BioTechnology | Immune System | Innate or Natural Immunity (Our Body's First Line of Defence)

BioTechnology | Immune System

INNATE/ NATURAL IMMUNITY

(OUR BODY’S FIRST LINE OF DEFENCE)

Can Immunity be Natural?

What is Innate Immunity or Natural Immunity in Bio Technology?

This post will clear your all doubt and logic on Innate/ Natural Immunity; I have tried to structure this post as SPECIAL NOTES LIKE feel to give more insight and increase readability.

In the previous post  https://deepalitalk.blogspot.com/2019/06/immune-system-basic-concepts-your.html,  I have explained some important terms related to our immune system which will help you in understanding the topic further.

Our body has a mechanism to defend itself against “foreign bodies” which is broadly termed as Immunity.

These “foreign bodies” are dust, infections and might be cancer cells.

·        Ideally Immunity is of two types,

                                                                                       

A)   Innate Immunity

B)   Adaptive Immunity

The above diagram gives us the first picture of both types of Immunity.

The innate process works as a “Hare” in our body in providing immunity while adaptive immunity process works slowly and steadily just like a “Tortoise”.

Now we will look into the innate immunity working process.

INNATE IMMUNITY:

A person is born with this type of immunity, so commonly it is also called as Natural Immunity.

Function- It gives an immediate defense against infections and is found in all plant and animal life.

Behavior- This Immunity is not adaptable and does not change with the individual’s lifetime.

·        Innate Immunity acts defensive in four different ways:

A)   Anatomical Barrier

B)   Physiological Barrier

C)   Phagocytic Barrier

D)  Inflammatory Barrier

A)  Anatomical Barrier:

Points to Remember:

·        The foremost and the basic barrier is the skin.

·        The outer layers of the skin are known as “Epithelial cells”.

·        They form a waxy layer which keeps out the infectious agents.

·        These cells are the innate immune system's first line of defense against infectious foreign organisms.

·        The skin internally is present as the lining of the intestine and lung.

·        In the intestines or lungs, movement caused by peristalsis or cilia brush up the infectious agents.

·        Mucus also provides immunity by trapping the infectious agents.

·        In the intestines, gut flora  prevent pathogenic bacteria by secreting toxic substances, or compete with pathogenic bacteria to attach on the cell surfaces.

Sometimes crying and food cravings work in our favor, because of the flushing action which makes tears and saliva to prevent infection of the eyes and mouth.

B)   Physiological Barrier:

Points to Remember:

·        Our body physiology is designed in such a way that whenever an infectious organism is there in our body, it starts working in such away to eliminate the pathogen from our body.

·        The most common is fever response. It stops the growth of micro organism by raising the body temperature which is not suitable for growth of pathogens.

·        The acidic environment of stomach and vagina also retard the growth of invading organisms.

·        The pH of urine being 6.0 is inhibitory in nature for any kind of microbial growth.

·        Several chemical mediators work in response to provide immunity.

·        The lysozyme of tears breaks off the bacterial cell wall while interferons induce an antiviral state in uninfected cells.

·        The Complement system facilitates phagocytosis. Both the terms play an very important role in immune system and will be discussed in upcoming  posts.

·        The antibacterial peptides kill the pathogenic bacteria.

C)  Phagocytic Barrier:

The term “phagocyte” refers to "eating cell”.

The process is simply explained in three steps:

1.     A phagocyte extends a portion of its plasma membrane around the pathogen until the particle is inside the cell.

2.     The pathogen is inside an endosome which merges with a lysosome.

3.     The enzymes and acid present in lysosome digest or kill the pathogen.

Points to Remember:

·        The most important feature of phagocytes is the ability to react with a highly specialized molecular signals produced by other cells called cytokines.

·        The phagocytic process play an important role in regular tissue development and maintenance and is an important part in healing process.

·        The phagocytic cells of immune system comprises of macrophages, neutrophils and dendritic cells.

D)  Inflammatory Barrier:

Points to Remember:

• Inflammation is the immune system response to pathogens stimulated by chemicals released from injured cells.
• It is the physical barrier against spread of infection and heals damage tissue after the clearance of pathogens.
• Chemicals produced during inflammation attract phagocytes or precisely neutrophils which trigger other parts of immune system.

These four barriers constitute the innate or natural immune response in our body, but some cells are also involved in evoking immune response in our body and are compiled in the first line of defense immune system.

These cells are as following:

i)                   Mast cells

ii)                Phagocytes (Macrophages, Neutrophils, Dendritic cells)

iii)              Basophils and Eosinophils

iv)               Natural killer cells

This comprises Innate immunity Part-I and in the next post, I am going to explain readers a complete glance of the above mentioned cells of immune system.

Please share and comment your thoughts and doubts.

Happy Bio Technology Learning & Good Luck!!!