HIV Flashcards
Describe the HIV genome.
It is diploid, with two RNA molecules
Which proteins do each of these HIV genes code for: env, gag, pol?
env: gp120 and gp41;
gag: p24 which is the virion core;
pol: reverse transcriptase, aspartate protease, integrase
A patient presents with low-grade fever and fatigue for weeks, with risk for HIV. How does this bug integrate its genome into host DNA?
Reverse transcriptase converts HIV viral RNA to double-stranded DNA, which is then integrated into the host DNA
You prescribe a patient an inhibitor that prevents HIV from binding to T cells. What three proteins should it target?
CXCR4, CCR5, and CD4
You are trying to develop a drug that targets the HIV envelope proteins. How are these proteins formed?
env gene encodes a gp160 precursor that is cleaved into gp120 and gp4, which are acquired through budding from the host cell plasma membrane
You are trying to develop a drug that targets the HIV envelope proteins. What is the function of these two proteins?
gp120 is the docking protein that helps HIV attach to CD4+ T cell
gp41 is a transmembrane glycoprotein that facilitates HIV fusion/entry
In early infection, the virus binds CCR5 on ____, while in late infection, the virus binds CXCR4 on ____.
Macrophages; T cells
During what phase of HIV infection does the CD4+ cell count drop most steeply? What else happens in this phase?
Acute phase (first 1–2 months); wide dissemination of virus, seeding of lymphoid organs
A man tests positive for HIV. How would you describe to him the four stages and associated symptoms of this disease?
Flu-like, acute HIV—Feeling fine, clinical latency—Falling count, constitutional—Final crisis, opportunistic infections
Where does the HIV virus replicate during the latent phase?
In the lymph nodes
Envelope acquired via 1)
1) budding from host cell
codes for the three enzymes: protease, RT and the integrase
pol
encodes for the virion core
Gag
encodes for the 160 glycoprotien envelope protein that is cleaved to GP120 and GP41
ENV
HIV transmission in males 1)
females 2)
1) predominantly male to male sex contact
2) heterosexual
HIV types of transmission:
3 ways
Sexual transmission
Bloodborne transmission
Maternal – Fetal/Neonatal transmission
HIV infection overview:
Primary infection takes place, then establishment of infection in 1)
1) gut associated lymphoid tissue (GALT)
2)
HIV infection overview:
chronic persistent infection of HIV where?
in the lymph nodes; this is why there is latent stage;
Stages of HIV:
1-4
Acute infection:
Latent stage
Falling Count (opportunistic diseases)
Death
Stages of HIV:
Acute stage: what causes the symptoms?
The VIREMIA of HIV peaks from three to six weeks AND the CD4+ is very low; then the viremia decreases and the latent stage kicks in;
Stages of HIV:
During latent stage, there are no symptoms; why?
Viremia–:> constant RNA copies;
CD4+ –> pretty constant
Stages of HIV: Falling count
what and why are there symptoms?
Constitutional symptoms and opportunistic diseases;
After the latent stage, Viremia INC exponentially;
CD4+–> dec rapidly;
Stages of HIV: AIDS
part of the falling count phase where the CD4+ count is 1)
less than 200
HIV pathogenesis:
HIV crosses the barrier and enters the 1);
HIV first interacts with dendritic cells, then infects the two potential target cells: 2); they are activated and then disseminated from the lamina propria to 3)
1) lamina propria
2) resting CD4+ T-cells or macrophages
3) lymphoid tissue
Generation of latency
1) = reservoir
1) Latently infected, resting CD4+ cells
Immune Effector Mechanisms:
Humoral response:
Anti-HIV Abs within 1) of primary infection with majority Abs against 2)
1) 3-6 weeks
2) gp41, gp120
Immune Effector Mechanisms:
Humoral response:
Antibodies against gp41 and gp120; these antibodies depend on 1); can also carry out 2)
1) N-linked glycosylation;
2) antibody dependent cellular toxicity (ADCC)
Immune Effector Mechanisms:
Cell-mediated response:
1-3)
CD4 T cells
CD8 cytotoxic T cells
NK cells
HIV serology:
1) corresponds to those times when the virus is avtively replicating; therefore it is increased during 2)
1) P24 antigen
2) acute phase when you see all the symptoms (6wks) AND symptomatic phase after latent is over
1) are produced once p24 antigen starts to decrease at about 6 weeks;
1) AntiEnv (envelope) antibodies and anti-p24 antibodies
When HIV patient dies, desc. serology
HIGH p24 antigen;
LOW anti p24 antibody
Acute HIV Syndrome: 1) after primary infection
1) 3-6 weeks
Acute HIV Syndrome:
dermatologic hallmark
white spots on tongue;
Acute HIV Syndrome: general s/s
Persistent fever, night sweats;
LYMPHDENOPATHY
Acute HIV Syndrome:
Neurologic
Meningitis, encephalitis, peripheral neuropathy, myelopathy
Acute HIV Syndrome: coincides w/
INC. viremia and dec. CD4+; goes away when latent stage starts
AIDS
CD4+ T cell count
Pneumonocystis pneumonia
tuberculosis
fungal infections
AIDS
Viruses cause Gastrointestinal issues:
Candidiasis
CMV,
HSV
Cryptospordia
AIDS
Kidney and Genitourinary infection:
Candidiasis, sexually transmitted infections
AIDS:Neurologic
Toxoplasmosis, Crytptococcosis, CMV, syphillis, amebiasis
Toxoplasmosis by Toxoplasma gondii
AIDS:Neurologic
