Immunological study of the outer membrane proteins of Vibrio harveyi: insights that link immunoprotectivity to interference with bacterial infection.
Vibrio harveyi is a bacterial pathogen that affects marine vertebrates and invertebrates. In this study, we identified 13 outer membrane proteins (OMPs) from a pathogenic V. harveyi strain and analyzed their immunological properties. In vivo immunogenicity analysis showed that antibodies specific to recombinant proteins of the 13 OMPs were detected in the antiserum of V. harveyi-infected rat. When used as subunit vaccines to immunize Japanese flounder (Paralichthys olivaceus), all OMPs were able to elicit specific serum antibody production in the vaccinated fish; however, only two OMPs (OMP173 and OMP214) induced high levels (>70%) of relative percent survival. Pre-incubation of V. harveyi with the antisera of protective OMPs significantly impaired bacterial infectivity against peripheral blood leukocytes (PBL), whereas the antisera of non-protective OMPs had no apparent effect on infection. OMP173 antibodies could bind whole V. harveyi cells and exhibit bactericidal effect in a complement-dependent manner. Passive immunization showed that fish received OMP173 antiserum before being infected with V. harveyi exhibited significantly reduced mortality rate and lower bacterial loads in liver, spleen, and kidney. Finally, treatment of FG cells with OMP173 prior to V. harveyi infection protected the cells from bacterial invasion to a significant extent. Take together, these results indicate that two of the examined OMPs induce protective immunity through production of specific antibodies that block bacterial invasion, and that one OMP is likely to be involved in host cell interaction during the infection process. Thus, the immunoprotectivity of the OMPs is probably associated with functional participations of the OMPs in bacterial infection.
Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, China.
Lan-ping
LP
Yu
Yong-hua
YH
Hu
Bo-guang
BG
Sun
Li
L
Sun
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D017756:Aquaculture; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D001428:Bacterial Vaccines / Q000008:administration & dosage*; D005393:Fish Diseases / Q000276:immunology* / Q000382:microbiology / Q000517:prevention & control; D005412:Flatfishes; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020539:Sequence Analysis, Protein; D022223:Vaccines, Subunit / Q000008:administration & dosage; D014733:Vibrio / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D014735:Vibrio Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines; D011994:Recombinant Proteins; D022223:Vaccines, Subunit
Immunoprotectivity; Infection; Outer membrane protein; Vaccine; Vibrio harveyi