Difference Between Innate and Acquired Immunity

Differences Between Innate And Adaptive Immunity

Innate and Acquired Immunity: Definitions, Examples, and Key Differences

The human body is equipped with multiple defence mechanisms to protect itself from disease-causing organisms. Broadly, there are three types of immunity in humans: passive immunity, innate immunity, and acquired immunity (also called adaptive immunity). In this article, we will explore the difference between innate and acquired immunity in simple terms, along with examples, a comparison table, and a few extra resources to help you remember these concepts better.

difference between innate and acquired immunity with example

What is Innate Immunity?

Innate immunity is present right from birth. It is non-specific, meaning it does not differentiate between various pathogens. Instead, it forms a general first line of defence against all foreign invaders. This defence system includes physical barriers like the skin and mucous membranes, as well as certain cells (for example, phagocytes) and proteins that attack foreign particles before they can cause significant harm.

Some types of innate immunity mechanisms include:

Physical Barriers: Skin, mucus, and the linings of the respiratory and digestive tracts.
Chemical Barriers: Enzymes in saliva, stomach acid, and antimicrobial proteins in bodily secretions.
Cellular Defences: White blood cells such as neutrophils, monocytes, and natural killer cells that target pathogens.

When you get a cut on your skin, for instance, the redness and swelling (inflammation) you observe is a part of the innate immunity response.

What is Acquired (Adaptive) Immunity?

Acquired immunity, also referred to as adaptive immunity, develops over an individual’s lifetime. It is highly specific, targeting particular pathogens after the body has been exposed to them (either through infection or vaccination). Once you recover from or are vaccinated against a specific disease, your immune system can remember that pathogen, resulting in a faster and more potent response if you encounter it again.

Key features of acquired immunity (adaptive immunity) include:

Specificity: Targets a particular pathogen.
Memory: Remembers the pathogen and mounts a stronger response during subsequent exposures.
Long-Lasting Defence: Often provides prolonged protection, especially in the case of vaccinations.

A classic difference between innate and acquired immunity, for example, is seen in diseases like chickenpox. Once infected, your body typically “remembers” the virus, making reinfection much less likely in most cases.

Comparative Table: Innate and Acquired Immunity Difference

The innate and acquired immunity difference can be easily understood through the following points:

Characteristics	Innate Immunity	Acquired (Adaptive) Immunity
Definition	Present at birth and non-specific	Develops after exposure to pathogens or through vaccination (specific)
Line of Defence	First line of defence	Second line of defence (activated if pathogens bypass innate immunity)
Response Time	Immediate	Slower initial response but more potent during re-exposure
Specificity	Non-specific	Highly specific to particular pathogens or antigens
Potency/Effectiveness	Generally lower compared to acquired immunity	Highly effective and increases repeated exposure
Inheritance	Can be inherited	It cannot be inherited; it must be developed by the individual
Memory	Does not have immunological memory	Has immunological memory, providing long-term protection
Distribution	Present in nearly all animals (vertebrates & invertebrates)	Exclusive to vertebrates (e.g., humans, birds, reptiles, amphibians)
Main Components	Physical barriers (skin, mucus), phagocytes, etc.	Specialised lymphocytes (T cells and B cells), antibodies, lymphoid organs like thymus and spleen
Examples	Inflammation after a cut or injury	Immunity developed after chickenpox infection or vaccination

Quick Quiz

Test your knowledge about innate and acquired immunity by answering these multiple-choice questions:

Which of the following is part of innate immunity?
A. T cells
B. B cells
C. Phagocytes (e.g. neutrophils)
D. Plasma cells
Answer: C (Phagocytes are a key component of innate immunity.)

Which statement best describes acquired immunity?
A. It does not require prior exposure.
B. It is inherited from parents.
C. It is highly specific and has a memory component.
D. It is always present at birth.
Answer: C (Acquired immunity is highly specific and able to remember pathogens.)

Which of the following is an example of passive acquired immunity?
A. Antibody transfer through breast milk
B. Phagocytosis
C. Skin acting as a physical barrier
D. Platelet formation
Answer: A (Maternal antibodies passed through breast milk represent passive immunity.)

FAQs on Difference Between Innate and Acquired Immunity

1. Are innate and acquired immunity both present in humans at birth?

Innate immunity is present at birth. Acquired (adaptive) immunity develops as the individual is exposed to different pathogens or receives vaccinations.

2. Can acquired immunity be inherited?

No. Acquired immunity cannot be inherited. Each person must develop or gain it individually by encountering pathogens or receiving vaccines.

3. Why is acquired immunity considered more specific than innate immunity?

Acquired immunity targets particular pathogens or antigens with precision. It recognises specific molecules on these pathogens, whereas innate immunity is a general, non-specific defence.

4. What are some examples of innate immunity at work?

Physical barriers like intact skin, chemical barriers like enzymes in saliva, and certain immune cells (e.g., macrophages) that rapidly respond to any threat without distinguishing the exact pathogen.

5. How does vaccination help in acquired immunity?

Vaccines introduce an inactivated or weakened form of a pathogen, prompting the body to generate specific antibodies and T cells. This builds up adaptive immunity without causing the actual disease.