I have found that mixing empty vector with antigen-encoding vector
decreases the resulting antibody response to the antigen, an effect I
attribute to cytokine-mediated downregulation of transgene as a result of
CpG stimulation. Others have found that this happens only with antigens
that are not secreted, see this :
Lee et al.
Immuno-stimulatory effects of bacterial-derived plasmids depend on the
nature of the antigen in intramuscular DNA inoculations
Immunology vol. 94 pp. 284-289
James
In article <a.mungul-2807991727300001 at mac017044.guys.icnet.uk>,
a.mungul at icrf.icnet.uk (Arron Mungul) wrote:
> Have many people experienced problems using cotransfected empty vector in
> immunisation protocols?
> e.g. did not include empty antigen (Ag) vector control in the following
> experiment:
>> Marker + Ag
> Marker + ?_
>> Could the empty antigen vector affect immunisation even if no proteins
> could be expressed in mammalian cells? (only has ampicillin marker under
> bacterial promoter).
> i only know of cases where the vector contains CpG islands and may raise
> an immune response, or if the promoter is bi-directional and produces
> cryptic epitopes within the vector, but am not sure about naked,
> non-expressing DNA.
>> your help is much appreciated
>> Arron Mungul
