III - vaccines Flashcards

1
Q

what is measles and what is it caused by

A

respiratory system infection
caused by a paramyxovirus

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2
Q

what is herd immunity

A

immunity developed by a group of vaccinated individuals

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3
Q

what is amantadine and how does it effect influenza virus

A

antiviral
blocks M2 ion channels on the envelope of the virus
prevents viral genetic material from exiting the virus

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4
Q

what are zanamivir and oseltamivir and how do they perform their role

A

they are neuraminidase inhibitors
inhibiting the neuraminidase enzyme prevents budding and therefore the release of new virus from the host cell

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5
Q

function of neuraminidase

A

cleaves polysaccharides of the host cell surface

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6
Q

what is hemagglutinin

A

proteins on the surface of influenza
bind to host cell surface

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7
Q

what are both hemagglutinin and neuraminidase

A

the two main influenza antigens

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8
Q

what are the subtypes of influenza A

A

H - hemagglutinin - types H1-H18
N - neuraminidase - types N1-N11

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9
Q

what are the lineages of influenza B

A

yamagata
victoria

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10
Q

what are the 2 mechanisms to generate variations in influenza

A

antigenic drift
antigenic shift

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11
Q

what is antigenic drift

A

overtime the amount of point mutations that occur results in an antigen that isn’t recognised by the antibody that recognised the original

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12
Q

what is antigenic shift

A

when an animal and human influenza infect the same cell
the ssRNA gets rearranged between them
leads to completely different antigens
unrecognised by antibodies

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13
Q

what influenza strain is the swine flu and what type of vaccines have been developed for it

A

H1N1
inactivated or live attenuated vaccines

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14
Q

what are antigenic drift/shift responsible for

A

drift - seasonal flu
shift - pandemics

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15
Q

what are the incubation periods of influenza and polio virus

A

influenza - 1-2 days
polio - 3 days

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16
Q

an effective influenza vaccine must be what

A

able to maintain high levels of serum antibodies because the disease is already underway before memory B-cells can be activated

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17
Q

what are the advantages/disadvantages of live attenuated vaccines

A

advantages - stronger immune response
usually lifelong immunity
disadvantages - requires refrigerated storage
may mutate to pathogenic form

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18
Q

what are the advantages/disadvantages of dead/inactivated vaccines

A

advantages - safer
refrigeration not required
disadvantages - weaker immune response
boosters usually required

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19
Q

list the vaccine types

A

live attenuated
dead/inactivated
conjugate
toxoid
subunit

20
Q

what are some live attenuated vaccines

A

polio
MMR
TB

21
Q

how is attenuation achieved and explain them

A

natural attenuation - inoculation (Jenner)
serial passage - select mutants with reduced toxicity

22
Q

what is chemical mutagenesis

A

it is a method of attenuating a virus
virus is extracted from a patient and cultured in human cells
they are then used to infect monkey cells
they pick up mutations that allow them to better effect monkey cells
lose ability to grown in human cells

23
Q

features of the sabin vaccine

A

given orally
induces IgA, IgG and IgM responses
consists of 3 attenuated serotypes of polio
gives immunity for all 3 strains
requires 2 extra boosters

24
Q

what is the wild-type progenitor strain genome of sabin made up of and how different is the sabin vaccine

A

7249 nucleotides
the sabin vaccine is different by only 9 nucleotides

25
Q

how does recombinant DNA allow for safer live attenuated vaccine production

A

able to isolate the virulence gene
either delete or mutate it
reversion to virulent form is basically impossible

26
Q

what key genes of malaria are deleted to produce its vaccine and what is the outcome

A

deletion of p52 and p36
prevents productive liver infection

27
Q

what are examples of deactivated vaccines

A

pertussis
cholera
typhoid
polio
influenza
zika

28
Q

how is a virus inactivated

A

application of heat or chemical - formaldehyde or alkylating agents
nucleic acids are destroyed
antigens remain intact

29
Q

why do inactivated vaccines only produce a humoral response

A

because pathogen does not replicate

30
Q

what is the main concept of a subunit vaccine

A

introduce only a subunit of the pathogen to host (only gp120/41)

31
Q

what are the 3 main subunits isolated to form a subunit vaccine

A

toxoids
capsular polysaccharides
recombinant protein antigens

32
Q

what are examples of subunit vaccines

A

hepatitis B
streptococcus pneumonia
diphtheria
tetanus

33
Q

what is the concept of a toxoid vaccine

A

exotoxin is purified and inactivated via formaldehyde

34
Q

what are examples of toxoid vaccines

A

diphtheria
tetanus

35
Q

what can increase the abilities of macrophages/neutrophils to phagocytose bacteria with the anti-phagocytic properties of their hydrophilic polysaccharide capsule

A

coating the hydrophilic capsule with complements and antibodies

36
Q

what is an adjuvant

A

any material that can increase the humoral and cellular immune response to an antigen

37
Q

how do adjuvants increase the immune response of inactivated/subunit vaccines

A

act directly on macrophages/neutrophils and dendritic cells
leads to adaptive immune response

38
Q

what is the process by which adjuvants stimulate the innate immune system

A

attract APC’s
stimulate pattern recognition receptors (TLR)
induces inflammasome activation
leads to antigen presentation on MHC molecules

39
Q

what can be used as an adjuvant

A

aluminium salts
virosomes
MPL
MF59

40
Q

what are the potential side-effects of adjuvant use

A

redness, swelling and pain at injection site
systemic reactions - fever, chills and body ache

41
Q

how do conjugate vaccines solve the problem of a poor immunogenic response

A

fuse a highly immunogenic protein to the weak vaccine

42
Q

give an example of a conjugate vaccine

A

haemophilus influenza type B (Hib) vaccine

43
Q

what does Hib cause

A

bacterial meningitis

44
Q

what does the conjugate vaccine of Hib consist of

A

the type b capsular polysaccharide fused to tetanus toxoid - highly immunogenic

45
Q

what do conjugate vaccines activate and not

A

activate - T helper and memory B cells
does not activate - memory T cells