title: Endotoxin contamination in commercially available pokeweed mitogen contributes to the activation of murine macrophages and human dendritic cell maturation.
abstract: 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-turbidimetric Limulus amebocyte lysate assay demonstrated that commercial PWM contained substantial endotoxin, over 10(4) 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.
authors.affiliation: International Vaccine Institute, SNU Research Park, San 4-8 Bongcheon-7 dong, Kwanak-gu, Seoul 151-818, Republic of Korea.
authors.forename: Jae Seung
authors.initials: JS
authors.lastname: Yang
authors.forename: Hye Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Ryu
authors.forename: Cheol-Heui
authors.initials: CH
authors.lastname: Yun
authors.forename: Dae Kyun
authors.initials: DK
authors.lastname: Chung
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Han
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002460:Cell Line; D049109:Cell Proliferation; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D004340:Drug Contamination; D004731:Endotoxins / Q000009:adverse effects*; D006801:Humans; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D029604:Phytolacca americana; D011043:Pokeweed Mitogens / Q000494:pharmacology*
chemical_list: D004731:Endotoxins; D011043:Pokeweed Mitogens