title: Protective immunity against Naegleria fowleri infection on mice immunized with the rNfa1 protein using mucosal adjuvants.
abstract: The free-living amoeba, Naegleria fowleri, causes a fatal disease called primary amoebic meningoencephalitis (PAM) in humans and experimental animals. Of the pathogenic mechanism of N. fowleri concerning host tissue invasion, the adherence of amoeba to hose cells is the most important. We previously cloned the nfa1 gene from N. fowleri. The protein displayed immunolocalization in the pseudopodia, especially the food-cups structure, and was related to the contact-dependent mechanism of the amoebic pathogenicity in N. fowleri infection. The cholera toxin B subunit (CTB) and Escherichia coli heat-labile enterotoxin B subunit (LTB) have been used as potent mucosal adjuvants via the parenteral route of immunization in most cases. In this study, to examine the effect of protective immunity of the Nfa1 protein for N. fowleri infection with enhancement by CTB or LTB adjuvants, intranasally immunized BALB/c mice were infected with N. fowleri trophozoites for the development of PAM. The mean time to death of mice immunized with the Nfa1 protein using LTB or CTB adjuvant was prolonged by 5 or 8 days in comparison with that of the control mice. In particular, the survival rate of mice immunized with Nfa1 plus CTB was 100% during the experimental period. The serum IgG levels were significantly increased in mice immunized with Nfa1 protein plus CTB or LTB adjuvants. These results suggest that the Nfa1 protein, with CTB or LTB adjuvants, induces strong protective immunity in mice with PAM due to N. fowleri infection.
authors.affiliation: Department of Microbiology, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea.
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Jong-Kyun
authors.initials: JK
authors.lastname: Yoo
authors.forename: Hae-Jin
authors.initials: HJ
authors.lastname: Sohn
authors.forename: Hee-kyoung
authors.initials: HK
authors.lastname: Kang
authors.forename: Daesik
authors.initials: D
authors.lastname: Kim
authors.forename: Ho-Joon
authors.initials: HJ
authors.lastname: Shin
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000281:Administration, Intranasal; D000562:Amebiasis / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D020808:Central Nervous System Protozoal Infections / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D009092:Mucous Membrane / Q000276:immunology* / Q000469:parasitology; D016848:Naegleria fowleri / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins