title: Vaccination with lentiviral vector expressing the nfa1 gene confers a protective immune response to mice infected with Naegleria fowleri.
abstract: Naegleria fowleri, a pathogenic free-living amoeba, causes fatal primary amoebic meningoencephalitis (PAM) in humans and animals. The nfa1 gene (360 bp), cloned from a cDNA library of N. fowleri, produces a 13.1-kDa recombinant protein which is located on pseudopodia, particularly the food cup structure. The nfa1 gene plays an important role in the pathogenesis of N. fowleri infection. To examine the effect of nfa1 DNA vaccination against N. fowleri infection, we constructed a lentiviral vector (pCDH) expressing the nfa1 gene. For the in vivo mouse study, BALB/c mice were intranasally vaccinated with viral particles of a viral vector expressing the nfa1 gene. To evaluate the effect of vaccination and immune responses of mice, we analyzed the IgG levels (IgG, IgG1, and IgG2a), cytokine induction (interleukin-4 [IL-4] and gamma interferon [IFN-γ]), and survival rates of mice that developed PAM. The levels of both IgG and IgG subclasses (IgG1 and IgG2a) in vaccinated mice were significantly increased. The cytokine analysis showed that vaccinated mice exhibited greater IL-4 and IFN-γ production than the other control groups, suggesting a Th1/Th2 mixed-type immune response. In vaccinated mice, high levels of Nfa1-specific IgG antibodies continued until 12 weeks postvaccination. The mice vaccinated with viral vector expressing the nfa1 gene also exhibited significantly higher survival rates (90%) after challenge with N. fowleri trophozoites. Finally, the nfa1 vaccination effectively induced protective immunity by humoral and cellular immune responses in N. fowleri-infected mice. These results suggest that DNA vaccination using a viral vector may be a potential tool against N. fowleri infection.
authors.affiliation: Department of Microbiology, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Hae-Jin
authors.initials: HJ
authors.lastname: Sohn
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Hee-Jong
authors.initials: HJ
authors.lastname: Yang
authors.forename: Yong-Joon
authors.initials: YJ
authors.lastname: Chwae
authors.forename: Kyongmin
authors.initials: K
authors.lastname: Kim
authors.forename: Sun
authors.initials: S
authors.lastname: Park
authors.forename: Ho-Joon
authors.initials: HJ
authors.lastname: Shin
mesh_terms: D000562:Amebiasis / Q000276:immunology / Q000517:prevention & control*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D020808:Central Nervous System Protozoal Infections / Q000276:immunology / Q000517:prevention & control*; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004337:Drug Carriers / Q000008:administration & dosage; D005260:Female; D005822:Genetic Vectors; D016086:Lentivirus / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D016848:Naegleria fowleri / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology*; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D016019:Survival Analysis; D014611:Vaccination / Q000379:methods*; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016207:Cytokines; D004337:Drug Carriers; C460560:Nfa1 protein, Naegleria fowleri; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA; D014614:Vaccines, Synthetic