I have observed a problem with a standard in one of our ELISA assays.
The standard is immunoglobulins diluted in glycerol (63%), Imidazol,
Thimerosal, HSA, Tween 20 and water. Normally the standard was kept at
-20C (in dilution), but was then moved to -80C. During a period of about
4-5 month a jump to higher responses of the standard was suddenly
observed and at the same time it was noticed that the standard solution
was freezed.
Can anobody tell me why a higher respons is observed? I would expect a
lower respons because of aggregation of the antibodies when the solution
is freezed. I also wonder that the lag period of 4-5 months is observed.
Any references to documentation of glycerol and its impact on stability
of immunoglobulins are very appreciated.
Thank you in anticipation
_____________________________
Karina Agergaard Andersen
Chemist
FVII QC Lab
Novo Nordisk A/S
Sauntesvej 13
DK-2820 Gentofte
Denmark
44 43 02 82 (direct)
KAAd at novonordisk.com
Changing the world of diabetes
Novo Nordisk's TakeAction! volunteer programme encourages employees to
join the fight against diabetes both locally and globally See how
<http://www.novonordisk.com/about_us/changing-diabetes-activities/TakeAc
tion.asp>
This e-mail (including any attachments) is intended for the addressee(s)
stated above only and may contain confidential information protected by
law. You are hereby notified that any unauthorized reading, disclosure,
copying or distribution of this e-mail or use of information contained
herein is strictly prohibited and may violate rights to proprietary
information. If you are not an intended recipient, please return this
e-mail to the sender and delete it immediately hereafter. Thank you.