Lecture #10 - Vaccines Flashcards

1
Q

Vaccines

A

• Vaccines work to prime the immune system by stimulating primary immune responses
- Should not cause disease
- Desired goal is the production of memory cells that can be activated if ever the pathogenic material is encountered at a later time
- Vaccines are especially beneficial to protect against viral infections
– Virus cannot be eliminated with chemotherapy (antibiotics & antimicrobial drugs)
- viral infection have v. few antivirals that exist & the one’s that do exist are typically reserved for Herpes infection, HIV, influenza
- if end up with infection & if immune system can’t clear it, it either stays or kills you, therefore vaccinating can help
*- vaccines are esp. effective for vial infections
— Prevention makes the most sense
• Some vaccines have greater risk factors than others
- some have allergic response, adverse response, or fine & protective

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2
Q

Vaccines are called

A

Artificial Active Immunity

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3
Q

Vaccines categories include:

A
  • Live attenuated vaccines
  • Whole agent inactivated vaccines
  • Subunit vaccines
  • Toxoid vaccines
  • Viral Vector vaccines
  • mRNA vaccines
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4
Q

Live attenuated vaccines offer…

A

only one on list that offers BOTH cell mediated & antibody mediated immunity

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5
Q

Whole agent inactivated vaccines, Subunit vaccines & Toxoid vaccines can only give

A

antibody mediated response

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6
Q

Live attenuated vaccines:

A

• Consists of pathogen that has been weakened

  • Usually accomplished by introducing a key mutation
  • Still maintains many of the properties of the wild-type pathogen (naturally occurring/disease causing form)
    Ex) virus can still adsorb and penetrate but CANNOT REPLICATE
  • Stimulates BOTH antibody and cell mediated immunity
  • micking real deal if you ever see infection in natural setting
  • give strongest, most beneficial immune response
  • Can spontaneously mutate back to the wild-type (*reversion to the wild-type)
    • Potential to cause disease that you are trying to prevent
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7
Q

Live attenuated vaccine process/idea

A
  • introduce virus to human’s cells in an artificial setting in a flask, let virus have its way with those cells by replicating & through multiple passages (split cells & put in diff flasks - dilute, give them fresh media, a flask & viruses in them)
  • allow virus to go through multiple replication rounds & as it goes through that, the outcome is that the virus is acquiring mutations over time
  • DON’T want mutations to be such that virus doesn’t have antigenic specificity that it once did - imp. that it has enough similarity to its initial form, that it’s gonna mount same immune response, otherwise vaccine is useless
    • but want there to be mutation such that this virus is gonna be deficit in terms of its ability to cause disease (b/c would cause paralytic polio for ex - dangerous)
  • idea: strike a balance
  • enough mutation - that it’s NOT able to cause disease
  • but not so much mutation - that it’s gonna be able to not mount an effective memory response if you ever see it
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8
Q

Describe how the Live attenuated vaccine stimulates BOTH antibody and cell mediated immunity

A

antibody mediated immunity - against EXOgenous antigen
- inject vaccine & its particles float in ECF - it’s exogenous, you need antibodies made to neutralize that

cell mediated immunity - against ENDOgenous antigen
- b/c virus has ability to go inside cell & create an abnormal cell that’s gonna be destructed by immune system

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9
Q

Live attenuated vaccines

Examples include:

A

Sabin vaccine against Poliovirus,

Rotavirus vaccine,

MMRV vaccine (Measles, Mumps, Rubella, Varicella),

some Rabies vaccines,

vaccine against Mycobacterium tuberculosis

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10
Q

Sabin vaccine against Poliovirus

A

(in case of reversion, can cause perilytic polio & infected person is shedding the infectious form of virus which can now spread to other hosts)

  • (FECAL ORAL virus - means normally be getting IgA, but fact this is injected; 1st always IgM & next is IgG (therefore most effective)
    • INJECTED IgM 1st –> IgG

Live attenuated vaccine

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11
Q

Rotavirus vaccine

A

(drank by babies to prime immune system along same port of passage that normal viral infection will prime)

  • live attenuated & *also give the natural route –> IgM 1st –> IgA (the best)
  • get antibody mediated & cell mediated immunity

Live attenuated vaccine

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12
Q

MMRV vaccine (Measles, Mumps, Rubella, Varicella),

A

Live attenuated vaccine

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13
Q

Some Rabies vaccines

A
  • caused by Rhabdovirus & not all vaccine avail is live attenuated, some are inactive

Live attenuated vaccine

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14
Q

Vaccine against Mycobacterium tuberculosis

A
  • BCG
  • not greatest, poor effectiveness, given only to children

Live attenuated vaccine

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15
Q

What is the type of antibody that we always begin by producing against an infection?

A

IgM

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16
Q

What type of antibody do we switch to if you’re getting a mucosal infection (RT, DT, repro T, etc.), what would be mucosal form of antibody?

A

IgA

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17
Q

Flu mist vaccine

A

Live attenuated vaccine

sprayed intranasally IgM –> IgG

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18
Q

Would you wanna give Flu mist vaccine (live attenuated, sprayed intranasally IgM –> IgG) to someone’s who’s pregnant, AIDS patient, transplant patient, etc.?

A

NO - b/c they are immunosuppressed
- don’t give live attenuated vaccines to these risks groups b/c they’re in a disadvantageous or vulnerable state (dangerous)

19
Q

Whole agent inactivated vaccines:

A

• INCLUDE INACTIVATED VIRUS

  • INCAPABLE of adsorption or penetration –> *remains EXOgenous antigen (only gives antibody mediated immunity ONLY)
  • NO RISK of causing disease

• ONLY stimulates antibody mediated immunity

(like you gutted infectious material, same way you removed vital organs & so infectious ability is gone, but external antigens have not changed (recognition events are still okay)

20
Q

Whole agent inactivated vaccines

Examples include:

A

Hepatitis B vaccination,

the flu shot, Rabies vaccine used in humans,

Salk vaccine for Poliovirus

21
Q

Hepatitis B vaccination

A

Whole agent inactivated vaccines

3 dose regimen - meaning weaker response; need to dose it

1st prime, 2nd people have protective titer (higher Ab levels/but not all), 3rd ~ everybody has protective Ab (higher Ab levels)

22
Q

The flu shot

A

Whole agent inactivated vaccine

injected: IgM –> IgG

  • not greatest for respir. infection
  • & only exogenous antigen, therefore not getting cell mediated immunity
23
Q

Rabies vaccine used in humans

A

Whole agent inactivated vaccine

vet’s

24
Q

Salk vaccine for Poliovirus

A

Whole agent inactivated vaccine

  • 0 risk of reversion to the wild type
  • no one will get perilytic polio b/c received it
  • some will get perilytic polio when receive Sabin vaccine (low risk factors)
25
Subunit vaccines:
- take recognizable traits out - but still get pieces if ever encounter real deal in the envir. • Include PURIFIED PROTEINS (antigen) taken from pathogenic bacteria and virus • Does NOT contain ANY infectious material - VERY SAFE • ONLY stimulates antibody mediated immunity - b/c EXOgenous antigen (only outside cell) - therefore, Ab mediated immunity only * Cost is inhibitory - don't put every viral antigen in each vaccine - do affinity asate, immunogenicity asate, binding asate - FIND STRONGEST IMMUNOGENICITY (get attention of immune system quickest & produce the strongest antibody binding - best affinity) to include
26
Subunit vaccines Examples include:
Hepatitis A vaccination, Human Papilloma Virus Vaccine, pneumoshot (contains purified capsule from Streptococcus pneumoniae), meningococcal vaccine (contains purified capsule from Neisseria meningitidis)
27
Hepatitis A vaccination
Subunit vaccine
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Human Papilloma Virus Vaccine
Subunit vaccine - indirect protection against cervical cancer (HPV)
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Pneumoshot
basically bacterial vaccine b/c capsule will be outermost layer (contains purified capsule from Streptococcus pneumoniae) Subunit vaccine
30
Meningococcal vaccine
(contains purified capsule from Neisseria meningitidis) Subunit vaccine
31
Toxoid Vaccines:
* Consist of BACTERIAL TOXINS that have been MODIFIED * Maintain the SAME ANTIGENIC PROPERTIES of the actual toxin - (think: stand in, in a movie - can't act same way but looks same) - Toxoid is INCAPABLE of causing the same EFFECTS as the toxin - - VERY SAFE • ONLY stimulate antibody mediated immunity • Often provide SHORT-LIVED protection - BOOSTER SHOTS NEEDED (*every 10-15 years)
32
Toxoid Vaccines Toxoid ex
Corynbacterium diptheriae produces dipheria toxin (causes respir. toxicity; destroys respir. cells) - suffocate ppl to death by forming pseudomem's considered EXOTOXIN (EXOgenous antigen) - secreted outside & can cause disease diptheria toxoid - (looks like real deal to be able to provide immune response that'll be protective, however not same b/c can't actually give you disease) - no toxic effects, but will provide memory response - therefore maintains same antigenic properties as actual toxoid
33
Toxoid Vaccines Examples include:
DTaP vaccine against diptheria toxin, tetanus toxin, and pertussis toxin
34
DTaP vaccine against diptheria toxin
Toxoid Vaccine DPT before (cellular pertussis - caused adverse effects/undesired symptoms; saw decreased vaccine uptake, but more effective) now DTaP - acellular - alleviated probs but vaccine is less effective, more ppl get
35
If described as exotoxin, do you figure in real life will you get a cell med. immune response against real deal?
NO - b/c. toxin stays outside (exogenous antigen) | - not a deficiency, just way it is - normally wouldn't see cell med. immunity & with vaccine don't either
36
If you've been vaxxed with DTaP or DPT, you still get infected, but...
when bacterium starts pumping out toxin, your memory response activate & don't get signs & symptoms of toxin disease
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Tetanus toxin
Toxoid Vaccines
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Pertussis toxin
Toxoid Vaccines
39
Conjugated vaccines:
- to deal with poor immunity that children normally have, you'll give a conjugated vaccine for some things • Consists of antigen that have been conjugated together - Increases the overall size of the antigen - Addresses limitations of naïve (ill-experienced) adaptive immune system in children - Increased immunogenicity= better protection BASICALLY 2 things together so bigger, so immune system is more likely to recognize, detect & initiate response & proceed as more
40
Polysaccharide vaccine against capsule of Haemophilus influenzae conjugated to protein
Conjugated vaccines could take diptheria toxoid & conjugate with capsular polysaccharide against H. influenza - then inject it - bigger (easier for immune system to see & recognize) - produce antibodies both (b/c see all of it as foreign antigen) - - protective response against everything
41
Viral Vector Vaccine
ex) Johnson & Johnson SARS-COV-2 vaccine ex) Adenovirus (genome) gene for SARS-COV-2 spike protein inject to vaccine recipient 1. Virus comes in & starts producing spike protein using host cell machinery 2. Spike protein secreted = EXOgenous antigen --> Ab production (against it) 3. Internally take MHC I & some antigen & traffic it into surface - MHC I & spike antigen will elicit an ENDOgenous antigen (cell med. immune response --> memory; when see real, you get destruction of virally infected cells)
42
mRNA Vaccine
ex) Pfizer vaccine - same idea as Viral Vector vaccine, BUT rather than stick genetic material into a viral vector, you stick mRNA of gene - liposome (aq core - polar in middle & polar outside - bilayer & then packed with mRNA inside) - goes into body, finds host cell & does exact same as viral vector (ribosome does translation) - MHC I & spike Ag (secreted spike protein)
43
For a mRNA Vaccine, how much spike protein gets secreted?
When ppl have adverse rxns, its going places idea: injecting in arm - from ECF, naturally go into lymphatic system - in LS, will activate immune cells there - IF leaves LS (not typical), then drains into blood & becomes systemically located - it can go anywhere & then have spike protein produced in other places & can bind SARS-COV-2 binds to ACE-II (BP mod.)