OBJECTIVETo investigate an effective purification method for removing endotoxin from Prevotella intermedia.

METHODSThe main protein ingredients of bacteria prepared from ammonium sulfate precipitation were further treated with octyl phenyl polyoxyethylene ether (Triton X-114), and then processed at 4°C, 37°C and 25°C. The obtained aqueous phase after at least two more cycle repeated operations was assayed for endotoxin by Western blotting, LAL-clotting method, in vitro cell stimulation and in vivo animal experiments.

RESULTSWestern blotting and LAL-clotting method demonstrated that the reduction in endotoxin level was greater than 99.99% and recovery of the proteins after endotoxin removal was greater than 90% with Triton X-114 treatment for 3 cycles. The cytokines expression level was lower in both in vitro cell stimulation and in vivo animal experiments than in untreated group (P < 0.05).

CONCLUSIONSThe extraction method provides a new choice for endotoxin removal from large volumes of the oral Prevotella intermedia.