|
For many patients, highly active antiretroviral therapy (HAART)
reduces human immunodeficiency virus (HIV) plasma viral load
to undetectable levels. Viral proliferation is not
completely suppressed, however, as evidenced by low level de
novo cell infection. With the withdrawal of therapy, viremia
returns. One reason for this is the presence of virions in
anatomical compartments that partially exclude the
penetration of one or more of the HAART drugs, i.e., drug
sanctuaries that act as viral reservoirs. Another reason can
be ongoing viral replication due to imperfect adherence to
the drug-taking regimen. Patients not fully adherent is more
likely to have subtherapeutic drug levels. The 2-LTR HJ.V
episomal DNA fraction represents an ephemeral form of the
virus that has recently infected cells. It can be quantified
and sequenced along with adjoining genes using primers that
cross the 2~L TR ligation site. We propose to sequence the
polymerase gene from the 2-LTR. episomal forms of HIV from
the blood and semen from patients whose adherence is being
followed by the use of MEMS caps electronic monitors and by
the concentration of the antiretrovirals in these fluids.
This will elucidate the residually replicating form of HIV
present in the blood and semen, allowing us to contrast the
relative permeability of antiretroviral compounds in the
seminal compartment to the resistant viral forms present. By
following these forms over a period of time, the seminal
compartment can be evaluated as a drug sanctuary and its
role in reemergent viremia can be assessed. It is our
hypothesis that, in the presence of adherence to an
antiretroviral regimen, the residually replicating HIV forms
that are found in seminal fluids will be the more fit drug
sensitive virus genotype for the drugs that poorly penetrate
blood-semen barrier. These will contrast to the concurrent
forms of virus in the blood which will be resistant. In the
absence of adherence, sensitive viral forms will be found in
both plasma and seminal fluid. In cases of emergent viremia,
the viral forms in the blood will phylogenetically cluster
with the residually replicating forms in the seminal
compartment, and the seminal will be a representative viral
sanctuary and reservoir. This will elucidate the virus
population dynamics and resistance acquisition in a
representative viral reservoir.
|
