In article <4irggf$b88 at newsgate.dircon.co.uk>, infobase at dircon.co.uk wrote:
> Information/discussion is requested on the ability of viral load, as
> currently measured in HIV-1 infection, to acurately reflect the
> changes in viral population which may be expected under the influence
> of RT inhibitors, protease inhibitors, NNRTI's and combinations of
> these drugs.
>> If these agents alter viral production so that defective or
> non-functional virions are produced, how would the current assays for
> viral load reflect that?
>> If these agents alter viral production so that non-intact viral
> particulate matter is produced instead of intact virions, how would
> the current assays for viral load reflect this?
>> Insight into these questions is crucial to ensure correct management
> of therapeutic decisions based on the viral load measure. Obviously,
> this measure is redundant if it cannot differentiate between
> functional and non-functional virions, or intact virions and particles
> of viral components.
Most labs (at least those I work with) approach the problem from 2
directions - first to measure the production of viral specific RNA - this
tells you what is happening inside infected cels. Second, assay the
ability of material produced to infect human cells - this tells you how
much of that viral message gives you active infective virus. We use PCR
for the first method and infection of a CD4 line for the second - both are
very sensitive and thus give a very accurate picture of viral load.
The problem of course, is that viral load apparently varies greatly with
time and location, so a large number of timepoints and different biopsies
need to be taken to get an accurate picture of what the effect of any
particular treatment is. Not an easy process!