Title of article :
Molecular Cloning and Immunogenicity Evaluation of PpiC, GelE,and VS87_01105 Proteins of Enterococcus faecalisas Vaccine Candidates
Author/Authors :
Kazemian, Hamid Department of Pathobiology - School of Public Health - Tehran University of Medical Sciences, Tehran, Iran , Pourmand, Mohammad Reza Department of Pathobiology - School of Public Health - Tehran University of Medical Sciences, Tehran, Iran , Siadat, Davar Department of Mycobacteriology and Pulmonary Research - Pasteur Institute of Iran, Tehran, Iran , Mahdavi, Mehdi Recombinant Vaccine Research Center - Tehran University of Medical Sciences, Tehran, Iran , Yazdi, Mohammad Hossein Department of Pharmaceutical Biotechnology and Biotechnology Research Center - Faculty of Pharmacy - Tehran University of Medical Sciences, Tehran, Iran , Avakh Majelan, Peyman Department of Pathobiology - School of Public Health - Tehran University of Medical Sciences, Tehran, Iran , Afshar, Davoud Department of Microbiology and Virology - School of Medicine - Zanjan University of Medical Sciences, Zanjan, Iran , Yaseri, Mehdi Department of Epidemiology and Biostatistics - School of Public Health - Tehran University of Medical Sciences, Tehran, Iran , Davari, Mehdi Department of Mycobacteriology and Pulmonary Research - Pasteur Institute of Iran, Tehran, Iran , Getso, Muhammad Ibrahim Department of Medical Mycology, School of Public Health - Tehran University of Medical Sciences - International College, Tehran, Iran
Abstract :
Background:Among the enterococci strains,Enterococcus faecalisis considered as one of the important nosocomial pathogens affectingimmunocompromised patients.In this study, the immunogenicity ofPpiC, GelE,and VS87_01105 proteins against enterococcal infection was investigated in a mice model. Methods:The genes encoding these proteins were cloned into pET21a expression vector,and the recombinant proteins were produced. Mice and rabbits were immunized with the purified recombinant proteins,and subsequently,mice were challenged with E. faecalis for the evaluation of their survival and bacterial clearances. The antibody responses to recombinant proteins were determined by ELISA assay, and opsonophagocytic activities of the antibodies were also measured. Passive immunization was performed using purified antibodies. Mice were challenged,and their survival and bacterial clearance were determined. Results:Immunized mice with PpiC, GelE,and VS87_01105 recombinant proteins showed 80%, 70%,and 40% survival rate, respectively. The survival rates among passively immunized mice that received500μgof IgG fraction in 100 μl PBS bufferofeach ofanti-PpiC, anti-GelE,and anti-VS87_01105 were 60%, 50%,and 20%, respectively. The rates of opsonization with anti-PpiC, anti-GelE,and anti-VS87_01105 antibodies at 1/10 dilutionwere77%, 64%,and 23%, respectively. Conclusion:Based on our findings, PpiC,and GelE proteins can protect the mice against E. faecalisATCC 29212 and effectively induce a protective antibody response. Thus, these proteins could be used as an additional therapeutic tool againstenterococcal infections. Further studies to determine the role of PpiC in ligand binding and demonstration of epitope mapping may establish a credible target for vaccination.
