Dummy Target For Virus'

[Patrick O'Neil]

On 23 Apr 1995, Robert Weitkamp wrote:

> 	Is it possible to help the immune system fight virus' by providing false
>targets for them.  For example (and forgive my lack of knowledge) could
>you create a particle that the bodies immune system would not immediatly
>go for and would be filtered out naturally by the kidneys or whichever
>organ does such a job, but would still have the proper surface receptors
>to attract a particular virus (such as appearing to be a nerve cell as in

Well...possible ideas for combating HIV include injection of free CD4 
receptor protein which would bind to the receptors of HIV, preventing 
infection.  The protein could cause an immune reaction primarily due to 
parts of the protein that, in a normal CD4 cell, never are exposed to the 
immune system (aka, lipid spanning helix and intracellular components) 
could cause an immune reaction.  The converse, injecting free HIV 
receptor proteins which would competitively bind to CD4 with the virions, 
could also be done, which would illicit an immune response against the 
protein if the infection hadn't already brought on a response.  
  You might get a little more elaborate:  produce liposomes (self 
organizing spheroids of lipid bilayer that form when cell membranes are 
disrupted and homogenized) with the receptor protein of interest inserted 
in the membrane.  Of course, how do you get the protein in the membrane 
in the first place AND in the correct orientation (receptor side out 
rather than towards the interior of the liposome)?

  I believe the first two have already been considered/tried.  Not sure as
to the efficacy however (Anyone?  I am certain I have read of such
trials).  The last proposal would be real tough.  Theoretically, the virus
would bind the receptor and then just dump its capsid/nucleocapsid into
the liposome (if the virus counts on endocytosis, then it might bind for a
while, then release and be free to bind again to false target or real
target).  In the case of HIV, the capsid might get dumped into the
liposome and either stall right there or dump its RNA and RT contents, and
stall.  Presumably, such liposomes would eventually be lost along with its
contents.  In any case, this would be technically VERY difficult. 

Patrick