This document discusses the nature of disease and the human immune system. It covers several topics: 1) The various causes of disease including pathogens, genetic disorders, toxins, and physical damage. It also describes the mechanisms by which pathogens can cause disease. 2) The immune system's three lines of defense - external barriers, internal inflammation and phagocytosis, and the adaptive immune system. 3) The different types of immunity, both natural and artificial, as well as active versus passive immunity. Vaccines are discussed as a way to artificially acquire active immunity. 4) The key cells and responses of the immune system, including antibodies, B cells, T cells, and the differences between humoral

1. BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

2. THE NATURE OFDISEASE
• Pathogenic Organisms
• Genetic Disorders
• Toxic Chemicals
• Other Environmental
Factors
• Physical Damage to Organs
• Nutritional Disorders

3. TYPES OF PATHOGENICORGANISMS
• Viruses
• Bacteria
• Protozoan
• Fungi
• Animal
• Parasites

4. MECHANISMS OF DISEASE BY
PATHOGENS
• Utilization of host nutritional resources
• Physical damage to host tissues
• Production of toxic substances
• Chromosomal and gene damage
• Body cells behave abnormally

5. DEFENSE MECHANISMS
1. External Defense
2. Internal Defense
3. Immune Defense

6. • Skin acts as barrier to microbes and viruses
- sweat has a low pH
• Mucus traps foreign particles
• Tears
- Lysozyme has antimicrobial action
• Gastric stomach acid
1st Line ofDefense

7. BodyCoverings: TheSkin
sweat
gland
epidermis
sebaceous
glands

8. BODY COVERINGS:MUCOUSMEMBRANES
mucus
cilia

9. • Phagocytic cells (WBCs)
- Natural Killer (NK) Cells: attack virus
infected cells
•
•
Inflammatory Response
Antimicrobial proteins
- Lysozyme
- Interferon
- Antibodies
2nd Line of Defense

10. MECHANISM OFPHAGOCYTOSIS

11. INFLAMMATORY RESPONSE
Histamine &
prostaglandins
released
Capillaries dilate
Clotting begins
Chemotactic factors
attract phagocytic
cells
Phagocytes
consume
pathogens & cell
debris

12. Lymphatic System3rd Line of Defense

13. IMMUNITY:
• The state of being immune from or insusceptible to a particular
disease.
• The condition that permits either natural or acquired
resistance to disease.
• The ability of the cell to react immunologically in the presence
of antigen.

14. How immunitydevelops
• During the body’s first encounter with a pathogen there
will be few lymphocytes with specific receptors
• It takes time to divide to form clones, B lymphocytes to
secrete antibodies, T lymphocyteproduction
• If the same pathogen invades again persisting memory
cells can give a faster, more effective response

15. CHARACTERISTICS OFIMMUNITY
• Recognition of self versus non-self
• Response is specific
• Retains a “memory” allowing an accelerated second
response
• Can respond to many different materials
• Involves lymphocytes and antibodies

16. TYPESOFIMMUNITY
• Active Immunity
- Naturally-Acquired Active Immunity
- Artificially-Acquired Active Immunity
• Passive Immunity
- Naturally-Acquired Passive Immunity
- Artificially-Acquired Passive Immunity

17. TYPESOF IMMUNITY

18. • An infection is an example of acquiring natural
immunity. It is called ACTIVE as your body needs to
work to produce the necessary antibodies
• When a mother breast feeds her baby she passes
antibodies to it. This is a way of acquiring PASSIVE
immunity as it is a way of gaining antibodies
without the immune system having to produce
them.
• The thick, yellowish milk (colostrum) that is
produced for the first few days after birth is
particularly rich in antibodies.
NATURAL IMMUNITY: ACTIVE ANDPASSIVE

19. ARTIFICIAL IMMUNITY: ACTIVE ANDPASSIVE
• An alternative to natural immunity
developing is to give vaccinations
(artificial immunity)
• Antigen is injected into the body.
• This may be in the form of an
inactivated bacterial toxin or
attenuated (not harmful) virus
which would promote ACTIVE
immunity;
• or the injection of antibodies or
antitoxins which would promote
PASSIVE immunity (eg Clostridium
tetani)

20. • The production of antibodies against a specific disease by
the immune system.
• Naturally acquired through disease
• Artificially acquired through vaccination
• Vaccines include inactivated toxins, killed microbes, partsof
microbes, and viable but weakenedmicrobes.
• Memory cells are only produced in active immunity.
• Protection for active immunity is permanent
whereas in passive immunity it is only temporary.
• Antigens are only encountered in active immunity.
• Active immunity takes several weeks to become active
but passive is immediate
ACTIVEIMMUNITY

21. • A vaccinated person has a secondary response based on
memory cells when encountering the specific pathogen.
• Routine immunization against infectious diseases such as
measles and whooping cough, and has led to the
eradication of smallpox, a viral disease.
• Unfortunately, not all infectious agents are easily
managed by vaccination.
• HIV vaccine in the works

22. • Passive Immunity- Protection against disease through
antibodies produced by another human being or animal.
• Ex. Maternal antibodies , Colostrum
• Passive immunity doesn’t last as long as active immunity
(only weeks or months):
• No lymphocytes are stimulated to clone themselves
• No memory cells have been made
• Effective, but temporary as this type of immunity can only
last as long as the antibodies/toxins last in the blood
PASSIVEIMMUNITY

23. • Passive immunity can be transferred artificially by injecting
antibodies from an animal that is already immune to a
disease into another animal.
• Rabies treatment: injection with antibodies against rabies
virus that are both passive immunizations (the immediate
fight) and active immunizations (longer term defense).

24. IMMUNESYSTEMRESPONSETOANTIGENS
A. Humoral Immunity
• Involves antibodies (secreted from B cells) dissolved inthe
blood plasma.
• Demonstrated as a immune response using only the blood
serum.
• Defense against bacteria, bacterial toxins, & viruses.
B. Cell-Mediated Immunity
• Involves the activities of specific white blood cells (Tcells).
• Defense against cancer cells, virus-infected cells, fungi,
animal parasites, & foreign cells from transplants.

25. LYMPHOCYTE FORMATION

26. BCells
• Mature in bone marrow
• Involved in humoral immunity
• Once activated by antigen,
proliferate into two types of
clones
• Plasma cells
that secrete antibodies and
• memory cells
that may be convertedinto
plasma cells at a later time

27. BCells
antibodies
Activationof B CellsbyAntigen
antigen

28. ClonalSelection

29. ClonalSelection
plasma cells memory cells
antibodies

30. TCells
• Mature in thymus
• Involved in cell-mediated immunity
• Activated when another cell presents
antigen to them
• Several types of T cells:
• cytoxic T cells,
• helper T cells,
• suppressor T cells,
• memory T cells

31. • There are two main types of T cells, and
each responds to one class of MHC
molecule.
– Cytotoxic T cells (TC) have antigen receptors
that bind to protein fragments displayed by
the body’s class I MHC molecules.
– Helper T cells (TH) have receptors that
bind to peptides displayed by the body’s
class II MHC molecules.
T Cells

32. Cytotoxic TCell
perforin
pores in target cell

33. Helper TCells
interleukin 1macrophage
helper
T cell
bacterium
bacterial
antigens
T cell receptor

34. Humoral Immune Response
time (days)
antibodyconcentration
first exposure
to antigenA

35. Humoral Immune Response
time (days)
antibodyconcentration
first exposure
to antigenA
primary response:
concentration of
anti-Aantibody
second exposure to
antigenA

36. Humoral Immune Response
time (days)
antibodyconcentration
secondary response:
concentration of anti-A
antibody
second exposure to
antigenA
first exposure
to antigen B

37. Humoral Immune Response
time (days)
antibodyconcentration
primary response:
concentration of
anti-B antibody
first exposure
to antigen B

38. Antibody
Molecule
• Antibodies constitute a group of globular serum proteins
called immunoglobins (Igs).
• A typical antibody molecule has two identical antigen-bindingsites
specific for the epitope that provokes its production.
antigen binding sites
antigen
light chains heavy chains

39. Mechanisms on AntibodyAction
• Precipitation of soluble antigens
• Agglutination of foreign cells
• Neutralization
• Enhanced phagocytosis
• Complement activation leading to cell lysis
• Stimulates inflammation
The binding of antibodies to antigens to form antigen-antibody
complexes is the basis of several antigen disposal mechanisms

41. The classical complimentary pathway, resulting in lysis
of a target cell

42. OVERVIEW OF IMMUNE SYSTEM RESPONSES

43. Abnormal immune function canlead
todisease
• Malfunctions of the immune system can produce effects
ranging from the minor inconvenience of some allergies to
the serious and often fatal consequences of certain
autoimmune and immunodeficiency diseases.
Abnormal ImmuneFunction
• Autoimmune Disease
• Allergy
• Immunodeficiency

44. Types of vaccines

45. VACCINATION
• Vaccination is a method of giving antigen to stimulate the
immune response through active immunization.
• A vaccine is an immuno-biological substance designed to
produce specific protection against a given disease.
• A vaccine is “antigenic” but not“pathogenic”.
One of the most effective «weapons» in medicine
1798 Edward Jenner immunizes first time against smallpox
1885 Louis Pasteur prepares the 1st vaccine against Rabbies
1927 BCG (bacillus Galmette-Guerin)
1955 Salk vaccine against poliomyelitis
1960 MMR (Measles, Mumps and Rubella)……..

46. TYPESOFVACCINES
• Live vaccines
• Attenuated live vaccines
• Inactivated (killed vaccines)
• Toxoids
• Polysaccharide and polypeptide
(cellular fraction) vaccines
• Surface antigen (recombinant) vaccines

47. LIVEVACCINES
• Live vaccines are made from live infectious
agents without any amendment.
• The only live vaccine is “Variola” small pox
vaccine, made of live vaccinia cow-pox
virus (not variola virus) which is not
pathogenic but antigenic, giving cross
immunity for variola.

48. LIVE ATTENUATED(AVIRULENT)VACCINES
• Virulent pathogenic organisms are treated to become
attenuated and avirulent but antigenic. They have lost their
capacity to induce full-blown disease but retain their
immunogenicity.
Attenuated– live microbe (usually virus) which has a
vital function inactivated by heat, chemicals or genetic
manipulation e.g. Rabies virus vaccine, MMR (Measles,
Mumps andRubella),BCG (Bacillus Calmette Guerin)
vaccine for M. tuberculosis
• Risk it could revert back to infectious agent
• will stimulate both cell mediated and antibody
mediated immune response

49. Live attenuated vaccines should not be administered to
persons with suppressed immune response due to:
• Leukemia and lymphoma
• Other malignancies
• Receiving agents corticosteroids and anti-
metabolic
• Radiation
• pregnancy

50. INACTIVATED (KILLED)VACCINES
• Organisms are killed or inactivated by heat or
chemicals but remain antigenic.
• They are usually safe but less effective than live
attenuated vaccines.
• The only absolute contraindication to their
administration is a severe local or general reaction
to a previous dose

51. TOXOIDS
• They are prepared by detoxifying the exotoxins of
some bacteria rendering them antigenic but not
pathogenic.
• Adjuvant (e.g. alum precipitation) is used to
increase the potency of vaccine.
• The antibodies produces in the body as a
consequence of toxoid administration neutralize
the toxic moiety produced during infection rather
than act upon the organism itself.
• In general toxoids are highly efficacious and safe
immunizing agents.

52. POLYSACCHARIDE AND POLYPEPTIDE
VACCINES
• They are prepared from extracted cellular fractions
e.g.meningococcal vaccine from the polysaccharide
antigen of the cell wall, the pneumococcal vaccine
from the polysaccharide contained in the capsule of the
organism, and hepatitis B polypeptide vaccine.
• Their efficacy and safety appear to be high.

53. SURFACE ANTIGEN (RECOMBINANT)
VACCINES
• It is prepared by cloning HBsAg gene in yeast cells
where it is expressed.
• HBsAg produced is then used for vaccine
preparations.
• Their efficacy and safety also appear to be high.

54. TYPES OFVACCINES
Live
vaccines
Live
Attenuated
vaccines
Killed
Inactivated
vaccines
Toxoids Cellular
fraction
vaccines
Recombinan
t vaccines
•Small
pox
variola
vaccine
•BCG
•Typhoid
oral
•Plague
•Typhoid
•Cholera
•Pertussis
•Plague
•Rabies
•Salk polio
•Intra-
muscular
influenza
•Japanise
encephalitis
•Diphtheria
•Tetanus
•Meningococcal
polysaccharide
vaccine
•Pneumococcal
polysaccharide
vaccine
•Hepatitis B
polypeptide
vaccine
•Hepatitis B
vaccine
•Oral polio
•Yellow
fever
•Measles
•Mumps
•Rubella
•Intranasal
Influenza
•Typhus

55. ROUTES OFADMINISTRATION
• Deep subcutaneous or intramuscular route
(most vaccines)
• Oral route ( oral BCG vaccine)
• Intradermal route (BCG vaccine)
• Scarification (small pox vaccine)
• Intranasal route
(live attenuated influenza vaccine)

56. SCHEME OFIMMUNIZATION
• Primary vaccination
• One dose vaccines (BCG, variola, measles, mumps, rubella, yellow
fever)
• Multiple dose vaccines (polio, DPT (diphtheria, pertussis, tetanus
toxoids), hepatitis B)
• Booster vaccination
Tomaintain immunity level after it declines after some time has elapsed
(DT,
MMR).

57. PERIODSOFMAINTAINEDIMMUNITY
BYVACCINES
• Short period
(months):
• Two years:
• Three to five years:
• Five or more years:
• Ten years:
• Solid immunity:
Cholera vaccine
TAB vaccine
DPT vaccine
BCG vaccine
Yellow fever vaccine
MMR (measles, mumps, and
rubella vaccines)

58. LEVELS OFEFFECTIVENESS
• Absolutely protective(100%): yellow fever vaccine
• Almost absolutely protective (99%): Variola,
measles, mumps, rubella vaccines, and diphtheria
and tetanus toxoids.
• Highly protective (80-95%): polio, BCG, Hepatitis
B, and pertussis vaccines.
• Moderately protective (40-60%) TAB, cholera
vaccine, and influenza killed vaccine.

59. The ColdChain
• The "cold chain" is a system of storage and transport of
vaccines at low temperature from the manufacturer to the
actual vaccination site.
• The cold chain system is necessary because vaccine failure
may occur due to failure to store and transport under strict
temperature controls.

60. The Cold ChainEquipment
Cold chain equipment consists of the
following:
(a)Walk in cold rooms: They are located at regional level,
meant to store vaccines up to 3 months and serve districts.
(b)Deep freezers (300 ltr) and Ice lined Refrigerators:
supplied to all districts and the WIC locations to store
vaccines. Deep freezers are used for making ice packs and
to store OPV and measles vaccines.
(c)Small deep freezers and ILR (140 ltr) : One set is
provided to PHCs, and Family Planning Centers

61. (d)Cold boxes:Coldboxes are supplied to all peripheral
centres. These are used mainly for transportation of
the vaccines.
(e)Vaccine carriers: Vaccine carriers are used to carry
small quantities of vaccines (16-20 vials) for the out
of reach sessions. 4 fully frozen ice packs are used for
lining the sides, and vials of DPT, DT, TT and diluents
should not be placed in direct contact with frozen ice
packs. The carriers should be closed tightly.
(f) Ice packs: The ice packs contain water and no salt
should be added to it.

62. • Among the vaccines, Polio vaccine is the most sensitive to
heat, requiring storage at minus 20 degree C.
• Vaccines which must be stored in the FREEZER
COMPARTMENT are : polio and measles.
• Vaccines which must be stored in the COLD PART but never
allowed to freeze are : typhoid, DPT, tetanus toxoid, DT, BCG
and diluents

63. VaccinationCoverage
• Vaccination coverage is the percent of at risk or
susceptible individuals, or population who have been
fully immunized against particular diseases by
vaccines or toxoids. Tobe significantly effective in
prevention of disease on mass or community level at
least a satisfactory proportion (75% or more) of the at
risk population must be immunized.

64. Waysof achieving satisfactory
immunization coverage
• Efficient immunization service; urban and rural
• Health awareness and cooperation of the public
• Periodic mass immunization campaigns, to cover
those who missed regular immunizations
• Outreach programs in rural and nomad areas, and
home visits

65. APPLICATIONS OF ACTIVEIMMUNIZATION
• Infants and children expanded immunization
program (schedule)
• Active immunization for adult females
• Vaccination for special occupations
• Vaccination for special life styles
• Vaccination for special environmental situations
• Vaccinations for special health status persons
• Vaccinations in travel
• Vaccines against bioterrorism