1. THE IMMUNITY SYSTEM
Dr. Hayat AL AKOUM

2. DEFINITION OF TERMS
 Immune system: group of cells, molecules,
and organs that act together to defend the
body against foreign invaders that may
cause disease such as bacteria, viruses or
fungi.
 Immunology: the study of our protection
from foreign macromolecules or invading
microorganisms and our responses to them.

3. DEFINITION OF TERMS
 Immunity: ability to resist damage from
foreign substances.
 Antigen: any molecules that trigger an
immune response; a protein that stimulates
an immune reaction, causing the production
of antibodies.
 Antibodies: proteins that fight infections; a
globulin produced by B cells as a defense
mechanism against foreign materials.

4. DEFINITION OF TERMS
Epidemiology: study of how disease
is produced, and its distribution in a
given population.
Pathogens: microorganisms or
proteinaceous substances capable of
producing disease.
Virulence: ability to cause diseases

5. DEFINITION OF TERMS
 Nosocomial infections: acquired in a health care
setting
 Immunocompetent : client whose immune system
is able to identify antigens and effectively destroy or
remove them.
 Immunocompromised: client whose immune
system is unable to effectively destroy or remove
antigens
 Mast cells: tissue cells that resemble a peripheral
blood basophil and that contains granules with
chemical mediators.

6. BASIC CLASSIFICATION OF IMMUNITY

7. WHAT IS THE IMMUNE SYSTEM
The body’s defense against disease causing
organisms, malfunctioning cells, and foreign particles

8. WHERE IS THE IMMUNE SYSTEM
Cells of the immune system are:
 Distributed throughout the body in the blood, lymph,
epithelial and CT.
 oArranged in small spherical nodules (lymphoid
nodules) found in CT and inside various organs.
 Found in the mucosa of digestive (tonsils, Peyer’s
patches), respiratory, reproductive, urinary systems are
MALT (mucosa-associated lymphoid tissue.
 Organized as differently sized organs—lymphoid
organs—the lymph nodes, spleen, thymus, bone
marrow.

9. IMMUNE SYSTEM COMPONENTS
 All parts of the body
that help in the
recognition and
destruction of foreign
materials. White blood
cells, phagocytes and
lymphocytes, bone
marrow, lymph nodes,
tonsils, thymus, and
your spleen are all part
of the immune system.

10. IMMUNE SYSTEM COMPONENTS
1. Leukocytes
1. Engulf and destroy
pathogens
(bacteria)
2. Suppress inflammation
3. Fight parasitic infections
4. Produce antibodies
and provide immunity
a. Granulocytes-
immediate response to
cell injury
• Neutrophils-
phagocytic, first cell to
site of cell injury
• Eosinophils-
hypersensitivity reaction
• Basophil-inflammatory
response
b. Agranulocytes-
fight infection
• Monocytes –phagocytosis
• Lymphocytes- production of
immunoglobulins

11. Class Percentage
of Total
Characteristics and Functions
IgG 75% Found in blood, lymph, and intestines
Active against bacteria, its toxins and viruses
Enhances phagocytosis, crosses placenta and is active in a
second response
IgA 10-15% Saliva, tears, bronchial, GI, prostatic and vaginal secretions
Provides local protection on exposed mucous membrane
surfaces and potent antiviral activity
Prevents absorption of antigens from food, and protects
against respiratory, GI, and GU infections
IgM 5-10% Levels decrease during stress
Found in blood and lymph
First antibody produced with primary immune response
High concentrations early in infection, decrease within about
a week
IgD <1% Unknown function, found in blood and lymph
IgE <0.1%
Found on mast cells and basophils
Involved in immediate hypersensitivity response
IMMUNOGLOBULIN CHARACTERISTICS AND FUNCTIONS

12. CELLS INVOLVED IN THE IMMUNE SYSTEM
 Macrophages
 B-cells
 T-cells
 NK-cells

13. LIFE IS A THREAT FROM EVERYTHING IN
NATURE

14. THE IMMUNE SYSTEM REACTS TO ANY
FOREIGN INVASION

15. IMMUNITY
Innate immunity Acquired immunity
Non-specific Immediate onset Specific Delay onset
Humoral
Immune Response
Cellular
Immune Response
Antibodies production
15
T-cell activation

16. 16
Primary Lymphoid Organs
o Bone Marrow and Thymus
o Maturation Site
Secondary Lymphoid Organs
o Spleen, lymph nodes,
o MALT (mucosal associated lymph tissue)
o GALT (gut associated lymph tissue)
o Trap antigen, APC (antigen-
presenting cell), Lymphocyte
Proliferation
ORGANS OF IMMUNE SYSTEM

18. CENTRAL IMMUNE ORGANS
Central Immune Organs are the sites of generation,
differentiation and maturation of immunocytes.
 Bone marrow
 Thymus
 Bursa of Fabricius (the
site of B cells
maturation in birds)
But absent in Humans

19. THE IMMUNE SYSTEM
An antigen (invading bacteria) enters the body.
A macrophage attacks the antigen and retains some
of the antigen’s protein on its surface.
The macrophage carries the protein markers to
lymphoid tissue; T-lymphocytes interpret them as
foreign.
Antibodies attack the antigens.

20. FUNCTIONS OF THE IMMUNE SYSTEM
 Defend and protect the body from infection
by bacteria, viruses, fungi and parasites.
 Removing and destroying damaged or dead
cells.
 Identifying and destroying malignant cells,
thereby preventing their further
development into tumors.

21. INFECTIO
N immunity
Bolus of infection x virulence
immunity
Disease =

22. FACTORS INVOLVED IN INFECTION
 Portal of entry
 Virulence of organism
 Aggressiveness
 Toxin production
 Dose (number) of pathogens
 Individual condition (predisposition) to infection

23. FACTORS CONTRIBUTING TO HIGH RISK OF
INFECTION IN OLDER ADULTS
 High prevalence of chronic conditions
 High rate of hospitalization and institutionalization
 Age-related changes

24. INTERVENTIONS TO STRENGTHEN THE
IMMUNE SYSTEM
 Promote good general health.
 Assure immunizations are current.
 Encourage foods that have positive effect on immunity
 Assist patient to maintain skin integrity.
 Teach stress management techniques.
 Encourage regular exercise.
 Counsel against overuse of antibiotics.
 Teach infection control measures.
 Adhere to strict infection prevention measures.

25. EFFECTS OF AGING ON THE IMMUNE SYSTEM
 Thymus gland progressively declines in size.
 Immature T-cells increase.
 T-cell function declines.
 Cell-mediated immunity is deficient.
 Serum distribution of IgA and IgG increase.
 Serum distribution of IgM and IgD decrease.
 Antibody response to vaccines is reduced.
 Skin loses macrophages.

26. EFFECTS OF FASTING ON THE IMMUNE
SYSTEM
 Increased:
 Macrophage activity
 Immunoglobulin levels
 Neutrophil antibacterial activity
 Improvement of:
 Cell-mediated immunity
 Ability of monocytes to kill bacteria
 Natural killer cell activity
 Reductions in:
 Free radicals
 Antioxidant damage

27. FACTORS AFFECTING THE IMMUNE SYSTEM
 Diet
 Exercise
 Immunization
 Stress
 Mind-body connection
 Antibiotic use

28. ORGANS INVOLVED IN STRESS RESPONSE
 Thymus
 Spleen
 Lymph nodes
 Stress can affect the function of the immune
system.

29. STRESS REDUCTION MEASURES
 Progressive relaxation
 Meditation
 Prayer
 Yoga
 Imagery
 Exercise
 Diversional activity

30. TRAITS CONSISTENT WITH A STRONG IMMUNE
SYSTEM
 Assertiveness
 Faith in God or a higher power
 Ability to trust and offer unconditional love
 Willingness to be open and confide in others
 Purposeful activity
 Control over one’s life
 Acceptance of stress as a challenge rather than a
threat
 Altruism
 Development and exercise of multiple facets of
personality

31. PROMOTING SAFE ANTIBIOTIC USE
 Assist patients in health promotion efforts.
 Adhere to strict infection control practices.
 Use alternatives to antibiotics whenever possible.
 Educate about the realities and risks of antibiotics.
 Advise patients not to save and use antibiotics for
future illnesses.

32. TYPES OF BODY DEFENSES AGAINST
DISEASE
 Nonspecific defenses
 Effective against any harmful agent
 Specific defenses
 Effective against a certain agent only

33. NONSPECIFIC IMMUNITY
 Nonspecific immunity is composed of successive
lines of defense.
 First line of defense: barriers
 Second line of defense: internal nonspecific responses
 Specific immunity is the final line of defense.

34. NONSPECIFIC IMMUNITY
THE FIRST LINE OF DEFENSE
Barriers
 Skin
 Mucous membranes
 Body secretions
 Body reflexes
 Sneezing
 Coughing
 Vomiting
 Diarrhea

35. NONSPECIFIC IMMUNITY
THE SECOND LINE OF DEFENSE
 Nonspecific Reponses Phagocytosis
 Neutrophils
 Macrophages
 Natural killer cells
 Inflammation
 Fever
 Interferon
 Complement

37. NONSPECIFIC IMMUNITY
Phagocytosis
White blood cells take in and destroy waste and
foreign material.
 Neutrophils
 Macrophages
Natural Killer Cell
 Type of lymphocyte found in lymph nodes, spleen,
bone marrow, blood
 Recognizes body cells with abnormal membranes
and secretes protein that breaks down cell
membrane

38. NONSPECIFIC IMMUNITY
Inflammation
 Infection is inflammation caused by pathogens
 Inflammatory reaction
 Heat, redness, swelling, pain
 Cells release histamine
 Leukocytes enter tissue
 Granulocytes, macrophages, mast cells
 Leukocytes and plasma produce inflammatory
exudate
 Pus is produced
 Lymph nodes enlarge

40. FACTORS THAT MAY IMPAIR HEALING
Factors Effect
Malnutrition
Protein deficient Prolongs inflammation and impairs healing
process
Carbohydrates and
kilocalorie deficient
Impairs metabolic process; proteins are
used for energy rather than healing
Vitamin deficits
Vit. A Limits epithelialization and capillary
formation
B-complex Inhibits enzymatic reaction that contributes
to wound healing
Vit. C Impairs collagen synthesis
Tissue Hypoxia Associated with an increase risk of infection
and impaired healing
Impaired blood supply Inadequate delivery of Oxygen and
nutrients

41. NONSPECIFIC IMMUNITY
FEVER
 As phagocytes work, they release substances that
raise body temperature.
 Stimulates phagocytes
 Increases metabolism
 Decreases some organisms’ ability to multiply

42. NONSPECIFIC IMMUNITY
INTERFERON
 Group of substances that prevent nearby cells from
producing more virus
 IFN α (alpha)
 IFN β (beta)
 IFN γ (gamma)
 Also acts nonspecifically on immune system cells

43. NONSPECIFIC IMMUNITY
COMPLEMENT
Specialized proteins in blood that are activated by
immune responses
Functions:
 Coats foreign cells
 Destroys cells
 Promotes inflammation
 Attracts phagocytes

45. SPECIFIC IMMUNITY
Power to overcome a specific disease agent
Characteristics
 Specific response to specific pathogens
 Acquired over lifetime
 Stimulated by antigens

46. SPECIFIC IMMUNITY
Antigens
 Foreign substances that
 Enter body
 Induce immune response of certain lymphocytes
 T cells
 B cells

47. SPECIFIC IMMUNITY
T Cells
 Originate in red bone marrow
 Mature in thymus
 Become sensitized to specific antigens
 Provide cell-mediated immunity

48. SPECIFIC IMMUNITY
Types of T cells
 Cytoxic T cells
 Helper T cells
 Regulatory T cells
 Memory T cells
Stimulated by antigen-presenting cells
 Macrophages
 Dendritic cells

50. SPECIFIC IMMUNITY
B Cells
 Originate and mature in red bone marrow
 Produce antibodies
 Provide humoral immunity
Cell types
 Plasma cells
 Secrete antibodies
 Memory b cells

52. SPECIFIC IMMUNITY
FUNCTIONS OF ANTIBODIES
 Bind antigen
 Promote phagocytosis
 Activate nk cells
 Neutralize toxins
 Activate complement

54. SPECIFIC IMMUNITY
TYPES OF SPECIFIC IMMUNITY
 Naturally acquired immunity
 Natural active immunity
 Natural passive immunity
 Artificially acquired immunity
 Artificial active immunity
 Artificial passive immunity

55. SPECIFIC IMMUNITY
NATURALLY ACQUIRED IMMUNITY
 Natural active immunity
 Acquired through contact with a specific disease
organism
 Natural passive immunity
 Acquired through transmission of maternal antibodies to
fetus and baby

56. SPECIFIC IMMUNITY
ARTIFICIALLY ACQUIRED IMMUNITY
 Artificial active immunity
 Acquired through contact with a vaccine
 Artificial passive immunity
 Acquired through delivery of manufactured antibodies to
individual

58. SPECIFIC IMMUNITY
TYPES OF VACCINES
 Live
 Attenuated
 Toxoid Killed by heat or chemicals
 Antigenic component
 Genetically engineered

59. SPECIFIC IMMUNITY
BOOSTERS
 Active immunity does not always last a lifetime
 Repeated inoculations (booster shots) help
maintain high titer of antibodies in the blood
 Number and timing varies with vaccines

60. DISORDERS OF THE IMMUNE SYSTEM
 Allergy
 Hypersensitivity
 Anaphylaxis
 Autoimmunity
 Immune deficiency diseases
 Congenital
 Acquired (e.g., AIDS)
 Multiple myeloma

61. DISORDERS OF THE IMMUNE SYSTEM
ALLERGY
 Abnormal reactivity to one’s own tissues
 Factors
 Disease
 Loss of immune system control
 Cross-reaction of antibodies and self antigens
 Treatments
 Immune-suppressing drugs
 Chemotherapy/stem cell replacement

62. DISORDERS OF THE IMMUNE SYSTEM
 Failure of immune system
 May involve any part of system
 Varies in severity
 Congenital or acquired (e.g., AIDS)
 HIV
 A retrovirus; uses reverse transcriptase enzyme

64. DISEASE DISORDERS OF THE IMMUNE SYSTEM
MULTIPLE MYELOMA
 Cancer of blood-forming bone marrow cells
 Effects of disease
 Lowered resistance to infection
 Anemia
 Bone pain
 Bone tissue loss
 Kidney failure
 Treatment
 Chemotherapy
 Bone marrow transplants

65. THE IMMUNE SYSTEM AND CANCER
 Immune surveillance
 Declines with age
 Immunotherapy
 T cells activated with interleukin
 Vaccines

66. TRANSPLANTATION AND REJECTION
SYNDROME
 Rejection syndrome caused by normal antigen–
antibody reaction
 Reduced by
 Tissue typing
 Immune suppression drugs