Retroviruses (HIV, HTLV) Flashcards
what is the biology of HIV?
enveloped with 2 copies of single stranded +RNA
what Virus attachment proteins (VAP) found on the envelope of HIV?
GP 120
GP 41
what is the major capsid protein found in HIV?
p24
what enzymes does HIV have?
integrases
proteases
reverse transcriptase
which of the 2 membrane proteins in HIV will define its tropism?
GP 120
what cells does HIV target?
CD4+ cells
antiviral drugs for HIV will target what protein of the virus?
gp 41
HIV protein Gp 120 will bind to what cell and what co-receptor if it’s M tropic?
it binds to CD4+ (memory CD4 T cells, Dendritic cells, macrophages) cells and its co-receptor CCR5
HIV protein Gp 120 will bind to what cell and what co-receptor if it’s T tropic?
if its T tropic it binds to CD4+ (activated T cells) cells and CXCR4
what will the HIV Gp 41 protein do?
it will fuse the viral envelope with cell plasma membrane
what is the first stage of HIV replication?
what symptoms are seen?
1st stage = we will replicate in the macrophages and dendritic cells in the lymph nodes
(swollen lymph nodes, and high virus, no antibodies)
what is the second stage of HIV replication?
2nd stage = virus lives inside T cells, disseminates throughout body but remains latent, it is in DNA form, low HIV virus, we have high antibodies
what is the 3rd stage of HIV replication?
3rd stage = virus is all over, shifts to CXCR4 in CD4 and attacks our active T cells and strats making many virion particles which will look for GP120
where do we find the largest amount of cases of HIV-1 infection?
sub-saharan africa
where do we find the largest amount of cases of HIV-2 infection?
West africa
who is at risk of being transmitted HIV?
intravenous drug abuser (sharing needles)
sexually active individuals (homosexuals, prostitutes)
newborns of HIV positive mothers
organ transplant patients
what cells are most prone to infection by AIDS and what cells are used for latency by the virus?
T cells and macrophages
CD4+ T cells by incorporating DNA into host genome
what individuals are most prone to be resistant to HIV infection?
CCR5 receptor deficient individuals
if there is a mutation in the GP 120 protein of HIV, how will this affect its tropism?
its tropism will shift from M-tropic to T-tropic
what is HIV’s pathogenesis?
1) lytic infection of CD4 T cells (having the virus infect start to infect some macrophages)
2) reduction in CD4 T cell numbers
what happens when you are have the HIV acute illness?
what symptoms are seen?
will see drop in CD4+ cell count
flu-like symptoms are seen
what happens when you have HIV latent infection?
what symptoms are seen?
the virus is in provirus form
test will be positive for HIV antibodies
destruction of CD4 cells will continue
no symptoms are seen
what happens during the symptomatic phase of HIV?
what symptoms will be seen?
CD4+ cell count is less than 500
increased level of virus
weight loss, continual diarrhea, extreme fatigue, **oral thrush **
what bacteria causes oral thrush seen in HIV symptomatic phase?
candida
what happens in full blown AIDS by HIV virus?
what symptoms are seen during this phase?
CD4 is less than 200
antibody test is negative
kaposi sarcoma, thrush, severe CMV, dementia
what are 3 opportunisitc infecions seen in AIDS?
1) Pneumocystis jiroveci Pneumonia (PCP)
2) Candidiasis (oral thrush)
3) cryptococcocis (meningitis)
what fungal infection is most defining of AIDS?
PCP
what is the most common fungal infection of the CNS?
cryptococcosis
what is the most common fungal infection overall?
candidiasis
what are 2 of the most common bacterial infections found in AIDS?
1) Mycobacterium avium intracellular complex (MAC) (lung and esophagus infection)
2) Salmonella typhimurium
what is the 2 most common viral infections found in AIDS patients?
1) CMV
2) Herpes Simplex Virus
what does CMV lead to in AIDS?
- retinitis
- esophagitis
- colitis (diarrhea)
cholecystitis
How do CMV infections differ in immunocompetent vs. immunosuppressed patients?
In immunocompetent patients, an acute CMV infection results in a syndrome resembling acute infectious mononucleosis.
In the immunosuppressed patient, CMV disease, whether acquired primarily or as a result of reactivation, may be a disseminated, fulminant, and lethal disease with multiorgan involvement.
what are 2 common parasitic infections found in AIDS patients?
1) CNS toxoplasmosis
2) Cryptosporidiosis
what is the most common pathogen found in diarrhea?
cryptosporidiosis
what is the most common focal space occupying lesions in AIDS patients?
CNS toxoplasmosis
what are 5 AIDS determining malignancies?
what virus causes each of these malignancies?
1) kaposi’s sarcoma - HHV-8
2) Burkitt’s lymphoma- EBV
3) Primary CNS lymphoma - EBV
4) Invasive cervical cancer- HPV
5) Anal squamous cell carcinoma - HPV
