Ultrasonication of pyrogenic microorganisms improves the detection of pyrogens in the Mono Mac 6 assay

The monocytic cell Line Mono Mac 6 is sensitive to pyrogens. When exposed t o pyrogens secretion of interleukin-6 is induced. However, some eukaryotic pyrogenic microorganisms are not detectable. The aim of this study is to in troduce a pretreatment of samples to expand the detection range of the assa y. The interleukin-6 inducing capacity Df a broad spectrum of UV-killed and ultrasonicated microorganisms is examined in Mono Mac 6 cells. The interle ukin-6 secretion is determined in a sandwich immunoassay (DELFIA). The Mono Mac 6 assay is able to detect UV-killed Bacillus subtilis, Staphylococcus aureus and Salmonella typhimurium, but neither Candida albicans nor Aspergi llus niger. After ultrasonication of the microorganisms it is possible to d etect C. albicans and A. niger. The interleukin-6 inducing ability of the e xamined microorganisms is in no case reduced after ultrasonic treatment. Ho wever, ultrasonication of S. aureus results in a 100-fold increase in the i nterleukin-6 response. Even after ultrasonication Streptococcus faecalis ca n not be detected. Ultrasonication is an easy and simple method for expandi ng the detection range in the Mono Mac 6 assay. (C) 2000 Elsevier Science B .V. All rights reserved.