re aids isnt a cd4 disease....

Christopher Savoie savoie at bioreg.kyushu-u.ac.jp
Thu Mar 30 21:45:56 EST 1995


Dear Ralph,

I appreciate your questions and I think thay are valid and worth
exploring.

However, I think that I must clarify my point a bit.

I am not implying that the CD8 cells are the "worst hit" by the 
virus.  (Forgive the sensationalism of my first posting... this
was meant to call attention to my article)  Of course the CD4 cells
are the worst hit because they carry the CD4 antigen constantly,
thus their name.  What I _am_ implying is that the CD8 cells
must also be effected by the virus due to their positivity for
CD4 during their development.  Since CTL (the cells responsible
for killing virally infected cells) are CD8 cells, any effects
(quantitative or qualitative) on this compartment must be important
in the pathogenisis of a viral disease.

McMichael et al have reported that CTL response to viral peptide
epitopes in the MHC class molecule dissipate at the end stage
of HIV disease.  This could be explained by the slow and steady
exhaustion of CD8 precursers via infection by HIV when these
cells are CD8CD4 dp.

Whether CD8 counts change during  the course of infection is secondary
to whether or not their function is affected by HIV. The 
CTL response is obviously lost (as reported in vitro and as evidenced 
by the occurence of cancers and viral infections, clinically).  
The problem is _how_ this response is lost.  Direct infection of 
CD8 precursers (which MUST happen) seems like the most probable
mechanism for the eventual loss of viral control (AIDS).


C.J. Savoie
Medical Institute of Bioregulation
Kyushu University
    





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