Neisseria meningitidis lipopolysaccharide modulates the specific humoral immune response to neisserial porins but has no effect on porin-induced upregulation of costimulatory ligand B7-2.
The role of lipopolysaccharide (LPS) in the specific humoral response to meningococcal porins was investigated by measuring anti-PorA or -PorB antibody levels in mice immunized with wild-type meningococcal strain H44/76 or with its recently described LPS-negative mutant. Two murine strains were used for these immunizations: C3H/HeJ, which is LPS hyporesponsive, or C3H/HeOuJ, which is LPS responsive. A high level of anti-PorB immunoglobulin G (IgG) response was induced in both strains of mice immunized with either organism. The response induced by the wild-type strain was greater in C3H/HeOuJ mice than in C3H/HeJ mice, while the response induced by the LPS-negative mutant was similar in the two murine strains. Additionally, the anti-PorB response was similar in C3H/HeJ mice immunized with either bacterial strain. In general, the anti-PorA IgG response was lower than the anti-PorB response. These findings indicate that the presence of LPS is not essential for the induction of an antineisserial porin humoral response but can augment such a response. To determine whether LPS has any effect on the B-cell-stimulatory effect of neisserial porins (essential for the adjuvant activity of neisserial porins), B cells from both murine strains were incubated with outer membrane complexes (OMCs) prepared from strain H44/76 and its LPS-negative mutant. OMCs from either meningococcal strain were able to increase the surface expression of the costimulatory ligand B7-2 on B cells from either murine strain. Consistent with previously reported findings, LPS does not significantly affect the ability of neisserial porins to induce the costimulatory ligand B7-2.
Bhasin
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Division of Infectious Diseases, Boston University School of Medicine and Evans Biomedical Research Center, Boston, Massachusetts 02118, USA.
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Wetzler
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D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000942:Antigens, Bacterial / Q000276:immunology*; D015703:Antigens, CD / Q000276:immunology*; D051940:B7-2 Antigen; D001426:Bacterial Proteins; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology*; D051379:Mice; D008809:Mice, Inbred C3H; D016296:Mutagenesis; D009345:Neisseria meningitidis / Q000235:genetics / Q000276:immunology*; D018272:Porins / Q000276:immunology*; D015854:Up-Regulation / Q000276:immunology*
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D015703:Antigens, CD; D051940:B7-2 Antigen; D001426:Bacterial Proteins; C497964:CD86 protein, human; C497965:Cd86 protein, mouse; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; C419549:PorB protein, Chlamydia trachomatis; D018272:Porins; C057699:porin protein, Neisseria