Antivirals and Vaccines Flashcards
How do antivirals work?
Block specific steps in virus life cycle
What is necessary for antivirals?
Must be active against virus replication, but not notmal celular function
Why is continued antiviral development required?
Virus resistence
What antivirals prevent entry?
Enfuvritide
Amantadine
Rimantadine
Enfuvritide
Prevents HIV from entering cell
Blocks refolding og gp41, which prevents membrane fusion
Amantadine and Rimantadine
Prevents Influenva from entering host cell
Blocks influenza ion channel (M2), preventing nucleocapsid release at the end of the cell entry process
What antivirals Prevent Genome Replicaiton
Acyclovir Glaniclovir Valganciclovir Forscarnet Ribavirin
Acyclovir
Acts as a nucleoside inhibitor for treatment of herpesvirus infections
First antiviral approved for clinical use
Most effective against HSV-1 and HSV-2, less effective against EBV, even less efective agains CMV
Glaniclovir
Effective against CMV - prevents genome replication
More toxic, due to interference with cellular kinase
Valganciclovir
Nucleoside inhibitor for EBV
Improved oral bioavailability
Forscarnet
Herpesvirus treatment
Prevents viral polymerase activity
IV administration
Toxic
Ribavirin
Nucleoside inhibitor for RNA viruses Many mechanisms Triphosphate inhibits polymerases Monophosphate form inhibits inosine monophosphate dehydrogenates, lowering GTP in cell Impairs capping of mRNA
Which antivirals prevent viral proteases
Ritonavir
Ritonavir
Treatment of HIV
Blocks cleavage of Gag-Pol polypeptode
Boosts the activity of other protease inhibitors because it also blocks the action of cellular proteases that act on other viral protease inhibitors
What are some antiviral challenges
Bioavailability
Specificity
Toxicity
Bioavailability of antivirals
Absorption into the body
Transport to site of infection
Intake by the cell
Therapeutic window (half-life)
Specificity of antivirals
Target the virus activities exclusively or with great preference
Toxicity of antivirals
Low impact on the patient
Natural Antivirals
Interferons
- more effective against RNA viruses than DNA viruses
- mechanism ofa ction is not well understood
Vaccination
The practice of inducing immunity to a pathogen
What are the 2 ways to introduce a pathogen?
Active immunization
Passive immunization
Active Immunization
Administering all or part of a pathogenic gent to induce antibodies or cell mediated immunity
Passive Immunization
Administration of exogenously produced antibodies
What are the 2 forms of vaccines
Live, attenuated
Killed
What are the three important immune cell types in vaccinations
B cells
CD8+ T-cells
CD4+ T-cells
What vaccines utilize B cells only?
Pneumococcal
HIB (unless conjugated to other antigens)
Which vaccines utilize B and T cell immunity
Influenza
Polio
Typhoid
What are some considerations to take for vaccines
Age
Special Populations
Why is age taken into considerations for vaccines?
Young children and the elderly have weaker immune systems, and they may not be able to respond to live, attenuated vaccines
Why are special populations taken into consideration for vaccines?
Immunocompromised persons may have greater need of vaccination or be counter-indicated for vaccine
There can be other complications, such as small pox vaccines for persons with eczema
