Immunity is the body’s self-defense to diseases.
When this immunity is compromised or weaker, then the diseases infect humans.
Immunity happens by two components in the body.
One is the anti-body component which neutralizes foreign bodies.
The other is cellular component which eats up and destroys the foreign organism.
So the way to prevent diseases is to build up immunity. There are three types of immunity
3 Types of Immunity
- Immunity based on response/ specificity
- Based on the components involved
- Based on the location of immunity.
- Natural immunity
- Adaptive immunity
- Acquired immunity
Natural Immunity: This is the immunity present from birth of an individual or animal. When a new infection enters the body, the body produces a complex set of immune reaction to neutralize the foreign body. This immunity is strong and prevents many infections during childhood.
Adaptive immunity: This is the immunity not present from the birth but develops after a first attack. For example a person who contracts chickenpox during childhood never gets it again. This is because the body has developed memory for that foreign infection and when it re-enters, there is quick response to neutralise and destroy it. This is developed immunity toward older infections is adaptive immunity.
Acquired immunity: This sounds similar to adaptive immunity. But it is acquired intentionally by use of vaccines in humans. This immunity is very specific for an infection or even to specific strain of infection. This immunity can last for few years to even lifetime.
Based on the components involved; Immunity is produced by two components of the body.
- Humoral immunity
- Cellular immunity
Humoral immunity is one where self-defense if done by antibodies. I.e. no cellular components are not involved. The end result is neutralization of foreign bodies.
Cellular immunity: Here the immune defense is by production of cellular components like macrophages, lymphocytes etc. The end result is destruction of foreign bodies.
Based on immune response region:
This is based on where the immune response happens. This is of two types like immunity in mucous layer. The immunity happening in blood or sera.