Immunity
General account of immunology:-
> Immunology is the study of the immune system and is a very important branch of the medical and biological sciences.
> The immune system protects us from infection through various lines of defence.
> If the immune system is not functioning as it should, it can result in disease, such as autoimmunity, allergy and cancer.
> The immune system consists of a complex network of cells and molecules, and their interactions.
Types of immunity:- There are two major types of immunity:
1. Innate Immunity or Natural or Non-specific Immunity
2. Acquired Immunity or Adaptive Immunity
1. Innate Immunity or Natural or Non-specific Immunity:-
> This type of immunity is present in an organism by birth.
> This is activated immediately when the pathogen attacks. Innate immunity includes certain barriers and defence mechanisms that keep foreign particles out of the body.
> Innate immunity refers to the body’s defence system.
> This immunity helps us by providing the natural resistance components including salivary enzymes, natural killer cells, intact skin and neutrophils, etc. which produce an initial response against the infections at birth prior to exposure to a pathogen or antigens.
> It is a long-term immunity in which our body produces the antibodies on its own. Our body has few natural barriers to prevent the entry of pathogens.
2. Acquired Immunity or Adaptive Immunity:-
> Acquired immunity or adaptive immunity is the immunity that our body acquires or gains over time. Unlike the innate immunity, this is not present by birth.
> The ability of the immune system to adapt itself to disease and to generate pathogen-specific immunity is termed as acquired immunity. It is also known as adaptive immunity.
> An individual acquires the immunity after the birth, hence is called as the acquired immunity.
> It is specific and mediated by antibodies or lymphocytes which make the antigen harmless.
> The main function of acquired immunity is to relieve the victim of the infectious disease and also prevent its attack in future.
> It mainly consists of an advanced lymphatic defence system which functions by recognizing the own body cells and not reacting to them.
> The immune system of our body identifies the pathogens which have encountered in the past. It is mainly caused when a person comes in contact with the pathogen or its antigen.
> Our body starts producing antibodies to engulf the pathogen and destroy its antigen.
> When it encounters for the first time, it is called a primary response. Once a body gets used to these pathogens, antibodies are ready to attack them for the second time and are known as naturally acquired immunity.