HIV Flashcards
Retrovirus
enveloped (+) ssRNA (two copies)
medium sized
contain reverse transcriptase
first human retrovirus
human T cell lymphotropic virus
simple vs complex retroviruses
simple - contain gag, pol, env genes
complex - gag, pol, env and other genes
retroviruses replicate
through DNA intermediate that integrates into the host chromosome
two most important retroviruses
deltaretrovirus and lentivirus
for retroviruses, there are many
different groupings (ex: alpha retrovirus, beta retrovirus, etc.)
deltaretrovirus
bovine leukemia virus
cancer causing - Human T- lymphotropic virus
Lentivirus
human immunodeficiency virus
slow onset of disease
causes neurological disorders/immunosuppression
have type D cylindrical core
classification of retroviruses is based on
diseases they cause
tissue tropism
host range
vision morphology
genetic complexity
rex and tax
HTLV genes
rex - regulation of RNA splicing and promotion of export to cytoplasm
tax - transactivation of viral and cellular genes
HIV primarily targets
CD4+ T cells
Viral glycoprotein spikes
bind CD4
trimer of gp120 and qp41
after binding to the receptor, the HIV virus then must bind to a
secondary receptor (co receptor)
CCR5 or CXCR4
CCR5
co receptor used upon initial infection of HIV
expressed on CD4 T cells
CXCR4
co receptor used during chronic infection of HIV
HIV origin
from chimpanzee in Central America
passed to humans when they hunted/ate them
late 1800s –> America in 1970s
HIV classification
HIV-1 - more virulent, more infective (major group M and minor groups with subtypes)
HIV-2 - largely confined to West Africa (8 subtypes)
HIV life cycle
- binding
- fusion
- reverse transcription
- integration
- transcription and translation
- assembly
- release
mechanisms of viral entry
- initial interaction between gp120 and CD4
- conformational change of gp120
- interaction with CCR5
- distal tips of gp41 inserted into cell membrane
- gp41 conformational change
- fusion of membranes
HIV transmission
sexual contact
exposure to infected body fluids or tissues
mother to child
Risk of HIV transmission routes
blood transfusion
child birth
needle sharing
prevalence of HIV
1.2 million people in US have, 13% don’t know they have it
new HIV infections have been declining
largest percentage of people living with HIV
in africa
stages of HIV infection
- acute HIV infection
- chronic HIV infection
- AIDS
acute HIV infection
large amount of HIV in blood
very contagious
flu-like symptoms
what can diagnose acute HIV infection?
antigen/antibody tests or nucleic acid tests
chronic HIV infection
asymptomatic HIV infection/latency
HIV active but produced in low amounts
HIV can still be transmitted
At the end of the chronic HIV infection stage,
HIV in the blood (viral load) goes up and CD4 cell count goes down
AIDS
most severe phase of HIV infection
damaged immune system –> opportunistic infection
high viral load
very infectious
without treatment, people with AIDS
typically survive for about 3 years
AIDS diagnoses and deaths have been
decreasing
proof that the drugs are working!
symptoms of HIV vs AIDS
AIDS symptoms are more severe (ex: meningitis, tumors) and HIV symptoms are more flu like (ex: myalgia, thrush)
Laboratory diagnoses of HIV
Home Access HIV-1 test system
OraQuick In-Home HIV test
RT-PCR
Real time RT-PCR can be used for testing in HIV to
quantitate the amount of virus in the blood
gives information about the amount of viral load
for HIV testing, western bot analysis can be used as a
conformation test
HIV medicines _____________ HIV, they help people _____________
don’t cure
live longer lives
HIV medicines prevent
HIV from advancing to AIDS
HIV medicines reduce
the risk of HIV transmission (this doesn’t mean do it raw, wear a condom!!)
types of HIV medications that block viral entry
fusion inhibitors (enfuvitide - Fuzeon)
CCR5 antagonists (maraviroc - Selzentry)
Post attachment inhibitors (ibalizumab - Trogarzo)
NRTIs and examples
nucleoside reverse transcriptase inhibitors
abacavir, emtricitabine, lamivudine, tenofivir disoproxil fumarate, zidovudine
how do NRTIs work?
they bind to the DNA chain and terminate it
OR
they bind to reverse transcriptase and denature it
NNRTIs and examples
non-nucleoside reverse transcriptase inhibitors
-virine’s
doravirine (Pifeltro)
efavirenz (Sustiva)
etravirine (Intelence)
nevirapine (Viramune XR)
rilpivirine (Edurant)
INIs and examples
Integrase inhibitors
-gravir’s
dolutegravir (Tivicay)
raltegravir (Isentress)
integrase inhibitors block
integration into the host genome
PIs and examples
protease inhibitors
-navir’s
atazanavir
darunavir
fosamprenavir
ritonavir
saquinavir
tipranavir
does HIV have a vaccine or cure?
NO
HAART cocktail
slows progression of the disease
NNRTI and two NRTIs
challenges for vaccine development for HIV
subtypes
circulating recombinant forms
unique recombinants
a successful vaccine for HIV must
block initial infection and elicit neutralizing antibody and cell mediated immunity
antigenicity diversity of HIV
primary target of neutralizing antibody, gp120, is different for the different HIV clades
HIV undergoes __________ due to high mutation rate and recombination
immune escape
prevention of HIV
safe sex
drug use (the HAART cocktail)
blood screens
the risk of transmitting HIV to the unborn child is
low
15-30%
HTLV is associated with
leukemias, sarcomas and lymphomas in many animals
HTLV is not ________ but __________
cytolytic
transformative
HTLV is endemic in
southern japan, the Caribbean, and central africa
HTLV is usually ___________ but can progress to ______
asymptomatic
ATLL
effective treatment for HLTV
AZT and interferon alpha
