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Vaccination with γ‐Irradiated Neospora caninum Tachyzoites Protects Mice Against Acute Challenge with N. caninum
Author(s) -
RAMAMOORTHY S.,
LINDSAY D. S.,
SCHURIG G. G.,
BOYLE S. M.,
DUNCAN R. B.,
VEMULAPALLI R.,
SRIRANGANATHAN N.
Publication year - 2006
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2005.00083.x
Subject(s) - neospora caninum , neospora , biology , vaccination , virology , splenocyte , antibody , attenuated vaccine , coccidiosis , immune system , isotype , interferon gamma , inoculation , microbiology and biotechnology , toxoplasma gondii , immunology , monoclonal antibody , medicine , virulence , veterinary medicine , biochemistry , gene
.Neospora caninum , an apicomplexan parasite, is a leading cause of bovine abortions worldwide. The efficacy of γ‐irradiated N. caninum strain NC‐1 tachyzoites as a vaccine for neosporosis was assessed in C57BL6 mice. A dose of 528 Gy of γ irradiation was sufficient to arrest replication but not host cell penetration by tachyzoites. Female C57BL6 mice were vaccinated with two intraperitoneal inoculations of 1 × 10 6 irradiated tachyzoites at 4‐wk intervals. When stimulated with N. caninum tachyzoite lysates, splenocytes of vaccinated mice, cultured 5 and 10 wk after vaccination, secreted significant ( P <0.05) levels of interferon γ, interleukin (IL)‐10, and small amounts of IL‐4. Antibody isotype‐specific ELISA of sera from vaccinated mice exhibited both IgG1 and IgG2a isotypes of antibodies. Vaccinated mice were challenged intraperitoneally with 2 × 10 7 N. caninum tachyzoites. All vaccinated mice remained healthy and showed no obvious signs of neosporosis up to the 25th day post‐challenge when the study was terminated. All unvaccinated control mice died within 1 wk of infection. Gamma‐irradiated N. caninum tachyzoites can serve as an effective, attenuated vaccine for N. caninum .