Regarding the infectivity of naked DNA

[Pearse Ward]

In article <3pqrkp$qql at cisunix1.dfci.harvard.edu>,
york at mbcrr.dfci.harvard.edu (Ian A. York) wrote:

> In article <wardp-2205951312040001 at oisin.usask.ca> wardp at herald.usask.ca
(Pearse Ward) writes:
> >
> >What's the evidence that said mice were protected by muscle cells
> >expressing viral proteins, as opposed to say APC's taking up the DNA? I
> 
> Some of the papers explicitly show that the muscle cells express the gene 
> of interest.  It seems almost impossible that some APC is not also 
> transfected at very low frequency and that they are responsible for the 
> protection; but the simpler explanation is preferred.
> 
I've read the papers and seen some evidence from people working here that
muscle cells can take up naked DNA, and that they can express foreign
cell-surface proteins, but so far i haven't seen any data that show
conclusively that this is the source of the immune response. Although this
may be the preferred explaination, it doesn't meant that it is the right
explaination.

The implication from this work is that the immune response generated is
cell-mediated immunity. Without antigen recognition by CD4+ cells, I don't
see how this is possible. Therefore, for this system to be working as
advertised, there must be some explaination as to how the exogenous
antigen gets presented to Th cells.

Pearse