SPECIFIC ASSAY FOR ENDOTOXIN USING IMMOBILIZED HISTIDINE - APPLICATION TO SERUM SAMPLE

The amount of endotoxin in the serum was measured by the new assay met hod of endotoxin using a filtercup, Limulus amebocyte lysate, and immo bilized histidine which is a specific adsorbent for endotoxin. The max imum recovery of endotoxin in the rabbit serum was obtained using acet ate buffer (pH 5.5, mu = 0.1) for the adsorption. Using this buffer, v arious kinds of endotoxin in water were adsorbed quantitatively on imm obilized histidine, and the activity of the adsorbed endotoxin was wel l recovered. The value of the amount of endotoxin in the bovine serum measured by the new assay method, which includes heat treatment (70 de grees C, 10min) after separation followed by washing, was closer to th at calculated from pyrogenic activities in rabbits than that measured by the PCA-Toxicolor method.