[extropy-chat] Re:BIO: Interesting HIV research- "A Clear and Present Danger"

[Robert J. Bradbury]

On Thu, 4 Mar 2004, Extropian Agroforestry Ventures Inc. wrote:

> http://www.newscientist.com/news/news.jsp?id=ns99994141

Ok, this is pretty simple.  HIV uses two receptors to get into
cells CD4 and CCR4 (I think).  Some people are defective in
CCR4 and can either not get HIV or its very very difficult.
Bacteria secrete lots of proteins for various reasons --
defense, to gather food, perhaps to attract other bacteria
with which they might exchange genomic material (though I've
never seen this proven -- I've never really checked).
What they have done is created an artificial gene which
they put into a natural bacteria that produces a secreted
soluble form of CD4.  This acts as as a "decoy" for any HIV
when it tries to enter the cells.  HIV binds instead to the
synthetic CD4 rather than the natural CD4 that is on the human
cells they would infect.  Because off normal vaginal secretions
the HIV viruses will eventually get flushed out either preventing
or significantly decreasing the infection rate.  The only flaw
that I can easily see in this one would not want to have sex
when a woman was having her period as HIV might be able
to get from the vagina into the bloodstream due to reduced
barriers.  But I'm not an expert in this -- it would probably
take an ObGyn to comment on it.

In a way this strategy is almost like putting an insulin
or antibiotic factory within your body -- though not
actually in your bloodstream where it is more likely
to make your immune system rather annoyed.  One could
legitimately call this the first real application of
bionanobots for in vivo medical therapy I think.  It
is going to take a lot of work to remove sufficient
molecules from the surface of bacteria to get them to
the point where your internal immune system would
tolerate them -- though they might be workable bound
within non-immunogenic membranes that only allow small
molecules in or out (this will work for most hormones).

> http://www.newscientist.com/news/news.jsp?id=ns99994742

Ok, they don't have a good explanation for this yet.
What it indicates is that patients who have the GBV virus
and remain infected with it seem to live significantly
longer than patients that don't.  The last paragraph
suggests that there may be GBV coat molecules that either
compete with HIV for access to the CD4 or CCR4 receptors
(as the case discussed above) or perhaps the GBV virus in
some way binds to proteins on the HIV virus and blocks
infection (or may even manufacture proteins that destroy
the HIV virus once inside the cell).

Good enough?
Robert