What is Immunity? Explain the types of Immunity? (Presentation) www.BiochemDen.in

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IMMUNOLOGY
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Satish Kumar.I
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Immunology means,
“Immunology is the science that
studies the structure and functioning of
the Immune system”.
Basically , IMMUNOLOGY is
the study of the Immune
response.
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Strategies of Resistance:
1. Immediate destruction of parasites on
surface layers by secretions of some
chemicals. (E.g.: Enzymes, Lysozymes,
acids, etc.)
2. Long term immune responses, which
represents our actual immune system.
3. Immediate immune response, collectively
referred as phagocytosis, Inflammatory
reactions.
Satish Kumar.I
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The term IMMUNITY,
It is Latin word, “immunis” that means
“free of burdens”
Originally denoted freedom from some kind
of service to the Roman state; now in
medical terms, it denotes
“freedom from disease”
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Immunity shows TWO related activities
Recognition
&
Response
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Types of Immunity
IMMUNITY
Innate Immunity Acquired Immunity
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1.Innate Immunity:
These are also referred as
“Non-specific immunity”
 This type of immunity shown any “non-self” material.
 These are the first line defense against infection.
 This Innate immunity can be divided into TWO types,
External Innate immunity (First line defense)
Internal Innate immunity (Second line defense)
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External Innate Immunity
The external defense comprises physical and
chemical barriers to the entry of pathogens into the body.
Physical barriers
Skin, is the largest water
proof (9.7m2) and germ proof
self-disinfecting, defense
organ
Mucous membranes, Mucus
secreted by mucus gland traps
the pathogens and immobilizes
them.
Mucus is clear, sticky mixture of
mucin (glycoprotein) and water.
It is present in all intestinal tract.
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Chemical barriers
1. Oily and sweat secreted by integument make the skin
acidic.
2. Saliva of buccal cavity contains LYSOZYME which
kill the microorganism.
3. GUT secretions like HCl provides acidic medium
which inhibits the growth of microbes.
4. Bile offers alkaline medium which check the growth
of microorganism in intestine.
5. The lacrymal glands secrete tears containing lysozyme
which prevent eye infections.
6. Cereminous glands of auditory canal secrete cerumen
(ear wax) which traps the dust and bacteria.
7. Vaginal bacteria produce lactic acid from the glycogen
thereby producing acidic environment to vagina as
female’s best natural defense against pathogens.
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Internal Innate Immunity
Body’s internal defense involve the participation of cellular
and non-cellular factors possessing antibacterial
property which have been found in blood and tissues.
It is a
“Second line defense”
These factors can be discussed under following heads.
1. Biochemical factors
2. Cellular factors
3. Other factors
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1.Biochemical factors:
The major biochemical factors are
Interferon
Complement system
Cellular factors
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a) Interferon:
These are group of soluble, non toxic
glycoproteins produced in small amount
by all the cells of the body.
A special defense system works specially
against viral infection they offers resistance
by blocking viral mRNA transcription
thereby disrupting the viral life cycle.
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b) Complement system
Complement system comprises set of 11 proteins found in the serum.
A series of 11 proteins that are activated by antigen-antibody
complexes.
Activation of the complement increases the phagocytosis and
destruction of the microbial organisms that enter the body of an
individual.
The system perform function in different ways-
1. Complement proteins ruptures the cell membranes of
microbes.
2. Stimulates mast cells to produce histamine
3. Strengthens the inflammatory reaction
4. Act as chemokines
5. Attract the phagocytes Staoti sthh Keu minafr.eI c ted area.
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c) Cellular factors
The phagocytic cells were originally discovered by
“Metchnikoff (1883)”
The phagocytic cells are of two types-i)
Microphages
ii) Macrophages
iii) Natural killer cells
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i) Microphages
Microphages are
“Polymorphonuclear leucocytes”
These are of Three types,
Neutrophils
Basophils
Neutrophils Satish Kumar.I
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16. ii) Macrophages
Macrophages are the cells of the Mononuclear phagocytic
system was originally called as
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“Reticuloendothelial system (RES)”
A major function of RES is
“The removal of RES is the removal of
foreign material that enter the body”.
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iii) Natural Killer cells:
These are the type of Lymphocytes
The cells lyses the (burst open) the
viral infected body cells and
abnormal cells which could form
tumors
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Other factors
“Fever”
&
“Inflammatory
reactions”
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A sudden rise in body temperature (pyrexia)
Fever
following an infection is an natural defense mechanism.
Rise in temperature accelerate the physiological
process and destroys the infecting pathogens.
In Fever ,
Stimulates the production of Interferon,
Increases WBC count of blood .
Mild fever strengthens the defense mechanism by
activating phagocytes and by inhibiting growth of
bacteria
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Inflammatory reactions
This is a non-specific defense response by the body
to an injury in the tissue.
The injured area shows the following characteristic signs
of inflammation.
i) A red color from blood accumulation – RUBOR
ii) A warmth from the heat of blood –CALOR
iii) A swelling from the accumulation of fluid – TUMOR
iv) Pain from injury to the local nerves - DOLOR
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2) Acquired Immunity
“This immunity develops due to an exposure to a foreign
substance (or) organism”
It is generally classified into TWO categories
Active
Immunity
Acquired Immunity
Passive
Immunity
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Active Immunity
Natural active
immunity
Artificially active
immunity
Passive Immunity
Natural passive
immunity
Artificially passive
immunity
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Active Immunity
Active immunity is the resistance developed by an
individual in response to an antigenic stimulus.
Active immunity involves the the synthesis of specific antibodies
(humoral immunity) or production of immunologically active cells (Cell
mediated immunity)
Natural acquired active immunity
Immunity is developed by the host in response to the
antigen that enters by Natural infection.
For example, a person attacked by measles or Small pox develops
natural active immunity as he recovers from the disease.
Artificially acquired active immunity
Immunity is attained by the host in response to the
antigen got by Vaccination.
Vaccines are preparations of live (attenuated) or killed microorganisms
(or) their products (toxoids).
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Passive Immunity
The immunity that non-immune individual acquires by receiving
antibodies (or) sensitized white blood cells from another immune individual
is known as “Passive immunity”
Natural acquired passive immunity
The immunity transferred from the mother to the child passively is
known as “Natural acquired passive immunity”.
In human beings this natural passive immunity occurs mainly
by the passage of antibodies (Immunoglobulin G) from the mother to her
unborn child through the placenta during the later part of pregnancy.
Artificially acquired passive immunity
Transfer of immunity from an immunized donor to a non
immune recipient by transferring antibodies (or) immunized lymphocytes is
known as “Artificially passive immunity”.
It is used in the treatment of Tetanus, Diphtheria, Gas gangrene, Snake bite.
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THANK YOU
Satish Kumar.I
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