Hi,

There are 2 major questions:

1- Are you sure about the quality of your LPS? Test it with LAL kit or analyse it with SDS-PAGE (with 8M urea).

2- Are you sure if it is not detoxified?

Micrograms of the Ecoli LPS causes die in mice!I tried LPS of Ecoli, Brucella, Salmonella and Pseudomonas before in mice and rabits.

I am not positive on the quality but I questioned this to Sigma who supplied me with a different lot and I am getting the same results (or lack of). How or when does LPS become detoxified? I am starting to think it is my resuspention methods - not alot of description of this in the literature - I have been using the phenol extraction LPS and first take it to 20mg/ml in PBS then I add D-Galn (reconstituted at 800mg/ml in sterile saline) and then take that and make it into an 800mg/kg D-Galn and vary the LPS dose (highest was 80mg/kg) again in saline - I had vortexed it a few times but lost alot in bubbles so now I have been putting in a 37C water shaker bath for 30 minutes before the IV injection - to my outbred ICR males (5-10weeks old). I thought giving more details may elucidate my issues.

I have finally seen some lethality - the variable I changed to get it was the mice

using C3H females and 24 hours in I have 75% death in 2 groups - .7mg/kg LPS and 1.2mg/kg LPS both sensitized w/D-Galactosamine - also I am now using 0111:B4 - I had switched to this with ICR mice with no results - I will be repeating the same today