%0 Journal Article %T Comparison of different lots of endotoxin and evaluation of in vivo potency over time in the experimental human endotoxemia model %A Dorien Kiers %A Guus P. Leijte %A Jelle Gerretsen %A Jelle Zwaag %A Matthijs Kox %A Peter Pickkers %J Innate Immunity %@ 1753-4267 %D 2019 %R 10.1177/1753425918819754 %X The experimental human endotoxemia model is used to study the systemic inflammatory response in vivo. The previously used lot of endotoxin, which was used for over a decade, is no longer approved for human use and a new Good Manufacturing Practices-grade batch has become available. We compared the inflammatory response induced by either bolus or continuous administration of either the previously used lot #1188844 or new lots of endotoxin (#94332B1 and #94332B4). Compared with lot #1188844, bolus administration of lot #94332B1 induced a more pronounced systemic inflammatory response including higher plasma levels of pro-inflammatory cytokines and more pronounced clinical signs of inflammation. In contrast, continuous infusion of lot #94332B4 resulted in a slightly less pronounced inflammatory response compared with lot #1188844. Furthermore, we evaluated whether lot #1188844 displayed in vivo potency loss by reviewing inflammatory parameters obtained from 17 endotoxemia studies performed in our centre between 2007 and 2016. Despite inter-study variability in endotoxemia-induced effects on temperature, heart rate, symptoms, and leukocyte counts, the magnitude of these effects did not decrease over time. In conclusion, although all lots of endotoxin induce a pronounced inflammatory response, the magnitude differs between lots. We observed no potency loss of endotoxin over time %K Endotoxemia %K in vivo %K lipopolysaccharide %K potency %K systemic inflammation %U https://journals.sagepub.com/doi/full/10.1177/1753425918819754