lecture 20 - HIV & AIDS Flashcards
elite controllers
people who get HIV but never AIDS. They make antbodies that neutralize nearly all known HIV strains
env reading frame makes…
gp41 and gp120 (joined)
does HIV infect the germ line?
NO
lentivirus means?
slow virus
polyprotein? enzyme required?
one long amino acid chain is translated and is then cleaved into multiple, functional proteins using the enzyme PROTEINASE
At what point is HIV invisible to the immune system
once viral cDNA incorporated into nuclear DNA
first observed in?
1979
which cells are targetted? how does HIV stop immune response and win?
eventually HIV particle numbers rise too high and destroy T helper cells and macrophages (CD4) at a rate that production of new cells can’t keep up with.
HIV proteinase structure
- 1 amino acid sequence (only 99 amino acids)
- 2 (identical) subunits
symptoms of AIDS
immune system can no longer function without T-helpers and unusual diseases, normally prevented in a healthy person, occur
response after initial infection or nuh?
YES, mild flu symptoms experienced (maybe not noticed) and HIV is neutralised and tagged for destruction by antibodies. VIRAL LOAD DROPS
integrase =
enzyme for incorporating cDNA into host cell’s DNA
3 open reading frames (genes) of HIV…
gag, pol, env - code for polyproteins
diameter of HIV virus?
100nm
HIV transmission
body fluids - semen, blood, breastmilk
why is HIV considered a lentivirus?
symptoms don’t occur until 5-10 years post infection
structure of proteins in HIV critical for?
drug design
can infection in babies be prevented?
YES, by drug treatment
gag open reading frame makes…
capsid and matrix
combination AIDS therapy
- AZT inhibitors for reverse transcriptase
- proteinase inhibitor
can you ever be cured?
NO, drugs only delay AIDS
on the outermost of the HIV particle is the _____ _________. Embedded in the membrane are _ ___ proteins and _ ___ proteins are attached to these ‘stalks’.. Beneath this layer you find the ______, within which is the ______ which holds _ strands of _____ and the enzyme _______ __________. Tommy’s dick is _____ m long.
on the outermost of the HIV particle is the plasma membrane. Embedded in the membrane are _3 gp41 proteins and _3 gp120 proteins are attached to these ‘stalks’.. Beneath this layer you find the matrix, within which is the capsid which holds 2 strands of RNA and the enzyme reverse transcriptase. Tommy’s dick is 3 m long.
pol reading frame encodes …
proteinase, reverse transcriptase, and integrase
retrovirus =
particle contains RNA genome
when infected cell is activated
DNA from HIV transcribes mRNA then translates the 9 genes and consequently 19 proteins
RNA to cDNA using
reverse transcriptase
how many cases worldwide? where is HIV predominant?
~40 million, ~20 million alone in Africa
cell-mediated response = ?
infected cells eliminated. Tagged to be destroyed because they have virus pieces on MHC molecules (similar to APCs)
length of HIV proteinase
99 amino acids - very simple (more so than lysozyme)
HIV life cylcle
- HIV’s gp120 binds to CD4 antigen receptor protein
- gd41 allows membranes to fuse and capsid enters T-cell
- reverse transcriptase makes double stranded DNA from single stranded viral RNA
- cDNA integrated into nuclear DNA (integrase).
- sits for years until T-cell is activated
- virus transcripted and gag, pol, env proteins made
- bud off into multiple new HIV particles
AIDS stands for? HIV stands for?
acquired immunodeficiency syndrome and human immunodeficiency virus
