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Difference Between Active And Passive Immunity

Active-And-Passive-Immunity

Do you wonder how we don’t always feel sick despite various different microorganisms in our surroundings?

It’s your immune system that keeps you safe from disease-causing viruses and bacteria by killing them before they harm you. It comprises cells, tissues, and organs that kill pathogens. The immune system is generally categorized into innate and acquired immunity. While innate immunity is naturally obtained, active and passive immunity belongs to the acquired immunity that we develop over time.

Let’s show you how they are classified and tell you all about immunity, including the differences between active and passive immunity for better understanding.

Comparison Table

FactorsActive immunityPassive immunity
Natural AcquirementAfter interaction with a pathogenThrough placenta or breastmilk
Immunity TypeHumoral and cell-mediatedAntibodies
Involved CellsB cells, antigen-presenting cells, T cellsImmunity cells are not involved
Immunological MemoryYesNo
Secondary ResponseYesNo
UsageProphylaxisPost-exposure treatment
EffectivenessEffective protectionMay not sometimes offer complete protection
Lag PeriodYesNo
Hypersensitivity ReactionsNoMay be
Immunocompromised PersonsUnsuitableSuitable choice

What is Immunity?

Before we talk about the dissimilarities between passive immunity and active immunity, it is important to understand how immunity works. Immunity means the resistance of a host to a foreign body that may cause harm. The tissues and cells which are a part of the immune system produce an immune response whenever a harmful external factor enters your body. The immune system saves you against environmental and internal disease-causing factors.

Types of Immunity

types-of-Immunity

Active and Passive Immunity Origin

Active and passive immunity are two types of acquired immunity. Acquired immunity is the type of immune response we acquire throughout our lifetime. It could be due to different channels like exposure to pathogens, diseases, infections, vaccination, or immunity from another person’s antibodies. Active and passive are obtained from different sources and act in different ways to prevent harm to the body.

Active Immunity

Active immunity is the most common type of immunity that your body acquires through external means. Immune B and T cells attack microorganisms, for e.g., bacteria, yeast, viruses, etc., that pass the body’s first line of action. Active immunity develops when a foreign body or a pathogen enters your body.

Once the immunity cells are activated to fight a particular pathogen, they remember it and respond the same way the next time.

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Passive Immunity

Passive immunity refers to the immunity developed by your body through another source. Two common examples of passive immunity include breastmilk and vaccines.

  1. When the mother breastfeeds the baby after being born, the milk contains antibodies to help the baby fight against diseases besides innate immunity.
  2. Another common example of passively acquired immunity is vaccination. When an organism is inoculated into your body, the body cells attack to kill it. The immune cells kill and memorize the pathogen to perform the same way if needed in the future.

While the pattern of acquiring active and passive immunity is dissimilar, a few other factors also distinguish active immunity from passive immunity. Here’s a list of the differences between active and passive immunity.

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Difference between Active and Passive Immunity

Definition

Active Immunity

If the immunity is acquired by the body itself to act on an external pathogen, it is called active immunity.

Passive Immunity

Alternatively, if an individual acquires immunity through antibodies from another human being, it is called passive immunity.

Natural Acquirement

Active Immunity

Active immunity is naturally acquired when the cells activate to fight against an invader.

Passive Immunity

On the other hand, passive immunity is naturally acquired through the mother’s placenta or breastmilk.

Type of Immunity

Active Immunity

It involves cell-mediated and humoral immunity.

Passive Immunity

Whereas it does not require activated immunity as the ready antibodies perform against pathogens.

Involved Cells

Active Immunity

Active immunity involves B cells, T cells, and antigen-presenting cells. They include helper T cells, cytotoxic T cells, memory T cells, memory B cells, plasma cells, macrophages, and dendritic cells.

Passive Immunity

Unlike active immunity, passive immunity does not involve any of the immunity cells.

Immunological Memory

Active Immunity

When the body cells respond actively to an entity, they remember the pathogen and produce the same response in the future.

Passive Immunity

Conversely, passive immunity, such as through breastmilk, does not produce immunological memory.

Secondary Response

Active Immunity

When the active immunity response is activated on exposure to an antigen, the body remembers it and fights it the same way as the first time.

Passive Immunity

In contrast, passive immunity stays for a short time as memory is not formed.

Usage

Active Immunity

As the cells remember the previous response, they are effective for prophylaxis.

Passive Immunity

However, passive immunity acquired through other sources is more suited as a post-exposure solution.

Protection

Active Immunity

Active immunity provides effective protection against foreign bodies once acquired.

Passive Immunity

In comparison, protection through passive immunity may not sometimes offer complete immunity and is not as effective as active immunity.

Lag Period

Active Immunity

Active immunity has a lag period to recall the previous interaction with the antigen.

Passive Immunity

Yet, passive immunity acts immediately without any lag period.

Hypersensitivity Reactions

Active Immunity

Active immunity developed by the body itself does not cause any reactions.

Passive Immunity

On the other hand, the introduction of passive immunity may cause a reaction or have side effects.

Immuno-Compromised Persons

Active Immunity

Active immunity is not the right choice for protecting immune-compromised people against pathogens.

Passive Immunity

Though passive immunity is more suited to people with compromised or deficient immune systems.

What is Immunocompromised?

Immunocompromised persons are those whose immune system has a reduced capability of fighting antigens and pathogens. There could be several reasons for immunocompromised, including intake of immunosuppressants that suppress your immune system. A person may be temporarily or permanently immunocompromised.

The Bottom Line

Immunity plays a critical role in ensuring health and saving you from diseases. While innate immunity is inbuilt, acquired immunity develops during the lifetime through different means. The acquired immunity might be active or passive, depending on how the immunity is developed. The body produces active immunity in response to a foreign body, while passive immunity is received through another person’s antibodies. Active immunity creates immunological memory. Subsequently, passive immunity is more suitable for immunocompromised people.

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