Characterization of temperature-sensitive strains of Neospora caninum in mice

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American Society of Parasitology

Temperature-sensitive (ts) strains of the Neospora caninum tachyzoites were selected by chemical mutagenesis and selection for growth at 32 C. Three ts strains and the parental, N. caninum wild-type strain, NC-1, were examined in the present study for their ability to cause disease in inbred BALB/c mice, outbred ICR mice, and chemically immunosuppressed ICR mice. In BALB/c mice, all 3 strains failed to induce clinical disease, whereas infection with the NC-1 strain caused central nervous system disease and death in some mice. No disease was observed in ICR mice inoculated with the 3 ts strains or the NC-I strain. All immunosuppressed ICR mice inoculated with the NC-1 strain died, whereas no immunosuppressed mice inoculated with the NCts-4 strain and only 1 of 5 mice inoculated with the NCts-8 and NCts-12 strains died. The NCts-4 and NCts-12 strains reverted to a wild-type phenotype when grown at 37 C. Vaccination of BALB/c mice with live, but not frozen NCts-8 strain tachyzoites induced significant (P < 0.05) protection following NC-1 strain challenge.

s48 toxoplasma-gondii, killed vaccine, sheep, challenge, pathogenicity, tachyzoites, infections, immunity, hamsters, mutants, parasitology
David S. Lindsay, Steve D. Lenz, Byron L. Blagburn and David A. Brake (1999). "Characterization of temperature-sensitive strains of Neospora caninum in mice," The Journal of Parasitology, Vol. 85, No. 1, pp. 64-67. DOI: 10.2307/3285701