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Flashcards in Vaccination Strategies Deck (23)
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1
Q

2 types of vaccines

A
  • killed (inactivated): diptheria-tetanus-pertussis

- live (attenuated): yellow fever

2
Q

Vaccine

A

A preparation of living or inactivated pathogens used as an antigen

3
Q

Vaccination

A

Administration of a living or inactivated pathogen to induce an immune response

4
Q

Protective immunity

A

Vaccine induced effectors (antibodies) prevent re-infection
- long-lived plasma cells in the bone marrow to maintain antibody levels in the bloodstream to neutralize the pathogen at the site of pathogen invasion

5
Q

Immunological memory

A

Vaccine-induced memory lymphocytes will not prevent re-infection, but can prevent disease or reduce severity of disease
- vaccine-induced memory lymphocytes circulate thru secondary lymphoid tissues

6
Q

What determines longevity of plasma cells?

A
  • differs with vaccines/antigens
  • with apoptosis, antibody levels drop below level of protection, require boosters or a second infection will be established
7
Q

Memory lymphocytes are exported from ____

A

Germinal center

  • rapidly reactivated to proliferate to provide protection and high levels in the bloodstream
  • requires a sufficient incubation period
8
Q

Example of inactivated vaccine

A
  • diptheria: inactivated toxin from corynebacterium diptheriae
  • tetanus: inactivated toxin from clostridium tetani
  • pertussis: surface protein antigen and the toxin from bordetella pertussis
9
Q

Characteristics of killed vaccines

A
  • killed vaccines generally result in an antibody response

- very poor inducer of cytotoxic T cells

10
Q

How many doses of a primary, killed vaccine are required?

A

Multiple doses
- germinal centers are short-lived with killed vaccines (antigen is non-replicating so only a few lymph nodes are engaged)

11
Q

Adjuvant

A

Substances that enhance the immunogenicity of antigens

  • aluminum hydroxide is common adjuvant in human vaccines
  • maintains a deposit of antigen at the site of injection
  • slow release of aluminum particles with antigen = uptake by macrophages and immature DCs
12
Q

Correlates of protection

A

Vaccine-induced immune responses that protect against disease
- antibodies must be present at the time of exposure to the pathogen

13
Q

Vaccine boosters DTP

A

Required every 10 years

- duration of effectors (antibody): D = 19 yrs, T = 11 yrs, P = 10 yrs

14
Q

Killed vaccines are handled as ____

A

Extracellular pathogen

- do NOT induce cytotoxic T cells

15
Q

Germinal centers of live vaccines

A

Germinal centers persist with replicating live vaccines

- adjuvant not required

16
Q

Live vaccine correlate of protection

A

Antibodies must be present at the time of exposure to the pathogen

17
Q

YF-17D

A

Induces DC maturation and cross-presentation

18
Q

Characteristics of live vaccines

A

Live vaccines can mimic a natural infection resulting in polyvalent immunity

  • neutralizing antibody
  • CD4+ helper T cell
  • CD8+ cytotoxic T cells
19
Q

Why do some vaccines need a booster?

A

For diseases in which antibody levels strongly correlate with protection
- decision for a booster is based on the persistence of antibodies and the incubation period of the disease (pace of pathogenesis)

20
Q

Persistence of antibodies

A
  • long lived plasma cells can have a finite lifespan (are not maintained after some vaccinations and require boosters)
  • memory B cells are maintained for decades after most vaccinations and natural infections
21
Q

Seronegative

A

Absence of specific antibody

22
Q

Are seronegative individuals protected from Corynebacterium diptheriae toxin?

A

If they have missed their boosters, then they become seronegative
- strictly dependent on memory cells since receptors are lost
- memory response requires 3-5 days to kick in
- diptheria pace of pathogenesis occurs in 2-5 days
= seronegative individuals are NOT protected (memory response is longer than the incubation period)

23
Q

Are seronegative individuals protected from hepatitis B virus?

A

In viral diseases, the pace of pathogenesis is generally slow

  • boosters are not recommended
  • if you become seronegative, then you will be protected due to long 45 day incubation period