title: Polymyxin B as inhibitor of LPS contamination of Schistosoma mansoni recombinant proteins in human cytokine analysis.
abstract: BACKGROUND
  Recombinant proteins expressed in Escherichia coli vectors are generally contaminated with endotoxin. In this study, we evaluated the ability of Polymyxin B to neutralize the effect of LPS present as contaminant on Schistosoma mansoni recombinant proteins produced in E. coli in inducing TNF-alpha and IL-10. Peripheral blood mononuclear cells from individuals chronically infected with S. mansoni were stimulated in vitro with recombinant Sm22.6, Sm14 and P24 antigens (10 microg/mL) in the presence of Polymyxin B (10 microg/mL).
  
  
  RESULTS
  The levels of cytokines were measured using ELISA. There was greater than 90% reduction (p < 0.05) in the levels of TNF-alpha and IL-10 when Polymyxin B was added to the cultures stimulated with LPS. In cultures stimulated with S. mansoni recombinant proteins in the presence of Polymyxin B, a reduction in the levels of TNF-alpha and IL-10 was also observed. However, the percentage of reduction was lower when compared to the cultures stimulated with LPS, probably because these proteins are able to induce the production of these cytokines by themselves.
  
  
  CONCLUSIONS
  This study showed that Polymyxin B was able to neutralize the effect of endotoxin, as contaminant in S. mansoni recombinant antigens produced in E. coli, in inducing TNF-alpha and IL-10 production.
authors.affiliation: Serviço de Imunologia, Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia, Salvador-Bahia, Brazil. luciana.imuno@gmail.com
authors.forename: Luciana S
authors.initials: LS
authors.lastname: Cardoso
authors.forename: Maria Ilma
authors.initials: MI
authors.lastname: Araujo
authors.forename: Alfredo M
authors.initials: AM
authors.lastname: Góes
authors.forename: Lucila G
authors.initials: LG
authors.lastname: Pacífico
authors.forename: Ricardo R
authors.initials: RR
authors.lastname: Oliveira
authors.forename: Sergio C
authors.initials: SC
authors.lastname: Oliveira