This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Bjerre, A. Articles by Brandtzaeg, P. Search for Related Content PubMed PubMed Citation Articles by Bjerre, A. Articles by Brandtzaeg, P. Social Bookmarking                   What's this?

Identification of meningococcal LPS as a major monocyte activator in IL-10 depleted shock plasmas and CSF by blocking the CD14-TLR4 receptor complex

Department of Pediatrics, UllvÅl University Hospital, Oslo, Norway, a.k.bjerre{at}ioks.uio.no

Berit Brusletto

The R&D Group, Department of Clinical Chemistry, UllevÅl University Hospital, Oslo, Norway

Reidun Øvstebø

The R&D Group, Department of Clinical Chemistry, UllevÅl University Hospital, Oslo, Norway

Gun Britt Joø

The R&D Group, Department of Clinical Chemistry, UllevÅl University Hospital, Oslo, Norway

Peter Kierulf

The R&D Group, Department of Clinical Chemistry, UllevÅl University Hospital, Oslo, Norway

Petter Brandtzaeg

Department of Pediatrics, UllvÅl University Hospital, Oslo, Norway

We have examined the in vitro stimulatory effects of lipopolysaccharide (LPS)-containing samples (meningococcal shock plasma, n = 10; non-shock plasma, n = 10; cerebrospinal fluid (CSF), n = 7) before and after immunodepletion of interleukin (IL)-10 in a monocyte target assay. We also studied the stimulatory effects of plasma collected from 3 patients with lethal septicemia caused by Streptococcus pneumoniae without detectable LPS but with 100-fold increased levels of heat-shock protein 70 (HSP70). HSP70 may, like LPS, activate monocytes via the Toll-like receptor 4 (TLR4). The samples were analyzed for LPS, tumor necrosis factor (TNF)-, IL-10 and HSP70; applied on human monocytes (purity > 95%) before and after IL-10 immunodepletion, in the absence or presence of CD14 blocking mAb (60bca) or the lipid A antagonist, Rhodobacter sphaeroides diphosphoryl lipid A (RsDPLA) which blocks TLR4. Monocyte activation was measured by increased TNF- secretion and tissue factor (TF) up-regulation by monocyte procoagulant activity (PCA). There was a positive correlation between patientplasma LPS levels (n = 10) and increases in TNF- secretion by the monocytes after immunodepletion of IL-10 ( r = 0.82). Pretreatment of the monocytes with mAbCD14 or RsDPLA reduced TNF- secretion to median 5% and 12%, respectively, of the levels before the receptor complex was blocked. The median levels of HSP70 were 543 ng/ml (range, 468—962 ng/ml) in pneumococcal shock plasma, 81.5 ng/ml (range, 41—331 ng/ml) in meningococcal shock plasma and 24 ng/ml (range, < 0.8—41 ng/ml) in meningococcal non-shock plasma. Pneumococcal septic shock plasmas with significantly higher levels of HSP70 (P < 0.05) did not induce TNF- secretion in the monocytes. The results strongly suggest that LPS in meningococcal shock plasma is the major activator of monocytes whereas HSP70 (in plasma concentrations up to 963 ng/ml) does not activate monocytes in this assay.

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?