1. Even 2,500 Years Ago, People Knew Immunity Worked.
Greek physicians noticed that people who survived smallpox never got it again.
The insight: Becoming infected by certain diseases gives immunity.

2. How does vaccination work?
Expose the patient to an Antigen
A live or inactivated substance (e.g., protein, polysaccharide) derived from a pathogen (e.g bacteria or virus) capable of producing an immune response

3. How does vaccination work?
Expose the patient to an Antigen
A live or inactivated substance (e.g., protein, polysaccharide) derived from a pathogen (e.g bacteria or virus)capable of producing an immune response
If the patient is subsequently exposed to infectious agent carrying this Antigen they will mount a faster immune response

4. Carrying antigens A and B
It works like this
Patient exposed to pathogen
Carrying antigens A and B
Molecular Biology of the Cell Alberts et al

5. Vaccines can be divided into two types
Live attenuated
Inactivated

6. Inactivated Vaccines fall into different categories
Whole
viruses
bacteria
Individual proteins from pathogen
Pathogen specific complex sugars
Fractional

7. Live Attenuated Vaccines have several advantages
Attenuated (weakened) form of the "wild" virus or bacterium
Can replicate themselves so the immune response is more similar to natural infection
Usually effective with one dose

8. Live Attenuated Vaccines also have several disadvantages
Severe reactions possible
especially in
immune compromised
patients
Worry about recreating
a wild-type pathogen
that can cause disease
Fragile – must be
stored carefully
MMWR, CDC

9. A number of the vaccines you received were live Attenuated Vaccines
Viral measles, mumps, rubella, vaccinia, varicella/zoster, yellow fever, rotavirus, intranasal influenza, oral polio
Bacterial BCG (TB), oral typhoid

10. Inactivated Vaccines are the other option
Pluses
No chance of recreating live pathogen
Less interference from circulating antibody than live vaccines

11. Inactivated Vaccines are the other option
Minuses
Cannot replicate and thus generally not as effective as live vaccines
Usually require 3-5 doses
Immune response mostly antibody based

12. Inactivated Vaccines are also a common approach today
Whole-cell vaccines
Viral polio, hepatitis A, rabies, influenza*
Bacterial pertussis*, typhoid* cholera*, plague*
*not used in the United States

13. Other Inactivated Vaccines now contain purified proteins rather than whole bacteria/viruses
Proteins hepatitis B, influenza, acellular pertussis, human papillomavirus, anthrax, Lyme
Toxins diphtheria, tetanus

14. Modern molecular biology has offered new approaches to make vaccines
Clone gene from virus or bacteria
and express this protein antigen
in yeast, bacteria or
mammalian cells in culture

15. Modern molecular biology has offered new approaches to make vaccines
2. Clone gene from virus or bacteria
Into genome of another virus (adenovirus, canary pox, vaccinia)
And use this live virus as vaccine

16. This allows T cells to recognize HIV infected cells,
for example, and even internal proteins
like reverse transcriptase can serve as antigens
An effective vaccine must get around
the strategies HIV uses to evade the immune system

17. To begin we need to ask some key questions
What should vaccine elicit?
Neutralizing antibodies
to kill free virus
T cell response to
kill infected cells OR

18. To begin we need to ask some key questions
What should vaccine elicit?
Neutralizing antibodies
to kill free virus
T cell response to
kill infected cells OR
OR BOTH?