Types of Vaccines II

1
Types of Vaccines II
2
Types of Vaccines III
3
The Perfect Vaccine

• 100 effective
• Oral dosage form
• No adverse effects
• Highly immunogenic
• life-long immunity from a single dose
• no boosters required
• Cheap
• Stable at room temperature
• no cold chain required

4
Combination vaccines

• DT
• DTaP
• DTaP-HepB-IPV
• HepA-HepB

• Hib-HepB
• MM
• MMR
• MMRV

5
The Bare Minimum Immunology

• MedCh 401 Spring 2006
• Lecture 2

6
Immunology

• The science of differentiating self from non-self
• Defense against invaders
• Bacterial
• Viral
• Fungal
• Parasitic
• Particulate (e.g., slivers)

7
Immune system characteristics

• Specificity
• Memory
• Tolerance

8
Blood cells

• RBCs - carry oxygen
• WBCs - immune cells
• lymphocytes
• Natural Killer cells
• Polymorphonuclear leukocytes (PMNs)
• macrophages

9
The immune system is...

• General and specific
• Innate (natural) and acquired (adaptive)
• Active and passive
• Natural and artificial
• Cell-mediated and humoral
• Primary and secondary immune responses

10
Some General Immune Responses

• Fever
• Malaise
• Inflammation
• Localized erythema

11
Essential Concepts

• Active
• Produced by ones own immune system, e.g.,
  development and recovery from disease
• More permanent (years)
• Passive
• Produced by other humans or animals and infused,
  injected, ingested or absorbed into recipient
• Transient (weeks to months)

12
Active Immunity

• Natural
• Host produces antibodies in response to infection
• Host develops protective response to live viral
  vaccine

• Artificial
• Host produces protective immune response to
  killed cells, detoxified toxins, etc.

13
Passive Immunity

• Natural
• Placental transfer of maternal antibodies (IgG)
• Transfer of maternal antibodies via nursing (IgA)

• Artificial
• injection of immune serum from person who has
  recovered from disease
• transfusion of hyperimmune serum from animal

14
Summary
15
Innate immunity

• Surface barriers
• Skin
• Ciliary action of respiratory epithelia
• Mucus in respiratory and urogenital tracts
• Acid pH of skin secretions
• Lysozyme in tears, saliva, perspiration
• Extreme acidity of stomach

16
Innate immunity II

• Normal flora
• Staphylococcus aureus on skin
• E. coli in gut
• Candida in vaginal tract
• Corynebacteria diphtheriae in laryngeal passage

17
Innate Immunity III

• Macrophages
• Kupffer cells - liver
• microglia - CNS
• mesoangial cells - kidney
• osteoclasts - bone
• Natural killer cells
• PMNs (and other WBCs)

18
Innate Immunity IV

• Complement system
• Enzyme cascade
• Not antigen-specific
• Enhances phagocytosis
• Stimulates inflammation, increasing capillary
  permeability to increase plasma and complement
  flow to injury
• Can directly lyse cells

19
Innate Immunity V

• Dendritic cells
• Langerhans cells
• Interstitial dendritic cells
• Interdigitating dendritic cells
• Circulating dendritic cells

20
Acquired Immunity I

• Cell-mediated - these are lymphocytes
• T cells
• TH2 (Helper) CD4 - activate T and B cells
• TH1 (DTH) - role in allergies
• TC (Cytotoxic) CD8, aka CTLs - kill cells with
  foreign Ag on the surface
• Memory
• B cells
• Plasma cells (produce antibodies)
• Memory B cells

21
Acquired immunity II

• Active
• Develop and recover from disease
• Passive
• Transplacental maternal antibodies (IgG)
• Maternal antibodies in human milk (IgA)

22
Summary
23
Variability of the immune response

• Avidity (binding affinity)
• low for recent infections
• high for secondary immune responses
• Specificity
• low for primary immune responses
• high for secondary immune responses

24
Immunoglobulins

• IgA - primary antibody in secretions half-life
  5 days
• IgM - primary antibody response half-life 5-10
  days
• IgG - secondary antibody response half-life
  21-24 days
• IgD - found on B cell surfaces
• IgE - bound to mast cells amplifies immune
  response

25
Antibody functions

• Opsonization - coating Ag with Ab enhances
  phagocytosis
• Steric hindrance - bind to surfaces of
  microorganisms and prevent attachment to cells
• Toxin neutralization
• Agglutination and precipitation - bind to surface
  of microbes and precipitate them reduces number
  of infectious units and enhances phagocytosis

26
Antibody functions II

• Complement activation
• induces inflammatory response
• attracts phagocytes to site of infection
• opsonizes cells with foreign antigens
• lyses some bacteria and viruses
• Antibody-dependent cell cytotoxicity - IgG
  enables Natural Killer cells to recognize and
  kill opsonized target cells

27
Primary v. Secondary Immune Responses
28
When good things go bad...

• Allergies
• Hay fever
• Delayed-type hypersensitivity
• Anaphylaxis
• Autoimmunity
• MS (CNS)
• Amyotrophic Lateral Sclerosis (ALS a-motor
  neurons of spinal cord)
• Primary biliary cirrhosis (liver)

29
Terms to Know

• Anaphylaxis
• Antigen
• Antibodies
• types
• functions
• Antigen-presenting cells
• Allergen

• Complement
• WBC v. RBC
• T and B Memory cells
• Natural v. artificial responses
• Active v. Passive responses
• B, T and Plasma cells
• Phagocyte