3 Types of Immunity | Body’s Self-defense to Diseases.

Immunity is the body’s self-defense mechanism to keep diseases at bay.

The body is susceptible to diseases and infections when this immunity is compromised or weakened.

Two components in the body execute immunity.

One is the anti-body component, which neutralizes foreign bodies from further actions in the body.

The other is the cellular component, which eats up and destroys the foreign organism.

So, the way to prevent diseases from microorganisms is to build up immunity. There are three types of immunity

3 Types of Immunity

1. Immunity based on specificity
2. Based on the components involved
3. Based on the location of immunity.

Immunity based on specificity is, again, of two types.

1. Innate immunity
2. Acquired immunity (Adaptive immunity)

Innate immunity

This form of immunity is present from the birth of an individual.

It is a non-specific defense against microbes.

It consists of different types of barriers that prevent the entry of microbes into the body. This innate immunity has 4 four components, like

1. Physical barrier
2. Physiological barrier
3. Cellular barriers
4. Cytokine barrier.

When a new pathogen enters the body, the body produces a complex set of immune reactions to neutralize the foreign body.

This type of immunity is strong and prevents many infections during childhood.

• See more details on examples of innate immunity.

Acquired immunity

Acquired immunity is one that develops in humans through exposure to pathogens or the use of vaccines or antibodies.

Immunity to specific pathogens is not present from birth but, it develops after first exposure to infectious agents.

For example, a person who contracts chickenpox during childhood never gets it again.

This is because the body has developed a memory for that foreign infection, and when it re-enters, there is a quick response to neutralize and destroy it.

This developed immunity towards previous infections is adaptive immunity.

It is very specific to an infectious microbe or to a specific strain of pathogen.

This immunity can last a few days to years or even a lifetime.

This can be again classified as active and passive type

Active Immunity

This is the body’s defense against microbes acquired through previous infection of vaccination.

This can be a long-standing immunity.

Example: Polio vaccination, DPT vaccination

Passive immunity.

Here, immunity is acquired due to the administration of antibodies into the body against a disease.

These antibodies will neutralize the specific pathogen and help overcome the infections.

However, these antibodies are short-lived, and immunity lasts only a few days.

Example: Rabies antisera is given to counter the rabies virus.

Based on the components involved,

Immunity is produced by two body components.

1. Humoral immunity
2. Cellular immunity

Humoral immunity

This is one where antibodies do self-defense without the involvement of cellular components. The end result is the neutralization of foreign bodies.

Cellular immunity

Here, the immune defense is produced by cellular components like macrophages, lymphocytes, etc.

The end result is the destruction of foreign bodies.

Based on the immune response

This is based on where the immune response happens. This is of two types, like

1. Primary response and
2. secondary response.

The primary response is slow or delayed in producing the antibodies. Also, it is short-lived.

The secondary response is swift, triggering a violent attack on infectious pathogens or toxins.

References

• Immunity Types
• Acquired immunity
• Anti Rabies Serum