Difference Between Innate and Adaptive Immunity

Introduction

Since childhood, we are given booster shots to make us immune to certain diseases such as tetanus, polio, etc. In 2020, we have seen the entire globe worry about immunity and seek various measures to strengthen it. We have seen how the vaccination campaign in India was carried out to ensure antibodies against the Covid-19 virus entered people's immune systems and protected them against the disease. 


What Exactly is Immunity? 

Immunity is the body's defence mechanism or system against problematic infections and diseases. Each day when we step out, we come into contact with many invisible pathogens. Look at how we wear masks to protect ourselves from Covid-19! The body's inbuilt mechanism that protects us from being harmed by these pathogens is the immune system or the power of immunity. It does this by producing antibodies that can fight off bacteria and pathogens. The immune system can thus be called a dynamic system that strives to keep us healthy and glowing. 


What is Innate Immunity? 

Innate immunity is the body's built-in capacity to combat pathogens and destroy dead or malfunctioning cells. This system contains organs, cells, tissues and various proteins. It is kind of a natural defence system within us, protecting us from harmful elements right from the moment we enter this world. 


What is Adaptive Immunity? 

As we grow up into teenagers and adults, our body acquires a form of immunity which is not present since birth. This is adaptive immunity, where the body is able to adapt and recover even if particular pathogens do enter. 

Let us look at the difference between adaptive and innate immunity. 

  • The Meaning 

Innate immunity is the body's natural defence system present since birth. 

Adaptive immunity is acquired as we grow through the various stages of life. 

  • The Functioning 

The innate immune system is not antigen-specific but rather acts as soon as an antigen enters the body. 

The adaptive immunity is antigen-specific. This response is created after the first time that the body comes into contact with the antigen. 

  • The Line of Defence 

Remember how we have the first and second line of defence in our army? 

Similarly, innate immunity is the primary line of defence that is activated as soon as antigens come in contact with the body. 

Adaptive immunity falls in the second line of defence once the antigen or pathogen has crossed the first barrier of innate immunity. 

  • Presence in the Body

Innate immunity is present in the body right from birth. 

However, adaptive immunity is an essential form of immunity that is acquired as we grow up and battle various antigens. 

  • Inducibility 

Innate immunity is not formed based on the presence or absence of its substrate, hence it is not inducible. 

However, adaptive immunity is inductive. 

  • Specificity 

Innate immunity is non-specific while adaptive immunity is specific in nature. 


The Cells and Molecules Involved 

Mast cells, dendritic cells, phagocytic leukocytes and natural killer cells are cells of the built-in immune system while interferon, acute-phase proteins, cytokines and complements are its molecules. 


Adaptive immunity has Killer CD8+ T-cells, Helper CD4+ T-cells, B-cells for its cells and its molecules are cytokines and antibodies. 


What are the Components? 

Skin, mucous membranes, epithelial cells and phagocytes are the components of innate immunity. 


Adaptive immunity consists of lymphoma organs that can produce T cells and B cells that have specialised abilities to fight antigens. 


What do they fight against? 

While innate immunity is able to fight any pathogens entering the body, adaptive immunity can fight only against specific infections. 


The Immunological Memory 

Innate immunity does not have any mechanism to keep the memory of pathogens but adaptive immunity has memory cells that can keep the memory of pathogens and antigens. 

  • Power 

Adaptive immunity has greater potency and effectiveness than innate immunity. 

  • The Response Time 

The response time for innate immunity is almost immediate while it is slower for adaptive immunity. 

  • The Inheritance 

Innate immunity is inherited from parents while that is not the case for adaptive immunity.

FAQs on Difference Between Innate and Adaptive Immunity

1. What are the anatomical and physiological barriers in the case of innate and adaptive immunity?

In the case of innate immunity, the anatomical and physiological barriers are skin, mucous membranes, temperature, pH, chemicals, etc. and in the case of adaptive immunity, it is lymph nodes, spleen, mucosal-associated lymphoid tissue, etc.

2. What is the basic difference between innate and adaptive immunity?

The kind of immunity that is present by birth in all individuals is innate immunity. It is the body’s natural defense system present right from birth and prevents us from harmful antigens. On the other hand, as we grow up, our body acquires the second kind of immunity that is known as adaptive immunity. Unlike innate immunity, adaptive immunity is not present by birth but is acquired by the body. Hence, it is also known as acquired immunity.

3. What kind of immunity is only exclusive to vertebrates?

Innate immunity that is present by birth is found in all organisms- vertebrates, and invertebrates. But adaptive immunity is found only in jawed organisms or vertebrates.

4. What are the factors that cause immune evasion in the case of innate immunity? How is it different from adaptive immunity?

Innate immunity mostly occurs as a result of pathogenic virulence factor because it is non-specific and neither does it consist of memory cells to keep the memory of the infection. However, in the case of adaptive immunity, it is triggered by the mutation of the recognized antigen since it is specific and also keeps the memory of the infection and the antigens.

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