Viral Vaccines Flashcards
(40 cards)
What are the two arms of the immune response? Briefly describe both.
1) Innate immunity: the innate immune system is based on distributed receptors that recognize certain molecular patterns, found in microbes. these receptors are called PATTERN RECOGNITION RECEPTORS
2) Adaptive immunity: based on antigen-specific responses of T and B lymphocytes
The innate immune system is ______ but _________, while the adaptive is ________.
Rapid; non-specific; specific
Which arm of the immune system makes the success of vaccines possible?
Adaptive immunity
What are the five phases of the adaptive immune response?
1) Antigen recognition
2) Lymphocyte activation (clonal expansion and differentiation)
3) Antigen elimination (antibodies and effector T cells)
4) Contraction (apoptosis of lymphocytes)
5) Memory (some lymphocytes survive in resting conditions)
Native cells expand and differentiate into effector cells in steps 1-3.
T cells and B cells are _______ cells of the adaptive immune response. These cells are required for recognition of foreign _______.
Following initial encounter with pathogen/vaccine, ______ T and B cells are established.
Re-exposure to the same pathogen reactivates _____ cells to control the __________ infection quickly and prevent disease.
effector; antigens
memory; memory; secondary
(T/F) Vaccines generates the expansion and differentiation of T and B cells like an infection would, creating memory cells.
True!
The first encounter with an antigen X produces a ________ response. Antigen X introduced at time zero encounters _____ specific antibody.
After a _____ phase, antibody against the antigen appears; its concentration ____ to a plateau and gradually ______.
When later challenged with antigen X, a very ______ and ______ antibody _______ response occurs, illustrating immunological memory!
Primary; little
Lag; rises; declines
Rapid; intense; secondary
Which one of these statements is false?
1) It takes a fairly short time (couple days) to generate memory cells.
2) The more we get exposed to the same antigen, the more rapid and robust the response will be (ex. boosters).
1!
It takes a long time (couple weeks) to generate memory cells.
What is the goal of vaccination?
The goal of vaccination is to trigger an immune response MORE RAPIDLY and with LESS HARM than a natural infection: in essence, to avoid the disease that often accompanies the first exposure while enabling establishment of LONG-LASTING IMMUNOLOGICAL MEMORY.
A vaccine is a ________ product that can be used to safely ______ an _______ response that confers _______ against infection and/or disease on subsequent exposure to a pathogen.
biological; induce; immune; protection
(T/F) Smallpox that caused infections that killed, crippled, or disfigured more than 1 in 20 of all humans is the one of the few human viruses to be eradicated.
False!
Smallpox that caused infections that killed, crippled, or disfigured more than 1 in 20 of all humans is the ONLY ONE human virus to be eradicated.
Who is Edward Jenner?
Edward Jenner invented the small pox vaccine.
He noticed all the people that were working with cow milk were developing lesions in their hands. He traced these people and figured out these people never got small pox.
He isolated the virus from the lesion and used it as a vaccine!
(T/F) The available smallpox vaccines contain live attenuated vaccinia virus, an orthopoxvirus closely related to variola virus that confers immunity against smallpox virus through cross-reactivity.
True!
What is SSPE? What was the consequence of measles vaccine on SSPE?
SSPE stands for subacute sclerosing panencephalitis which is a brain disease that was a late consequence of measles infections in few patients.
When measles was prevented with vaccines, SSPE disappeared 15-20 years later!
(T/F) Technical and economic problems can prevent the widespread use of vaccines in developing countries, where mortality from diseases that are virtually eliminated in developed countries are still high.
True!
*there r still many diseases for which we lack effective vaccines
Describe herd immunity.
Herd immunity is an important feature of vaccine-induce protection.
If there is no vaccination, infection passes from individuals with disease to susceptible individuals.
If there is vaccination but below threshold for herd population, infection can still pass to susceptible individuals not vaccinated.
If there is herd immunity, infection CANNOT SPREAD in the population and susceptible individuals are indirectly protected by vaccinated individuals.
(T/F) Herd immunity is the same for all pathogens (the same % of population has to be vaccinated).
False!
Each pathogen transfers in a different way. Thus, the % of population that has to be vaccinated to protect everyone is different.
Why are there still not effective vaccines made for infections like TB, malaria and HIV?
In some infections (malaria, TB, HIV) antibodies are INSUFFICIENT to prevent reinfection or to eliminate the pathogen, and cell-mediated immunity alone is insufficient to provide full immunity.
It is sometimes not the absence of an immune response to the pathogen that is the problem, but rather that this response does not effectively clear the pathogen, eliminate the pathogenesis, or prevent reinfection.
(T/F) Measles vaccines are effective worldwide.
False!
They are heat-sensitive, which makes their use difficult in tropical countries; heat stability is being improved!
What are the 6 features of effective vaccines?
1) Safety
2) Protective (must protect against illnesses)
3) Gives sustained protection (several years)
4) Induces neutralizing antibody (to prevent infections of cells like neurons that can not be replaced)
5) Induces protective T cells (intracellular pathogens are more effectively dealt with cell mediated responses)
6) Practical considerations: COST, biological stability, ease of administration, few side effects.
Which one of the statements is false?
1) Very low toxicity is acceptable in vaccines.
2) Vaccine must be able to generate long-lived memory, important in poorer countries where it is impractical to get boosters.
3) Successful vaccines must induce long-lasting protection while being safe + inexpensive.
1!
Even LOW toxicity is unacceptable in vaccines.
Immunization can be passive or active.
Differentiate between passive and active immunization.
Passive immunization: direct administration of the products of the immune response (antibodies/immune cells) obtained from an appropriate donor to a patient. SHORT-TERM effects.
Active immunization: the process of inducing an immune response by exposure to attenuated or killed virus preparations or with purified viral proteins. LONG-TERM effects
(T/F) Passive immunization can only be artificially acquired.
False!
It can be NATURALLY or ARTIFICIALLY acquired.
Give an example of naturally-acquired passive immunization.
Neonates benefit from passive immunization following birth because some of the mother’s antibodies pass into the fetal bloodstream via the placenta.
This passive process provides transient protection to the immunologically naive newborn.
