Types of Immune System

We, humans, have two types of Immune system and are classified based on whether they are present at the time of birth or not.

1. Innate Immune System.
2. Adaptive Immune System.

Innate Immune System

Immune System fights against microbes and prevent their entry inside the body.

Innate Immune System is composed of cells and proteins that are always present and are ready to fight against microbes in the infection area. Innate Immune System is present from the time of our birth.

Main elements of the innate immune system are –

• Dendritic cells.
• Phagocytic leukocytes.
• Natural killer (NK) cell.
• Physical epithelial barriers.
• Circulating plasma proteins.

Adaptive Immune System

The adaptive immune system is required to fight against pathogens that cannot be controlled by innate immune defences. It is also referred to as the acquired immune system because it is acquired during the course of life. They are specific to the type of pathogen invading the body.

All the components of the adaptive immune system are generally inactive however when activated these components adjust to the presence of all the infectious agents by proliferating and developing a potent mechanism for eliminating the microbes.

Two Types of adaptive responses are – humoral immunity moderated by antibodies which are developed by B lymphocytes and cell-mediated immunity, moderated by T Lymphocytes.