Vaccines (EXAM 3) Flashcards

1
Q

Herd immunity

A

-most of the population is vaccinated to protect the few vulnerable
-reduces infection rate in the poulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How do Vaccines impact Public health

A

-The number of incidences decreases
-Sanitation is a major factor in the decrease of water-borne diseases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How is active immunity obtained?

A

Natural: by infection
Artificial: by Vaccination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are examples of diseases protected by active immunity?

A

-COVID, Measles, Mumps, Rubella (MMR), Polio, Hep A, Hep B
-safer alternative to natural infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How is passive immunity obtained?

A

Natural: Maternal antibodies; IgA (breast milk), IgG (placenta)
Artificial: Monoclonal Ab -> Tetanus Antitoxin (TAT); Diphtheria antitoxin (DAT); Snake antivenins etc
-> Serum sickness can be caused by immune complexes due to passive immunization (mAb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Difference between innate and adaptive immunity

A

Innate: immediate response, non-specific, no memory -> Macrophages, NK-cells, dendritic cells, Granulocytes

Adaptive: specific, take time build T-cells and Ab, strong immune memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Difference in primary and secondary infection in an adaptive immune response

A

-Second exposure by the same pathogen leads to a strong and fast
immune response due to rapid clonal expansion of T and B cells

-Vaccination mimics the first infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do bodies recognize antigens?

A

TLRs recognize patterns on antigens (PAMPs) (like repeated patterns in aggregates of protein drugs)
-some TLRs are intercellular to bind endogenous antigens (viral) or broken particles of microbes
-C-type lectins recognize yeast-produced antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Process of Vaccine mediated active immunity

A

Antigen exposure -> APC take up and present antigen to CD4 Th cells -> CD4 TH cell secrete cytokines and activate CD8 T-cells and B -cells -> CD8 develop to CD8 cytotoxic Tcells and B-cells secrete Ab
-> formation of memory cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Types of Vaccines

A

-Live, attenuated: most effective (polio-Sabin/BCG for TB)
-Dead or inactivated: (polio-Salk/choler vaccine)
-Sub-unit vaccine: hepatitis B, meningococcal, pneumococcal, Haemophilus influenza)
-Toxoids (diphtheria and tetanus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are ways to inactivate Bacteria or Viruses - Attenuation

A

-elimination of a pathogen’s virulence

-Serial passage in unnatural hosts (oral polio vaccine (Sabin),
MMR and BCG (bacterial)
-Mutagenic treatment (Nitrosoguanidine tx for Salmonella
typhii)
-Heat or chemical treatment (e.g. formaldehyde, phenol etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does attenuation in an unnatural host work?

A

-Isolation from a patient -> grown in vitro in human cells
-infect monkey cells and passaged -> the virus mutates to survive and thereby loses its virulence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Advantages and Disadvantages of Live-attenuated

A

Advantages:
-produce more antigens -> strong cell and humoral (Ab) immune response
-fewer doses

Disadvantages:
-incorporation into host DNA, viral shedding, and contamination
-not suitable for immunosuppressed patients
-not for certain viruses (Hep, HIV, cancer-causing virus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How can pathogens be inactivated for vaccines?

A

-Chemicals: formaldehyde, glutaraldehyde
-heat

-used in polio (Salk), typhoid, pertussis vaccines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which vaccine has been attenuated genetically?

A

-Cholera vaccine (Vaxchora)
-through controlled deletions in the DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are genetic-mediated attenuations different from Sabin-type attenuations?

A

Genetically attenuated vaccine cant get virulent again bc the gene causing the virulence is deleted

17
Q

Inactivated Exotoxins

A

-Exotoxins of Cornybacterium depitheriae, Bordetella pertussis, Clostridium tetani

-Formaldehyde deactivates exotoxins through crosslinking (become toxoid)-> aggregation -> now susceptible to immune system - by adsorbing onto colloidal aluminum salts?

18
Q

Subunit vaccines
What is the characteristics of Subunit vaccines?

A

Conbining parts of a pathogen that by themselves are not very virulent
-e.g. Vaccine against Anthrax -> B. anthracis + Virus antigen -> adsorbed onto an aluminium salt (adjuvant)

19
Q

Polysaccharide Conjugate

A

Combining Bacterial cell wall polysaccharides (not enough antigenicity/PAMPs) with tetanus toxoid adjuvant

-e.g.: Haemophilus influenza type b (Hib)

20
Q

Ingredients in Vaccines

A

Thimerosal - Preservative
Aluminum salts - Adjuvant
Sugar, gelatin - Stabilizer
Formaldehyde - inactivation agent
Neomycin - antibacterial
egg protein - cell culture material

21
Q

Why do adjuvants cause a stronger immune response?

A

-increases the number of immune cells produced as a response (quantitative effect)
-Depot effect: adjuvanted antigens are exposed to the immune system for a longer time
-enhanced APC function bc of pattern recognition of TLR (aggregated)

-more cytokine release and better delivery into lymph nodes

22
Q

Adjuvants used in Vaccines

A

-o/w emulsion with squalene

23
Q

Moa SARS-Cov2 Vaccines

A

DNA Vaccines (AstraZeneca, JJ): non-replicating chimpanzee adenovirus to carry DNA coding for COVID spike protein -> gene to mRNA and mRNA to spike protein -> triggering an immune response

mRNA (Moderna/Pfizer): Lipid nanoparticle carries spike protein mRNA -> nanoparticle fuses with the cell membrane and releases the mRNA into cytosol -> translation into protein -> triggering immune response

24
Q

What happens to the mRNA Vaccine once administered?

A

spike proteins ae build -> and picked up by APC and carried to adjacent lymph nodes

25
What is the purpose of Lipids in the mRNA vaccines
They build the liposomes, that protects the mRNA, since the mRNA is very unstable
26
What is the purpose of Salts in the mRNA vaccine?
Salts: Buffering agent - multiple buffers can be used to work in pairs -> if the pH goes up or down Sucrose: Stabilizing agent
27
What are convalescent serum
Anti-bodies gained from humans that recovered from a disease (COVID) -> Isolate and expressed in CHO cells to produce Ab -> for passive immunization
28
What is the pathophysiology of cystic fibrosis?
-Chloride (CFTR) channels in the cell membrane do not work -> Cl(-) influx/efflux is needed to dilute the secreted mucus -> becomes thick in cystic fibrosis -difficulties breathing -disrupts mucociliary clearance through cilia-> causes bacterial infection, chronic inflammation, neutrophil invasion is higher
29
How can be cystic fibrosis treated? (not cured)
Pulmozyme (DNAse)-> breaking down DNA also helps in post-COVID patients
30
How does Rasburicase help in treating cancer patients?
To prevent gout -Recombinant Urate oxidase breaking down Uric acid (not soluble) to Allantoin (water-solube -> excreted) -Anticancer therapy lysis cancer cells causing the release of nucleic acid -> to Hypoxanthine/xanthine -> Uric acids