Flashcards in Antivirals (12) Deck (71):
Varicella Zoster, Herpes, and Cytomegalovirus are all part of what group of viruses?
T/F: Hep B is a DNA virus.
T/F: Hep C is a DNA virus.
Respiratory syncytial virus is part of which family?
T/F: Influenza is a orthomyxovirus that is an RNA virus.
T/F: HIV-1 and HIV-2 are both RNA retroviruses.
T/F: Different viruses can produce the same disease symptoms.
Also some viruses can cause different diseases
What is the life cycle for DNA viruses?
DNA polymerase to replicate DNA -> RNA polymerase to make RNA -> translation to make amino acids
What is unique about Hep B's life cycle?
DNA virus but can use reverse transcriptase to go from RNA -> DNA
Retroviruses use which non-mammalion enzyme to turn their RNA -> DNA?
Which type of virus will make DNA and splice it into the host genome?
T/F: Herpes viruses like to use their own DNA polymerase.
What is different about DNA and RNA viruses uncoating process?
DNA: uncoated at membrane into cytoplasm
RNA: endocytosed into cytoplasm, uncoated at nucleus
How does HIV (retrovirus) attach to a host cell?
GP120/41 binds to CD4 receptor
In the adaptive immune system, ____________ like macrophages swallow up foreign particles and present them through MHC II to _________ to scan.
antigen presenting cells; CD4+ Helper cells
What cells produce interferons?
Interferons direct leukocyte killing
What cells produce antibodies?
B-cell with help from Th2 cells
The adaptive immune response includes cellular and humoral immunity. What is the difference?
Cellular: killer cells destroy viral infected cells
Humoral: B-cell and antibody response
What are the two effects of interferon?
1. Activate killer cells
2. Induce resistance in uninfected cells
T/F: Active immunization takes weeks to develop and is prophylactic.
What is passive immunization?
Inject someone with antibodies
What types of receptors are found on specialized interferon producing cells like dendritic cells?
Toll-like receptors - rapidly secrete interferons
What stimulates normal cells to produce interferon?
Double stranded RNA
What does the interferon produced from the innate immune response do?
Tells other cells to resist the virus
Which interferon is used therapeutically?
T/F: Interferon is effective against RNA, DNA, and retroviruses.
T/F: Most antiviral agents have a wide spectrum.
Targeting specific aspect of virus
What are the four DNA viruses?
4. Hep B
What are the three RNA viruses?
3. Hep C
Along with HIV-1 and 2, which other virus utilizes reverse transcriptase?
What are three ways that drugs affect DNA viruses?
1. Inhibit viral DNA polymerase
2. Affect RNA
3. Inhibit HSV attachment
How base analogs (Acyclovir, Ganciclovir, Lamivudine) work?
Resemble DNA/RNA bases to antagonize DNA polymerase/RNA transcriptase
T/F: Acyclovir lacks a sugar ring.
T/F: Base analogs are active on their own.
Must be metabolized
*How is acyclovir so selective for viral cells?
Activation is started by Viral thymidine kinase - found in infected cells only
What happens if acyclovir is added to the viral DNA?
New DNA further inhibits replication
T/F: Thymidine kinase is the target of acyclovir.
DNA polymerase is target; thymidine kinase helps activate it
*T/F: Acyclovir is especially effective against herpes.
*Which base analog is most effective against CMV?
*Why is ganciclovir more selective for CMV?
While herpes has thyrimidine kinase, CMV has UL97 which activates Ganciclovir
T/F: The hep B reverse transcriptase is similar to HIV reverse transcriptase.
50% the same
*Which base analog inhibits hep B reverse transcriptase?
Lamivudine (3TC, Epivir)
T/F: Lamivudine is used against both Hep B and HIV.
What is the mechanism of Ribavirin?
Inhibits production and use of RNA
What makes Ribavirin special?
It is broad spectrum, used against DNA and RNA
What is the mechanism of Docosanol (Abreva)?
_____ is the most frequent cause of pneumonia in healthy adults.
M2 channels are found in which type of influenza?
Influenza A = M2
Influenza B = BM2
What is the purpose of the M2 receptor?
Open to allow genome release when in acidic endosome
*Which drugs block the M2 receptor and prevent the uncoating step?
DO NOT block BM2
Only affective against Influenza A
What is the role of the neuraminidase?
Mediates release from the cell by cleaving sialic acid
Which drug inhibits neuraminidase and therefore virus release?
T/F: Tamiflu is only active against influenza B.
Both A and B
What are the drug targets for Hep C?
1. NS3-4A Protease (Simeprevir)
2. NS5B RNA Polymerase (Sofosbuvir)
3. NS5A (Ledipasvir)
What is the function of LTRs in the HIV genome?
They are the splicing substrate that integrase binds to
Also recruit transcription factors for RNA production
Which drugs are nucleoside and nucleotide reverse transcriptase inhibitors in retroviruses?
Zidovudine (AZT) and Lamivudine (3TC)
T/F: Nevirapine (NVP) is a non-nucleoside reverse transcriptase inhibitor.
T/F: Resistance is common in HIV treatment.
T/F: Non-nucleoside inhibitors are only effective against HIV-1.
T/F: Activated oncogenes promote cell growth.
What is the effect of an increase in cyclin D?
Decreased cell cycle time -> more mitosis
What type of receptor does cyclin D act on?
Receptor tyrosine kinase
Why is combo therapy used to treat cancer?
To avoid resistance
Preferable to use agents with different mechanisms
How does cytotoxic therapy select for cancer cells?
Targeting cells in mitosis
What are the three mechanisms for cytotoxic therapy?
1. Inhibition of nucleotide/DNA synthesis
2. Microtubule/topoisomerase inhibition
3. DNA damage
*What is the most common side effect of cytotoxic therapy?
What are two ways DNA damage kills cells?
PARP and p53
Methotrexate resembles ______ and inhibits __________.
folate; dihydrofolate reductase
also inhibits purine ring synthesis
________ is a base analog that is ultimately activated to a version attached to deoxyribose forming FdUMP, and FdUMP inhibits thymidylate synthase which lowers TMP and DNA synthesis
T/F: Taxol inhibits the disassembly of tubulin.