Microbio Week 10 - Viral Immunology & Viral Vaccines (Exam 3) Flashcards
What are innate defenses specific to?
General class of the pathogen
T/F: Innate defenses are specific to the pathogen itself
FALSE, innate defenses are specific to the general class of the pathogen
What defenses respond first to initial exposures?
Innate
What do innate defenses do to the pathogen?
Slow or stop it
What defenses respond to secondary exposures?
Adaptive
What parts of the adaptive response act fast to prevent disease when encountered with a secondary exposure?
Neutralizing ABs and CTLs
What type of barriers can stop a microbe from infecting a person?
Physical barriers
Name 5 examples of physical barriers that can stop a microbe from infecting a person
Skin
Coughing
Sneezing
Mucus
Stomach acidity
____________ compounds can also act on viruses to prevent infection
Antimicrobial
If a virus can circumvent the physical barriers and infect a cell, what type of cell is triggered?
Type I interferon
What do Type I interferons tell your body?
That an infection is happening
What do pattern recognition receptors recognize in an infected cell? What do they stimulate?
Recognize viral RNA + DNA
Stimulate Type I interferons
What do interferons induce in infected cells and neighboring cells?
Wide variety of genes
What do interferons help guide?
Immune response
What do interferons activate?
Antiviral proteins
What response have many viruses figured out ways to reduce?
Type I interferon response
What type of cells are important in viral infections?
NK cells
What do NK cells kill? What does this stop?
Infected cells, stopping the viral spread
Note from lecture: NK cells also kill cells without MHC I
What are NK cells most well-known for recognizing?
Cells that down-regulate their MHC I
Why do many viruses down-regulate MHC I?
To escape CTL killing
What 2 cells are essential in bridging the innate and adaptive immune responses?
Macrophages and dendritic cells
Which specific type of dendritic cell makes large amounts of Type I interferons when there is a viral infection?
Plasmacytoid dendritic cell
Why are plasmacytoid dendritic cells able to make large amounts of Type I interferons when there is a viral infection?
They sense viral infections without being actively infected
Can viruses stop interferon production in plasmacytoid dendritic cells?
NO, because plasmacytoid dendritic cells are able to produce Type I interferons without an active infection
What are the 2 critical parts of the adaptive immune response to viral infections?
Neutralizing ABs and CTLs
What do neutralizing ABs bind to? What does this prevent?
Surface of the virus, prevents virus from infecting a cell
What do viral antigens encountered in the mucosa primarily produce?
Dimeric IgA
Which antibody is produced in large quantities in mucosal surfaces, gut, and upper/lower respiratory tract?
Dimeric IgA
Viruses with a vimeric stage (virus in the blood) primarily produce which type of antibody?
IgG
Why are CTLs critical for viral infections?
They kill infected cells and keep chronic viral infections in check
What are the 4 ways viruses can subvert the immune system?
- Escape neutralizing ABs by antigenic drift
- Block Type I interferon response
- Down-regulate MHC I to prevent getting killed by CTLs
- Kill immune cells
If you encounter the same strain of a virus, you are generally protected from reinfection due to what 2 things?
Long-lived plasma cells and secreted ABs
Which 2 locations are neutralizing ABs present before re-encountering a virus?
Mucosa and blood
Neutralizing ABs already present in mucosa and blood bind directly to the virus and prevent re-infection. What can happen after this?
Another round of affinity maturation, so you end up for even more ABs against this virus
What are the 3 possibilities when you encounter a different/new strain of a virus for the first time?
- Cross-protection
- Partial cross-protection
- No cross-protection
New strain is recognized with good affinity by ABs from a previous strain, resulting in no infection or sickness
Cross-protection
ABs bind with a lower affinity, so they cannot prevent some cells from being infected. The infection will clear faster and there might be fewer symptoms since you will get neutralizing ABs faster than in a primary infection.
Partial cross-protection
Results in less spread of the virus. Memory CTLs from the previous infection might recognize and clear the infected cells, reducing the infection’s severity
Partial cross-protection
Like a new infection
No cross-protection
What 3 things are needed for an effective vaccine?
- Neutralizing AB response to the virus
- Viral proteins that induce neutralizing ABs
- Stimulation of an immune response
What are 2 things that stimulate an immune response in a vaccine?
- Attenuated virus or whole killed/inactivated virus
- Adjuvant
Attenuated viruses or whole killed/inactivated viruses have viral-specific signals that activate what type of receptors in immune cells in order to turn on the immune response?
Pattern recognition receptors
Substance that activates the immune system
Adjuvant
Viruses with viral-specific signals that activate pattern recognition receptors in immune cells in order to turn on the immune response
Attenuated viruses or whole killed/inactivated viruses
What type of virus vaccine: attenuated, inactivated, or subunit?
Replicate just a little - immune system sees it as a regular viral infection and mounts an immune response. Immune response clears the virus before you get sick
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Tend to be excellent vaccines
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Measles, mumps, rubella (MMR)
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Varicella Zoster (chickenpox)
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Rotavirus
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Nasal influenza vaccine
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Yellow fever vaccine
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Smallpox/Mpox (vaccinia) (not for general public)
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Oral polio (not used in US)
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Military only-Adeno type 4 and 7 (live virus)
Attenuated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Virus does not replicate at all. Can still start immune response since the vaccine contains viral proteins and nucleic acids that trigger an immune response.
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Adding an adjuvant will result in a better immune response. Many more virus particles are needed, and more booster shots are required for complete immunity.
Inactivated virus vaccine
Which virus vaccine requires more virus particles: attenuated or inactivated?
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Inactivated polio vaccine (used in US)
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Hep A vaccine
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Rabies vaccine
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Influenza vaccine
Inactivated virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Just contains part of a virus. No chance of infection.
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Must use correct protein to get a neutralizing AB response. Adjuvant is very helpful.
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
HA only influenza vaccine
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Hep B vaccine
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
Human papilloma (HPV) vaccine
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
New shingles vaccine
Subunit virus vaccine
What type of virus vaccine: attenuated, inactivated, or subunit?
mRNA vaccines producing 1 or 2 viral proteins
Subunit virus vaccine
What antibody is transferred from mother to baby in the 3rd trimester?
IgG
What antibody is transferred from mother to baby in colostrum and breast milk?
IgA
Why are some immunizations not done until the baby is 1 years old?
Due to naturally occurring maternal ABs (IgG and IgA)
Waiting 12 months after birth is most important with which vaccine?
Measles, mumps, rubella (MMR)
If you give a baby a vaccine before they turn 1, maternal ABs will bind the ________ virus, preventing it’s replication. This will inhibit the attenuated strain from infecting cells and prevents _________ _________ in the baby. Then, when the maternal ABs leave, the baby has no protection
attenuated; immune response
Some ABs are given ______________ to help prevent infection
post-exposure
Name 3 types of ABs that can be given post-exposure to help
- IGs from healthy blood donors
- Hyperimmune IG from people with a high titer to a specific infection
- Monoclonal ABs to specific viruses
What type of ABs for post-exposure to Hep A and measles?
IGs from healthy blood donors
What type of ABs for post-exposure to rabies, chickenpox, CMV, and vaccinia?
Hyperimmune IG from people w/ a high titer
What type of ABs for post-exposure to RSV-given pre-exposure and SARS-CoV-2?
Monoclonal ABs
In what cases is it possible to prevent infection after exposure by vaccination if done quickly?
Rabies
Hep A
Hep B
Smallpox
What refers to the fact that the spread of infectious disease requires contact between a non-immune person (susceptible) and an infected person?
Herd immunity
What will ultimately benefit non-immune people?
Herd immunity
Vaccination needs to reach a certain percentage of the population to protect the community, but it usually spans ________%
75-95
Adjuvants are added to vaccine because they increase…
The immune response to a subunit vaccine
Viruses use several means to subvert the immune response. What method would allow them to reinfect the same person?
Mutating their genome
Why is an attenuated vaccine so useful? Pick the statement that is false.
a. Limited replication of the virus mimics a real infection.
b. Proteins are present in the correct form to elicit a neutralizing antibody response
c. They are the safest, more people want them.
d. Less virus needs to be make than a whole killed virus vaccine.
c. They are the safest, more people want them.
Attenuated virus vaccines tend to have a higher risk of adverse events. These can be mild, like sore arms or fever, or, in very rare cases, serious.
Immunoglobulin is most commonly used ________________ to prevent a viral infection.
post-exposure
Passive immunization only lasts about a month and for this reason it is given if a possible exposure event has occurred. Antibodies given pre-exposure are really only used for RSV in premature infants.
The presence of ___________ can prevent infection of the person. This is called sterilizing immunity.
neutralizing ABs
The presence of ____________ reduce the effectiveness of some vaccines.
maternal ABs
___________ can clear a cell if it becomes infected faster than in an initial infection.
Memory CTLs
________________ vaccine needs to be able to replicate to be effective.
Attenuated
A ______________ vaccine contains all of the virion proteins but does not replicate
inactivated
A ____________ vaccine contains just part of the virus and need to contain an adjuvant.
subunit