Immuno 19 Flashcards
What is variolation?
term for delivery of initial smallpox vaccine either intranasally or intradermally (scratch on the arm)
What is vaccinia?
another name for the virus used to vaccinate against smallpox (vaccinia virus)
What is vaccination?
the deliberate administration of either killed or living forms of a pathogen, or antigens derived from that pathogen in an effort to elicit an immune response that will prevent infection upon exposure
What is immunization?
the deliberate provocation of an acquired immune response by introducing antigen into the body
What are killed or inactivated vaccines?
any vaccine that employs killed pathogens as the antigen
the pathogens can be killed either by chemical treatment, heat, or irradiation
What are attenuated vaccines?
any vaccine protocol that employs “weakened” pathogens as the immunogen;
pathogens can be weakened by several methods, and the result is that the attenuated pathogen’s ability to cause disease is either weakened or destroyed
What is a subunit vaccine?
vaccines that employ only part of the pathogen as the vaccine immunogen toxoid: an inactivated toxin used as a vaccine immunogen whose toxic activity has been destroyed (usually by chemical treatment)
Before the 1800s, smallpox epidemics were fairly routine and were devastating because the virus was easily transmitted from person-to- person, and because smallpox killed approximately 25% of those that became infected.
Before the 1800s, smallpox epidemics were fairly routine and were devastating because the virus was easily transmitted from person-to- person, and because smallpox killed approximately 25% of those that became infected.
How was smallpox first addressed/vaccinated?
The first efforts to prevent deadly smallpox infections was to take dried pustules from people that suffered relatively mild symptoms from a smallpox infection. These pustules were then used to inoculate uninfected people by scratching their skin with these pustules; the process was known as variolation.
Variolation killed anywhere from 1-10 percent of people that took this “vaccine”, but people were still willing to play the odds.
When was the first vaccine produced? By whom?
Edward Jenner in the 1780s
How did Kylie Jenner (and Tyga) make the first vaccine?
Jenner noticed that milkmaids seldom became infected with smallpox, and those that did suffered very mild disease symptoms. He somehow made the connection that milkmaids were being infected with a virus known as cowpox, and he believed that the cowpox infection was immunizing them against smallpox. It turned out that he was right.
Cowpox is a virus that is very similar to smallpox, except that it is not very virulent in humans. The surface proteins of cowpox are very similar to those expressed on the surface of smallpox.
It turned out that immunization (or infection) with cowpox elicited neutralizing antibodies specific for the surface proteins of the
virus. These antibodies are the most important immune response for clearing/preventing infection with cowpox.
It turned out that the antibodies raised against cowpox surface determinants would also neutralize smallpox virions.
This vaccine was the first and only vaccine to ever be completely effective.
By 1975, no cases of smallpox were being seen anywhere in the world. In 1979, smallpox was declared completely eradicated, and vaccine programs for smallpox were discontinued. Before 1979, everyone in this country was required to take the smallpox vaccine. I had mine when I was about 6 years old. I still have the characteristic scar at the vaccination site on my shoulder.
By 1975, no cases of smallpox were being seen anywhere in the world. In 1979, smallpox was declared completely eradicated, and vaccine programs for smallpox were discontinued. Before 1979, everyone in this country was required to take the smallpox vaccine. I had mine when I was about 6 years old. I still have the characteristic scar at the vaccination site on my shoulder.
What is an example of a killed-subunits/toxoid vaccine?
1) Diptheria-tetanus-pertussis
What is an example of a whole killed virion vaccine?
inactivated polio vaccine
What are some examples of live attenuated virus vaccines?
1) measles, mumps, and rubella
2) varicella
3) Rotavirus
4) Influenza (can also be killed attenuated)
5) yellow fever
What is an example of a heptavalent/diphtheria vaccine?
Pneumococcal conjugate
What is an example of a subunit vaccine?
Hep B
What is an example of a conjugated capsule subunit vaccine?
Meningococcus C
What is an example of a Gardasil: virus-like particles vaccine?
HPV
How do live attenuated viruses work?
These are all vaccines against viral pathogens, and because the vaccine formulation is an attenuated virus, the goal of the vaccine is to deliver the immunogens of the pathogen into the MHC class I pathway with the goal of activating a CD8+ T cell effector response.
For the vaccines that are either killed, subunit, or conjugated capsular vaccines, what is the goal?
the goals are to deliver the immunogen(s) into the MHC class II pathway, and to elicit a potent B cell (antibody) response against the pathogen.
What are some factors that make a ‘good’ vaccine?
1) safe
2) protective
3) sustained protection (An ideal vaccine is one that will elicit protective immune responses that will last a lifetime. This is a very high standard.)
4) Induced neutralizing antibodies (whether or not this is important clearly depends on the pathogen being vaccinated against. Neutralizing antibodies can be very important, but for some pathogens they have little if any role in protective immune responses)
5) Induces protective T cells (same as for neutralizing Abs. Can be critically important, sometimes T cells have no protective role.)
T or F. The immune system is designed to respond to physiological amounts of antigen/mmunogen.
T.
(Left-Hand Panel): In the left hand panel, you see a graph that shows what happens when subjects are immunized with increasing concentrations of antigen (note that this is on a log10 scale). The immunogen dose is shown on the X-axis and the antibody response intensity is shown on the Y-axis. You can see that a threshold amount of antigen had to be administered before any real immune response was elicited. As the dose of immunogen increased, the immune response that resulted increased too, until really high doses were administered. Once the dose got high enough, the response to vaccination actually went down.
(Right-Hand Panel): Now, looking at the right-hand panel: in this panel, the vaccination that was done is the left-hand panel was repeated, and then each study participant was given a booster immunization with the 10e3 dose. The secondary immune response was then measured. What is very clear is that the participants that received very low primary doses responded very poorly to the booster immunization. This is known as low-zone tolerance, and it indicates that the immune system is designed to not respond to very low concentration of antigens, and in fact, when really low doses of antigens are administered, any responding lymphocytes are subject to being removed from the repertoire. Participants that received medium doses upon primary immunization responded very well to the booster immunization. Those that received very high primary doses responded very poorly to the booster immunization. This indicates that the immune system is designed to tolerize itself against any antigen that is supplied in amounts that are too high to be physiological for an infection. This is known as high zone tolerance.
Effective vaccination is also difficult because the route of vaccination needs to match the normal route of infection for maximum benefit.
Effective vaccination is also difficult because the route of vaccination needs to match the normal route of infection for maximum benefit.
