Antiviral Vaccines Flashcards
(16 cards)
Given the many types of vaccines available, discuss why a live attenuated virus vaccine may
be the best choice for use against infectious viral diseases
they mimic natural infections with a weakened strain. they induce strong and long-lasting immunity in both cell-mediated (t-cells to clean up and recover) and humoral (b-cells to prevent further infections) immunity.
Why are most of the vaccines against viral diseases given during childhood?
they have a low IgG (big contributor to the immune system), it takes several years to fully develop the immune system.
A recent problem with the campaign for the eradication of polio (2004-2005) is a perfect
example of an unexpected “adverse event”. What was the adverse event?
an adverse event is when a bad outcome comes after a drug. During the 2004-2005 campaign, in countries with low vaccination coverage, the use of OPV led to outbreaks of vaccine-derived poliovirus. This occurred when the weakened virus in the vaccine (which is still live, albeit attenuated) mutated and regained the ability to cause paralysis.
Define the term “herd immunity”. The ability of some vaccines to induce herd immunity has
long been thought of as a positive property. Discuss some of the ethical issues surrounding
herd immunity
a sufficiently high vaccine coverage to limit the spread of a virus.
-Maing someone take the vacine
-religios reasons
How would you construct a subunit chimeric vaccine using a viral vector for use against a
human virus?
chimeric = hybrid/ many antiboies
1. choose a viral vector to deleiver the genetic material
2. pick an antigenic protein from target virus like spike protien or nucleocapsid protien
3. insert 1 or more genes for protein into viral vector
4.add adjuvants
5. produce vaccine
Subunit vaccines generally stimulate only humoral immunity. What modifications or
additions to these vaccines could enable the stimulation of both humoral and cellular
immunity in a vaccinated individual?
-Add adjuvants
-chimeric subunit vaccines
-use DNA or mRNA
What is the difference between a DNA vaccine and an mRNA vaccine? How were the two
mRNA vaccines developed by Pfizer/BionTech and Moderna ?
DNA:
-use DNA to endcode for antigens
-goes to the nucleus as episome
-transcribed to mRNA
-creates protien antigen to innicate immune response
mRNA:
-mRNA is genetic material
-immediatly transcribed into antigen protien (doesnt need to go to nuclecus)
-therefore quicker
-encodes a prefusion stabilized spike protien
-packed in lipid nanoparticals to make it more stable
what are the 4 types of immunization?
- passive: antibodies from one source to another to prevent infection. wont provide long-term immunity
- Maternal: placenta to fetus, colostrum, milk through breast feeding
- post-exposure prophylaxis: injection of immune globulin or monoclonal abs.
- Active immunization: natural infection or using vaccines to trigger immune reponse against future infections by the same virus.
what are the 4 types of active immunization?
- attenuated live
- inactivated
- subvirion (subunit)
- new vaccine tech (viral vector, DNA, Plant-based, and mRNA)
what are the disadvantages to live attenuated vaccines?
require refrigeration
issues in those with weakened immune systems
reversion to wild virulent type
recombination with natural viruses to produce virulent virus
contamination with other viruses
what is inactivated viral vaccines? advantages and disadvantages?
getting a virus then inactivating by heat or chemicals
+: safe, no risk for reversion to virulence, no need for cold storage
-: not as effective, requires multiple doses, enduces mostly humoral respone, risk if not full killed
what is subvirion (split vaccines)?
wildtype or recombinant virus (using master strain) containing HA gene from predicted strains are tested and mass produced in embryonated chicken eggs or cell cultures.
-affect humoral response
-adaptation can occur educing efficacy
-immune senesence
what is cell-mediated immunity?
T-cells, clean up and recover from an infection
-dosnt use antibodies
What is humoral immunity?
B-cells: to neutralize viruses and prevent furter infections
-uses antibodies
What is recomninant viral vectors
The expression of a viral surface antigen using another virus as a vector.
-recombinant vesicular stomatitis virus (rVSV) expressing glycoprotein of Zaire ebola virus
what are plant-based vaccines?
-genetic engineering of plant to express an antigen
-then we eat the raw plant to trigger mucosal immunity
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