Exam 2 Flashcards
(213 cards)
why are there only a few effective antiviral medication?
Viruses are intimately dependent on the metabolic pathways of their host cells for replication
Where in the life cycle are possible mechanisms of action of antivirals?
Receptor binding, uncoating, nucleic acid and protein synthesis, assembly, release and to modulate the immune system
Acyclovir is restricted to which virus?
Herpesvirus
What does acyclovir require to be activated?
virus enzymes in the infected host cell. They are necessary to convert the prodrug into active form, which then interferes with virus replication.
Acyclovir is the synthetic nucleoside analog of _________
Deoxyguanosine
Mechanism of antiviral effect of acyclovir?
Stop the growing viral DNA chain (due to lack of necessary attachment points) and Competitive inhibition of viral DNA Polymerase
why is acyclovir nontoxic to the unaffected host cells
the enzymes herpesvirus thymidine kinase and virus DNA polymerase are viral enzymes that are not found in host cells
how can herpesvirus develop resistance to acyclovir?
absence or lack of viral thymidine kinase
Amatadine inhibits replication of most strains of _________ by blocking _________of the virus
Influenza A; uncoating
The M2 ion channel is the target of ______
Amantadine
how does amantadine affect the M2 channels in a virus?
clog the channel and prevent it from pumping protons into the virion. (the protons lower the pH in the interior so that the viral RNA’s can be released)
Amatadine can also alter conformation of _______ and thus also blocks viral assembly
hemagglutinin
Neuraminidase inhibitors enzymes are synthesized by _______
Influenza A and B
Neuraminidase is important is what activity of viruses?
Spreading
targets for Anti-Retroviral therapy
Inhibit fusion, inhibit integration, inhibit reverse transcriptase, inhibit protease
Zidovudine is a potent _____
antiviral (retroviruses)
AZT/ZDV resemble what?
thymine deoxyribonucleotide-triphosphate
Mechanisms of actions for AZT/ZDV?
Competitive inhibition of reverse transcriptase activity and inhibition of growth of the cDNA transcribed from the viral RNA
reverse transcription of virus genome takes place in the _____of a cell
cytoplasm
what are the four “W’s” of immunization?
Where, when, who, why
the original live-attentuated virus vaccine form naturally occurring attenuated viruses?
cowpox
Most of the live-attenuated virus vaccines in common use were derived by ___________________________
attenuation of viruses by serial passage of cluttered cells
__________ and _________ viruses were produced by attenuation of viruses by serial passage in heterologous hosts (specifically which host)
Rinderpest and classical swine fever; Rabbits
Vaccines produced by attenuation of viruses by selection of cold-adapted mutants and reassortments would be safer in what conditions?
lower temps such as nasal cavity bc they would replicate better.