BIOC51H3 Lecture : Readings 9 notes
11 Aug 2010
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Readings 9
-AIDS causes more deaths than TB, malaria, car accidents, homicides and wars
-the AIDS epidemic has wrought its greatest devastation in sub-Saharan Africa
-in industrialized countries of North America and Western Europe, overall infections are much lower
than sub-Saharan Africa
-HIV establishes a new infection when a bodily fluid holding the virus, usually blood or semen, carries it
from an infected person onto a mucus membrane or bloodstream of an uninfected person
-programs to curb the spread of HIV have seen success in promoting reducing risky sexual practices and
condom use
-the increasingly widespread abuse of methamphetamine is associated with risky behaviour and a
greater chance of contracting HIV
-HIV is an intracellular parasite that cannot reproduce on its own
-HIV invade specific types of cells and uses the enzymatic machinery to make copies of itself, killing the
host cell in the process
-during the extracellular phase, the virus moves from host to host
-during the intracellular phase, the virus replicates
-HIV attaches to two proteins on the cell called CD4 and a coreceptor and fuses with the host cell
membrane to spill its contents
-ZÀ]µ[]o}]Pv}uvZ}]vvZoo
-reverse transcriptase transcribes RNA into DNA, integrase splices the DNA genome into the host cell
genome and protease prepares viral proteins
-new virions, after replication, bud off the cell membrane and enter the bloodstream to infect the host
even more or another host
-drugs that interrupt ZÀ]µ[o](Ço]v}]v(Á]ZZZ}oo[vÌÇu](µv]}v
and cause side effects
-HIV parasitizes helper T cells of the immune system that play a crucial role in response to invading
pathogens
-ZZ}[}Áv]uuµv}vontributes to the development of immunodeficiency
-T cells derive from stem cells in bone marrow and generate precursors that mature in naïve T cells in
the thymus
-an activated T cell yields effector and memory cells that circulate through the blood
-naïve and memory T cells are long lived while effector cells are short lived
-µ]v]uuµv]À]}vµ]vP,/s]v(]}vvµo]uoÇoZ}Ç[µoÇ}(Zod
oov}ooZZ}[(v
-in the initial or acute phase of infecti}vU,/sÀ]]}vvZZ}[}ÇvP]v}o]
explosively by killing memory T cells
-the acute phase ends when viral replication slows and the concentration of virions drops due to the
immune system response
-in the chronic phase, the immune system struggles to recover from initial losses while continuing to
fight the virus
-µ]vPZZ}v]ZUZ]uuµv}vµvZ}µPZZZ}[µoÇ}(vbÀvuu}Ç
helper T cells by stimulating them to divide into effector cells
-replacement of lost helper T cells ultimately depends on the production of new naïve T cells by the
thymus
-,/suPZ}vu}ÁvoÇuZv}Uµ]vPÇo]v]vZ]uuµvÇu[
capacity to regenerate
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Document Summary
Aids causes more deaths than tb, malaria, car accidents, homicides and wars. The aids epidemic has wrought its greatest devastation in sub-saharan africa. In industrialized countries of north america and western europe, overall infections are much lower than sub-saharan africa. Hiv establishes a new infection when a bodily fluid holding the virus, usually blood or semen, carries it from an infected person onto a mucus membrane or bloodstream of an uninfected person. Programs to curb the spread of hiv have seen success in promoting reducing risky sexual practices and condom use. The increasingly widespread abuse of methamphetamine is associated with risky behaviour and a greater chance of contracting hiv. Hiv is an intracellular parasite that cannot reproduce on its own. Hiv invade specific types of cells and uses the enzymatic machinery to make copies of itself, killing the host cell in the process. During the extracellular phase, the virus moves from host to host.
