Field Efficacy of Recombinant R7 Vaccine against Chicken Leucocytozoonosis

Ito, Akira; Gotanda, Tohru

doi:10.1292/jvms.66.483

Cited by 15 publications

(16 citation statements)

References 14 publications

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“…It has been reported that the AGP test can be used as diagnostic method for detection of SSA from 10 to 13 days after infection (Morii, 1972(Morii, , 1974(Morii, , 1978. However, as we have shown previously, it is very difficult to detect SSA in the serum of infected chickens in the field (Ito & Gotanda, 2004). The rR7 antigen used in this study is derived from a gene for an outer membrane protein of 2GS.…”

Section: Discussionmentioning

confidence: 95%

“…The AGP test is the only assay available commercially and it is widely used in Japan, but has a low sensitivity and is relatively slow. In addition, antibody induced by the vaccine based on oil-adjuvanted recombinant R7 (rR7) protein, which is used to control leucocytozoonosis in Japan, cannot be detected using the AGP test (Itoh & Gotanda, 2002, 2004.…”

Section: Introductionmentioning

confidence: 99%

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A rapid assay for detecting antibody against leucocytozoonosis in chickens with a latex agglutination test using recombinant R7 antigen

Ito¹,

Gotanda²

2005

Avian Pathology

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A method for detecting antibody against leucocytozoonosis in chickens by latex agglutination (LA) was developed using latex beads coated with recombinant R7 (rR7), an outer membrane antigen of secondgeneration schizonts of Leucocytozoon caulleryi. Compared with the agar gel precipitation test, which is widely used in Japan, LA could detect antibody induced by L. caulleryi infection with greater sensitivity. No agglutination was detected with sera from specific pathogen free or layer chickens that had not been vaccinated with oil-adjuvanted rR7 antigen, or infected with L. caulleryi, nor with sera from chickens inoculated with other pathogens, establishing the specificity of the assay. The LA test was also able to be used to quantify serum antibody induced by vaccination, which is not possible with the agar gel precipitation test. This study has shown that LA using the rR7 antigen is a simple, quick, and useful method for detecting antibody against L. caulleryi.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

A rapid assay for detecting antibody against leucocytozoonosis in chickens with a latex agglutination test using recombinant R7 antigen

Ito¹,

Gotanda²

2005

Avian Pathology

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“…Because of its potentially severe impact on poultry production, research on Leucocytozoon in Japan has mainly focused on L. caulleryi infection in domestic chickens, with the objectives to develop protective immunity and vaccinations for the pathogen [14,15]. Leucocytozoon infection has been reported among wild birds of Japan [9,17], however, no classification and genetic analyses of detected Leucocytozoon sp.…”

Section: Discussionmentioning

confidence: 99%

Phylogenetic Comparison of Leucocytozoon spp. from Wild Birds of Japan

Sato

Hagihara

Yamaguchi

et al. 2007

The Journal of Veterinary Medical Science

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ABSTRACT. Eight species of Japanese birds were found to be infected with Leucocytozoon species using microscopic analysis. We used PCR and sequence analysis of the mitochondrial cytochrome b gene (cyt b) to compare the genetic background among these detected protozoa species. In 20 individuals of 22 samples, a single amplified band was detected from 6 of 8 bird species; 9 Japanese rock ptarmigans (Lagopus mutus japonicus), 4 large-billed crows (Corvus macrorhynchos), 2 carrion crows (C. corone), 2 scops owls (Otus scops), 1 Japanese grosbeak (Eophona personata), and 2 brown-eared bulbuls (Hypsipetes amaurotis), respectively. Phylogenetic analysis based on the partial cyt b sequences revealed that all Leucocytozoon isolates in Japan closely grouped with other Leucocytozoon species previously reported in the literature. Among the Japanese isolates, the phylogenetic tree suggested that L. lovati from the Japanese rock ptarmigan may be basal to the parasites found in other bird species. Our study is the first to identify the molecular relationships among Leucocytozoon parasites in the avifauna of Japan. KEY WORDS: cyt b, Japan, Lagopus mutus, Leucocytozoon, wild bird.

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“…We developed a subunit vaccine (leucocytozoonosis vaccine ''Hokken'' [LV]) against this disease using Escherichia coli-expressed immunogenic recombinant R7 (rR7) antigen derived from the outer membrane of the second-generation schizont (2GS) of L. caulleryi (Itoh & Gotanda, 2002). This vaccine is already in use in Japan (Ito & Gotanda, 2004). The molecular structure of rR7 antigen is similar to that of candidate vaccine recombinant antigen of malaria parasites, which are closely related to L. caulleryi taxonomically, especially the circum sporozoite protein of Plasmodium vivax (Zavala et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Booster responses by oral vaccination with transgenic plants against chicken leucocytozoonosis

et al. 2013

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We developed a transgenic potato (TrP/R7) expressing the recombinant R7 (rR7) antigen for use as an oral vaccine to protect against a chicken protozoan disease, chicken leucocytozoonosis. The TrP/R7 potato was produced by Agrobacterium tumefaciens-mediated transformation and regeneration, and the R7 gene insertion into potato chromosomes was confirmed by genomic polymerase chain reaction and Southern hybridization. rR7 antigen expression in TrP/R7 potato was also confirmed by sandwich enzyme-linked immunosorbent assay and western blotting using an antibody against the second-generation schizont of Leucocytozoon caulleryi. A transgenic potato clone with the highest rR7 antigen expression (3 mg rR7 antigen per gram of fresh-weight potato leaves) was selected, cultivated, and used in oral administration experiments to examine its ability to boost immunity. Chickens were immunized with chicken leucocytozoonosis vaccine ''Hokken'' by injection, and chickens that developed moderate levels of antibody titres were fed with TrP/R7 leaves. Chickens fed with TrP/R7 leaves showed increased antibody responses. In contrast, chickens fed with non-transgenic potato leaves showed a continuous decrease in antibody titres. Furthermore, chickens fed with TrP/R7 potato leaves showed strong resistance against experimental challenge with L. caulleryi infection. This study demonstrates the use of a plant-based oral vaccine to boost immunity against a protozoan disease.

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Field Efficacy of Recombinant R7 Vaccine against Chicken Leucocytozoonosis

Cited by 15 publications

References 14 publications

A rapid assay for detecting antibody against leucocytozoonosis in chickens with a latex agglutination test using recombinant R7 antigen

A rapid assay for detecting antibody against leucocytozoonosis in chickens with a latex agglutination test using recombinant R7 antigen

Phylogenetic Comparison of Leucocytozoon spp. from Wild Birds of Japan

Booster responses by oral vaccination with transgenic plants against chicken leucocytozoonosis

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