Semester 2: Vaccines and Vaccine Immunology Flashcards Preview

2nd year - Microbiology > Semester 2: Vaccines and Vaccine Immunology > Flashcards

Flashcards in Semester 2: Vaccines and Vaccine Immunology Deck (42):
1

What is immunization?

The process of producing a long-term, adaptive immunological response to a pathogen

2

What are the conditions that a vaccine should fulfill.

Prevent the establishment and spread of a given infection
Produce antibodies against one or more epitopes of the pathogen
Provide lifelong protection (memory response)
Be immunogenic against the desired antigen
Be safe

3

What is passive immunity with regards to vaccine?

The transfer of active immune mediators to a host
Typically antibodies
Maternal transfer
Artificial transfer
Provides protection against antigen
Does not provide memory

4

What is active immunity with regards to vaccines?

The production of active immune mediators within a host
Innate adaptive (humoral and cellular)
Provides protection against antigen
Provides immune memory

5

What is innate immunity?

Antigen non-specific
Involves recognition of PAMPs and DAMPs
Produces antimicrobial cytokines/chemokines, leads to inflammation, complement activation and clearing
Provides limited immunological memory

6

What is adaptive immunity?

Antigen-specific
involves recognition of antigenic peptides following antigen presentation by APCs
Produces a cellular response (T cell, cytotoxic)
Humoral response (B-cell, antibody)
Immunological memory and sterilizing immunity

7

When was the first vaccine administered?

1796 to a 6 year old boy for smallpox, inoculated with scrapings of cowpox lesions

8

What characteristics does an ideal vaccine have?

Produces a lifelong memory response to infection that is sufficient to prevent disease following subsequent exposure to a given pathogen

9

Which immune processes should be taking place when a person is vaccinated?

Both innate and adaptive
Innate influences the nature of the adaptive response

10

Which immune response is crucial to efficacy?

Adaptive response

11

What are the four vaccine types?

Live attenuated
Killed/inactivated
Subunit
Toxoids

12

What are live attenuated vaccines?

Live/viable whole bacteria, virus etc
Often replication-deficient
May be strains of pathogen that do not cause disease in host (smallpox vaccine)
Grown in vitro

13

What are the advantages of live attenuated vaccines?

Highly immunogenic
Best mimics exposure to the pathogen
Induces a response against multiple components of the pathogen

14

What are the disadvantages of live attenuated vaccines?

Highly immunogenic
May cause mild illness
Difficult to develop against highly mutagenic pathogens

15

What are killed/inactivated vaccines?

Non-living/non-viable whole bacteria, virus etc
Do not replicate, do not elicit de novo bacterial/viral gene expression
Inactivation by heat, irradiation, chemical inactivation

16

What are the advantages of killed/inactivated vaccines?

Vaccine components cannot replicate
Contains multiple epitopes/antigens

17

What are the disadvantages of killed/inactivated vaccines?

Relatively less immunogenic than live attenuated vaccines
May cause mild illness
Chemical inactivation compounds may elicit adverse reactions (Formaldehyde)

18

What are subunit vaccines?

Contain one or more components of a pathogen
Do not replicate, do not elicit de novo bacterial/viral gene expression
May be delivered in a recombination vector

19

What are the advantages to subunit vaccines?

Vaccine components do not replicate
Higher safety profile

20

What are the disadvantages to subunit vaccines?

Relatively less immunogenic than live attenuated or inactivated vaccines
Contains limited epitopes/antigens
Does not effectively mimic the natural exposure of the host to pathogen

21

What are toxoid vaccines?

Contains a modified or inactivated toxic component of a pathogen
I.e. diptheria toxoid, tetanus toxoid
Does not replicate, is not toxic, elicits immune response against bacterial/viral ect. toxin

22

What are the advantages to toxoid vaccines?

Vaccine components cannot replicate
Higher safety profile?

23

What are the disadvantages to toxoid vaccines?

Relatively less immunogenic than live attenuated or inactivated vaccines
Contains limited epitopes/antigens
Does not effectively mimic the natural exposure of the host to pathogen

24

Why are vaccines recommended to immunocompromised patients?

To reduce risk of complication in response to exposure to disease

25

What vaccines are CI'd in severely immunocompromised patients?

Live vaccines

26

What vaccine components may elicit allergic reactions?

Formaldehyde
Egg albumin

27

What vaccines are CI'd in pregnant patients?

Live vaccines

28

What would cause you consider the possibility of neurological complications in response to a vaccine?

History of Guillian-Barre syndrome (autoimmune) in response to vaccine

29

What vaccines are grown in chick embryos and therefore may contain egg albumin?

Influenza virus
Measles, mumps, rubella (MMR)
Rabies virus
Yellow fever virus

30

What preservatives are added to vaccines?

Formaldehyde
Thimersoal (mercury)
Antibiotics

31

Why are adjuvants/immunogens added to vaccines? What substances are added?

added to vaccines to instigate or potentiate an immune response to the vaccine epitopes
Alum, aluminum
Squalene

32

What is squalene?

An organic component (cholesterol precursor) produced by all plants and animals, including humans.
Higher levels of anti-squalene antibodies found in patients suffering from gulf war syndrome

33

What is gulf war syndrome?

Spectrum of acute and chronic illnesses observed in military following exposure to a variety of chemical weapons, depleted uranium, combat stress, and vaccines.
Fatigue, muscle weakness, myalgia, cognitive impairment, rash, diarrhea
Unclear etiology - no link to squalene

34

What is vaccine-associated paralytic poliomyelitis? What is the incidence rate?

Reversion of vaccine strain to a neurovirulent strain of virus (oral polio vaccine)
Incidence rate - 1:2,400,000 cases

35

What is a possible risk from the rotavirus vaccine?

Intussusception
1~2:100,000 infants

36

What are the four childhood vaccines?

Pentavalent combination (Diptheria toxoid, tetanus toxoid, acellular or whole killed pertussis, inactivated poliomyelitis, H.influenza serotype b)
Pneumococcal vaccine (strep pneumoniae polysaccharides or conjugated to modified DT)
Meningococcal (neisseria meningititis polysaccharides or conjugated to modified DT/TT)
MMR (measles mumps rubella all live attenuated)

37

What are the adult vaccines?

Human papillomavirus
Poliovirus (salk killed oral poliovirus vaccine)
Influenza virus (2 A serotypes and 1 B serotype, live attenuated or killed whole)
Tetanus (toxoid vaccine, booster every 10 years)

38

What are the vaccinations for travel to high risk areas?

Hep A
Hep B
Yellow fever virus
Salmonella typhi (typhoid fever)
Vibrio cholera

39

Why do some vaccines need boosters?

Duration of protection of different vaccine formulations is highly variable. Many influences on the maintenance of memory T cell and memory B cells. Some vaccines require booster shots to re-stimulate the immune system
Some vaccines schedules requires multiple stimulations to achieve lifelong immunity (HPV, HAV, HBV)

40

What are current vaccines in development?

HIV vaccines
Cancer vaccines

41

What is the MOA of cancer vaccines?

Post exposure prophylaxis, therapeutic vaccines
Vaccine immunizes against tumor-associated antigens (TAAs)
Many clinical trials in progress

42

What are the emerging vaccine platforms?

DNA-based vaccines
Dendritic cell-based vaccines (stimulate with DC with antigen to achieve antigen presentation. DCs removed and then immunized via peptide/DNA/viral vector. Immunized DCs are reintroduced to the patient to stimulate immune response)
Plant based vaccines (transgenic plants to produce large-scale subunit vaccines)
CAR vaccines (Chimeric antigen receptors, stimulates T cell mediate response associated with better antitumor responses)