The capacity to recognize the intrusion of any material foreign to the body and to mobilize cells and cell products to help remove the particular sort of foreign material with greater speed and effectiveness is known as immunity.
Defense lines
There are three defense lines in our body:
- The first defense line is formed by the physical and chemical barriers.
- The second line of defense is formed by the phagocytes.
- The immune system forms the third line of defense of our body.
Immune system
The immune system is derived from mesoderm.
Antigen
An antigen or immunogen is a foreign substance, often a protein that stimulates the formation of antibodies. The term antigen comes from antibody antibody-generating substance.
The immune system has two main components:
- Lymphocyte
- Antibodies
Lymphocyte
Lymphocytes are examples of agranulocytes and belong to white blood cells. There are two major types of lymphocytes
T-lymphocytes and B-lymphocytes.
Helper T-lymphocytes – These lymphocytes recognize the antigen and inform other cells. Thus helping to produce immunity.
Suppressor T-lymphocytes – They are involved in controlling immune responses.
B-lymphocytes – Have been given the name due to their first Discovery from Bursa of Fabricius, which is a lymphoid tissue in birds around the cloaca.
In humans, these are produced and released in mature form from bone marrow. There are two types of B-lymphocytes:
- Plasma cell clones – which synthesize and secrete antibodies in plasma
- Memory cells – These keep the information or memory of antigens encountered
Antibodies
Antibodies/Immunoglobulin is a global protein manufactured by B-lymphocytes then secreted into the lymph and blood where they circulate freely. These are Y-shaped molecules. Whenever any foreign particle tries to enter our body antibodies detect them and fight against them.
There are two basic types of immunity:
- Inborn or innate immunity – The ability of innate immunity to kill microorganisms is not specific. The first and second lines of defense are part of innate immunity.
- Acquired or adaptive immunity – Highly specific protection is provided by innate immunity, but it takes several days for this system to become fully functional.
There are two types of the acquired immune response:
- Cell-mediated response
- Antibody-mediated response or hormonal response
Types of Acquired Immunity:
- Active immunity
- Passive immunity
Natural active immunity – When a person is exposed to an infection, becomes ill, and in most cases survives, then the immunity develops against the disease is known as natural active immunity.
Natural passive immunity – If a source of antibodies is natural then this type of immunity will be called Natural passive immunity. For example, Antibodies from a mother can cross the placenta and enter the fetus. In this way, they protect the baby until its immune system is fully functional.
There are many ways to boost your immune system:
Stay hydrated – Drinking plenty of water is good for health and also boosts the immune system. Drinking plenty of water will flush out toxins from our bodies and will make our blood oxygenated.
Sleep – Failure to get enough sleep will increase the chances of illness and also slow down the process of recovery.
Level of vitamin B12 – Vitamin B12 is essential to make the immune system healthy. When there is a decrease in B12 in the body it can limit immune responses.
Limit sugar intake – Excess sugar intake inhibits our immune system’s response to bacteria for several hours. So, it is necessary to limit sugar intake.