answer to answer to a thought: augmenting T-cells in HIV infection

Basavaraju Shankarappa bsh at MED.PITT.EDU
Thu Jul 21 09:23:47 EST 1994


In article <1994Jul19.194833.1 at opal.tufts.edu>, rganssen_imm at opal.tufts.edu writ
es:
|> In article <30cldk$40u at agate.berkeley.edu>, frauwirt at mendel.Berkeley.EDU (Ken
 Frauwirth (BioKen)) writes:
stuff deleted::
|> July 19
|> Improvement of HIV-patients own T cells to combat the virus has one BIG
|problem. The T cells are probably the first targets of the virus. Although th
|> might not be killed in a direct way by the virus, the number of CD4 T cells (
helper T
|> cells) decrease during progression of the disease. So it is questionable
|> whether the approach of activating T cells will work in case of HIV. Actually
|> It has already been tried by giving AIDS patients IL-2 which is able to
|> activate T cells and NK cells. Thus far no positive results.

	I realize that IL-2 administration to boost CD4s have failed.
But do we have enough "evidence" to believe that increasing the  
CD4 numbers will only give rise to more targets for the virus.  With HIV
our logic has not necessarily stood up to the test many times.  So either   
we have to find ways that a patient can live without CD4 cells or
examine a possibility that successful augmentation of CD4s will in indirect
ways promote prolongation of progression.   There has to be an explanation
for the fact that long term non progressors in spite of their high CD4 count
still do not provide all that attractive target for the HIV to devour all 
those cells.  

Raj Shankarappa
bsh at med.pitt.edu



:Although T cell improvement may prove difficult to use as a cure, it
:still has potential use as a vaccine.  In addition, if the hypothetical
:"AIDS resistance" gene could be targeted to stem cells, it might even be
:useful as a cure (although it would require time to replace the
:susceptible T cells with resistant ones).  The idea is not to activate
:T cells, as much as it is to prevent the disease from destroying them.
:As for the lack of positive results with IL-2, this is not terribly 
:surprising.  High-affinity IL-2 receptors are only present on activated T 
:cells, so very high levels of IL-2 would be required to "boost" an immune
:response, especially in immunosuppressed individuals.
:Ken Frauwirth                  _           _
:frauwirt at mendel.berkeley.edu  |_) *    |/ (_ |\ |
:Dept. of Molec. & Cell Bio.   |_) | () |\ (_ | \|  
:Univ. of Cal., Berkeley   .sig made under strict rabbinical supervision





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