title: Recombinant α-actinin subunit antigens of Trichomonas vaginalis as potential vaccine candidates in protecting against trichomoniasis.
abstract: Human trichomoniasis caused by Trichomonas vaginalis is one of the most common sexually transmitted diseases with more than 200 million cases worldwide. It has caused a series of health problems to patients. For prevention and control of infectious diseases, vaccines are usually considered as one of the most cost-efficient tools. However, until now, work on the development of T. vaginalis vaccines is still mainly focused on the screening of potential immunogens. Alpha-actinin characterized by high immunogenicity in T. vaginalis was suggested as a promising candidate. Therefore, the purpose of this study was to evaluate the protective potency of recombinant α-actinin against T. vaginalis infection in a mouse intraperitoneal model.
  
  
  
  Two selected coding regions of α-actinin (ACT-F, 14-469 aa and ACT-T, 462-844 aa) amplified from cDNA were cloned into pET-32a (+) expression vector and transfected into BL21 cells. After induction with IPTG and purification with electroelution, the two recombinant fusion proteins were emulsified in Freund's adjuvant (FA) and used to immunize BALB/C mice. Following intraperitoneal inoculation with T. vaginalis, the survival rate of mice was monitored for the assessment of protective potency. After immunization, the antibody level in mouse serum was assessed by ELISA, splenocyte proliferation response was detected with CCK8 and cytokines in the supernatant of splenocytes were quantified with a cytometric bead-based assay.
  
  
  
  We successfully obtained purified ACT-F (70.33 kDa) and ACT-T (61.7kDa). Both recombinant proteins could provide significant protection against T. vaginalis challenge, especially ACT-T (with 100% protection within one month). Meanwhile, high levels of specific total IgG and subtypes (IgG1 > IgG2a) were detected in sera from the immunized mice. Our results also revealed a statistically significant increase in splenocyte proliferation and related cytokine (IFN-γ, IL-6, IL-17A and IL-10) production after repeated stimulation with the corresponding antigens in vitro.
  
  
  
  Immunization with both ACT-F and ACT-T could confer partial to complete protection and trigger strong Th1/Th2 mixed humoral and cellular immune responses in the mouse host. This suggested that recombinant α-actinin subunit antigens may be promising vaccine candidates against trichomoniasis.
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences and Key Laboratory for Tropical Disease and Control of the Ministry of Education, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China.
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Xie
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences and Key Laboratory for Tropical Disease and Control of the Ministry of Education, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China.
authors.forename: Jiang-Mei
authors.initials: JM
authors.lastname: Gao
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences and Key Laboratory for Tropical Disease and Control of the Ministry of Education, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China.
authors.forename: Ya-Ping
authors.initials: YP
authors.lastname: Wu
authors.affiliation: Bioinformatics Core Laboratory, Chang Gung University, Taoyuan, 333, Taiwan.
authors.forename: Petrus
authors.initials: P
authors.lastname: Tang
authors.affiliation: Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK.
authors.forename: Geoff
authors.initials: G
authors.lastname: Hide
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences and Key Laboratory for Tropical Disease and Control of the Ministry of Education, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China. laidehua@mail.sysu.edu.cn.
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Lai
authors.affiliation: Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences and Key Laboratory for Tropical Disease and Control of the Ministry of Education, Zhongshan College of Medicine, Sun Yat-Sen University, Guangzhou 510275, The People's Republic of China. lsslzr@mail.sysu.edu.cn.|Ecosystems and Environment Research Centre and Biomedical Research Centre, School of Environment and Life Sciences, University of Salford, Salford M5 4WT, UK. lsslzr@mail.sysu.edu.cn.
authors.forename: Zhao-Rong
authors.initials: ZR
authors.lastname: Lun
mesh_terms: D000185:Actinin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000276:immunology*; D003001:Cloning, Molecular; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D016052:Protozoan Vaccines / Q000276:immunology*; D011817:Rabbits; D013154:Spleen; D014245:Trichomonas Infections / Q000517:prevention & control*; D014246:Trichomonas vaginalis / Q000378:metabolism*
chemical_list: D000953:Antigens, Protozoan; D016207:Cytokines; D016052:Protozoan Vaccines; D000185:Actinin
keywords: Alpha-actinin; Recombinant protein; Trichomonas vaginalis; Vaccine