Q: We have a question about two 192-IgG-SAP (Cat. #IT-01) lots. According to your data sheet there is an approximate 4-fold difference in ED50 between your new lot and old lot. We also observed a clear difference in behavior between animals dosed with the new batch and the old one. It is thus obvious that the new lot needs to be diluted to achieve the same results, however, we are uncertain if this can be calculated just based on the ED50 values. Do you have any experience about dose-responses with the different lots in terms of size of lesion?
A: We don’t have an exact correlation between in vitro and in vivo activity, unfortunately. We state on the data sheet to check a new batch on a small number of animals.
“There may be lot-to-lot variation in material; working dilutions must be determined by end user. If this is a new lot, you must assess the proper working dilution before beginning a full experimental protocol.”
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