Part 6: Antiviral agents Flashcards

1
Q

viruses use host cell ____ and ____ to reproduce

A

biochemica pathways and replication machinery

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

many viruses are catergorized into 2 groups ___

A

RNA and DNA viruses

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

Herpes simplex virus, and varicella zoster virus are examples of ____ type viruses

A

DNA

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

HIV, Hepatitis, Influenza, SARS-CoV2 are examples of ___ type viruses

A

RNA

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

what are reverse transcribing viruses?

A

RNA viruses that use an enzyme (reverse transcriptase) to create viral DNA that is integrated into the host genome prior to replication

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

what enzyme is used by reverse transcribing viruses

A

reverse transcriptase

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

give an example of a reverse transcribing virus

A

HIV

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

why is it so hard to target viruses with drugs?

A

because they are simplistic mOs that use host materials; and many of them mutate extensively

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

1st step for viral infection

A

viral attachment and entry into host cells

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

2nd step for viral infection

A

genetic material is released intto the cytoplasm (uncoating)

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

3rd step for viral infection

A

once all the componenets are in the cytoplasm, replication begins

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

replication process depends on the virus, but in general, there are a few viral and host ____ and ____ involved

A

enzymes and replication machinery

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

4th step in viral infection

A

new viral particles are packaged and released to infect other host cells

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

what happens to the host cel during viral infection?

A

functions become impaired and are often killed in the process

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

if the host cell is not destryed by the virus, it may express____ on its surface

A

viral proteins

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

what is the point of a host cell displaying viral proteins on its surface?

A

causes the immune system to recognize the virus and begin to kill any cells with the antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

t/f the immune response to viruses can oftne cause significant damage to our host cells as well

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

vira; drugs that have been optimized for pharmacological treatment often involve targetting _____ or ____

A

the virus entering or exiting the host cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

some antiviral work by rying to increase the host ___

A

immune response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are immunomodulators?

A

pharm agents that interact with cells of the immmune system to boost the responsiveness and promote recognition of foreign agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

____ are a more specific approach to prime the immune system and promote memory of an infectious agent to facilitate a larger scale immune response should the infection ever show up

A

vaccinations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

give an example of a drug used to treat herpes simplex virus

A

acyclovir

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

give 2 examples of drugs used to treat hepatitis C

A

ribavirin, IF-A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

give 3 examples of drugs used to treat HIV

A

maraviroc, emtricitabine etravirine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
give an example of a drug used to treat influenza
oseltamavir
26
give 3 examples of drugs used to treate COVID
remdeivir, hydroxychloroquine, bamlanivimab
27
what do DNA viruses like HSV do once theyve entered a host cell?
use a combo of host and their own enzymes to replicate their DNA and create new particles
28
acyclovir is an antiviral drug that is a ____ analogue
guanosine nucleoside
29
acyclovir is similar enough to endogenous nucleosides that they are incorporated into the ____
viral DNA
30
adding acyclovir into the viral DNA strand, what happens?
acyclovir is missing the key group in adding the next nucleotide, the chain will be ended
31
acyclovir binds to the viral ___ complex to be added to the growing viral DNA strand
DNA polymerase
32
t/f acyclovir bind more strongly than endogenous nucletides so the DNA polymerase complex does not dissociate as easily
t
33
what is the significance of acyclovir binding to DNA polymerase?
inhibits progression of viral DNA synthesis and prevents the virus from replicating in the host cell
34
the mechanims of acyclovir and similar drugs is specific to the viral DNA replication process because the first step in creating the _____ is catalyzed by a viral enzyme, not a host enzyme
nucleotide monophosphate
35
t/f the host-made nucleotides will not contain acyclovir, only the viral ones
true
36
t/f HSV cannot be completely cleared from the host, but can be managed to an asymptomatic level
t
37
HSV infections are more easily transmited from ___- sores containing high # of viral particles
open
38
how can resistance to nucleoside analogues like acyclovir happen?
mutations of viral enzymes responsible for incorporating acyclovir into nucleotides ; mutations in DNA polymerase
39
ribavirin is a ____ analogue
nucleoside
40
Ribavrin gets incorporated into the ____ and impairs ___
viral synthetic pathways; viral RNA synthesis
41
ribavirn becomes a ___ nucleotide inside the cell
phosphorylated
42
interferon ___ has been shown to have benefit in patients with hepatitis C infections
alpha
43
interferons increase the activation of host ____ cells which recognize foreign bodies and infected host cells and destroy them
cytotoxic T
44
why are interferons not commonly used?
non-specific activation of immune system causes systemic effects
45
Maraviroc is an antiviral agent that blocks ____ receptors on the surface of host cells
CCR5
46
what is the purpose of Maraviroc binding to the CCR5 receptors on host cells?
prevents HIV from entering the host cell
47
t/f not all HIV strains bind to the CCR5 receptor, so Maraviroc does not always work
t
48
is Maraviroc approved in Canada for prophylactic HIV?
no
49
____ and ___ inhibitors can also be used to reduce the replication of HIV within host cells and release of viral particles
integrase and protease
50
___ is the key enzyme in the replication of HIV
reverse transcriptase
51
the ____ enzyme was one of the first targets addressed by HIV treatment
reverse transcriptase
52
there are 2 classes of reverse transcriptase inhibitors: ___ and ___
nucleoside type (NRTIs) and non-Nucleoside type (NNRTIs)
53
give an example of an NRTI
emtricitabine
54
give an example of an NNRTI
etravirine
55
what is Emtricitabine?
NRTI, nucleoside reverse transcriptase inhibitor
56
Emtricitabine is converted to ____ inside cells
triphosphate nucleotides
57
MOA of NRTIs
structurally similar to endogenous nucleosides and get incorporated into the HIV viral DNA, resulting in chain termination
58
emtricitabine has a similar MOA as ____
acyclovir
59
do NNRTIs resemble nucleosides?
no
60
NNRTIs are not structurally similar to nucleosides, but have high affinity for ____
HIV reverse transcriptase enzyme
61
MOA of Etavirine?
inhibits the enzymatic action of reverse transcriptase, preventing the production of HIV viral DNA in host cells
62
t/f reverse transcriptase inhibitors are usually given in combination with other anti-HIV agents to attack the virus from multiple aspects of replication
t
63
t/f in some situations, multiple reverse transcriptase inhibitors are used togther in attempt to counteract HIV mutations and resistance to single agenst
t
64
the yearly flu vaccine is based on predictions of ___
which strains will be the most problematic this year
65
what is neuraminidase?
one viral enzyme expressed by influenza that can be targetted
66
____ is the viral enzyme required to allow the newly synthesized influenza particles to be released from the host cell
neuraminidase
67
why is neuraminidase required for influenza to release viral particles?
our human cells dont bud or release little packages
68
give an example of a neuraminidase inhibitor
oseltamavir (tamiflu)
69
oseltamavir has been shown to be effective at reducing the severity of ____ and ____ infections if administered early
influenza A and B
70
ideally, oseltamivir needs to be taken within ___ hrs of exposure to influenza or within ___ hrs of onset of symptoms
48; 24
71
explain the replication process of COVID
virus enters cells by binding to angiotensin converting enzyme 2 (ACE) receptors, internalized, virla RNA is released from endosomes into the host cell cytoplasm where the viral genome is replicated and packaged into new particles for release and more infection
72
what re 2 drug currently being discussed wrt COVID?
remdesivir and hydroxychloroquine
73
what is remdesivir?
antiviral developed as potnetial treatmet for Ebolsa, now as potnetial for COVID
74
what is hydroxychloroquine?
antimalarial drug now considered for COVID
75
what type of antiviral is remdesivir?
nucleoside analogue
76
resdemavir has structural similarities to ___
adenosine
77
how does resdemavir work>
remdesivir nucleoside is processed during viral nucleotide biosynthesis ans is incorporated into the viral RNA, causing chain termination and preventing replication
78
is resdemavir approved in Canada for COVID?
yes, with several conditions , includin gwithdrawing approval if ADRs occur
79
hydroxychloroquine is used in some autoimmune diseases such as ___
Lupus
80
does hydroxychloroquine have scientific evidence to support its use in COVID?
no
81
t/f the antiviral actions of hydroxychloroquine are not as well understood as those of remdesivir
t
82
what is the proposed antiviral mechanism of hydroxychloroquine?
reduce viral endosome acidification, which prevents the viral components from being relased into the host cell cytoplasm
83
what are some of the ADRs of hydroxychloroquine?
irreversible blindness and possibly life-threatening arrhythmias, GI disturbances, neurologic effcets
84
what drug was Trump given for COVID?
REGN-COV2
85
what is an example of a neutralizing antibody used to treat COVID?
bamlanivimab
86
neutralizing antibodes used for COVD bind to the __
spike protein
87
MOA of neutralizing antibodies in treatment of COVID
binds to spike protein, prevents entry of the virus into the host cells, reduces ciral replication, and then has cell get recognized by immune system
88
protective immunity wears off over time and is ineffective when viruses ___
mutate