Pharmacology & Toxicology
Re: Poster 774
On Mon Dec 14, Christopher M Tan wrote
> Dr. Metwally,
> Interesting poster. I was curious, what about controlling for the role of pertussis toxin-mediated ADP
> ribosylation of Gi alpha subunits, outside of using PTx as an adjuvant? Further, do you have any indication
> of whether any of the other secreted peptides have any vasoreactivity or any other roles? Tim Reudelhuber's
> lab (U of Montreal) has shown that pre-renin (the precursor to renin, which is involved ultimately in
> Angiotensin synthesis) possesses biological activity outside of is role as a precursor to renin. So,
> conceptually, the notion is there that precursor forms have direct and indirect roles.
We don't think that the role of PTx as far as ADP ribosylation of Gi alpha is releveant in this assay. PTx is given 5 weeks prior to testing, so presumably any acute effects of PTx have disappeared (as far as ribosylation of Gi alpha) PTx seems to be purely useful in the sensitization because when given with ovalbumin as an adjuvant. The senstization does not occur as frequently in its absence (lower titer, or no sensitization). One item of note, PTx as an adjuvant seems to increase the duration of sensitization from a week to up to 3 or 4 months.
With regards to your second question, there isn't any indication currently that the precursor of SGP-T has any biological activity.
Tue Dec 15