HIV Disease Course Flashcards
HIV disease course
acute mononucleosis-like syndrome can occur early
virus can persist for a long time, perhaps years
degeneration of the immune system occurs ultimately, due to the loss of CD4+ cells
death due to opportunistic infections or wasting
gp120
outer membrane coat proteins that direct the HIV virus specifically to T-cells and macrophages
CCR5
coreceptor with CD4 that allows for virus entry into T cells
integrase
a protein that is important for DNA integration int othe host genome
key HIV genes
Pol
IN
env
tat
rev
vif
vrp
vpu
nef
pol
polymerase reverse transcriptase, protease, and integrase
IN
enzymes
env
envelope transmembrane and usrface glycoproteins
tat
transactivator positive - regulator of transcroption
rev
regulator of viral expression - regulator of viral transcript splicing
vif
viral infectivity - inhances viral infectivity
vpr
viral protein R translocation of preintegration complex to nucleus
transactivator
arrests cell cycle
induces apoptosis
vpu
viral protein U - downregulates CD4, enhances virus release from cells
nef
negative regulation factor - downregulates CD4 and enhances viral infectivity
Describe the process of HIV progression.
first there is a latent phase where the body is able to replace the dying lymphocytes, but after a few years, the body fails to keep up, and other diseases take over
1) swollen lymph nodes, fever, night sweats, wasting syndrome
2) CMV infection, severe HSV infections, shingles, thrush, hairy leukoplakia
3) Karposi’s sarcoma, PCP, and other fungal and protozoan infections
HIV balance between cell death and new cell synthesis
infected T-cells die within 48 hours
assymptomatic infection
5% infected, 10^9 cells die daily
protective immune responses
neutralizing antibodies
cytotoxic T cells contribute to loss of CD4+ cells
loss of CD4+ cells leads to breakdown of protetctive responses
host resistance to HIV
mutations int he gene for CCR5 result in the absence of the functional coreceptor
this leads to resistance to HIV infection
HAART (highly active anti-retroviral therapy)
refers to the administration of a combination of drugs for therapy, often two nucleoside analogs and one protease inhibitor
the combination of drugs significantly reduces the frequenct of emergence of drug-resistant HIV mutants
origin of HIV
zoonosis - a disease communicable to humans from other animals
five lines of evidence for the zoonosis of HIV
1) similarities in genome organization
2) phylogenetic relatedness
3) prevalence in the natural host
4) geographic coincidence
5) plausible routes of transmission
arboviruses
viruses that are carried by blood-feeding insects such as mosquitoes or ticks
togaviridae
flavivirdae
bunyaviridae
reoviridae
togaviridae
65nm
enveloped
icosahedral
RNA class IV
ss+, 5’-cap, 3’-polyA
1 seg, 7 genes, 10-12kb
ex. rubella
flaviviridae
45nm
enveloped
icosahedral
RNA class IV
ss+, 5’-cap
1 segment, 6-7 genes, 9.5-11kb
examples of flaviviridae
yellow fever
dengue virus
HCV
West Nile virus
St. Louis encephalitis
Japanese encephalitis
west nile virus
first isolated from infected woman in Nile District of Uganda in 1937
can lead to fatal encephalitis
birds are natural host, passed to humans by mosquitos
flavivirus, positive strand RNA
japanese encephalitis virus
example of emerged disease that is spreading
flavivirus
more cases than all other arboviruses comibned
15,000 fatalities anually
50% of survivors ahve significant neurologic efects
SARS
servere acute respiratory syndrome
1) contaegous and sometimes fatal
2) first appeared in China in Nov. 2002
3) death rate estimated to be 10%
4) likely cause new type of coronavirus
5) soonotic transmission from civets/bats
6) spread largely through droplets or feces
7) superinfectors are individuals that transmit to many
8) 10-20% infected require respirators and intensive care
coronaviridae
120nm
enveloped
helical capsid
RNA class IV
ss+, 5’-cap, 3’-polyA
1 segment, 6-8 genes, 27-33kb
ex. SARS, MERS, human corona
