title: [Generation of Aeromonas hydrophila ghosts and their evaluation as oral vaccine candidates in Carassius auratus gibelio].
abstract: The bacterial ghost (BG) system is a novel vaccine delivery system endowed with intrinsic adjuvant properties. Bacterial ghosts are nonliving Gram-negative bacterial cell envelopes devoid of cytoplasmic contents while maintaining their cellular morphology and native surface antigenic structures. They are produced by PhiX174 protein E-mediated lysis of Gram-negative bacteria, and can induce humoral and cellular immune response, including mucosal immune responses. Plasmid pElysis consisting E gene was transformed into AhJ-1. Through shifting the culture temperature from 28 degrees C to 42 degrees C, A. hydrophila J-1 (pElysis) was induced to lyse and the OD600 value of culture media was measured every 15 minutes during the induction. The lysed bacteria were observed by scanning electron microscopy (SEM). The A. hydrophila ghosts (AHG) used as oral vaccine were also investigated. The OD600 value of A. hydrophila J-1(pElysis) began to decline after 30 min of induction, and after 75 min of induction, the OD600 value decline speed become slowly. The efficiency of ghost induction in non-lyophilized A. hydrophila was 99.99%, 16 hours post induced, no live bacteria can be detected in culture. Scanning electron microscopy observation proved that most lysed bacteria were emptied. Fish vaccination experiments shows that the antibody evoked highest degree after 5 weeks by oral administration of bacterial ghost vaccine and the agglutination antibody titer reached 2(7) and continued two weeks, while the agglutination antibody titer of formalin killed vaccine only reached 26 and only maintained one week. After challenged with the parent strain J-1, the survival rate of bacterial ghost vaccinated fish was higher than the control group and formalin killed vaccine group, the relative percent survival (RPS) was 78.95% (16/20), but the RPS of formalin killed vaccine group was 57.9% (12/20). This suggests that the bacterial ghost vaccine has higher potential to induce protective adaptive immunity than normal vaccine.
authors.affiliation: School of Life Science & Technology, China Pharmaceutical University, Nanjing 210009, China. chuweihua2002@yahoo.com.cn
authors.forename: Weihua
authors.initials: W
authors.lastname: Chu
authors.forename: Xiyi
authors.initials: X
authors.lastname: Zhuang
authors.forename: Chengping
authors.initials: C
authors.lastname: Lu
mesh_terms: D000284:Administration, Oral; D016980:Aeromonas hydrophila / Q000235:genetics / Q000276:immunology*; D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D006054:Goldfish / Q000276:immunology* / Q000382:microbiology; D016905:Gram-Negative Bacterial Infections / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D014611:Vaccination
chemical_list: D001428:Bacterial Vaccines