Types Of Immunity!
WHAT IS IMMUNITY?
The immune system is a collection of biological processes that take place within an organism, which first identifies pathogens and tumor cells and then kills them to protect them from the disease. It is able to identify a wide variety of agents ranging from viruses to parasitic worms, as well as distinguishing these agents from the healthy cells and tissues of the organism so that it does not react against them and the whole system runs smoothly. Work with immunity.
Two type of immunity:-
Innate immunity is the inborn capacity of the body to resist pathogens. By chance, if the organisms enter the body, innate immunity eliminates them before the development of any disease. It is otherwise called the natural or non-specific immunity. This type of immunity represents the first line of defense against any type of pathogen.
Cells involved in innate immunity:-
NK cell is a large granule that kills the tumor cells that form in the body.
This is why some people have had time to smoke but they have not got cancer. It is part of the innate immunity.
The monocyte enters the tissue and is converted into macrophages.
Macrophages are 5-10 times larger than monocytes, with increased levels of hydrolytic enzymes and cytokines, which increase their phagocytic capacity.
Macrophages perform a variety of functions in different tissues.
Macrophages are known by different names in different tissues, which are:-
- Intestinal macrophage in the gut.
- Alveolar macrophage in the lung.
- Histiocytes in connective tissue.
- Kufffer cells in the liver.
- Mesangial cells in the kidney.
- Microglial cells in the brain.
- Osteoclasts in the bone.
Neutrophils have a diameter of 11-14μm. It has a nucleus divided into many polyps (Multiple nuclei).
Therefore, these polymorphic nuclei are called PMNL-Polymorphic Nuclear Leucocyte.
Particles are found in their biomass so they are granular cells.
This is 50-70% of the total WBC. It stays in the blood for 7-8 hours. And then travels to the tissues.
Their life span is 3 – 4 days.
Neutrophils are called neutrophils because they are stained by both acidic and alkaline dyes. (Neutro – Indifferent)
It is the phagocytic cell that is the first immune cell to respond to inflammation.
Eosinophils are 11-15μm in diameter. They have a bilobed nucleus.
These are also granular cells like neutrophils. It is called eosinophil because it is stained by the acid staining eosin (Phill – affection).
This cell is phagocytic.
Granules of eosinophils contain a variety of hydrolytic enzymes, which kill parasites that are too large to be eaten by neutrophils.
Basophils are a small number of granular cells found in the blood and tissues. But it is not a food particle-like eosinophils and neutrophils.
The cytoplasm contains large amounts of major basophilic granules.
Containing histamine, heparin, serotonin, and other hydrolytic enzymes.
Histamine, heparin, serotonin are responsible for allergies.
These are called basophils because they are stained by the alkaline staining methylene blue. (Base-base)
Acquired immunity is the resistance demented in the body against any specific foreign body like bacteria, viruses, toxins, vaccines. It is the most powerful immune mechanism that protects the body from invading organisms or toxic substances.
Two Types Of Acquired Immunity:-
Active immunity is acquired by activating the immune system of the body. The body develops resistance against disease by producing antibodies following the exposure antigens.
Active immunity is acquired either naturally or artificially:-
Active Natural Immunity:-
Naturally acquired active immunity involves the action of the immune system in the body to produce antibodies.
Active Artificial Immunity:-
Active artificial immunity is a type of immunization achieved by the administration of vaccines or toxoids.
passive immunity is produced without challenging the immune system of the body. It is done by the administration of serum or gamma globulins from a person who is already immunized to a non-immune person.
passive immunity is acquired either naturally or artificially:-
Passive Natural Immunity:-
Passive natural immunity is acquired from the mother before and after birth. Before birth, immunity is transferred from the mother to the fetus in the form of maternal antibodies through the placenta. After birth, the antibodies are through the milk.
passive Artificial Immunity:-
Passive artificial immunity is developed by injecting previously prepared antibodies using serum from humans or animals. Antibodies are obtained from the person affected by the disease or from animals, particularly horses which have been immunized artificially. The serum containing the antibody is administered to people who have developed the disease it is also used as a prophylactic measure. Prophylaxis refers to medical or public health procedures to prevent diseases in people who may be exposed to the disease in a later period.
Some type of cell in Immunity:-
Mainly two types of sell highly role played in immunity:-
It literally means ” cell eating”. It is a common method of feeding among the protozoa and lower metazoa.
It is also the way in which white blood cells engulf cellular debris and uninvited microbes in the blood. Like WBCs, there are other phagocytes, such as the macrophages found in connective tissue and liver sinusoids.
In the phagocytes, an area of the plasma membrane coated initially with Antin-myosin form a pocket that engulfs the solid material. The membrane-enclosed vesicle, phagosome, then detaches from the cell surface into the cytoplasm when are digested by lysosomal enzymes.
All lymphocytes are released into circulation and are differentiated into two categories.
Type of Lymphocytes:-
- T-lymphocyte or T cells, which are responsible for the development of cellular immunity.
- B-lymphocyte or B cells, which are responsible for humoral immunity.
Lymphocyte that enters thymus from circulation is processed into T-lymphocytes.
The processing occurs mostly during the period between just before birth and a few months after birth.
Thymus secretes a hormone called thymosin, which plays an important role in immunity. It accelerates the proliferation and activation of lymphocytes in thymus. It also increases the activity of lymphocytes in lymphoid tissues.
The B-lymphocytes were first discovered in the bursa of Fabricius in the bird, hence the name B-lymphocytes. Bursa of Fabricius is a lymphoid organ situated near the cloaca of birds. Bursa is absent in mammals and the processing of B-lymphocytes takes place in liver and bone marrow.