1. Vaccines stimulate immunity
Cary High

2. Objectives Understand the purpose of a vaccine
Explain the three lines of natural immunity
Describe the four types of vaccine development strategies
Identify the advances made by the early vaccines developed in the US

3. Deadly Childhood Diseases in US
Were common in your grandparent’s childhood.
Many of them got diseases such as diphtheria, whooping cough, polio and small pox. Many of them lost friends to these diseases
The ones that got the diseases and survived developed PERMANENT immunity

4. Childhood Diseases in the US
Are rare today
due to vaccines that activate the IMMUNE SYSTEM.
This gives the body the ability to fight off the germs causing the disease

5. Scientists working on vaccines
Immunologists
Molecular biologists
Biochemists
others

7. Body’s Natural Immunity
IMMUNE SYSTEM: 3 lines of defense
Barrier defenses
Internal defenses:
starts with the production of WBCs in the bone marrow which become specialized and circulate throughout the body.
They often collect in the lymph nodes (located in armpits, neck and groin).
This is why you have swollen glands when fighting off a cold.

8. First Line of Defense Nonspecific Barriers to Infection Skin
Mucous Membranes
Cough
Sneeze

9. Second Line of Defense EATER CELLS:
Macrophages – special WBCs that attacks invading microorganisms, engulfs it and breaks it down into pieces.
This results in a surface-antigen notification system being sent out to the rest of the immune system.

10. Third Line of Defense SMART CELLS:
The antigens cause the formation of specific antibodies by the B-cell lymphocytes
T-cells support B-cells for rapid enemy antigen recognition with future exposures (memory T cells)

11. Vaccines imitate the invader and stimulate immune response
Using several strategies:
Live “attenuated” viruses / bacterium (too weak to cause the disease but strong enough to activate immune response)
Inactivated or killed viruses / bacterium (microorganism is killed using chemicals but leave the surface antigen in tact; antigen recognition stimulates immune system)
Recombinant DNA-based used for viruses that will not grow in cultured cells
Experimental Vaccines from engineered viruses and bacteria

12. Recombinant DNA - based
Because these viruses/bacteria do not grow in cultured cells, it is impossible to develop live or inactivated vaccines for them.
Scientists identify a subunit of the virus/bacterium and use recombinant DNA technology to produce vaccine.
The subunits activate the body’s immune response, but do not cause the disease.

13. Recombinant DNA

14. Experimental Vaccines
Scientists are:
Trying to engineer viruses / bacteria with specific genes deleted that will stimulate immune response without causing the disease
They could also carry the antigens for several diseases, making them a SUPER VACCINE.
Pharming: developing pharmaceutical vaccines in plants may provide more efficient and safer vaccine that is more stable for distribution.
They are working creating new antigens that form antibodies to trigger specific immune response to cancer.

15. Early Vaccines
Small Pox – in 1776 Edward Jenner developed a vaccine used an attenuated virus (cowpox)
Polio – virus that infected spinal fluid and led to paralysis; many put on iron lung machines to breath. In 1950, Jonas Salk discovered an injectable inactive vaccine. In 1961, Albert Sabin advanced this by creating an attenuated vaccine that is delivered orally

16. Recombinant Vaccines
Hepatitis B – attack the liver and can cause death. Mild cases improve with in 6 months. However, 10% of those cases become carriers and can transmit the disease to others.
This virus refuses to grow in a cultured dish so scientist engineered the vaccine using recombinant DNA technology (cloned gene put into the DNA of a yeast cell).
Hep-B vaccine is the FIRST BIOENGINEERED VACCINE

17. Goal of vaccination program
to achieve Herd (Community) immunity
When a critical portion of a community is immunized against a contagious disease, most members of the community are protected against that disease because there is little opportunity for an outbreak. Even those who are not eligible for certain vaccines—such as infants, pregnant women, or immunocompromised individuals—get some protection because the spread of contagious disease is contained.

18. Vaccination schedule: US children
Age
Hep B
Oral Polio
DPT
Heameophilus
MMR
2 months X
4 months
6 months
12-15 months
15-18 months
4-6 years
14-16 years

19. Q/A
If a child gets an infectious disease, before he gets his routinely scheduled vaccine, and survives, does he still need the vaccine?
A nursing home patient is experiencing a pervasive case of psoriasis on her skin. Is she more susceptible to an infectious disease? Why or Why not?

20. More Q/A
Name the first recombinant DNA vaccine made available in the US.
What is the difference between a vaccine made with an attenuated virus and one made with an inactive virus?
Can you catch the disease from the vaccine (live or inactive)?
What is the purpose of a vaccine?
What is the purpose of a vaccination program?