virus, enters your body, it will begin to mount an immune response to try to attack the pathogen. The T-cells in your bloodstream will attach to the pathogen and then present the pathogen to the B-cells in the bloodstream. The B-cells are the ones that create the antibody that can attack and kill the pathogen.
Antibodies are proteins that are specifically made to deactivate and kill pathogens.The B-cells will also save a copy of the antibody, so your body can remember how to make the antibody if the pathogen comes into the body again. This then makes you immune to the pathogen, since your body will already know how to kill the pathogen as soon as it arrives.You may recall this happening if you’ve ever had the chicken pox before. Once the virus that causes chicken pox entered your body, your immune system created antibodies to attack the virus.
Anytime you were exposed to chicken pox after that, you didn’t develop a case of chicken pox because your body fought it off. Years ago, parents would try to have all of their children get the chicken pox at the same time so they could build immunity at the same time. That was, of course, prior to the chicken pox vaccine.
That brings us to the other way in which active immunity is acquired.
Artificial Active Immunity
The other way to get active immunity is to get a vaccine for the disease or illness. This is known as artificial active immunity.
The vaccine contains an inactive version of the pathogen. Even though the pathogen isn’t active, it still causes your immune system to mount an immune response. The same process takes place with the T- and B-cells, just like in a natural active immunity scenario, making you immune to the disease.
This time; however, you’re artificially injected with the pathogen, and you don’t actually get the disease. The antibody that is created for the inactive form will also work again should the active form of the pathogen ever enter your body. In addition to the chicken pox, there are many vaccines that are administered to produce active immunity, such as those against polio, hepatitis B and the flu.
Let’s review.Active immunity is when you become resistant to a particular disease because your body created antibodies against the pathogen that causes the disease. Natural active immunity occurs when you actually get the disease, and artificial active immunity occurs when you get a vaccine, composed of an inactive version of the pathogen.
The vaccine will cause an immune response, but it won’t actually cause the disease. The antibodies for the inactive form still work on the active form of the pathogen.
Active Immunity: Key Terms
- Immunity: having a resistance to a disease
- Active immunity: when the body becomes resistant to a disease through the creation of antibodies against the pathogen causing the disease
- Natural active immunity: happens when the body gets invaded by a pathogen
- Artificial active immunity: occurs when the body receives a vaccine containing an inactive form of a pathogen
- Antibodies: proteins designed to deactivate and kill pathogens
- T-cells: cells that attach to pathogens in the bloodstream
- B-cells: cells that create antibodies
As this lesson comes to conclusion, students should be able to:
- Define active immunity
- Describe the types of active immunity
- Recall how vaccines work in the body