Kikuchi Ken
   Department   School of Medicine(Tokyo Women's Medical University Hospital), School of Medicine
   Position   Professor
Article types Original article
Language English
Peer review Peer reviewed
Title Molecular characteristics of an adhesion molecule containing cholesterol-dependent cytolysin-motif produced by mitis group streptococci.
Journal Formal name：Microbiology and immunology
Abbreviation：Microbiol Immunol
ISSN code：13480421/03855600
Domestic / ForeginDomestic
Volume, Issue, Page 65(2),pp.61-75
Author and coauthor Matsumoto Airi, Tabata Atsushi, Ohkura Kazuto, Oda Hiroki, Kodama Chihiro, Ohkuni Hisashi, Takao Ayuko, Kikuchi Ken, Tomoyasu Toshifumi, Nagamune Hideaki
Publication date 2021/02
Summary Streptococcus pseudopneumoniae (SPpn) is a relatively new species closely related to S. pneumoniae (SPn) and S. mitis (SM) belonging to the Mitis group of the genus Streptococcus (MGS). Although genes encoding various pneumococcal virulence factors have been observed in the SPpn genome, the pathogenicity of SPpn against human, including the roles of virulence factor candidates, is still unclear. The present study focused on and characterized a candidate virulence factor previously reported in SPpn with deduced multiple functional domains, such as lipase domain, two lectin domains, and cholesterol-dependent cytolysin-related domain using various recombinant proteins. The gene was found not only in SPpn but also in the strains of SM and SPn. Moreover, the gene product was expressed in the gene-positive strains as secreted and cell-bound forms. The recombinant of gene product showed lipase activity and human cell-binding activity depending on the function of lectin domain(s), but no hemolytic activity. Thus, based on the distribution of the gene within the MGS and its molecular function, the gene product was named mitilectin (MLC) and its contribution to the potential pathogenicity of the MLC-producing strains was investigated. Consequently, the treatment with anti-MLC antibody and the mlc gene-knockout significantly reduced the human cell-binding activity of MLC-producing strains. Therefore, the multifunctional MLC was suggested to be important as an adhesion molecule in considering the potential pathogenicity of the MLC-producing strains belonging to MGS, such as SPpn and SM.
DOI 10.1111/1348-0421.12868
PMID 33331679