What is immunity and it’s types and importance of immunity for human being

IMMUNITY :-

Terminology :

1. Allergy : allergy is an appropriate or the exaggerated reactions of the immune system can only occur on subsequent exposure.

2. Antibody :- A blood protein produced in response to counteracting a specific antigen.

3. Antigen :- An antigen is a substance which when introduced parentrally into the tissues, stimulates the production of an antibody or immune cell and which can combine specifically.

4. Active immunity :- the immunity that results from the production of antibodies in response to an antigen.

5. Auto immunity :- production of antibodies against the tissues of its own body produces auto immune disease or hypersensitivity reactions.

6. Antisera :- A blood serum containing antibodies against specific antigens, injected to treat a protect against specific diseases.

7. Auto immune disease :- A condition in which the body develops an immunological reaction against its own tissues.

8. Hypersensitivity :- some form of immune reaction instead of providing examptions or safety to affected individual can produce severe and sometimes fatal results.

9. Immunization :- the fact or process of becoming immune , as against a disease .

10. Immunoglobulins :- any class of proteins present in the serum and cells of the immune system, that function as antibodies.

11. Immunity :- It is a resistance offered by an individual to infection by microorganisms or injury by their products is called immunity .

12. Passive immunity :- The short – term immunity that results from the introduction of antibodies from another person to animals.

13. Toxoid :- A toxin that has been treated to destroy its toxic properties without affecting its antigenic properties.

14. Vaccine :- Vaccine is an immune – biological substance designed to produce specific protection against a given disease.

IMMUNITY :-

Introduction :-

The term “ immunity is defined as resistance exhibited by the host against any foreign antigen including microorganisms. This resistance plays a major role in prevention of infectious diseases.

Evolutionary immunology also looks at different cell types of the system and the historical development of the ability to recognize foreign antigenic material.

Meaning :-

Immunity derived from the latin word “ immunitias” that means freedom from disease.

Definition :

Immunity is defined as the resistance of the body towards the harmful effects caused by the pathogenic organisms and other toxic factors.

The term “ immunity “ is defined as the resistance of the body towards the harmful effects caused by the pathogenic organisms and other toxic factors.

Immunity is broadly classified into two types .

1. Innate immunity or Natural immunity .

2. Acquired immunity or Adaptive immunity .

Natural Immunity Or Innate Immunity :-

Innate immunity is also known as Natural immunity .

Resistance developed in an individual naturally at birth due to their genetic makeup , is known as Natural Immunity.

Natural immunity that transferred from one generation to other generation.

It is the resistance which individual possesses by birth. It is not formed due to prior contact with microorganism and its products.

It acts immediately against the microbial.

It does not have a memory component.

Cells of innate immunity are non specific.

1. Species immunity :

Individual of certain species are either susceptible to particular infections or resistant to some infections.

E.g. Chicken pox is usually affecting human being but not affect chickens. Salmonella typhi is also affecting human being while mice are resistant.

2. Racial immunity :-

Different races of certain species show differences in susceptibility to infection. E.g. Negroes are susceptible to tuberculosis but white are not susceptible.

3. Individual immunity :

Resistance is individually varying within the same species.

E.g . Homozygus twins exhibit similar degree of resistance or susceptible to lepromatous leprosy.

Factor

Following are the factors which influence individual immunity:

Age , Hormone and Nutrition.

1. Age :-

Resistance ability is naturally lowered in baby as well as old age people.

2. Hormonal influence :-

Increased glucose level in blood due to diabetes, is also influencing the resistance of individual.

3. Nutrition :

When the individual fails to receive nutritious food appropriately , this may depresses all types of immune response.

Mechanism of innate immunity

There are two types of mechanism. They are surface mechanism, and systemic mechanism.

Surface mechanism :

These include Physical barrier, Chemical barrier and Biological barrier.

Physical Barrier

It encompasses skin,skin secretion,mucus and mucous secretions.

1. Epithelial surfaces :

v Skin :

Skin is usually made up of thick keratinous layer.

It seems to be a protective barrier, (Mechanical) since it is not allowing the microbes to be entered inside.

The removal of microbes from the surface of skin is due to the continuous shedding of epithelial cells.

v Skin secretion :

Sweat and sebaceous secretions are the common the common skin secretions.

v Sweat :

Sweat is secreted by a small tubular like gland called sweat gland which has high concentration of salt, saturated fatty acid, unsaturated fatty acid and lactic acid.

These effectively act upon pathogenic microbes, there by diminishing their growth and multiplication. It is otherwise called as sudoriferous gland.

v Sebum :

Sebaceous glands are secreting the fluid called sebum; usually these glands are microscopic exocrine glands of skin.

Moreover sebum has been the waxy matter from a protective film over the surface of the skin, sebum contains high lipid content, which may be dissociated by the enzyme of gram positive organisms into unsaturated fatty acids, such as oleic acid, which has strong potential action on microbes in skin.

v Mucus :

Viscid fluid substance secreted by mucus membrane and some glands called mucus, which contain mucin, epithelial cells, leukocytes, inorganic salt and water (eg) ropy secretion of sublingual and submandibular glands.

As the mucus membrane of respiratory system, digestive system and genito urinary system is composed of mucus secretions and stratified squamous epithelial cells, microorganism can not easily penetrate into body . thus the mucus membrane acts as a physical protective barrier. .

Acquired immunity :

This immunity is specific for a particular disease in which and individual acquires during the course of her/his life. As it specific for disease, it is known as specific immunity.

It is of two types:

1. Active immunity

2. Passive immunity

1. Active immunity :

It is a resistance developed by an individual in response to the microbes or their products (Antigenic stimulus).

The entry of antigen result in activation of immune competent cells production antibodies or activated T cells.

Active immunity require a considerable time for its development but once developed , persists for long duration may last for year.

The active immunity is of 2 types .

1. Natural Acquired Active Immunity

2. Artificial Acquired Active Immunity

Natural Acquired Active Immunity : immunity which an individual develop as a result of natural contact with microbes.

Following infections the patient in must cases, will be immune to further infection.

e.g: Influenza, common cold, small pox.

Artificial Acquired Inactive Immunity :

Immunity which an individual acquires as a result of artificial inoculation of microbes i.e. immunization with microbes or their products.

For immunization , various immunizing agents such as vaccines or microbial products obtained from micro organisms . e.g Toxins.

Passive immunity :-

Passive immunity is of 2 types .

1. Naturally acquired passive immunity

2. Artificial acquired passive immunity.

Naturally acquired passive immunity :

In newborn babies, normally there is no acquired active immunity because of immature immune system but they are resistant to a number of infections such as measles, chickenpox, diphtheria.

This resistance is due to transfer of ready made antibodies from mother to foetus.

Artificially acquired immunity :

Passive immunity can be acquired artificially by injecting antibodies produce in some other human animal.

This immunity lasts for short duration Eg: the half-life diphtheria antitoxim in several days.