1. Vaccination & True Immunity
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2. Memory Cells T cells activate B cells
B cells go through cell divisions
Cell cloning  through mitosis
Produce the same antibody
There are two types of cloned B cells
Antibody secreting plasma cells
Secrete antibodies immediately
Fight off first infections
Memory cells
Do not secrete antibodies during the first infection
Long lived & remain in blood stream waiting for a secondary infection

3. Fundamental Principles of Immunity
Apply for all types of infection
Challenge and Response
Immune system must be challenged by an antigen during first infection to develop immunity
Macrophages, T cells, B cells
Clonal selection
Particular B cells & multiple divisions
Memory Cells
Provide long term immunity
You must experience a pathogen (antigen) to produces these cells

4. Active and Passive Immunity
The event just described represent active immunity
Active immunity always  memory cells  long term immunity
Passive Immunity
When one organisms acquire antibodies which were produced in another organism
Only the organism which produced the antibodies has the memory cells
Acquiring antibodies = only short term benefit

5. Examples of Passive Immunity
Transfer of antibodies from mother to fetus through the placenta
Memory cell are not transferred
Breast milk (colostrum)
High antibody concentration
Injection of antibodies
Antivenoms produced for treatment of poisonous snake and spider bites

6. Immunity may be natural or artificial
Acquired from mother; immunity from infection
Artificial:
Due to inoculation from vaccine

7. Vaccines and Immunity
You must be exposed to a specific pathogen in order to become immune to it
For many diseases, scientists have developed vaccines that act as the first exposure to the pathogen

8. How are vaccines produced?
Several methods:
Select a particular “weak” strain of the pathogen
Heat the pathogen
Chemical treatment of the pathogen
The leukocytes responsible will recognize the weakened pathogen & primary immune response will take place
Includes formation of memory cells

9. More on vaccines
Vaccines do not prevent an infection, but, when exposed to the real pathogen, secondary immune response is quicker than primary
After vaccination, most people respond so quickly to the real pathogen that only very mild symptoms (or no symptoms) result

10. Graph of antibody production
in the primary and secondary
Immune response
Secondary immune
response
produces more
antibodies in less time
Second exposure
to same antigen
First exposure
to antigen
Primary
immune
response

11. Turn and talk What are the benefits and dangers of vaccines?
Why do many nations, including the U.S., require vaccines?

12. Benefits and Dangers
Most people agree vaccination has benefited humankind
Some diseases, like smallpox, have been eliminated (no reported case since 1977)
Result of WHO smallpox vaccination program
However, not all are happy …
Being forced by a governmental agency
Individual right to make decisions about their health

13. Benefits Possible total elimination of the disease
Seen with smallpox; possible with polio & measles?
Decrease spread of epidemics and pandemics
Implications of increased international travel
Preventative medicine is typically more cost-effective
Vaccine is cheaper than treating the disease
Vaccinated individual benefits b/c the full symptoms of the disease do not have to be experienced to gain immunity.

14. Danger
Prior to 1999, many vaccines contained thimerosal, a mercury-based preservative
Mercury: neurotoxin; infants & young children susceptible
Perception exists that multiple vaccines given to children in a short time frame may “overload” their immune system
Anecdotal evidence that MMR vaccine link to autism
Measles, mumps, rubella
Hot issues topic
In some cases, vaccines lead to allergic reactions

15. Practice #1
Which type of cell is responsible for secondary immune responses to a pathogen?
A. Cytotoxic T-cells
B. Phagocytes
C. Macrophages
D. Memory cells

16. Practice #2
Some infectious diseases are treated by injecting the patient with antibodies after they have been exposed to the disease. What type of immunity is this?
A. Artificial and active
B. Artificial and passive
C. Natural and passive
D. Natural and active

17. Practice #3 Which is not true of active immunity?
A. It can be produced by exposure to a disease causing organism.
B. It can be produced artificially.
C. It can be produced by a virus.
D. It can be transferred via the colostrum.

18. #4 Which curve shows the response of the immune system
to a vaccine, followed by an infection?