1. BIOE 301 Lecture Nine Amit Mistry Feb 8, 2007

2. BIOE 301 – Lecture 9 WARM-UP What type of immune defense is involved in each of the following: A flu virus infects your cells You step on a rusty nail and it pierces your skin You’re exposed to chicken pox (you already had it as a kid)

3. 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

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 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. Influenza Pandemic CDC Public Service Announcement http://www.pandemicflu.gov/ 1918-19: Spanish Flu 50-100 million deaths 1957-58: Asian Flu 1-4 million deaths 1968-69: Hong Kong Flu 750,000 deaths www.cdc.gov http://en.wikipedia.org/wiki/Pandemic

8. 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 http://students.washington.edu/grant/rand om/sneeze.jpg

9. 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

10. Influenza Viral Reproduction - 2 pH slowly reduced in endosome, due to proton pump in membrane 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

11. 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

12. 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 http://www.cdc.gov/flu/weekly/usmap.htm

13. 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 Interferon – protein that fights infection, but also causes: Fever Muscle aches Headac hes Fatigue

14. Genetic Shift and Flu Pandemics Genetic Shift 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. http://www.cdc.gov/flu/avian/facts.htm

15. Why do we need vaccines? Pathogen = Offense Immune System = Defense Vaccines  “Stealing the playbook”

16. Vaccination Vaccination: Practice of artificially inducing immunity Goal of vaccination: Stimulate both cell mediated and antibody mediated immunity that will protect the vaccinated person against future exposure to pathogen Want the vaccine to have: Maximum realism Minimum danger

17. 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

18. History of Vaccination Seventh Century Indian Buddhists drank snake venom to induce immunity (through toxoid effect) 1700’s Variolation against smallpox

19. History of Vaccination 1798 - 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

20. 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

21. Types of Vaccines Non-infectious vaccines Flu, plague DTaP, Pneumococcus Live, attenuated bacterial or viral vaccines Chicken Pox, MMR Carrier Vaccines DNA Vaccines Experimental

22. 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

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

24. Cell culture allows development of: live, attenuated vaccine Grow cells: Removed from tissue In vitro (in glass) By supplying nutrients and other factors Specific O 2 and CO 2 (pH level) Glucose, ions Serum from blood: proteins

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

26. Carrier Vaccines Use virus or bacterium that does not cause disease to carry viral genes to APCs e.g. vaccinia for Smallpox vaccine http://www.bt.cdc.gov/agent/smallpox/vaccination/fa cts.asp http://www.bt.cdc.gov/agent/smallpox/vaccination/fa cts.asp 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 Why can’t you make a booster vaccine with carrier?

27. 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

28. 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 + 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 DNA Vaccines Experimental…

29. 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

30. Your Flu Shot If you got your flu shot this season, and skip it next season, you are more likely to get the flu next season…Why?

31. Vaccines How Are They Tested?

32. 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

33. Vaccine Testing Human Trials Phase I 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 TrialsEbola Vaccine Trials http://www.npr.org/rundowns/segment.php?wfId=1513230

34. 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

35. 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

36. Vaccine Testing Role of the FDA: 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

37. 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)

38. Vaccine Schedule 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!! http://www.christianpoint.org/inspirati on/images/crying_baby.jpg

39. Recommended Vaccine Schedule

40. History of the Rotavirus Vaccine Withdrawn from the market after post-licensure surveillance indicated small number of adverse effects http://www.npr.org/templates/story/story.php?storyId=3262013 http://www.npr.org/templates/story/story.php?storyId=5126636

41. Vaccines Are They Effective?

42. Effects of Vaccination in US DiseaseMax # of Cases# Cases in 2000 %  Diphtheria206,929 (1921)2-99.99 Measles894,134 (1941)63-99.99 Mumps152,209 (1968)315-99.80 Pertussis265,269 (1952)6,755-97.73 Polio21,269 (1952)0-100 Rubella57,686 (1969)152-99.84 Tetanus1,560 (1923)26-98.44 HiB~20,000 (1984)1,212- 93.14 Hep B26,611 (1985)6,646-75.03

43. 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

44. Smallpox One of world’s deadliest diseases 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, 10-15 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

45. Childhood Immunization 1977: Goal to immunize at least 80% of world’s children against six antigens by 1990 Measles Diphtheria Pertussis Tetanus Polio Tuberculosis

46. Measles Pertussis

47. Diptheria

48. http://www.npr.org/templates/story/story.php?storyId=849775 http://www.npr.org/templates/story/story.php?storyId=3870193

49. Vaccines What is Still Needed?

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

51. Summary of Lecture 9 How do vaccines work? 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

52. Turn in Project Task 2 today Next Time HW 5 due on 2/13/07 HIV/AIDS vaccine development

53. To learn more Influenza http://www.cdc.gov/mmwr/mguide_flu.html Avian Flu: http://www.cdc.gov/flu/avian/ http://www.pandemicflu.gov/ Original Antigenic Sin http://www.rice.edu/sallyport/2003/fall/sallyp ort/flu.html http://www.rice.edu/sallyport/2003/fall/sallyp ort/flu.html An overview of vaccines http://www.accessexcellence.org/AE/AEC/CC/ vaccines_how_why.html http://www.accessexcellence.org/AE/AEC/CC/ vaccines_how_why.html