Outer membrane vesicles from Neisseria meningitidis: Effects on cytokine production in human whole blood

The Norwegian group B meningococcal outer membrane vesicle (OMV) vaccine co nsists of outer membrane proteins (OMPs) as main antigens with significant amounts of lipopolysaccharide (LPS; 5-9% relative to protein). We have stud ied the ability of this OMV vaccine preparation to induce secretion of pro- inflammatory cytokines, tumour necrosis factor alpha (TNF-alpha), interleuk in 1 beta (IL-1 beta), interleukin 6 (IL-6), interleukin 8 (IL-8) and anti- inflammatory cytokines, interleukin 4 (IL-4), interleukin 10 (IL-10) and in terleukin 13 (IL-13) in a human whole blood model. Plasma levels of TNF-alp ha, IL-1 beta, IL-6 and IL-8 were massively increased; mean peak levels of TNF-alpha 44696 +/- 7764, IL-1 beta 38043 +/- 5411, IL-6 10057 +/- 1619 and IL-8 30449 +/- 5397 pg/ml were obtained with an OMV-LPS concentration of 1 mug/ml; corresponding levels in control plasmas were below the detection l imit of the assay. Mean maximal level of IL-10 (2540 +/- 144 pg/ml) was obt ained at OMV-LPS concentration of 10 mug/ml, after 24 h; while the level in control plasma was below detection limit. OMV-LPS did not induce release o f IL-4 and IL-13 in doses from 0.001-10 mug/ml. The present results show th at OMVs from meningococci have potent pro-inflammatory properties and are l ikely to contribute to the observed local and systemic inflammatory effects . (C) 2001 Academic Press.