title: Cloning, Expression, Invasion, and Immunological Reactivity of a Mammalian Cell Entry Protein Encoded by the mce1 Operon ofNocardia farcinica.
abstract: Bacterial mammalian cell entry (Mce) proteins have been implicated in pathogen invasion of mammalian host cells. The aim of this study was to examine the invasion-conferring ability ofmce1Eoperon-encoded proteins,in vivoexpression of Mce1E in cells from infected mice and rabbits, and Mce1E immunogenicity.Nocardia farcinica mce1Ewas cloned into pet30a(+) vectors, expressed inEscherichia coli, and purified. Invasion assays, transmission electron microscopy (TEM), immunoblots, and enzyme-linked immunosorbent assay (ELISA) detection of cytokines were conducted. TEM confirmed the invasion of HeLa cells by Mce1E-coated beads. The antigenicity ofE. coli-expressed recombinant Mce1E was confirmed in immunoblots with sera fromN. farcinica-infected mouse and rabbit sera. Co-incubation of Mce1E with splenocytes ofN. farcinica-infected mice demonstrated upregulation of interferon (IFN-γ), but not interleukin (IL)-4 or IL-10, in the cultural supernatant. These findings demonstrate that Mce1E may facilitateN. farcinicainteractions with and invasion of mammalian cells. Notably, Mce1E are expressed and elicited antibody responses in mice and rabbits during infection. Besides, it may play a role in cell-mediated immune reactions and cause host inflammation responses toN. farcinicainfection.
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Xingzhao
authors.initials: X
authors.lastname: Ji
authors.affiliation: Office of Emergency Response, Chenzhou Center for Disease Control and PreventionChenzhou, China; School of Public Health, University of South ChinaHengyang, China.
authors.forename: Xiaoluo
authors.initials: X
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Xuexin
authors.initials: X
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Si
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Shuai
authors.initials: S
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Tang
authors.affiliation: School of Public Health, University of South China Hengyang, China.
authors.forename: Xiuqin
authors.initials: X
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China.
authors.forename: Zhenjun
authors.initials: Z
authors.lastname: Li
keywords: IFN-γ; Mce1E; entry protein; nocardiosis; recombinant protein expression