Infection And Immunity Andy Watts Flashcards
CMV is a herpes type virus
It can cause eye disease and blindness
HIV tends to only cause it if the CD4+ cell count is less than ______
Less than 100mm^3
Candidiasis is the most common opportunistic infection resulting from HIV. It is most likely if the CD4+ count is less than________
200/mm^3
TB is often the first sign that someone has HIV
It is more frequent in those with CD4+ cell counts less than ____?
200/mm^3
But can occur at any cell count
Around ____ of late stage HIV patients are infected with Mycobacterium Adium complex (MAC)
50%
Not everyone will show symptoms (recurrent fevers, painful intestines, weight loss)
HIV primarily infects _____ cells
HIVs ______ protein binds to ____ receptors
CD4+ T cells
gp120 protein binds to CD4 receptors
What are CD4s co-receptors?
CCR5 and CXCR4
In HIV we see elevated T cell proliferation, yet it is classified as T cell depletion, why?
Even though T cells increase in number in HIV, they’re all infected with HIV, only they ones infected are stimulate to proliferate. Even though the quantity is increased, the QUALITY of these T cells is depleted. It’s quality not quaintly that matters…..
What is the most potent factor known to increase risk of the M.tuberculosis bacterium progressing rapidly into TB disease?
HIV
How do NNRTIs work?
They bind to the allosteric binding site of reverse transcriptase, causing a conformational change in the active site, so viral reverse transcriptase can no longer work to replicate DNA
How does Fuzeon work?
Fusion inhibitor
Blocks entry of HIV into cells
Mimics the components of gp41, prevents normal fusion
How does Maraviroc work?
CCR5 inhibitor
Blocks attachment of HIV to CCR5 receptor
So it’s only effective in patients with HIV that uses CCR5
How do integrase inhibitors work?
Virus requires the enzyme integrase to integrate it’s genetic material into hosts DNA
These inhibitors block this
Prevents virus adding it’s DNA so prevents it replicating
Is fixed dose combination a Seperate class of medication?
No it’s a combination of the other classes
Includes antiretrovirals : combination of 2 or more medications from one or more different classes , these antiretrovirals then combined into one single pill
Vaccines are good against influenza because they provide protection. BUT?
But we need a specific vaccine for each virus
What is influenza viruses Antigenic Drift?
A gradual accumulation of mutations
Allow the hemagluttnin on the virus surface to avoid the neutralising antibodies produced by the host
Epidemic strains of the virus are thought to have changes in 3 or more of the antigenic sites
Amantadine is an influenza drug, it’s an M2 inhibitor. How does it work?
Interferes with the function of the the transmembrane domain of the M2 protein of influenza A virus
Also interferes with virus assembly during replication of influenza virus A viruses
Decreases the release of influenza virus A particles from the host cell
How long does Amantadine reduce the duration of influenza illness by?
1 day when administered within 2 days of the onset of illness
(Uncomplicated influenza)
Amantadine has activity against influenza __ viruses only, through inhibiting _______
A
Inhibits replication
Through inhibiting M2
What are some of the problems of amantadine?
Rapid development of resistance in 30% of treated patients
Resistance can develop in 2-5 days
Not recommended by NICE
What’s the name of the drug that was developed as a less toxic alternative to Amantadine?
Rimantadine
Structurally similar
Similar mechanism
Not recommended by NICE due to resistance problems
What are the two main Neuraminidase inhibitors now in use for influenza?
Relenza (Zanamivir)
Tamiflu (Oseltamivir)
How do neuraminidase inhibitors work?
They are COMPETITIVE inhibitors that compete with the natural receptors on influenza for the neuraminidase active site
Neuraminidase is needed to release the new virus from the cell surface by cleaving Salic acid, so these inhibitors stop this
What’s the big advantage of neuraminidase inhibitors?
Active against ALL strains of influenza A B and C
And active against all serotypes!
Zanamivir
A diskhaler device used for those aged over _______
Must be administered ____ after onset of illness
Decreases length of illness by approximately _______
Over 7 years
Within 48 hours after onset
Decreases length by 1 day
What’s the bioavailability of Zanamivir ?
Around 10-20%
Tamiflu (Oseltamivir) is approved for treatment of influenza A and B in those aged ______
And for prophylaxis in those aged ______
Over 1 year treatment
Over 13 years prophylaxis
Oseltamivir is taken orally
It’s a prodrug
What’s its bioavailability?
80%
