Immunity and its types

1. IMMUNITY
-THE SIGN OF SECURITY-
Dr. N. Yogananth
Dept of Biotechnology
Mohamed Sathak College of Arts and Science
Chennai - 119

2. IMMUNOLOGY
Study about the immune system, it is called Immunology
Immune system is a system of biological structures and
processes within an organism that protects against disease
To function properly, an immune system must detect a wide
variety of agents, from viruses to parasitic worms, and
distinguish them from the organism's own healthy tissue.
Edward Jenner, is often called "the father of
immunology“. He was discovered the smallpox vaccination in
1978.

3. IMMUNITY
3
The term immunity refers to the body’s specific
protective response to an invading foreign agent or
organism
The human body has the ability to resist almost
all types of organisms or toxins that tend to
damage the tissues and organs. This is known as
immunity.
It is a Latin term “IMMUNIS” means EXEMPT,
referring to protection against foreign agents.

4. 4

5. Innate immunity
• It is comes because of genetic and
constitutional make up.
• It has no relation ship with previous
bacterial infection and immunisation. So
it is called non-specific immunity
• It acts as first line of diffence against
infections, micro organisms, their products
before they cause disease.

6. • The various non specific diffence mechanisms
are present.
1.Physical and mechanical factors.
2.Biochemical factors
3.Cellular factors
4.genetic factors.
5.Other factors.

7. Physical and mechanical factors
 The barriers prevent the entry of pathogens to resist infection.
 Ex; skin, mucous membrane, coughing and sneezing, etc.
 Skin has the out layer of Stratum corneum, which is
impermeable to the infectious agents .
 The mucus traps the microorgnisms because of its sticky nature.
 Cilia, present in respiratory passage, it trap the M.Os. Hairs in
the nose acts as a coarse filter.
 The coughing and sneezing helps to driving out the foreign
particles that enter the digestive and respiratory tracts
 The peristaltic movement of the intestine pushed away the m.os
 The lacrimal secretions (tears) of eyes flushing the Mos.
 One way flow of urine from the bladder during micturation.

8. Biochemical factors
8
• Secrition of the skin: Sebaceous and sweat glands act as
antiseptics activity
• Human milk: this is very rich in anti bacterial substances.
Ex:IgA, lacto feritin, neuraminic acid etc. they fight against
E.coli and Staphylococci.
• Secrition of the digestiv tract: stomach play a microbicidal effect
because the presence of Hcl in the gastric juice.
• Nasal secretion and saliva: These secretions contain
mucopolysaccharides which inactive certain viruses
• Lysozymes: The tears, nasal, saliva, WBC cells, human milk contain
this enzyme. It possess the bactericidal property
• Interferans: It is a natural antiviral agent which is present all type of
cells
• Compliment: It found in the serum. The role is the opsonize the mos
• Normal flora: the baceriocins, colicin etc.., are produced by flora
lived in our skin and guts. They possess antimicrobicidal property

9. Cellular factors
•Phagocytosis: The process of cell eating or swallowing is called
phagocytosis.
•The PMN and MNP (mononuclear phagocytic system) are
involved in this process.
Phagocytic action are divided into 4 stages:
i) Chemotaxis:
Phagocytes reach the site of infection attracted by chemotactic substances
ii) Attachment:
Infective agent gets attached to phagocytic membrane
iii) Ingestion:
Phagoctes engulf the infective material into vacule
Membrane of phagosome fuses with lysosomes to form a phagolysosome.
iv) Intracellular killing:
Most bacteria are destroyed by phagolysosomes by hydrocytic enzymes of lysosomes
NK cells: It is a large granular lymphocytes which has natural
cytotoxicity property can kill the range of tumor cells

10. Genetic factors
Species immunity:
If one species is resistant to certain infection and the other species is
susceptible to the same infection then it is called as species immunity.
 EX: Human beings are highly susceptible for the common cold
whereas dogs are not susceptible for the virus causing cold
• Racial immunity:
•Racial differences are known to be genetic in origin.
•EX: Genetic resistance to Plasmodium falciparum seen in some parts
of Africa and Mediterranean coast but not Asian countries
•Individual immunity:
The difference in innate immunity exhibited by different individuals
in a race.
 The genetic basis of individual immunity is seen in twins.
EX: Homozygous twins exhibit similar degrees of resistance or
susceptibility to leprosy and Tuberculosis, whereas heterozygous
twins do not shows such condition

11. Other factors
Temperature:
 Temp is also important in determining the innate immunity
 For example Gonococci are readily to killed at temp over 400C and fever
therapy was originally used for gonococcal infectio
Inflammation:
• Inflammation occurs as a result of tissue injury or irritation, initiated by
entry of pathogens or other irritants.
• It’s a nonspecific defence mechanism.
• Inflammtion leads to vasodilatation, increased vascular permeability and
cellular infiltration.
• Microorganisms are phagocytosed and destroyed due to increased
vascular permeability, which helps to dilute the toxic products present.
Fever:
 Rise of temperature fallowing infection is a natural defence mechanism. It
destroyes the infecting organisms.
 Fewer also stimulates the production of interferon which helps in
recovery from viral infection

12. Acquired immunity
• The acquiring of immunity from out side source is known as
acquired immunity.
• It is result of action of 2 major groups of ells.
1.lymphocytes
2.antigen presenting cells
This immunity is initiated by the recognition of a foreign antigen
and the response to this recognition.
It is highly adaptive and has 4 important features.
1.antibody specificity-
2.diversity.
3.immunological memory.
4.recognition self from non-self.

13. Active immunity
• It is the production of immunity against particular organisms
after exposure.
Functioning immune system
–
B lymphocytes and T lymphocytes
Antibody production
Production of immunologically active cells
Kill or suppress the antigen
Resistance developed by individual as a result of antigenic stimulus
Once developed, it is long-lasting, second immune response is rapid.
Immunological memory is present

14. • Natural active immunity:
This immunity develops by natural processes like
infections.
Ex: the infection like measles or small pox are cured by the
active function of the immune system.
• Artificial active immunity:
Immunity is attained by the host in response to the antigen
got by vaccination.
Vaccines are preparations of live (attenuated) or killed
microrganisms or their products .
Ex: polio vaccine, cholera vaccine etc.

15. Passive immunity
•In Passive immunity the individual is given antibodies produced by
someone else
•Acquiring of the antibodies passively from an immunized donor to a
non-immunized recipient is known as passive immunity.
• No active role from host’ immune system. No need antigenic
stimulus. Preformed antibodies are administered.
• No latent period. Immediately after administration, renders
active protection.
• Immunity is transient, lasting days to weeks, only till the
passively transmitted antibodies are metabolised and eliminated.
• Factor of Immune elimination limits the usefulness of repeated
passive immunisation.
• Less effective, acts immediately so it provides ‘instant immunity’.

16. Natural passive immunity: The immunity transferred from the
mother to child passively is known as NPI.
Ex: Transfer of anti bodies from the mother to the feotus
through the placenta (IgG Antibodies)
Artificial passive immunity: the transfer anti bodies and
sensitised lymphocytes from immunized donar to the non-
immunized recipient artificially.
API is therapeutically used in the treatment of tetanus,
diphtheria, gas gangrene, snake bite
Ex:antibodies produce in the horse serum and
GMOS(genitically modified organisms).

17. THANK YOU