1. VACCINE IMMUNOLOGY

2. Vaccination vs. Immunisation
Vaccination is the term used forgiving a vaccine - that is the process of introducing a substance to a host (i.e. Injection or droplets).
Immunisation is the term used for the process of both getting the vaccine and becoming immune to the disease as a result of the vaccine.
Vaccination – named from the use of vaccinia, or cowpox, to induce immunity to variola (smallpox) in humans.

3. Early history of vaccination
7th Century - Indian Buddhists drank snake venom (for snakebites).
10th/17th Century China – “inoculation or variolation” (for smallpox).
Variolation (inoculation)- introduced to Europe from Turkey in

4. History of vaccination
Lady Mary Montague, who witnessed variolation in Istanbul, came back UK and had her daughter inoculated. She then advised the royal family to have their children inoculated .
As a safeguard, the procedure was first tested on six prisoners (death penalty). All survived and pardoned. Royal children inoculated and survived and variolation became fashionable in Europe.

5. Edward Jenner

6. History of vaccination
14 May 1796
Edward Jenner used material from a cowpox
pustule on the hand of Sarah Nelmes to vaccinate James Phipps (8 yr boy).
1 July 1796
Jenner used virulent smallpox matter to challenge James Phipps.
Experiment successful: Phipps survived many subsequent exposure over 20 yrs

7. Smallpox vaccination
300 million people died of smallpox in the first three-quarter of the 20th Century.
Smallpox eradicated in 1979 because of mass vaccination programme

8. Goals of vaccination In individuals - prevention of disease
In populations - eradication of disease

9. Immunisation Schedule in Saudi arabia
*BCG (Bacillus Calmette-Guérin) is the current vaccine against TB.

10. Vaccination saves lives
Infant vaccination programmes have saved approx. 3 million deaths worldwide annually
Hepatitis B (900,000),
measles (900,000),
tetanus (400,000),
H. influenzae (400,000),
pertussis (350,000),
yellow fever (30,000),
diphtheria (5,000)
polio (800)

11. Major diseases that could be prevented by no effective vaccines yet

12. Types of immunisation Active Passive
Administration of antigen (modified infectious agent or toxin) resulting in active production of immunity eg. antibodies
Passive
Administration of antibody-containing serum or sensitised cells

13. Active Passive natural (unintended) deliberate - vaccination
Placental transfer (IgG)
colostral transfer (IgA)
transfer of human Ig or cells

14. A good vaccine should be:
Safe - no significant side effects
Effective, and preferably long-lasting
Stable in storage
Cost-effective for the target population

15. Types of vaccines Live attenuated vaccines
Inactivated vaccines (killed)
Subunit vaccines

16. Types of vaccines Live attenuated Inactivated
Measles, mumps, rubella, polio, BCG (TB)
Inactivated
Heat killed organisms  typhoid, cholera, pertussis
Toxoid  (inactive form of toxin, capable of inducing Ab to toxin which causes disease). eg. Diptheria, tetanus

17. Types of vaccines Subunit Polysaccharide (PS), conjugate PS
eg. Pneumococcal PS, meningococcal PS
Recombinant DNA products / purified proteins
eg. hepatitis B, influenza proteins

18. Live vaccines Advantages single, small dose given by natural route
local & systemic immunity
resembles natural infection
Advantages
contaminating virus,
reversion to virulence
inactivation by climatic changes
Disadvantages

19. Inactivated (killed) vaccines
Advantages
safe
stable, so for each batch the safety and efficiency is known
multiple doses and boosters needed
given by injection - unnatural route
high antigen concentration needed
variable efficiency
Disadvantages

20. Polio Vaccines as a example
1958, killed (inactivated) virus ‘Salk’ vaccine introduced, but cannot replicate in cytosol to produce ‘endogenous’ peptides for presentation to CD8+ T cells
1962, Switched to oral live attenuated virus ‘Sabin’ (OPV) , more potent, but can rarely revert back to a virulent strain causing vaccine associated paralytic polio (VAPP).
2004, changed to inactivated polio vaccine

21. Safety
Live
vaccines
Killed
vaccines
Single
proteins
Immunogenicity

22. Principles of Vaccination
To induce a primary response without direct exposure to the infective pathogen
To induce immune memory so that a more rapid and efficient protective response are induced if the original pathogen is ever encountered again

23. Vaccination - like a minor infection at an epithelial surface
Antibody
Tc-dependent M activation
Cytotoxic T cells

24. T cell-mediated immunity

26. Function of Antibody -1

27. Function of Antibody -2
Opsonisation
IgG1, IgG3, IgG4, IgA

28. Function of Antibody -3 Antibody-dependent cellular cytotoxicity(ADCC)
IgG1, IgG3

29. Function of Antibody -4 -Activation of the complement cascade IgG IgM
IgA
IgM

30. The affinity as well as the amount of antibody increases with repeated immunization
© 2001 by Garland Science

31. Primary vs Memory response

32. immunogen + adjuvant enhanced response=
To hold the antigen and release it slowly
local inflammation, attract immune cells, eg. APC
enhance Ag uptake, processing and presentation by APC
promoting local cytokine production

33. Adjuvants Alum. hydroxide suspension
Pertussis toxin - mixed with Diphtheria and Tetanus toxoid  DTP triple vaccine

34. Polysaccharide vaccines
Encapsulated bacteria
Polysaccharide vaccines
Against Hib, menigococcus, pneumococcus.
Capsular PS, virulence factor

35. Immune response to PS vaccines

36. Limitations of polysaccharide vaccines
T cell independent antigen:
Stimulate B cell for antibody production without T-cell help
Poorly immunogenic in infancy
(Not effective in young children)
No memory
But Effective in older children and adults

37. Making PS Ag T-cell dependent - conjugate vaccines
PS conjugated to a carrier protein to create a “T cell antigen”
Tetanus toxoid
polysaccharide
T-cells recognise the protein (eg. TT) and activated
Activated T cells provide signals (eg cytokines) to ‘help’ B-cells to produce antibodies

38. Conjugate polysaccharide vaccines
Protein Ag attached to PS allow T cells to help PS-specific B cells.
© 2001 by Garland Science

39. Conjugate polysaccharide vaccines
© 2001 by Garland Science

40. Immune response to Conjugate PS vaccines

41. Advantages of conjugate vaccines
More immunogenic than PS vaccines
Effective in young children as well
T cell involvement and Immunological memory
Long-term protection

42. Limitation of conjugate vaccines
Limited serotype coverage
Increase in non-vaccine serotypes after vaccination
expensive

43. Herd Immunity
Unimmunised individuals are also protected against a disease as well as most others immunised in the community.
Herd immunity needs substantial coverage of population by vaccination.
If substantial portion of community not immune then introduced virus can circulate and cause disease in nonimmune group.

45. Passive Immunisation
Provide antibodies - whole serum or immunoglobulin (mainly IgG).
Provide immediate protection, eg rabies, tetanus, diphtheira.
No long term protection.

46. Haemolytic disease in the newborn
RhD- mother with RhD+ fetus can develop anti-Rh antibodies and cause haemolysis to the newborn and subsequent pregnancy. 46

47. Antenatal and postnatal administration of anti-RhD immunoglobuin to RhD- mother can prevent haemolysis in the newborns

48. SUMMARY

49. The end