Open AccessEndotoxin Contamination in Commercially Available Pokeweed Mitogen Contributes to the Activation of Murine Macrophages and Human Dendritic Cell Maturation
Author(s) -
Jae Seung Yang,
Hye Jin Kim,
YoungHee Ryu,
CheolHeui Yun,
Dae Kyun Chung
Publication year - 2006
Publication title -
clinical and vaccine immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.649
H-Index - 77
eISSN - 1556-6811
pISSN - 1556-679X
DOI - 10.1128/cvi.13.3.309-313.2006
Subject(s) - pokeweed mitogen , proinflammatory cytokine , tlr4 , lipopolysaccharide , biology , microbiology and biotechnology , immunology , chemistry , inflammation , biochemistry , peripheral blood mononuclear cell , in vitro
Commercially available pokeweed mitogen (PWM) has been reported to activate macrophages, leading to production of proinflammatory cytokines and nitric oxide (NO). However, we found that polymyxin B (PMB), a specific inhibitor of endotoxin activity, inhibited the PWM-induced expression of proinflammatory cytokines and NO and the activation of Toll-like receptor 4 (TLR4). A kinetic-turbidimetricLimulus amebocyte lysate assay demonstrated that commercial PWM contained substantial endotoxin, over 104 endotoxin units/mg of the PWM. A PWM repurified by PMB-coupled beads no longer induced the expression of proinflammatory cytokines, TLR4 activation, or dendritic cell maturation. However, the repurified PWM remained able to induce proliferation of human lymphocytes, which is a representative characteristic of PWM. These results suggest that commercial PWM might be contaminated with a large amount of endotoxin, resulting in the attribution of misleading immunological properties to PWM.