5 Major Types Of Adaptive Immunity And Its Characteristics!

Adaptive immunity is the second line of defence against bacteria, viruses, dust, and other toxic chemicals in the body. It protects the body when we are exposed to diseases or vaccinated. Thus, adaptive immunity is a defence mechanism that involves specialised immune cells and antibodies that attack and fight infections in the body. The features of adaptive immunity make it very effective at protecting us from many infection-causing microorganisms.

Indeed, adaptive immunity evolution helps to show how it changes over time; this protection system keeps working as the immune system confronts many pathogens throughout your life, thus creating an archive of immunological experiences.

The continuous process of explaining and educating about adaptive immunity ensures a progressive enhancement in the adeptness of the adaptive immune system to counteract an array of threats over time. Therefore, this blog explores significant types of adaptive immunity cells to help you understand how they fight infections and highlight the importance of maintaining them. You will also learn about adaptive immunity features or characteristics to understand it better. So, keep reading!

Table Of Contents

1. What Is Meant By Adaptive Immunity?

2. 5 Types Of Adaptive Immunity

3. 7 Major Characteristics Of Adaptive Immunity

4. Adaptive Immunity VS Innate Immunity

5. The Final Say

6. FAQs

7. References

What Is Meant By Adaptive Immunity?

Adaptive immunity refers to the body's sophisticated defence against pathogens like bacteria, viruses, or fungi. This specific and acquired immune response involves the recognition of particular antigens associated with these pathogens. Unlike the innate immune system, which provides immediate, generalised protection, adaptive immunity develops over time and "adapts" to recognise and neutralise specific threats.

Critical components of adaptive immunity include specialised white blood cells called lymphocytes, which comprise B and T cells. B cells produce antibodies, proteins that can bind to and neutralise specific antigens, while T cells play a crucial role in coordinating and executing targeted immune responses against pathogens.

Adaptive immunity possesses memory, allowing the immune system to "remember" previous encounters with specific pathogens. This memory enables a quicker and more efficient response upon re-exposure to the same pathogen, contributing to the body's ability to mount a strong and specific defence against a wide range of infectious agents. The adaptive immune system plays a fundamental role in vaccinations, where exposure to a harmless pathogen stimulates the development of memory cells, providing long-term protection against potential infections.

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5 Types Of Adaptive Immunity

Adaptive immunity comprises of humoral and cell-mediated immunity, each defending against pathogens in distinct ways. Let us have a look at different types of immunity that fall under the umbrella of adaptive immunity: 

1. Humoral Immunity

It targets extracellular pathogens mediated by antibodies produced by B cells. Upon encountering foreign substances, naive B cells differentiate into plasma cells, which release specific antibodies. These antibodies circulate in the body, neutralising pathogens and marking them for destruction by other immune cells. The body relies on this crucial process to eliminate bacteria, viruses and other extracellular pathogens. Antibodies play a significant role in binding to these pathogens; they mark them for destruction by other immune cells through opsonisation (the process by which an antigen is labelled or tagged to be destroyed), which expedites their clearance from the body.

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2. Cell-Mediated Immunity

Cell-mediated immunity, reliant on T cells, actively fights intracellular threats. The activation of T cells - including cytotoxic T cells– eliminate infected cells and helper Ts that coordinate immune responses - occurs through antigen-presenting cell involvement. This crucial type plays a significant role in eliminating viruses, intracellular bacteria; as well as cancerous cells: it prevents both infections and tumours. Furthermore, cell-mediated immunity regulates and modulates immune responses, ensuring a balanced defence mechanism.

3. Passive Immunity

Involves transferring pre-formed antibodies or immune cells for immediate but temporary protection. Naturally acquired through placental transfer or breastfeeding, passive immunity safeguards newborns. It can also be induced artificially, as in antivenom therapy or prophylactic treatment, but doesn't provide long-term immunity. The duration of passive immunity varies, depending on factors such as the half-life of transferred antibodies and the individual's metabolic rate.

4. Active Immunity

An individual's immune system activation results from exposure to pathogens or vaccines. This triggers a response leading to memory cell production, offering long-lasting protection. Active immunity can occur naturally through infection or artificially induced via vaccination, priming the immune system for rapid and robust responses. The duration and effectiveness of active immunity may vary based on factors such as the strength of the initial immune response and the presence of memory cells.

5. Specific Immunity

B and T lymphocyte cells are known for their accuracy in finding antigens because they have receptors specifically tailored to recognise certain antigens and engage in specific immunity. They play a part in specific immunity by making sure responses are directed right at invaders like germs or abnormal cells, which is different from the broader defence of innate immunity. Additionally, because it can change its response to various disease-causing agents, our body's protective systems are strengthened as a whole and specific immunity plays a crucial role.

7 Major Characteristics Of Adaptive Immunity

Also known as acquired immunity, adaptive immunity is a specific type of immune response providing targeted defence against pathogens. Let’s explore these significant characteristics of adaptive immunity to understand it in a better way:

1. Specificity

Adaptive immunity is particular in its recognition and response to pathogens. It can distinguish between different pathogens, such as bacteria, viruses, fungi, and parasites, and recognise specific strains or subtypes within those pathogens.

2. Memory

One of the defining features of adaptive immunity is its ability to "remember" previous encounters with specific pathogens. After initial exposure, adaptive immune cells, such as B and T cells, develop memory cells that can recognise and mount a faster and more robust response upon subsequent encounters with the same pathogen. This creates immunological memory, providing long-lasting protection.

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3. Diversity

The adaptive immune system has a vast repertoire of B and T cell receptors, proteins on the surface of these cells that can recognise specific antigens (molecules on pathogens). This diversity allows the immune system to recognise various pathogens and adapt its response accordingly.

4. Antigen Recognition

Adaptive immunity relies on the recognition of antigens. Antigens are specific molecules (e.g., proteins, carbohydrates) on the surface of pathogens or substances produced by them. B cells recognise antigens directly, while T cells require antigen presentation by antigen-presenting cells (such as dendritic cells) to trigger an immune response.

5. Primary And Secondary Response 

The adaptive immune system showcases a dynamic dual-phase response: upon encountering a novel pathogen, it initiates its primary defence. This initial phase requires some days for the immune cells to mobilise and recognise the invader. However, during this activation period, there exists what we call 'lag', consequently allowing pathogenic replication and causing symptomatic expressions.

Upon re-exposure to the same pathogen, the adaptive immunity demonstrates its hallmark: a swift and potent secondary response. This occurs through memory cells–formed during initial encounters with the pathogen in question; these facilitate an accelerated, more powerful reaction. Thus, The body can neutralise pathogens rapidly due to this heightened speed and efficiency of secondary responses; it often prevents symptom development or significantly reduces their severity.

6. Humoral And Cellular Responses

Adaptive immunity involves both humoral and cellular responses. The humoral response involves the production of antibodies by B cells, which can neutralise pathogens or mark them for destruction. The cellular response involves the activation of T cells, which can directly kill infected cells or coordinate immune responses.

7. Self-Tolerance

Adaptive immunity possesses mechanisms to distinguish between self and non-self antigens, preventing immune responses against the body's cells and tissues. This self-tolerance is crucial to avoid autoimmune reactions.

Also Read: 3 Day Immune Boosting Diet Plan And 8 Immune Boosting Foods 

Adaptive Immunity VS Innate Immunity

Note these significant differences between adaptive immunity and innate immunity for better understanding:

The Final Say

The adaptive immune system keeps improving its skill to identify and fight different threats from both external pathogens as well as internal abnormalities. The way innate and adaptive immunity work together shows how complicated and effective our body's protection against infections is, creating a defence with many layers.

The quick action of innate-like T cells and the precise targeting from B cell-made antibodies work together to protect our health. Adaptive immunity has amazing memory and precision, so after the body meets a specific danger once, it can defend against it better and quicker if it comes back again. This complex system highlights how the body can change and improve its defences, demonstrating the wonders of immune strength and helping our health in general.

After knowing its causes and characteristics, including immune memory and antigen recognition, the possibility of developing targeted and personalised approaches to fight infectious diseases, autoimmune disorders, plus other cancers becomes increasingly promising through adaptive immunity.

FAQs

1. What is the adaptive immunity system?

The adaptive immune system is a complex and highly specialised defence mechanism in vertebrates. It is responsible for recognising and mounting targeted responses against specific pathogens, utilising immune cells such as T and B lymphocytes. Unlike the innate immune system, adaptive immunity exhibits memory, enabling the body to remember and respond more effectively to previously encountered threats.

2. What are the 4 characteristics of adaptive immunity?

Adaptive immunity is characterised by specificity, diversity, memory, and self/non-self recognition. Specificity refers to the ability to recognise and target specific pathogens. Diversity involves a wide range of responses to different antigens. Memory allows the immune system to "remember" and respond more rapidly to previously encountered threats. Self/non-self recognition ensures that the immune response targets only foreign substances while sparing the body's cells.

3. What is the difference between innate and adaptive immunity?

Innate immunity is the immediate, nonspecific defence mechanism that provides the first line of protection against pathogens. It includes physical barriers, chemical defences, and various cells, such as phagocytes. On the other hand, adaptive immunity is a highly specific and targeted response that develops more slowly but provides long-term protection. It involves the activation of T and B lymphocytes and the creation of memory cells.

4. What is passive and adaptive immunity?

Passive immunity is a temporary form of immunity acquired through the transfer of pre-formed antibodies or immune cells from one individual to another through maternal antibodies passed to an infant or artificially through medical interventions like antibody injections. On the other hand, adaptive immunity is the body's active immune response, involving the production of antibodies and memory cells following exposure to a pathogen or through vaccination.

5. Are there any adaptive immunity disorders?

Yes, some disorders can affect adaptive immunity. Examples include immunodeficiency disorders, where the immune system is compromised and cannot effectively respond against pathogens. Autoimmune diseases, conversely, result from the immune system mistakenly attacking the body's cells. Understanding and addressing these disorders is crucial for developing effective medical interventions and therapies to restore or modulate adaptive immune function.

References

• 20.3B: Types of Adaptive Immunity - Medicine LibreTexts

• The innate and adaptive immune systems - InformedHealth.org - NCBI Bookshelf

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