HIV/AIDS Flashcards
What are gp120 and gp41? Where do they come from?
- Envelope proteins acquired through budding from host cell plasma membrane.
- Cleavage of gp160
What are the functions of gp120 and gp41
gp120: docking glycoprotein; attachment to host CD4+ T cells
gp41: transmembrane glycoprotein used for fusion and entry
What is gag (p24)? p17?
gag (p24)–capsid protein
p17- matrix protein
How does reverse transcriptase work?
Reverse transcriptase synthesizes dsDNA from RNA;
dsDNA integrates into the host genome
HIV binds to which receptors on T-cells? on macrophages?
Virus binds CCR5 (early) or CXCR4 (late) co-receptor and CD4 on T cells.
Binds CCR5 and CD4 on macrophages
Homozygous and heterozygous CCR5 mutations
Homozygous CCR5 mutation results in immunity from HIV
Heterozygous CCR5 mutation results in a slower course of the disease
HIV diagnosis:
ELISA and Western Blot assay
ELISA: sensitive, high-false positive rate with low threshold. It is a RULE OUT TEST
Western Blot: + results from ELISA are confirmed with Western Blot. It is specific, high-false negative rate, and a high threshold. It is a RULE IN TEST
What is the purpose of an HIV PCR test?
Determines viral load. The amount of viral RNA in the plasma. Higher loads are associated with poorer prognosis. Also used to monitor drug therapy
AIDS diagnoses: 3
- CD4+ cell count
ELISA/Western blot look for?
When are they falsely negative/positive?
What is the best way to test infants/babies?
They look for antibodies to viral proteins.
Often falsely negative in the first 1-2 months of HIV infection.
Often falsely positive initially in babies born to infected mothers. gp120 crosses the placenta.
PCR test for infants
Four stages of untreated HIV infection:
- Flu-like (acute)
- Feeling fine (latent)
- Falling CD4+
- Final crisis
Systemic disease of HIV+ patient:
Causes low grade fevers, cough, hepatosplenomegaly, and tongue ulcer.
Oval yeast cells within macrophages
CD4+
Histoplasma capsulatum
Dermatologic disease in HIV+ patient:
fluffy white, cottage-cheese lesions
pseudohyphae, oral if CD4+
Candida albicans
Dermatologic disease in HIV+ patient:
hairy leukoplakia
EBV
GI disease in HIV+ patient:
Chronic watery diarrhea
Acid-fast cysts in stool when CD4+
Cryptosporidium
