title: Recombinant outer membrane secretin PilQ(406-770) as a vaccine candidate for serogroup B Neisseria meningitidis.
abstract: Secretin PilQ is an antigenically conserved outer membrane protein which is present on most meningococci. This protein naturally expressed at high levels and is essential for meningococcal pilus expression at the cell surface. A 1095 bp fragment of C-terminal of secretin pilQ from serogroup B Neisseria meningitidis was cloned into prokaryotic expression vector pET-28a. Recombinant protein was overexpressed with IPTG and affinity-purified by Ni-NTA agarose. BALB/c mice were immunized subcutaneously with purified rPilQ(406-770) mixed with Freund's adjuvant. Serum antibody responses to serogroups A and B N. meningitidis whole cells or purified rPilQ(406-770) and functional activity of antibodies were determined by ELISA and SBA, respectively. The output of rPilQ(406-770) was approximately 50% of the total bacterial proteins. Serum IgG responses were significantly increased in immunized group with PilQ(406-770) mixed with Freund's adjuvant in comparison with control groups. Antisera produced against rPilQ(406-770) demonstrated strong surface reactivity to serogroups A and B N. meningitidis tested by whole-cell ELISA. Surface reactivity to serogroup B N. meningitidis was higher than serogroup A. The sera from PilQ(406-770) immunized animals were strongly bactericidal against serogroups A and B. These results suggest that rPilQ(406-770) is a potential vaccine candidate for serogroup B N. meningitidis.
authors.affiliation: Department of Bacteriology, Tarbiat Modares University, Tehran, Iran. haghi@modares.ac.ir
authors.forename: Fakhri
authors.initials: F
authors.lastname: Haghi
authors.forename: Shahin Najar
authors.initials: SN
authors.lastname: Peerayeh
authors.forename: Seyed Davar
authors.initials: SD
authors.lastname: Siadat
authors.forename: Habib
authors.initials: H
authors.lastname: Zeighami
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D005260:Female; D036781:Fimbriae Proteins / Q000276:immunology*; D005620:Freund's Adjuvant / Q000008:administration & dosage; D007106:Immune Sera / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008589:Meningococcal Infections / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D038541:Neisseria meningitidis, Serogroup B / Q000276:immunology*; D011994:Recombinant Proteins / Q000276:immunology; D058248:Serum Bactericidal Antibody Assay
chemical_list: D000907:Antibodies, Bacterial; D007106:Immune Sera; D007074:Immunoglobulin G; D022401:Meningococcal Vaccines; D011994:Recombinant Proteins; C084295:pilQ protein, bacteria; D036781:Fimbriae Proteins; D005620:Freund's Adjuvant