I need to eliminate LPS from a recombinant protein produced in E. coli to use it for activating T cells. What is the best way? How can I measure the content of LPS after the treatment?
Lucigen has come up with it's new genetically modified BL21 (DE3) known as (ClearColi BL21DE3), which has the capability of producing clean and functional proteins free from endotoxin. By employing this novel E.coli strain, you do not need to eliminate LPS from your protein.
If this is a one-off thing for an experiment and the amount of protein is relatively small, Pierce -and others- sells columns for removing endotoxin from protein samples. See e.g. http://www.piercenet.com/product/pierce-high-capacity-endotoxin-removal-resin. How to measure LPS depends on your objective; the most popular alternative are the commercially available LAL kits.
I'd rather not to clone the protein again, so I'll try first the kit Alejandro suggested. I had used another kit but the protein seemed to be bounded to LPS and I could not separate from the column. Maybe this kit will work better.