answer to an answer to a thougt

[Ken Frauwirth BioKen]

In article <1994Jul19.194833.1 at opal.tufts.edu>, rganssen_imm at opal.tufts.edu writes:
|> In article <30cldk$40u at agate.berkeley.edu>, frauwirt at mendel.Berkeley.EDU (Ken Frauwirth (BioKen)) writes:
|> > Along the lines of a "general factor", but still trying to "improve" the
|> > patients own T cells, there is the possibility of using retrovirally
|> > introduced genes to beef up the immune cells.  The advantage to this is that
|> > a retrovirus (mutated to prevent replication, of course) can be targeted to
|> > a specific tissue or cell type.  For example, using a deactivated HIV-like
|> > vector could target a resistance gene (yet to be developed) to CD4+ T cells.
|> > This obviates the need to remove cells from the patient.  In fact, this type
|> > of gene therapy is already in the works for genetic diseases (cystic
|> > fibrosis, for example).
|> > 
|> 
|> 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 they
|> 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.
|> 
|> 
|> Richard   
|> not

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.

BioKen
-- 
Ken Frauwirth                  _           _
frauwirt at mendel.berkeley.edu  |_) *    |/ (_ |\ |
Dept. of Molec. & Cell Bio.   |_) | () |\ (_ | \|  
Univ. of Cal., Berkeley   .sig made under strict rabbinical supervision