inbred vs outbred for potency testing - (Mar/02/2007 )
We use an outbred strain of mouse and can get fairly huge variation which has proven to be very difficult to track down to whether it is the in vivo part of the assay or the subsequent in vitro analysis of the antibodies. In one dose group of 10 mice we can see a few making wonderful neutralising antibody reponses whilst others make virtually none.
I have suggested moving to an inbred mouse strain to try and standardise the response but in conversation with NIBSC they didn't think this would make much difference. Anyone have any thoughts on this.
this is only my opinion, but I would use the outbred mice. your data might not be as pretty, but the model that's closest to reality is always more meaningful
We use and prefer inbred mice or even rats for that matter. Ofcourse, variations in mice due to differences in strains and background can give unexpected results.
Even if we get any result from unknown or different strains, we prefer to confirm it with inbred ones.
I completely agree with you for experimental testing but I didn't explain well enough I think. It's not about pretty data (though i know exactly what you mean in that respect). If we were testing the reponse to the vaccine in a heterogenous population I would completely agree with you, in that outbred would mirror reality better.
However the purpose of this assay is to measure manufacturing consistency between batches. The response does not have to be consistant to show potency in a human population it has to show that if one batch measures at xng ED50 that the next batch measures yng ED50. Currently there is so much variation in the indicators (mice or some have argued PRNT assay) that it is difficult to be confident that the results are valid.
hmm, I stand corrected and I see your point 
I was thinking of the problem from a different direction