Micro 6. Flashcards
What is HIV?
a zoonotic disease - introduced to humans by chimpanzees in central Africa
What is treatment for HIV?
HAART - highly active antiretroviral therapy
What is PEP?
post exposure prophylaxis - the use of antiretroviral drugs after a single high-risk event to stop HIV from making copies of itself and spreading through your body - must be used within 3 days
Who has the highest risk of HIV in the US?
gay/bisexual African American Men - especially younger
Upon exposure, who is most likely to become infected with HIV?
women
What do HIV virions infect?
lymphoid cells that are embedded in the vaginal and rectal epithelium - tissue macrophages, dendritic cells, etc
Where do visions migrate after initial infection?
to lymph nodes
What are the main symptoms of acute HIV infection?
fever, weight loss, sores and thrush of mouth, myalgia, hepatomegaly, nausea, vomiting, rash, lymphadenopathy, headache, neuropathy, malaise
Bacteriology HIV
ssRNA, (+) strand, slow to cause disease (lentivirus), two copies in each vision (diploid - for more variability)
What receptors must be present on a cell in order to induce HIV attachment and fusion? (early in infection)
CD4 and CCR5 coreceptor
Mutations in what change the coreceptor HIV binds to on CD4 cells? What is the advantage of this for the virus?
mutations in Env change binding to CXCR4 instead of CCR5 - this helps cells fuse together
What is mRNA synthesis completed by?
host RNAPII
What is replication phase I?
genomes are reverse-transcribed in the cytoplasm (by RT) and then integrate (IN) of HIV into host chromosome
What is replication phase II?
mRNA by host RNAPII and genome synthesis - protease cleave for final step of maturation
When can syncytia be formed?
after virion maturation - a multinucleate cell - multiple fusions of cells
What is Env?
HIV - composed of TM (transmembrane, gp41) and SU (surface gp120 domains) and cleaved by host proteases - SU binds CD4 and chemokine receptors which causes conformation change in TM - TM inserts in target cell membrane and induces virus entry
CCR5
for macrophages
CXCR4
for T cells (mutations in Env in order to infect these cells)
What is the primer in reverse transcription of HIV?
tRNA bound to ssRNA
What is the primary obstacle to eradicating HIV from a person?
viral genome becomes part of the cell for the life of the cell creating a reservoir of latent virus
What does discontinuation of HAART allow?
viral relapse from latent reservoir
Do patients successfully treated with HAART after 10 years exhibit an appreciable decrease in the size of the latent reservoir?
NO
Mature virion
infectious - HIV protease cleaves Gag into subunits resulting in capsid assuming its trapezoidal shape
Immature virion
not infectious - formed when they bud from plasma membrane
