D HIV infection

Question 1

transmission is likely due to

Answer 1

transfer of infected cells

Question 2

course of infection w/o treament

Answer 2

acute phase lasts for weeks. person has flu-like symptoms. asymptomatic phases last 10 years. symtomatic stage person has aids. symptoms include infections and cancer. will die

Question 3

the acute phase

Answer 3

person is infected w/R5 strain. viral pop remains homogenous. most infection occurs at mucosal surfaces. once infected CD4+ t cells produce large amounts of HIV virions. after weeks neutralizing antibodies and Tc cells reduce viremia

Question 4

why does # of CD4 + t cells in blood decrease

Answer 4

apoptosis. at end of acute phage CD4 and t cells increase to nearly normal

Question 5

the asymptomatic phase

Answer 5

degree of virions in this stage determines how fast disease will progress in infected person

Question 6

the asymptomatic phase

Answer 6

virus contd to be replicated b/c virions remain low due to adaptive IS. steady decrease in CD4 and t cells. reverse transcriptase makes 65 times more error than the polymerase. produces many variants of HIV and virus pop becomes heterogenous. this is antigenic drift. some visions evade the IS which prevents production of vaccine. some become resistant

Question 7

at the end of asymptomatic phase

Answer 7

an exofore virion is produced, more virulent, replicate fasted, kill more cd4 and t cells, and cause formation of syncytia

Question 8

define syncytia

Answer 8

several cd4 and t cells will fuse together forming a multi necleated cell

Question 9

symptomatic phase

Answer 9

at this stage viral pop becomes homogenous for C4 strains. # of CD4+ cells drop below 200cells/ul. w/onset of infection and cancer person is said to have AIDS. level of viremia increase. cd4 cells decrease and viremia decreases