Download Vaccine Case Study Answer Key File

Case Study ANSWERS
Vaccines: The Needle of Hope
Nelson Text p. 206
Part I:
a) Dairy maids often had cowpox sores on their hands. Suggest a possible source of the virus.
Source of the cowpox sores was probably the cows milked by the dairy maids.
b) Assuming that the virus is contagious, would you expect to find that cowpox would infect
people other and diary maids? Give your reasons.
The virus would likely infect anyone who worked with the cows or with people with
cowpox
c) What dangers did Jenner’s untried procedure hold for young James Phipps?
After the injection of smallpox he could have developed smallpox or even died
d) Jenner’s experiment was successful; however, many modern day scientists would argue
against using humans for such a test. Why do you think using humans as a first test subject
is no longer accepted?
There are laws against using humans as subjects for experimentation without their
permission. Usually tried on other animals first. Is this acceptable?
e) What makes the cowpox virus less virulent than smallpox? Cowpox is less virulent than
smallpox because smallpox reproduces faster than cowpox and therefore the immune
system cant make antibodies quick enough.
f) Explain why cowpox antibodies stop the spread of smallpox in the human body? The
cowpox antibodies are similar in shape to the smallpox antibodies therefore they bind to
smallpox antigens and stop them from invading cells (cowpox most likely led to smallpox)
Part II:
g) Explain why the reproduction of the virus (rabies) inside the host cell makes it especially
dangerous. Because the virus reproduces inside the cell, the immune system of host can’t
“find” it and therefore, can’t produce the antibodies against it.
h) Why do the symptoms of rabies not show up immediately after the virus enters the first
cell? Symptoms of rabies don’t show up until the virus has reproduce inside cells.
i) Why did Pasteur want to weaken the rabies virus before injecting it into a person? Pasteur
wanted to weaken the virus so the immune system could make antibodies before the virus
could reproduce enough to cause the disease in host.
j) Draw a diagram showing how the virus is defeated when it emerges from the body cells
after it incubation period. Diagram with the correct shape antibodies should be available
to bind with the antigens when the virus emerges from the cell.
Part III:
k) Propose an explanation for why an antibody would work well against one type of polio but
not against another. Different types of viruses means that they will have a different protein
coat and therefore different shaped antigens. Antibodies shape is specific to antigen shape.