Rino Rappuoli

The Region Comprising Amino Acids 100 to 255 of Neisseria meningitidis Lipoprotein GNA 1870 Elicits Bactericidal Antibodies

ABSTRACT GNA 1870 is a novel surface-exposed lipoprotein, identified by genome analysis of Neisseria meningitidis strain MC58, which induces bactericidal antibodies. Three sequence variants of the protein were shown to be sufficient to induce bactericidal antibodies against a panel of strains representative of the diversity of serogroup B meningococci. Here, we studied the antigenic and immunogenic properties of GNA 1870, which for convenience was divided into domains A, B, and C. The immune responses of mice immunized with each of the three variants were tested using overlapping peptides scanning the entire protein length and using recombinant fragments. We found that while most of the linear epitopes are located in the A domain, the bactericidal antibodies are directed against conformational epitopes located in the BC domain. This was also confirmed by the isolation of a bactericidal murine monoclonal antibody, which failed to recognize linear peptides on the A, B, and C domains separately but recognized a conformational epitope formed only by the combination of the B and C domains. Arginine in position 204 was identified as important for binding of the monoclonal antibody. The identification of the region containing bactericidal epitopes is an important step in the design of new vaccines against meningococci.

Signal transduction and bacterial virulence

Introduction: An Overview of Bacterial Signal Transduction.- 1. Signal Transduction and Iron-Mediated Regulation of Virulence Factors.- 2. BvgAS Dependent Phenotypic Modulation of Bordetella Species.- 3. Signal Transduction and Environmental Stress in Control of Pseudomonas Aeruginosa Virulence.- 4. PhoP/PhoQ: Regulating Salmonella Adaptation to Host Microenvironments.- 5. Regulation of Virulence in Vibrio Cholerae by the ToxR System.- 6. Environmental Control of Virulence Functions and Signal Transduction in Yersinia Enterocolitica.- 7. Signal Transduction and Virulence Gene Regulation in Shigella spp.: Temperature and (maybe) a Whole Lot More.- 8. Control of Listeria Monocytogenes Virulence by the Transcriptional Regulator PrfA.- 9. Signal Transduction in Staphylococci and Other Gram-Positive Cocci.

Pertactin antigens extracted from Bordetella pertussis and Bordetella bronchiseptica differ in the isoelectric point

Abstract Pertactin, which is a membrane-associated antigen of Bordetella pertussis and which is present in many acellular vaccines against whooping cough, has been reported to be similar to the homologous protein in Bordetella bronchiseptica. By running parallel experiments using proteins derived from the two species, we show that the isoelectric point of pertactin from B. pertussis is lower than reported and clearly distinguishable from the homologous protein of B. bronchiseptica.