Exam 3 HIV Retrovirology Flashcards
HIV is part of the ____ family
Lentivirinae
Lentivirinae viruses are characterized as:
Slow, neurologic, or immunosuppressive
Morphology of HIV capsid
- D-type capsid
- Central, cone shaped cylindrical
HIV regulatory genes
- Tat
- Nef
- Vpu
Tat function
Transcriptional activator
Nef function
Reduces MHC I expression
Vpu function
Enhances virion release
HIV gp120 binds primary host cell receptor ____ and has a high affinity for binding host co-receptor ____
CD4; CCR5
HIV gp120 is _____ (initial)
M-tropic
HIV - ____ strains M-tropic; early infection of _____
CCR5 or R5; Macrophages and dendritic cells
After M-tropic initial infection, HIV subsequently moves to the ____ and spread to _____. This is termed _____ or later infection
Lymph nodes; CD4 T cells; T-tropic
Reverse transcriptase is highly error prone, which causes:
Rapid generation of many new strains (HIV clades and antigenic variants)
____ is most common and most pathogenic in the US
HIV-1
HIV-1 causes _____ (90% cases in the US)
M-type “major”
HIV gp41 facilitates:
- Fusion with macrophages, dendritic cells, microglial cells
- Fusion with T cells R4 strains
HIV envelope gp120 binds ____ and co-receptor CCR5 or R5 of _____
Host CD4; Macrophages
____ predominates in early (initial) infection
M-tropic
HIV envelope gp120 binds host _____ and co-receptor CXCR4 or R4 of _____
T-cell CD$; T-helper cells
____ predominates in late infection
T-tropic
People with CCR5 delta-32 have:
Partial resistance to R5 strains (M-tropic)
Those who have the CCR5 delta-32 gene are _____ that make up ___ of the population
Homozygous mutants; 1%
First gene edited embryos altered ____ receptor in vitro
CCR5
HIV co-receptor CXCR4 is ____ (structure)
Heptahelical
type of GPCR
HIV integration and replication begins with ssRNA (+) genome and uses _____ to create a ____ strand. This is the _____ function
RTase; DNA strand (-); reverse transcription
During HIV replication, RTase degrades the RNA strand of the RNA-DNA hybrid. This is termed _____ function
Ribonuclease H function
After RNA degradation, RTase creates ______. This is termed the ____ function
complementary DNA strand; DNA polymerase
____ splices HIV into host genome to create a provirus
Integrase
Once a provirus is created and HIV has gotten into the host genome, _____ transcribes mRNA
Host RNA polymerase
HIV early stage events
Integration, provirus
HIV late stage events
- Provirus (latency period)
- Host cell activation
- Host RNA polymerase to transcribe genome
Transcription factor active in immune response is _____ which binds ___ to activate HTLV or HIV
NFkB; LTR
HIV incubation period
1-10 years
During the HIV incubation period, ____ > _____
Resting cells > Half life
When do antibodies to HIV become detectable?
2 weeks to 2 months
CD4+ cells begin to deplete _____ after infection
Months to years
When is HIV infection considered AIDS?
Less than 200 cells/microliter
When does seroconversion of HIV occur?
2 weeks to 2 months
What are the stages of clinical course of HIV infection?
- Stage 1: acute infection, high viral titers
- Stage 2: Sub-clinical infection, low-level replication
- Stage 3: High viral replication
During what stage of HIV infection is the AIDS-related complex found (ARC)?
Stage 2
What happens during stage 3 of HIV infection?
- CD4 count < 200 cells/microliter
- AIDS
What does AIDS stand for?
Acquired immune deficiency syndrome
Oral symptoms of HIV infection
- Severe periodontitis (usually acute)
- Oral candidiasis (tongue, palate, tonsils)
HIV diagnosis and treatment: lymphocytes are ____
Low (lower than reference range)
HIV diagnosis and treatment: HIV involves ______
Destruction of T cells
List the steps of HIV pathogenesis (7)
- Loss of T-helper function
- Reduced CD4 cell count
- Immune system failure
- Th1, Th2 function impaired
- Loss of DTH function
- Opportunistic infections
- Unusual neoplasms
Infective HIV virions _____ found in whole saliva of patients
Rarely (cannot exist in cell free state in saliva)
