title: Functional assays for evaluation of serogroup B meningococcal structures as mediators of human opsonophagocytosis.
abstract: Functional flow cytometry and chemiluminescence (CL) assays have been modified to identify serogroup B meningococcal structures that mediate anti-meningococcal opsonophagocytosis. Serogroup B meningococcal outer membrane vesicles (OMV) were adsorbed to fluorescent latex beads (OMV-beads) and opsonized with acute phase and convalescence sera from patients with serogroup B meningococcal disease. Phagocytosis of these beads by human monocytes and polymorphonuclear leukocytes (non-lymphocytes) was dependent on both antigen exposure on the bead surface and on serum opsonization. OMV-beads opsonized with serum from a patient recovering from meningococcal disease, caused 97% of the non-lymphocytes to phagocytose an average of 15.8 beads per cell with a CL response of 46,550 mVs, whereas opsonized control beads were phagocytosed by 19% of the non-lymphocytes with 1.1 beads per cell and a CL response of 53 mVs. Increased amounts of functional, anti-OMV opsonins were detected during infection, and opsonized OMV-beads elicited phagocyte responses of similar magnitude to those of opsonized whole meningococci. Phagocyte internalization of OMV-beads was confirmed by confocal laser scanning microscopy. We conclude that epitopes on the meningococcal outer membrane are recognized by anti-meningococcal opsonins in these functional phagocytosis assays, which provide a basis for subsequent evaluation of various purified bacterial components as mediators of human opsonophagocytic responses and hence future vaccine constituents.
authors.affiliation: Medical Department B, University of Bergen, Haukeland Hospital, Norway. anne.lehmann@ffhs.uib.no
authors.forename: A K
authors.initials: AK
authors.lastname: Lehmann
authors.forename: A
authors.initials: A
authors.lastname: Halstensen
authors.forename: J
authors.initials: J
authors.lastname: Holst
authors.forename: C F
authors.initials: CF
authors.lastname: Bassøe
mesh_terms: D000942:Antigens, Bacterial / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D008163:Luminescent Measurements; D009345:Neisseria meningitidis / Q000276:immunology*; D009895:Opsonin Proteins / Q000502:physiology; D010587:Phagocytosis
chemical_list: D000942:Antigens, Bacterial; D009895:Opsonin Proteins