HIV Flashcards
Retrovirus
converts viral RNA into DNA. DNA gets integrated into host DNA to form a provirus
Acute HIV syndrome
flu-like symptoms
active virus replication happens in blood and CSF
Lymphoid organs “seeded:”” with virus
When does seroconversion take place
6-9 weeks after exposure to virus
Window period
patient is producing antibodies, but all serologic tests are negative . This is a dangerous time because they could be passing the virus without realizing it
Asymptomatic Infection (aka latent phase)
seropositive
can last a really long time (10 years)
unknown exactly what triggers a patient to go from the latent to active phase
AIDS-related complex (ARC)
majority of patient’s don’t go through this phase. Those that do tend to have high viral loads
without treatment they die relatively quickly of AIDS
What are the symptoms of ARC
persistent fevers, night sweats, weight loss, chronic diarrhea, inflammatory skin conditions, lymphadenopathy
some get oral candidiasis and/or chronic mucocutaneous herpes simplex infection
Clinic findings of AIDS
recurrent infections
kaposi’s sarcoma or non-hodgkin’s lymphoma
progressive wasting syndrome (cachexia)
dementia
What is responsible for cachexia
TNF-alpha
Clinical definition of AIDS
CD4+ count drops below 200
HIV variants that use ____ (expressed on macrophages and memory T cells) are called _____
CCR5
R5
HIV variants that use ______ (expressed on T cells) are called ______
CXCR4
R4
HIV that can bind to both CCR5 and CXCR4 is called what?
R5X4
Plasma membrane-expressed gp120 binds to what
CD4 on nearby cells
What does the binding of gp120 to CD4 initate? and what is the result?
membrane fusion
passes HIV genomes to uninfected cells
What happens once HIV is inside the cell?
viral replication or proviral state
transcription factors _____ and______ which bind HIV long terminal repeastz that control viral gene transcription
NFkB
SP1
_____ and _____ induces HIV transcription/replication in T cells
TNF-alpha
IL-2
What induces HIV replication in monocytes and macrophages
IL-1, IL-3, IL-6, TN-alpha, IFN-gamma, and GM-CSF
How does HIV affect monocytes/macrophages
they are not as prone to lysis
instead they can serve as in vivo reservoir and transport the virus throughout the body
What are macrophage and/or virus-mediated effects on CNS
AIDS dementia complex, which leads to memory loss
Dementia
direct virus infection of neurons or destruction of neurons by macrophage-derived cytokines
How does HIV affect T cells
lyses them
How does HIV kill T cells
direct lysis by budding HIV
virus production which interferes with cellular protein synthesis
syncytia formation
binding of gp120 to infected and uninfected T cells results in antibody response, ADCC
CTL mediated destruction
2 other ways HIV messes with the immune system
binding of free gp120 to CD4 of uninfected cells makes those cells unable to bind to class II MHC proteins destroys follicular dendritic cell network
Truncated CCR5 variants
seronegative even after repeat exposure to HIV
What type of response was found in female gambian/kenyan sex workers to repeat exposure to HIV
no significant antibody response, but potent CTL response
after leaving the industry and coming back more were infected, possibly because absence of frequent exposure to HIV
Who might get a false positive with ELISA testing?
multiparous females
patients with autoimmune disease
What test should you use if you get two positives with ELISA?
Western blot
PCR
very sensitive
can use to determine if neonates have been infected
