A basic understanding of Immunity

1. Nutritional Immunology
-Immunity
ROSHINA RABAIL
LECTURER, GOVERNMENT COLLEGE WOMEN UNIVERSITY, FAISALABAD, PAKIS TAN.
M.PHIL HUMAN NUTRITION AND DIETETICS
FORMER DIETITIAN CMH OKARA CANTT. & SHIFA INT. HOSPITAL ISLAMABAD
9/8/2020 ROSHINA RABAIL 1

2. IMMUNITY
The term immunity is derived from the latin word immunitae, which referred to
the protection from the legal prosecution offered to roman senators during their
tenure in office.
Refers to the resistance exhibited by the host towards injury caused by
microorganisms and their products.
Protection against infectious diseases
Distinguishes self from non-self
Eliminate potentially destructive foreign substances from body
9/8/2020 ROSHINA RABAIL 2

3. Immunity: Natural and Acquired
Long ago, physicians realized that people who had
recovered from the plague would never get it again—they
had acquired immunity.
This is because some of the activated T and B cells
become memory cells.
 next time an individual meets up with the same antigen,
the immune system is set to demolish it.
Immunity can be strong or weak, short-lived or long-
lasting, depending on the type of antigen, the amount of
antigen, and the route by which it enters the body.
9/8/2020 ROSHINA RABAIL 3

4. Immunity can also be influenced by inherited genes. When faced with the same antigen, some
individuals will respond forcefully, others feebly, and some not at all.
An immune response can be sparked not only by infection but also by immunization with
vaccines. Vaccines contain microorganisms—or parts of microorganisms—that have been
treated so they can provoke an immune response but not full-blown disease.
Immunity can also be transferred from one individual to another by injections of serum rich in
antibodies against a particular microbe (antiserum).
For example, immune serum is sometimes given to protect travelers to countries where
hepatitis a is widespread. Such passive immunity typically lasts only a few weeks or months.
Infants are born with weak immune responses but are protected for the first few months of life
by antibodies received from their mothers before birth. Babies who are nursed can also receive
some antibodies from breast milk that help to protect their digestive tracts.
Immunity: Natural and Acquired
9/8/2020 ROSHINA RABAIL 4

5. IMMUNITY
INNATE
Non
specific
Species Racial
Individual
Specific
ACQUIRED
Active
Artificial
Natural
Passive
9/8/2020 ROSHINA RABAIL 5

6. INNATE IMMUNITY ACQUIRED IMMUNITY
Resistance to infection which individual
possesses by virtue of his genetic and
constitutional make up
Early defense response against microbes
Immune response Non specific
Innate response do not alter on repeated
exposure
Memory effect absent
Not affected by immunisation or prior
contact
The resistance that an individual acquires
during life
Later defense response
Immune response is highly specific
Adaptive response improves with each
successive encounter with same
pathogen
Memory effect present
Is improved by immunisation
9/8/2020 ROSHINA RABAIL 6

7. 9/8/2020 ROSHINA RABAIL 7

8. INNATE IMMUNITY
It consists of cellular and biochemical defense mechanisms that are in place even
before infections and poised to respond rapidly to infections. These mechanisms react
only to microbes and not to non-infectious substances
Innate
Immunity
Species Racial Individual
9/8/2020 ROSHINA RABAIL 8

9. Species immunity
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.
Refers to the total or relative refractoriness to a pathogen, shown by all members of
species.
 Person obtains by virtue of being a part of the human species.
 Determines whether or not a pathogen can multiply in them.
For e.g.
 All human beings are totally unsusceptible to plant pathogens and to, many animal
pathogens, such as render pest or distemper.
Pasteur’s experiments on anthrax in frogs, which are naturally resistant to the disease
but become susceptible when their body temperature is raised from 25° to 35°C.
9/8/2020 ROSHINA RABAIL 9

10. Racial immunity
Racial immunity - natural immunity shared by all members of a
particular race. innate immunity, natural immunity - immunity to disease
that occurs as part of an individual's natural biologic makeup.
Racial differences are known to be genetic in origin
For e.g.
 People of Negroid origin in USA are more susceptible than the Caucasians to
tuberculosis.
 Genetic resistance to Plasmodium falciparum Malaria seen in some parts of
Africa and Mediterranean coast. A hereditary abnormality of red cells (sickling)
prevalent in the area, confer immunity to infections by malarial parasite.
9/8/2020 ROSHINA RABAIL 10

11. Individual immunity
 The difference in innate immunity exhibited by different
individuals in a race
 The genetic basis of individual immunity is seen in twins.
For e.g.
Homozygous twins exhibit similar degrees of resistance or
susceptibility to Lepromatous leprosy and Tuberculosis.
9/8/2020 ROSHINA RABAIL 11

12. Determinants of innate immunity
I. Species and strains
II. Age
III. Hormonal Influences
IV. Nutrition
9/8/2020 ROSHINA RABAIL 12

13. MECHANISMS OF INNATE IMMUNITY
I. Epithelial surfaces
Skin
Mucosa of the respiratory tract
Human eye.
Flushing action of urine
II. Antibacterial substances in Blood
and tissues
III. Inflammation
IV. Fever
V. Cellular factors
9/8/2020 ROSHINA RABAIL 13

14. 9/8/2020 ROSHINA RABAIL 14

15. ACQUIRED/ADAPTIVE IMMUNITY
• A person is said to be immune when he possesses specific protective
antibodies or cellular immunity as a result of previous infection or
immunization or is so conditioned by such previous experience as to respond
adequately to prevent infection.
• Because this form of immunity develops as a response to infection and is
adaptive to the infection, it is called adaptive immunity.
• The characteristics of adaptive immunity are
 Specificity for distinct molecules.
 An ability to remember and respond more vigorously to repeated exposure to the same
microbe.
Hence it is also called as specific immunity.
ROSHINA RABAIL 15

16. ROSHINA RABAIL 16

17. ACTIVE IMMUNITY PASSIVE IMMUNITY
1. Produced actively by host’s immune
system
Received passively by the host
2. Induced by infection or by contact
with immunogens (vaccines,
allergens etc).
No participation by the host’s immune
system
3. Affords desirable and effective
protection
Conferred by introduction of
readymade antibodies
4. Immunity effective only after a lag
period (time required for generation
of antibodies).
Protection transient and less effective
Immunity effective immediately
5. Immunological memory present;
subsequent challenge more
effective (booster effect)
No immunological memory
subsequent administration of
antibodies less effective due to
immune elimination
6. Negative phase may occur No negative phase
7. Not applicable in immunodeficient
hosts
Applicable in immunodeficient hosts
ROSHINA RABAIL 17

18. Natural Active immunity
 This results from either a clinical or
in apparent infection.
 Immunity following chicken pox and
measles infection is usually life long
Artificial Active Immunity
This is the resistance induced by
vaccines.
Vaccines are preparations of live or
killed microorganisms or their products
used for immunization.
ACQUIRED/ADAPTIVE IMMUNITY
ROSHINA RABAIL 18

19. Types of Vaccine
 Bacterial vaccines:
◦ Live (BCG vaccine for
T.B.).
◦ Killed (Cholera
vaccine).
◦ Subunit (Typhoid Vi
antigen).
◦ Bacterial products
(Tetanus Toxoid).
 Combinations
If more than one kind of
immunizing agent is included
in the vaccine, it is called a
mixed or combined vaccine.
• DPT (Diphtheria – pertussis
- tetanus)
• MMR (Measles, mumps and
rubella).
• DPTP (DPT plus inactivated
polio).
 Viral Vaccine:
◦ Live (Oral polio vaccine
– Sabin).
◦ Killed (Injectable polio
vaccine – Salk).
◦ Subunit (Hepatitis B-
vaccine).
Immunizing agents that are used for immunoprophylaxis
ROSHINA RABAIL 19

20. Natural Passive immunity
This is the resistance passively transferred from the mother to the baby. In
human infants, maternal antibodies are transmitted predominantly through the
placenta.
Human colustrum, which is also rich in IgA antibodies and resistant to intestinal
digestion.
Synthesis of antibodies (IgM) occurs at 20th week of IUL but its immunogenic
capacity is still inadequate at birth. It is only by about the age of three month
that the infants acquire a satisfactory level of immunological independence.
ROSHINA RABAIL 20

21. Artificial passive immunity
This is the resistance passively transferred to a recipient by administration of
antibodies.
Passive immunization is indicated for immediate and temporary protection in a
non-immune host
Employed for the suppression of active immunity, when the latter may be
injurious.
Used as treatment of some infections.
Hyper immune sera of animal or human origin, convalescent sera and pooled
human gamma globulins are used for prophylaxis and therapy.
Rh immune globulin is used during delivery to prevent immune response to the
Rhesus factor in Rh-negative women with Rh-positive babies.
ROSHINA RABAIL 21