Innate and Adaptive Immunity Mechanisms

Organisms should protect themselves constantly from harm that is caused by pathogens. For example, viruses and bacteria. Our immune system provides this protection through numerous pathways. The response of the immune system is broken down into two types of immunity. One is the innate immunity that an organism is born with. On the other hand, adaptive immunity found in vertebrates consists of specialised cells and processes that act as a shield against pathogens. 

On the other hand, adaptive immunity is something that an organism acquires after being exposed to a disease.

Innate Immunity Mechanism

The innate immune mechanisms contain some physical barriers as well as cellular and chemical defences. Our body is protected from invasion with the help of physical barriers. It includes various body parts like our skin and eyelashes, etc. Then there are chemical barriers that work as a defence mechanism and have the ability to destroy the harmful agent. It includes mucus, stomach acid, and tears.

The other defence mechanism of the innate immune response is nonspecific like the cellular defence. They are capable of identifying the substances and pathogens that are quite dangerous and work to destroy them or at least neutralise them.

There are other ways also to categorise the innate response components that are by external defences. For example, skin and tears and on the other hand, internal defences, for instance, stomach acid as well as cellular defences. External defences offer defence against pathogens and internal defences provide the second line of defence mechanism.

Adaptive Immunity Mechanism

Adaptive immunity can be defined as an organism’s acquired immunity and that too to a particular pathogen. As such, it’s also known as acquired immunity. Adaptive immunity as such is not immediate. Also, it does not always last throughout the entire lifespan of an organism. Although it may last.

The adaptive immune mechanism is known by clonal expansion of T and B lymphocytes, which releases many antibody copies so that it can neutralise as well as destroy their targeted antigen. The first time a novel disease agent encounters the body, its response is called the primary immune response. When B lymphocytes, which are known as B cells, encounter an antigen, its response is the creation of antibodies that are specific to the antigen which is designed to neutralise or destroy it.

Similarly, B cells also create memory cells. These are B cell types that survive for decades and during subsequent exposure can detect pathogens.

It takes time for the body to create antibodies that are antigen-specific the first time, and thus, this mechanism takes a bit longer than the subsequent responses. If the same pathogen is encountered by an organism the second time, the response of the immune system will be faster and even more robust as compared to the primary immune response. This increased speed is due to the memory cells.

Types of Adaptive Immunity

The above discussion of adaptive immunity explains active immunity. This means it is the immunity that occurs after the exposure of the pathogen. Another adaptive immunity is passive. Passive immunity is when an organism receives some external antibodies that can protect against the disease. This protection may occur from the mother to the baby via the placenta or through breast milk, or even by injection that is given to defend against a particular disease.

Innate vs Adaptive Immunity 

Now, let us understand the primary difference between innate and adaptive immunity. Innate immune response takes immediate effect and is non-specific. Their defence mechanism is internal as well as external. Its efficacy length is lifelong. On the other hand, Adaptive immune response takes effect over time. It is specific and is known as active and passive immunity. Its length of efficacy is all short-term as well as long-term as well as life-long.

The role of immunological memory

Immunological memory may be defined as the immune system’s ability to respond more effectively and rapidly to a previously encountered pathogen. Because of the memory cells, the body can recognize the disease agents that have come into the body’s contact previously.

It is because of the immunological memory that our body can be vaccinated against infectious diseases. Once our body creates the required antibodies to quell a pathogen, it can do so quickly when the pathogen is encountered again in the future. This is especially true when you get infected with a disease or get inoculated with a dead form of the disease through a vaccine.

Comparison of Innate and Adaptive Immunity 

Let us now compare and contrast innate and adaptive immunity. Innate immunity can be said to be the first immunological as well as the non-specific mechanism that assists in fighting against infections. This immune response mechanism is rapid, occurs hours after aggression, and is mediated by various cells that include basophils, phagocytes, mast cells, and eosinophils, along with the complement system.

Adaptive immunity on the other hand develops by innate immunity that eliminates infectious agents. It relies on the heavily regulated interplay between T cells, B cells, and APCs.

Conclusion

A very critical feature of innate and adaptive immunity mechanisms is the immunologic memory or even the system’s ability to learn as well as record its experiences with a variety of pathogens, which leads to rapid and effective immune responses on subsequent exposure to similar as well the same pathogens.