title: Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.
abstract: Neisseria gonorrhoeae (N. gonorrhoeae) outer membrane protein reduction modifiable protein (Rmp) has strong immunogenicity. However, anti-Rmp antibodies block rather than preserve the antibacterial effects of protective antibodies, which hampers the development of vaccines for gonococcal infections. We herein constructed an Rmp deletion mutant strain of N. gonorrhoeae by gene homologous recombination. The 261-460 nucleotide residues of Rmp gene amplified from N. gonorrhoeae WHO-A strain were replaced with a kanamycin-resistant Kan gene amplified from pET-28a. The resultant hybridized DNA was transformed into N. gonorrhoeae WHO-A strain. PCR was used to screen the colonies in which wild-type Rmp gene was replaced with a mutant gene fragment. Western blotting revealed that the Rmp deletion mutant strain did not express Rmp protein. Rmp deletion did not alter the morphological and Gram staining properties of the mutant strain that grew slightly more slowly than the wild-type one. Rmp gene mutated stably throughout 25 generations of passage. Antibody-mediated complement-dependent cytotoxicity assay indicated that the antibodies induced by the mutant strain had evidently higher bactericidal activities than those induced by the wild-type strain. Further modification of the Rmp deletion mutant strain is still required in the development of novel live attenuated vaccines for gonorrhea by Opa genes deletion or screening of phenotypic variant strains that do not express Opa proteins.
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, China.
authors.forename: Guocai
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Pathogen Biology, Heze Medical College, Heze, Shandong, China.
authors.forename: Rushan
authors.initials: R
authors.lastname: Xie
authors.affiliation: Clinical Testing Center, College of Clinical Medicine, Yangzhou University, Yangzhou, Jiangsu, China.
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, China.
authors.forename: Yanli
authors.initials: Y
authors.lastname: Mao
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, China.
authors.forename: Shuangxi
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China; Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Jiao
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Anatomyand Neurobiology, Central South University School of Basic Medical Sciences, Changsha, Hunan, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Xiong
authors.affiliation: Department of Pathogen Biology and Immunology, Yangzhou University School of Medicine, Yangzhou, Jiangsu, China.
authors.forename: Mingchun
authors.initials: M
authors.lastname: Ji
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology; D017353:Gene Deletion; D006069:Gonorrhea / Q000235:genetics / Q000276:immunology*; D006801:Humans; D009344:Neisseria gonorrhoeae / Q000235:genetics* / Q000254:growth & development / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; C051591:Rmp protein, Neisseria