IMMUNITY

                            IMMUNITY

DEFINITION

Immunity is defined as the capacity of the body to resist pathogenic agents. It is the   ability of body to resist the entry of different types of foreign bodies like bacteria,  virus, toxic substances etc.

TYPES

1. INNATE IMMUNITY OR NON SPECIFIC IMMUNITY

Innate immunity is the inborn capacity of the body to resist pathogens. Innate immunity eliminates them before the development of any disease.

2. ACQUIRED IMMUNITY

Acquired immunity is the resistance developed in the body against any specific foreign body like bacteria viruses toxins vaccines or transplanted tissue.

TUPES OF ACQUIRED IMMUNITY

1. CELLULAR IMMUNITY

2. HUMORAL IMMUNITY

1. CELLULAR IMMUNITY

Cell mediated immunity is defined as the immunity developed by cell mediated  response. It is also called cellular immunity or T cell immunity. Cell mediated immunity does not involve antibodies. Cellular immunity is the major defence mechanism against infections by viruses fungi and few bacteria like tubercle bacillus.

ANTIGEN PRESENTING CELLS

Antigen presenting cells are the special type of cells in the body

3 types

1. Macrophages

2. Dendritic cells

3. B lymphocytes

1. Macrophages

Macrophages are the large phagocytic cells. Which digest the invading organism to release the antigen. The macrophages are present along with lymphocytes in almost all the lymphoid tissues.

2. Dendritic Cells

Dendritic Cells are nonphagocytic in nature. Based on the location.

3. B Lymphocytes

B Lymphocytes also act as antigen presenting cells. Thus the B cells function as both antigen presenting cells and antigen receiving cells.

2. HUMORAL IMMUNITY

Humoral immunity is defined as the immunity mediated by antibodies which are secrete the antibodies into the blood and lymph. The blood and lymph are the the body fluids. Since the B immunity is called humoral immunity or B cell immunity. Antibodies are the gamma globulins produced by B Lymphocytes.

ROLE OF ANTIGEN PRESENTING CELLS

The ingestion of foreign organisms and digestion of their antigen by the antigen presenting cells are already explained.

ROLL OF PLASMA CELLS

Plasma cells destroy the foreign organisms by producing the antibodies. Antibodies are the globulin in nature. The rate of the antibody production is very high i.e. each plasma cell produces about 2000 molecules of antibodies per second.

ROLE OF MEMORY B CELLS

Memory B cells occupy the lymphoid tissues throughout the body. The memory cells are in inactive condition until the body is exposed to the same organism for the second time.

ROLL OF HELPER T CELLS

Helper T cells are simultaneously activated by antigen. Activated helper T cells secrete 2 substances called interleukin-2 and B cell growth factor

ANTIBODIES OR IMMUNOGLOBULINS

An antibody is defined as the protein that is produced by B Lymphocytes in response to the presence of an antigen.

TYPES OF ANTIBODIES

1. IgA (Ig alpha)
2. IgD (Ig delta)
3. IgE (Ig epsilon)
4. IgG (Ig gamma)
5. IgM (Ig mu)

NATURAL KILLER CELL

Natural killer cell is a large granular cell that plays an important role in defence mechanism of the body. It is derived from bone marrow. NK cell is said to be the first line of defence in specific immunity particularly against viruses .

NK cell kills the invading organisms or the cell of the body without prior sensitization. It is not a phagocytic cell but its granules contains hydrolytic enzymes such as perforins and granzymes. These hydrolytic enzymes play an important role in the lysis of cells invading organisms.

FUNCTIONS OF NATURAL KILLER CELL

1. Destroys the viruses

2. Destroys the viral infected or damaged cells which might from tumors

3. Destroys the malignant cells and prevents development of cancerous tumors.

CYTOKINES

Cytokines are hormones like small proteins acting as intercellular messengers by binding to specific receptors of target cells.

Types of cytokines

1. Interleukins

2. Interferons

3. Tumor necrosis factors

4. Chemokines

5. Defensins

6. Cathelicidins

7. Platelet activating factor.

IMMUNIZATION

Immunization is defined as the procedure by which the body is prepared to fight against a specific disease. It is used to induce the immune resistance of the body to a specific disease.

1. PASSIVE IMMUNIZATION

Passive immunization or immunity is produced without challenging the immune system of the body. It is done by administration of serum or gamma globulins from a person who is already immunized to a non immune person.

Passive Natural Immunization

Pasive natural immunization is acquired from the mother before and after birth. Before birth immu6is transferred from mother to the fetus in the form of maternal antibodies through placenta. After birth the antibodies are

transferred through breast milk.

Passive Artificial Immunization

Passive Artificial Immunization is              developed by

injecting previously prepared antibodies using serum from humans or animals. Antibodies are obtained from the persons affected by the disease or from animals particularly horses which have been immunized artificially.

ACTIVE IMMUNIZATION

Active immunization or immunity is acquired by activating immune system of the body. Body develops resistance against dosease by producing antibodies following the exposure to antigens. Active immunity is acquired either naturally or artificially.

Active Natural Immunization

Naturally acquired active immunity involves activation of immune system in the body to produce antibodies. It is achieved in both clinical and subclinical infections.

Clinical infection

Clinical infection is defined as the invasion of the body tissues by pathogenic microorganisms which reproduce multiply and cause disease by injuring the cells secreting a toxin or antigen antibody reaction. During infection the plasma cells produce immunoglobulins to destroy the invading antigens.

Subclinic infection

Subclinic infection is defined as an infection in  which symptoms are very mild and do not alert the affected subject. The disease thus produced may not be severe to develop any manifestations.

IMMUNE DEFICIENCY DISEASES

1. Congenital immune deficiency disease

2. Acquired immune deficiency disease  (AIDS)

AUTOIMMUNE DISEASES

1. Insulin dependent diabetes mellitus

2. Myasthenia gravis

3. Hashimoto thyroiditis

4. Graves disease

5. Rheumatoid arthritis.

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Milan Tomic

Hi. I’m Designer of Blog Magic. I’m CEO/Founder of ThemeXpose. I’m Creative Art Director, Web Designer, UI/UX Designer, Interaction Designer, Industrial Designer, Web Developer, Business Enthusiast, StartUp Enthusiast, Speaker, Writer and Photographer. Inspired to make things looks better.

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