Pox No Longer Upon Us
first part of the lesson will use historical documents
to help students understand the development and use
of vaccines. The historical documents allow for the
students to work with qualitative observations; these
documents contain several hypotheses that remain the
working basis of immunization.
During the second part of this lesson students will examine primary and secondary
immune responses as they relate to the production of antibodies. The students
will be asked to note the difference between the two responses based on a graph
which they will construct. Once the students have completed both the historical
documents and graph, they will be asked to relate both sets of information to
will be able:
Articulate the relationship of the vaccine to primary
and secondary immune responses of the body.
2. Explain how knowledge about vaccinations developed.
The human body contains many B and T cells which together
can respond to a multitude of antigens. Clonal selection
theory explains the effectiveness in which the body
can respond to an antigen. That is, there exists
a variety of B cells within the human body which
have a different kind of antigen receptor on their
cell surfaces. It is the activation of one of these
that creates the selection for cloning. These B cells
can produce effector cells called plasma cells that
will produce antibodies to fight this particular
antigen. Plasma cells are short lived. These activated
B cells will also produce memory cells, although
at a much lower proportion, that can remain in the
body for years. These memory cells can, when activated
by the same specific antigen, divide quickly and
produce more effectors.
Let us say that the body is exposed to a particular antigen for the first time.
This antigen activates the lymphocytes to produce clones and in turn, these clones
produce specific effectors and memory cells. The invader is thus destroyed and
there are now memory cells of this specific invader. This is a primary immune
response. The next time that the person is exposed to this particular antigen
the response is much faster and will produce a higher level of antibodies. This
secondary immune response is the direct result of memory cells produced during
the primary immune response. It is because of these memory cells and their rapid
response that we can immunize against diseases.
Vaccinations are simply the injection of small amounts of attenuated virus or
bacteria or their protein into the body. This exposure to an antigen will cause
the body to have a primary response that will not make them ill with the disease
but will produce memory cells for that specific antigen. It is the production
of memory cells that will protect the person against future illness since these
B and T cells can quickly respond the invader and overwhelm it. During the late
1700s, an English physician named Edward Jenner observed that people, who had
been ill with cowpox, would not become ill with smallpox, a related but much
more harmful virus. He used cowpox to inoculate a small child in 1796. Later
testing proved that the child was immune to both cowpox and smallpox. Although
Jenner is given much credit for producing the first vaccine, there were others
before him using the same principle to produce immunity. Lady Montague was documented
to have brought some of the ideas from Turkey to England.
(Note: World Health Organization declared smallpox eradicated in 1977, while
routine vaccination of the American public ended in 1972. Stocks of smallpox
virus still remain in laboratories here in the United States. Also the U.S. government
retains vaccines made from live vaccinia—not dead—for use in case
of an outbreak.)
and Resource Websites
Center for Disease Control
Fordham University (Modern History Source Book) http://www.fordham.edu
World Health organization http://www.who.gov
of California http://www.library.ucla.edu
Campbell, Neil A. 1996. Biology. 4th ed. Benjamin/Cummings
Publishing Co., Inc., Menlo Park, Ca.
DiSpezio, Michael. 1997. The Science of HIV. Automated
Graphic Systems, USA.
1. Provide students
with a copy of the instruction
sheet and direct them
in pairs to read historical
documents and respond
to the questions found on the data
Note that the left side of the data sheet corresponds
to the letter from Lady Montague and the right side
to that of the journal entries of Edward Jenner.
2. Once students have filled out the sheet share
with them that Edward Jenner is typically given credit
for developing vaccinations. Who else should be given
credit? Lady Montague? What about the women in the
market in Turkey? Can the basis for vaccinations
be traced even further back?
3. Share with the students that when the human body
is exposed to an antigen, the lymphocytes respond.
One of these responses is to produce antibodies which
will help eliminate the intruder. This first reaction
to an invader is called the primary immune response
and the cells that are producing the antibodies are
short lived. However, a second set of cells are produced
and they remember this particular antigen and can
produce the antibody when needed. These memory cells
will respond when the body is invaded for a second,
third or even fourth time by the same invader. In
fact these memory cells remain in the body for many
years following the first invasion. This should be
somewhat of a review from the earlier lessons on
4. The students should then, on a separate sheet
of graph paper, graph the data of antibody production.
They will assume that at time 0 the body was invaded
by an unknown antigen. That person was then exposed
for a second time to the same antigen on day 40.
5. Students should answer the questions below the
graph. What do they note about the type of pathogen
that a vaccine is used to combat?
mathematical information and background information,
students should be able to describe the relationship
of the vaccine to primary and secondary immune responses
of the body in the charts.
Using historical information, students should synthesize
information and be able to describe how knowledge about
vaccinations was developed in their responses in the chart.