3. Definition:
• It is the ability of the body to
recognise,destroy and eliminate antigenic
material(bacteria, virus, protein etc.) which is
foreign to its own. (ref.Park)
• The ability of the body to resist almost all
types of organisms or toxins that tend to
damage the tissues and organs.
4. Historical Aspect
• Study of immunity/concept about immunity dates back to
1000 A.D.
• Its concept was first observed by Chinese. They began to
practice a form of immunization by drying and inhaling
powders derived from the crusts of small pox lesions.
• The first clinical description of immunity which arose from
a specific disease-causing organism is probably Kitab fi al-
jadari wa-al-hasbah ('A Treatise on Smallpox and Measles',
translated 1848 written by the Islamic physician Al-Razi in
the 9th century. In the treatise, Al Razi describes the clinical
presentation of smallpox and measles and goes on to
indicate that exposure to these specific agents confers
lasting immunity (although he does not use this term
5. • The first scientist who developed a full theory of
immunity was Ilya Mechnikov after he
revealed phagocytosis in 1882.
• Around the fifteenth century in India,
the Ottoman Empire, and east Africa, the practice
of inoculation (poking the skin with powdered
material derived from smallpox crusts) became
quite common. This practice was first introduced
into the west in 1721 by Lady Mary Wortley
Montagu
6. • Edward Jenner introduced the far safer
method of deliberate infection
with cowpox virus, (smallpox vaccine), which
caused a mild infection that also induced
immunity against smallpox. By 1800 the
procedure was referred to as vaccination.
7.
8. Classification/Types of immunity/Two
arms of immunity
• Innate Immunity (Non specific, natural or non
adaptive immunity)
• Acquired Immunity (Specific or adaptive
immunity)
9. INNATE
IMMUNITY
1. Here antigenic exposure
is not required
2. Not specific
3. Non Adaptive
4. Onset of response-
immediate
5. Found in both
invertebrates and
vertebrates.
ACQUIRED
IMMUNITY
1. Antigenic exposure is
required
2. Specific
3. Adaptive
4. Delayed response
5. Found only in vertebrates
10. INNATE IMMUNITY
Genetic or constitutional
• Individual immunity
• Species related
• Race related
• Age related
Physiological barrier at the portal of entry
• Skin
• Mucous membrane
13. ACTIVE IMMUNITY
Active immunity can be acquired in three ways:
• following clinical infection e.g., chickenpox,
rubella and measles.
• following subclinical or in apparent infection
e.g., polio and diphtheria
• Following immunization with an antigen which
may be a killed vaccine, a live attenuated
vaccine or toxoids.
14. PASSIVE IMMUNITY
• By administration of an antibody-
• By transfer of maternal antibodies across the
placenta. Human milk also contains protective
antibodies
• By transfer of lymphocytes, to induce passive
cellular immunity( this procedure is in
experimental stage)
15. ACTIVE IMMUNITY
1. Develops after active participation
of host to generate the immune
response.
PASSIVE IMMUNITY
1. There is no active participation of host.
2. Needs lag period of 7-10 days. 2.Doesnot need lag period
3. Onset of action- delayed 3. Immediate onset of action
4. Duration of action- prolonged 4. Duration of action-shorter
5. Induced by-exposure to
antigen
5.induce by –cytotoxin T cell
6. Chance of Hypersensitivity
Development-No
6. Yes
7. Immunological memory-yes 7. no
18. CELLULAR IMMUNITY
Cellular immunity plays a fundamental role in
resistance to infection.
Cells of Acquired immunity:
T-Lymphocyte
B-Lymphocyte
19.
20. POINTS CELLULAR HUMORAL
1.
Produced by T-Cell Ig
2.
Function Concerned with intra
cellular organisms
Extracellular organism
3.
Virus infected cell kills -
4.
Tumor cell kills -
5.
Graft cell kills -
6.
Large parasite kills -
7.
Neutralization of
virus
No Yes
8.
Opsonisation of
virus
No Yes
9.
Neutralization of
toxin
No Yes
10.
Hypersensitivity TYPE IV TYPES I, II, III, V,VI
21. IMMUNE RESPONSE
o PRIMARY RESPONSE:
It occurs after first exposure to an antigen.
Mature B cells are activated by antigen
Antibody appears in blood usually 7-10 days
after first exposure to antigen
IgM antibody first appears and then IgG or
IgA,appears. Antibody appears in small
amounts. Maximum in 2 months, then
declines.
22. o SECONDARY RESPONSE
It occurs on re-exposure to the same antigen.
Memory B cells are activated by the antigen.
Antibody appears in blood on subsequent
exposure to the same antigen.
Mostly IgG antibody which is of much higher
level and remains high for longer period.
23. • ANTIGEN:
Substance that binds with antibody and/or
antigen binding receptor on lymphocyte.
• IMMUNOGEN:
Substance that induces an immune response.
‘All immunogens are antigens but all antigens
are not immunogen’
24. • ANTIBODIES:
These are the immunoglobulin that react
specifically with the antigen that in the first
place stimulated their production.
• IMMUNOGLOBULIN:
These are glycoproteins made up of heavy and
light polypeptide chains.
‘All antibodies are immunoglobulins but all
imunoglobulins are not antibodies’
25. HERD IMMUNITY
It is defined as “the level of resistance of a community
ore group of people to a particular
disease.
Herd immunity implies group protection beyond that
afforded by a protection of immunized individual.
It is seen that if 70-80% of people of the community is
immunized, the community remains free of the
infection. The 30% who could not be immunized get
the benefit of immunity by just being the member of
the immunized community.
26. That is, it concerns the freedom from infection
of individuals of individuals within a herd by
sole virtue of the influence of the herd
structure on the transmission among
individuals.
Production/Achievement of herd immunity:
NATURAL PROCESS:
a) Following attack of the disease
b) Following in apparent or subclinical infection.
27. ARTIFICIAL PROCESS:
a. Immunization
Merits of immunity:
I. Provides immunological barrier to the spread of
disease.
II. The epidemic wave declined with a build up of herd
immunity following natural infection.
III. If the herd immunity is sufficiently high, the
occurrence of an epidemic is regarded as highly
unlikely.
28. • IMMUNIZATION:
It is defined as a technique by which immunizing
agents are introduced into the body for the
production of antibody to prevent disease.
30. VACCINES
Vaccine is an immune-biological substance
designed to induce specific protection against a
given disease. It stimulates the production of
protective antibody and other immune
mechanisms.
32. • LIVE VACCINE:
Some vaccines contain live, attenuated microorganisms. Many of
these are active viruses that have been cultivated under conditions
that disable their virulent properties, or that use closely related but
less dangerous organisms to produce a broad immune response.
Although most attenuated vaccines are viral, some are bacterial in
nature. Examples include the viral diseases yellow
fever, measles, mumps, and rubella, and the bacterial
disease typhoid. The live Mycobacterium tuberculosis vaccine
developed by Calmette and Guerin is not made of
a contagious strain but contains a virulently modified strain called
"BCG" used to elicit an immune response to the vaccine.
33. • The live attenuated vaccine containing
strain Yersinia pestis EV is used for plague
immunization. Attenuated vaccines have some
advantages and disadvantages. They typically
provoke more durable immunological
responses and are the preferred type for
healthy adults. But they may not be safe for
use in immunocompromised individuals, and
on rare occasions mutate to a virulent form
and cause disease.
34. • KILLED VACCINE
Some vaccines contain inactivated, but
previously virulent, micro-organisms that have
been destroyed with chemicals, heat, or
radiation. Examples include the polio
vaccine, hepatitis A vaccine, rabies vaccine and
some influenza vaccines
35. CHARACTERISTIC KILLED VACCINE LIVE VACCINE
No. of doses multiple single
Need for adjuvant yes no
Duration for immunity shorter longer
Effectiveness of
protection
lower greater
Immunoglobulins
produced
IgG IgA and IgG
Mucosal immunity
produced
Poor yes
CMI produced Poor yes
Residual virulent virus
in vaccine
possible no
Reversion to virulence no possible
Interference by other
viruses in host
no possible
Stability at room temp high low
36. • Toxoid
Toxoid vaccines are made from inactivated toxic
compounds that cause illness rather than the
micro-organism. Examples of toxoid-based
vaccines include tetanus and diphtheria. Toxoid
vaccines are known for their efficacy. Not all
toxoids are for micro-organisms; for
example, Crotalus atrox toxoid is used to
vaccinate dogs against rattlesnake bites.
37. • CELLULAR FRACTIONS:
Vaccines in certain instances, are prepared from
extracted cellular fraction, e.g. Meningococcal
vaccine from the polysaccharide antigen of the
cell wall,pnemococcal vaccine from the
polysaccharide contained in the capsule of the
organism and hepatitis B polypeptide vaccine.
38. • COMBINATIONS
If more than one kind of immunizing agent is
included in the vaccine, it is called mixed or
combined vaccine. The aim of such types of
vaccines is:
Simple administration
Reduces cost
Minimizes the no. of contacts of the patient
with the health system
41. IMMUNOGLOBULIN PREPARATION
Normal Human Ig
It is an antibody rich fraction, obtained from a
pool of at least 1000 donors.
WHO has laid down definite standards for it’s
preparation:
Preparation should contain at least 90% intact
IgG
It should be as free as possible from IgG
aggregates.
42. All IgG subclasses should be present.
There should be a low IgA concentration
The level of antibody against at least two
bacterial species and two viruses should be
ascertained.
43. • Example:
o Normal human Ig is used to prevent
measles in highly susceptible individuals.
o To provide temporary protection(upto 12
weeks) after hepatitis A infection for
travellers to endemic area.
44. • Human specific immunoglobulin is prepared from the
plasma of individuals with have high antibody levels
against a specific infection. These individuals are either
recovering from the specific illness or have been
recently immunised.
Specific immunoglobulin preparations are available for:
• hepatitis B - used following needle stick injury
• tetanus - used in suspected tetanus infection
• rabies - used in suspected rabies infection
• herpes zoster - used to protect susceptible children
45. ANTISERA OR ANTITOXINS
• The term antiserum is applied to materials
prepared in animals.
• Is nonhuman blood serum containing
monoclonal or polyclonal antibodies that is
used to spread passive immunity to many
diseases.
• he most common use of antiserum in humans
is as antitoxin or antivenom to
treat envenomation.
46. • Example:-
ATS-
Prophylactic use-in case of tetanus prone
wounds
Curative use- to cure tetanus.
ARS-
As pre and post exposure prophylaxis
47. ADS } both prophylactic as well as curative
purpose
AGS } both prophylactic as well as curative
purpose.
