9.1 Biology of HIV and AIDS Flashcards
is there a cure for HIV
no
what do infected indiviudals need to take for life
anti viral drugs to stop viral repilcation of HIV in the host cells
what type of virus is HIV
+ssRNA - has ttwo particles of them
- lentivirus
subtypes of HIV
HIV-1 and HIV-2
what is an animal resevior
where the virus can grow and replicate and be transmitted from
origins of HIV-1
chimpan zees and gorilla
origins of HIV2
in the west africa
differences between HIV 1 and 2
hiv2 RESTRICTED int he africa
- HIV2 viral load lower than HIV 1
- HIV2 has a lowe transmission rate than HIV1
- most people with HIV2 doesn’t progress to AIDS
how many lineages does HIV2 have and the transmission rate between them
8
- A-B spread within the humans
- C-H - infected humans but no transmission
how many lineages of HIV1
and what are they
4
- M - pandemic
- O
- N
- P
how many subtypes of group M of HIV 1 are there
9
- leading to high risk individuals > muitlpe infections
- there’s little difference between the groups
stages of HIV lifecyle
- attachment
- fusion
- unocating where the capsid is released
- reverse transcription
- nuclear import
- integration of viral DNA into the cell’s DNA
- transcription
- nuclear export of mRNA
- protein synthesis of the vrial proteins
- assembly of the proteins and released into outside
- maturation
what receptor of the HIV interact with what receptors on the host cell so the virus can fuse
gp120 on the HIV surface interacting with host receptors of CD4 and co receptor on the T cell
how does the interaction wit CD4 receptor lead to fusion
- once the receptors are bound between the virus and the host cell
- causes conformational change
- releases fusion peptide into the plasma membrane
- brings the virus close
- leads to direct fusion between HIV envelope and T cells
what does the HIV need to do to make the infection permanent
-
stages in the HIV lifecycle where HIV can be intertuppted
-binding
-fusion
reverse transcription
integration
maturation
what drugs can inhibit reverse transcription of HIV RNA to DNA
nucleoside (NRTIs) and non nucleoside reverse transcriptase inhibitors (NNRTIs)
mechanism of action of NRTIs
- put itself in the viral DNA
- compete with virus nucelosides
- inhibit transcription so inhibting HIV replication
does NRTIs have an effect on infected cells
no
how does NRTIs incorporate into the host cell
the phosphate groups of the nucleioside in the drug form a bond with hydroxyl group of the viral nuceloside
mechanism of NNRTIs
-bind directly to the reverse rranscriptase so blocks consversion of RNA into DNA
function of HIV protease
cleavea HIV polyprotieins into structrual proteins and enxymes
- essential for assembly of the virus
mechanisms of protease inhibtiors (PIs)
- inhibits the cleavage of the HIV protease
- so HIV not released fromt the host cells
What cells does the HIV infect
T, B, dendritic cells
- the virus would be delivered to the lymph nodes where active viral replication can occur
diff between acute and chronic infection of HIV
acute is the inital stage of HIV and last until the body makes ABs
- chronic is the stage after the viral replication takes place at low levels
what happends to the T cells during acute infection
CD4 T cells decline temp
- CD8 T cells increase temp
- anti HIV ABs appear
symptoms of acute infection infection
swollen lymph nodes, fever, rash
what is AIDS
acquired immunodeficiency syndrome
- acquired after HIV
- increases vunleerbaility to infection s
- decreased activity of the IS
why does HIV envolve rapidly
the replication is error-prone and has high viral load
what do HIV drugs do in general
suppress replciation
- taken for life
- effective if only the replication is blocked completely
how does the mutation interfre with the mechanism of NRTIS
removes the NRTIs from the viral RNA
how does the mutation interfere with NNRTIs
cant block the process of reverse transctiptase
why is it hard to make a vaccine for HIV
- big varaibility of HIV
- glyco shielding of the envelope of glycoprotein around the virus
- immune escape
how does glycan envelope fo the virus prevent HIV drugs interactions
restrict the penetration of AB into the envelope
