Infection And Immunity Andy Watts

Question 0

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 ______

Answer 0

Less than 100mm^3

Question 1

Candidiasis is the most common opportunistic infection resulting from HIV. It is most likely if the CD4+ count is less than________

Answer 1

200/mm^3

Question 2

TB is often the first sign that someone has HIV

It is more frequent in those with CD4+ cell counts less than ____?

Answer 2

200/mm^3

But can occur at any cell count

Question 3

Around ____ of late stage HIV patients are infected with Mycobacterium Adium complex (MAC)

Answer 3

50%

Not everyone will show symptoms (recurrent fevers, painful intestines, weight loss)

Question 4

HIV primarily infects _____ cells

HIVs ______ protein binds to ____ receptors

Answer 4

CD4+ T cells

gp120 protein binds to CD4 receptors

Question 5

What are CD4s co-receptors?

Answer 5

CCR5 and CXCR4

Question 6

In HIV we see elevated T cell proliferation, yet it is classified as T cell depletion, why?

Answer 6

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…..

Question 7

What is the most potent factor known to increase risk of the M.tuberculosis bacterium progressing rapidly into TB disease?

Answer 7

HIV

Question 8

How do NNRTIs work?

Answer 8

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

Question 9

How does Fuzeon work?

Answer 9

Fusion inhibitor
Blocks entry of HIV into cells
Mimics the components of gp41, prevents normal fusion

Question 10

How does Maraviroc work?

Answer 10

CCR5 inhibitor
Blocks attachment of HIV to CCR5 receptor
So it’s only effective in patients with HIV that uses CCR5

Question 11

How do integrase inhibitors work?

Answer 11

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

Question 12

Is fixed dose combination a Seperate class of medication?

Answer 12

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

Question 13

Vaccines are good against influenza because they provide protection. BUT?

Answer 13

But we need a specific vaccine for each virus

Question 14

What is influenza viruses Antigenic Drift?

Answer 14

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

Question 15

Amantadine is an influenza drug, it’s an M2 inhibitor. How does it work?

Answer 15

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

Question 16

How long does Amantadine reduce the duration of influenza illness by?

Answer 16

1 day when administered within 2 days of the onset of illness
(Uncomplicated influenza)

Question 17

Amantadine has activity against influenza __ viruses only, through inhibiting _______

Answer 17

A
Inhibits replication
Through inhibiting M2

Question 18

What are some of the problems of amantadine?

Answer 18

Rapid development of resistance in 30% of treated patients
Resistance can develop in 2-5 days

Not recommended by NICE

Question 19

What’s the name of the drug that was developed as a less toxic alternative to Amantadine?

Answer 19

Rimantadine

Structurally similar
Similar mechanism

Not recommended by NICE due to resistance problems

Question 20

What are the two main Neuraminidase inhibitors now in use for influenza?

Answer 20

Relenza (Zanamivir)

Tamiflu (Oseltamivir)

Question 21

How do neuraminidase inhibitors work?

Answer 21

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

Question 22

What’s the big advantage of neuraminidase inhibitors?

Answer 22

Active against ALL strains of influenza A B and C

And active against all serotypes!

Question 23

Zanamivir
A diskhaler device used for those aged over _______
Must be administered ____ after onset of illness
Decreases length of illness by approximately _______

Answer 23

Over 7 years
Within 48 hours after onset
Decreases length by 1 day

Question 24

What’s the bioavailability of Zanamivir ?

Answer 24

Around 10-20%

Question 25

Tamiflu (Oseltamivir) is approved for treatment of influenza A and B in those aged ______
And for prophylaxis in those aged ______

Answer 25

Over 1 year treatment

Over 13 years prophylaxis

Question 26

Oseltamivir is taken orally
It’s a prodrug
What’s its bioavailability?

Answer 26

80%