HIV Disease Course

Question 1

HIV disease course

Answer 1

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

Question 2

gp120

Answer 2

outer membrane coat proteins that direct the HIV virus specifically to T-cells and macrophages

Question 3

CCR5

Answer 3

coreceptor with CD4 that allows for virus entry into T cells

Question 4

integrase

Answer 4

a protein that is important for DNA integration int othe host genome

Question 5

key HIV genes

Answer 5

Pol

IN

env

tat

rev

vif

vrp

vpu

nef

Question 6

pol

Answer 6

polymerase reverse transcriptase, protease, and integrase

Question 7

IN

Answer 7

enzymes

Question 8

env

Answer 8

envelope transmembrane and usrface glycoproteins

Question 9

tat

Answer 9

transactivator positive - regulator of transcroption

Question 10

rev

Answer 10

regulator of viral expression - regulator of viral transcript splicing

Question 11

vif

Answer 11

viral infectivity - inhances viral infectivity

Question 12

vpr

Answer 12

viral protein R translocation of preintegration complex to nucleus

transactivator

arrests cell cycle

induces apoptosis

Question 13

vpu

Answer 13

viral protein U - downregulates CD4, enhances virus release from cells

Question 14

nef

Answer 14

negative regulation factor - downregulates CD4 and enhances viral infectivity

Question 15

Describe the process of HIV progression.

Answer 15

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

Question 16

HIV balance between cell death and new cell synthesis

Answer 16

infected T-cells die within 48 hours

assymptomatic infection

5% infected, 10^9 cells die daily

Question 17

protective immune responses

Answer 17

neutralizing antibodies

cytotoxic T cells contribute to loss of CD4+ cells

loss of CD4+ cells leads to breakdown of protetctive responses

Question 18

host resistance to HIV

Answer 18

mutations int he gene for CCR5 result in the absence of the functional coreceptor

this leads to resistance to HIV infection

Question 19

HAART (highly active anti-retroviral therapy)

Answer 19

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

Question 20

origin of HIV

Answer 20

zoonosis - a disease communicable to humans from other animals

Question 21

five lines of evidence for the zoonosis of HIV

Answer 21

1) similarities in genome organization
2) phylogenetic relatedness
3) prevalence in the natural host
4) geographic coincidence
5) plausible routes of transmission

Question 22

arboviruses

Answer 22

viruses that are carried by blood-feeding insects such as mosquitoes or ticks

togaviridae

flavivirdae

bunyaviridae

reoviridae

Question 23

togaviridae

Answer 23

65nm

enveloped

icosahedral

RNA class IV

ss+, 5’-cap, 3’-polyA

1 seg, 7 genes, 10-12kb

ex. rubella

Question 24

flaviviridae

Answer 24

45nm

enveloped

icosahedral

RNA class IV

ss+, 5’-cap

1 segment, 6-7 genes, 9.5-11kb

Question 25

examples of flaviviridae

Answer 25

yellow fever

dengue virus

HCV

West Nile virus

St. Louis encephalitis

Japanese encephalitis

Question 26

west nile virus

Answer 26

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

Question 27

japanese encephalitis virus

Answer 27

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

Question 28

SARS

Answer 28

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

Question 29

coronaviridae

Answer 29

120nm

enveloped

helical capsid

RNA class IV

ss+, 5’-cap, 3’-polyA

1 segment, 6-8 genes, 27-33kb

ex. SARS, MERS, human corona