1. BME 301
Lecture Nine

2. Summary of Lecture 8 Pathogens: Bacteria and Virus Levels of Immunity:
Barriers  First line of defense
Innate  Inflammation
Phagocytes
Complement
Adaptive  Immunologic memory
Antibody mediated immunity
Cell mediated immunity  Pathogens within cells
Diversity to recognize 100 million antigens

3. Class Activity 2
The Immune System

4. Q3: How can technology solve health care problems?
CS1: Prevention of infectious disease

5. Outline Pathogens: How They Cause Disease
The Immune System: How We Fight Disease
How Vaccines Work
The Power of Vaccines: Childhood Illnesses
Designing a New Vaccine: HIV/AIDS

6. Roadmap of CS 1 Science Engineering Vaccines: From idea to product
Organisms that cause disease
Immunity
Engineering
How to make a vaccine
Vaccines: From idea to product
Societal Impact
Health and economics
Ethics of clinical trials
Developed world/Developing world

7. Viruses Three basic problems each must solve
How to reproduce inside a human cell
How to spread from one person to another
Inhale
Eat
During birth
Intimate physical contact
How to evade the immune system

8. Influenza Viral Reproduction - 1
Must get inside human cell to use cell’s biosynthetic machinery
Influenza virus binds to cell receptor
Induces receptor mediated endocytosis

9. Influenza Viral Reproduction - 2
pH slowly reduced in endosome, virus releases its single stranded RNA and polymerase proteins
RNA segments and polymerase proteins enter nucleus of infected cell
Cell begins to make many copies of the viral RNA and viral coat proteins

10. Influenza Viral Reproduction - 3
New viral particles exit nucleus and bud from cell
Viral polymerase proteins don’t proofread reproduction
Nearly every virus produced in an influenza infected cell is a mutant

11. Influenza Viral Spread Infected person sneezes or coughs
Micro-droplets containing viral particles inhaled by another person
Penetrates epithelial cells lining respiratory tract
Influenza kills cells that it infects
Can only cause acute infections
Cannot establish latent or chronic infections
How does it evade immune extinction?
Antigenic drift
Caused by point mutations
Yearly vaccination

12. Influenza How does the virus cause symptoms?
Cells of respiratory tract are killed by virus or immune system
Resulting inflammation triggers cough reflex to clear airways of foreign invaders
Influenza infection results in production of large quantities of interferon
Fever
Muscle aches
Headaches
Fatigue
MMR Weekly

13. Genetic Shift and Flu Pandemics
Animals co-infected by different strains of virus
Viral gene segments randomly reassociate
Reassortment of virus segments from birds, pigs, etc is source of new strains that infect humans
How does this happen?
Virus shed in bird feces, gets into pigs' drinking water
Humans handle and/or cough on the pig
New virus - segments from humans, birds & pigs
China:
Breeding ground for new influenzas strains
Proximity of humans, pigs, and ducks in China
Asian flu, Hong Kong flu, etc.

14. Vaccines
How Are They Made?

15. Vaccination Vaccination: Goal of vaccination:
Practice of artificially inducing immunity
Goal of vaccination:
Make memory T helper cells, memory killer T cells, and memory B cells that will protect the vaccinated person against future exposure to pathogen
Want the vaccine to have:
Maximum realism
Minimum danger

16. What is needed to make memory cells?
Memory B Cells & Memory Helper T Cells:
B and T cell receptors must see virus or viral debris
Memory Killer T Cells:
Antigen Presenting Cells must be infected with virus

17. Types of Vaccines Non-infectious vaccines
DTaP
Pneumococcus
Live, attenuated bacterial or viral vaccines
Chicken Pox
Carrier Vaccines
DNA Vaccines

18. Non-infectious vaccines
Killed bacterial or inactivated viral vaccines
Treat pathogen with chemicals (like formaldehyde)
Impossible to guarantee that you have killed all the pathogen
Salk (inactivated) Polio vaccine, rabies vaccine
Subunit vaccines
Use part of pathogen OR
Use genetic engineering to manufacture pathogen protein
No danger of infection
Hepatitis A & B, Haemophilus influenza type b, pneumonoccocal conjugate vaccines
Toxoid vaccines
Bacterial toxins that have been made harmless
Diphtheria, tetanus and pertussis vaccines
This approach will make memory B cells and memory helper T cells, but NOT memory killer T cells
Booster vaccines usually required

19. Live, attenuated vaccines
Grow pathogen in host cells
Produces mutations which:
Weaken pathogen so it cannot produce disease in healthy people
Pathogen still produces strong immune response that protects against future infection
Sabin Polio vaccine (oral Polio)
Measles, mumps, rubella, varicella vaccines
This approach makes memory B cells, memory helper T cells, AND memory killer T cells
Usually provide life-long immunity
Can produce disease in immuno-compromised host

20. Cell Culture: Live, Attenuated Vaccine
Grow cells:
Removed from tissue
In vitro (in glass)
By supplying nutrients and other factors
Specific O2 and CO2 (pH level)
Glucose, ions
Serum from blood: proteins

21. Passaging Cells Dissection/ Primary Organ Breakdown… Cell Line
Add media for growth
Incubate
Divide -> transferred
Secondary
Cell Line

22. Carrier Vaccines
Use virus or bacterium that does not cause disease to carry viral genes to APCs
e.g. vaccinia for Smallpox vaccine
This approach makes memory B cells, memory helper T cells, AND memory killer T cells
Does not pose danger of real infection
Immuno-compromised individuals can get infection from carrier
Carrier must be one that individuals are not already immune to
Cannot make booster vaccines with carrier (must use different carrier for booster)

23. DNA Vaccines
DNA injections can produce memory B cells and memory T killer cells
Reasons are not fully understood
Make a DNA vaccine from a few viral genes
No danger that it would cause infection

24. Types of Vaccines Non-infectious vaccines
No danger of infection
Does not stimulate cell mediated immunity
Usually need booster vaccines
Live, attenuated bacterial or viral vaccines
Makes memory B cells, memory helper T cells, AND memory killer T cells
Usually provides life-long immunity
Can produce disease in immuno-compromised host
Carrier Vaccines
Does not pose danger of real infection
Immuno-compromised individuals can get infection from carrier
DNA Vaccines

25. Effectiveness of Vaccines
Vaccination Effectiveness
About 1-2 of every 20 people immunized will not have an adequate immune response to a vaccine
Herd Immunity
Vaccinated people have antibodies against a pathogen
They are much less likely to transmit that germ to other people
Even people that have not been vaccinated are protected
About 95% of community must be vaccinated to achieve herd immunity
Does not provide protection against non-contagious diseases – eg tetanus

26. Vaccines
How Are They Tested?

27. Vaccine Testing Laboratory testing Animal Model
Animal must be susceptible to infection by agent against which vaccine is directed
Animal should develop same symptoms as humans

28. Vaccine Testing Human Trials Phase I NPR Story – Ebola Vaccine Trials
Small number of volunteers (20-100)
Usually healthy adults
Last few months
Determine vaccine dosages that produce levels of memory B or T cells that are likely to be protective
Evaluate side effects at these dosages
FDA must approve the vaccine as an Investigational New Drug (IND)
NPR Story – Ebola Vaccine Trials

29. Vaccine Testing Human Trials Phase II
Larger number of volunteers (several hundred)
Last few months to few years
Controlled study, with some volunteers receiving:
Vaccine
Placebo (or existing vaccine)
Endpoints: Effectiveness, safety

30. Vaccine Testing Human Trials Phase III
Large number of volunteers (several hundred to several thousand)
Last years
Controlled double blind study, with some volunteers receiving:
Vaccine
Placebo (or existing vaccine)
Neither patients nor physicians know which was given

31. Vaccine Testing Role of the FDA: Post-licensure surveillance
Licensure by FDA required before a company can market the vaccine (about a decade)
Each batch of vaccine must be tested for safety, potency, purity and sample lot must be sent to FDA
Post-licensure surveillance
Doctors must report adverse reactions after vaccination to FDA and CDC
Vaccine Adverse Events Reporting System (VAERS)
As many as 12,000 reports per year, 2,000 serious
Most are unrelated to the vaccine

32. Vaccine Testing
Recommendations by health departments and expert physician groups
When should vaccine be used
Who should receive it
Weigh: risks and benefits of the vaccine, costs of vaccination
Legislation:
States determine which vaccines are required by law
All 50 states have school immunization laws
Can be exempted based on:
Medical reasons (50 states)
Religious reasons (48 states)
Philosophical reasons (15 states)

33. Vaccine Schedule By age two: 20 shots!! Single visit: Up to 5 shots!!
Birth
Hepatitis B
2 Months
DTap #1
Polio #1
Hib #1
Hepatits B #2
Pneumococcus #1
4 months
DTaP #2
Polio #2
Hib #2
Pneumococcus #2
6 months
DTaP #3
Hib #3
Pneumococcus #3
12 months
MMR #1
Varicella
15 months
Hib #4
Polio #3
Hepatitis B #3
Pneumococcus #4
DTap #4
4-6 years
MMR #2
Polio #4
DTaP #5
11-12 years
Tetanus, Diphtheria
By age two:
20 shots!!
Single visit:
Up to 5 shots!!

34. Recommended Vaccine Schedule

35. History of the Rotavirus Vaccine
Withdrawn from the market after post-licensure surveillance indicated small number of adverse effects

36. Vaccines
Are They Effective?

37. History of Vaccination
Seventh Century
Indian Buddhists drank snake venom to induce immunity (through toxoid effect)
Second millennium
Variolation against smallpox
Central Asia, China, Turkey
1721
Variolation against smallpox moves from Turkey to England

38. History of Vaccination
History: Edward Jenner noted:
Smallpox and Cowpox:
Milkmaids frequently contracted cowpox which caused lesions similar to that smallpox
Milkmaids who had cowpox almost never got smallpox
Jenner’s (unethical) experiment:
Collected pus from cowpox sores
Injected cowpox pus into boy named James Phipps
Then injected Phipps with pus from smallpox sores
Phipps did not contract smallpox
First to introduce large scale, systematic immunization against smallpox

39. History of Vaccination
1885: Attenuation
Louis Pasteur - first vaccine against rabies
Early 1900s: Toxoids
Diphtheria, tetanus
1936
Influenza
1950s: Tissue Culture
Polio (Nobel Prize for Enders, Robbins, Weller)
1960s:
Measles, Mumps, Rubella

40. Effects of Vaccination in US
Disease
Max # of Cases
# Cases in 2000
% D
Diphtheria
206,929 (1921) 2
-99.99
Measles
894,134 (1941) 63
Mumps
152,209 (1968)
315
-99.80
Pertussis
265,269 (1952)
6,755
-97.73
Polio
21,269 (1952)
-100
Rubella
57,686 (1969)
152
-99.84
Tetanus
1,560 (1923) 26
-98.44
HiB
~20,000 (1984)
1,212
Hep B
26,611 (1985)
6,646
-75.03

41. Effects of Vaccination
Smallpox
First human disease eradicated from the face of the earth by a global immunization campaign
1974
Only 5% of the world’s children received 6 vaccines recommended by WHO
1994
>80% of the world’s children receive basic vaccines
Each year: 3 million lives saved

42. Smallpox One of world’s deadliest diseases Elimination of smallpox
Vaccine available in early 1800s
Difficult to keep vaccine viable enough to deliver in developing world
Elimination of smallpox
1950: stable, freeze dried vaccine
1950: Goal  Eradicate smallpox from western hemisphere
1967: Goal achieved except for Brazil
1959: Goal  Eradicate smallpox from globe
Little progress made until 1967 when resources dedicated, million cases per year at this time
Strategies:
Vaccinate 80% of population
Surveillance and containment of outbreaks
May 8, 1980: world certified as smallpox free

43. Childhood Immunization
1977:
Goal to immunize at least 80% of world’s children against six antigens by 1990

46. rtsp://audio.npr.org/me/ me.10.smil

47. Vaccines
What is Still Needed?

48. What Vaccines are needed?
The big three:
HIV
Malaria
Tuberculosis

49. Summary of Lecture 9 How do vaccines work? How are vaccines made?
Stimulate immunity without causing disease
How are vaccines made?
Non-infectious vaccines
Live, attenuated bacterial or viral vaccines
Carrier Vaccines
DNA Vaccines
How are vaccines tested?
Lab/Animal testing
Phase I-III human testing
Post-licensure surveillance
Impact of vaccines

50. Assignments Due Next Time
Two reading assignments:
WTIND - p. 147, 172, ,
CPS
WA5 (Vaccines)