Explore the Different Types of Immunity
In our previous blog, we learned how the immune system works, the cells and organs involved and how these protect the body against many infections, but did you know that there are also various types of immunity?
In this blog, you are going to have a closer look at each type of immunity i.e 4, it’s importance and the vital role it plays. Let’s start!
Types of Immunity
1. Active Immunity
Active immunity is a type of immunity that is created by our own immune system when we come in contact with a harmful pathogen. We are exposed to these throughout our day, it could be when we eat, breathe or even what we touch. Luckily, most of these will not result in any harmful diseases, as our immune system works to ward them off.
Another crucial function that active immunity undertakes is protection for a long time in the form of immunological memory. This memory contains cells B & T that work to recognize the pathogens. Although these cells circulate in our body at a very low level, once they sense an outside invader, they start to multiply in number and send signals to all other organs of the immune system to activate themselves.
The importance of active immunity is:
- Quick response to outside invader
- Highly specific, so the immune system is ready when the pathogen is encountered.
The one thing that drives active immunity most are vaccines. When an individual takes a vaccine, their immune system treats it like any other exposure, while doing so, it generates an immunological memory. As vaccines are developed to not cause illness, the body gains the benefits of the exposure without having to fight off the particular infection. In short, it prepares our immune system for a future encounter with the infection and provides us protection.
2. Passive Immunity
Passive immunity is a type of immunity that is achieved by something other than one’s own immune system. Unlike active immunity, passive immunity is short-lived as the antibodies in this type of immunity are not continuously replenished, as would occur in an individual whose immune system is responding directly.
Passive immunity can occur from:
Antibodies that are maternal :
The mother has antibodies that protect the unborn and newborn child. These antibodies are shared by either:
Placenta: When a woman is pregnant, blood circulates throughout the placenta to provide protection and nourishment to the fetus that is developing. As this blood circulates, the immune cells and antibodies circulate with it. Although the developing fetus is not exposed to any pathogens in the uterus, they are exposed to viruses, bacteria etc during and after birth, which is another reason why the types and levels of antibodies in the baby’s blood match those of the mother’s.
Breast Milk: The first few days after birth, the mother produces protein-rich breast milk called colostrum. This milk contains higher levels of antibodies that protect the intestinal surface as well as has a lower nutritional value than milk following birth. This exchange of antibodies from mother to child via breast milk provides the baby with passive immunity, and suggests its importance for the baby before it can generate its own protection.
3. Innate Immunity
Innate immunity is a type of immunity that protects the body against infections by generating a quick immune system response once a pathogen attacks it. Innate immunity is made up of various barriers that defend against viruses, bacteria, parasites as well as any foreign substances or even block their pathway to spread and move throughout the body. This entails:
- Physical barriers- This is skin, the gastrointestinal tract, respiratory system, the nose, the throat, body hair, eyes, eyelashes etc.
- Defense mechanisms- such as mucous, gastric acid, saliva, tears, sweat, secretions etc.
- General immune responses- Like inflammation that enables the movement of blood to the site of infection and complement that is an immune response that marks pathogens for destroying them and then makes a hole in their cell membrane.
The innate immune system always targets foreign or non-self substances and is activated by the presence of antigens and their chemical abilities.
4. Adaptive Immunity
Adaptive immunity is the type of immunity that occurs after the exposure to a pathogen or infection or also when we get a vaccination. It is also called acquired immunity. It is mostly activated when innate immunity is not sufficient enough to fight off these harmful substances and uses an immunological memory to learn about the threat and enhances the immune system to give a strong response accordingly. The perfect example of this is seen in our lives, when we get a cold, the first time around the recovery time is more. The second time when it reappears, the recovery time shortens.
Since there is an immunological memory with adaptive immunity, it provides longer protection, unlike innate immunity.
In a nutshell, the immune system is complex yet vital for our survival, and contains a group of cells, organs and as we saw in this blog 4 types of immunity, that work in perfect harmony, synchronization as well as accordingly to protect the body and fight off outside invaders that could cause irreparable harm.