Subcutaneous and intestinal vaccination with tachyzoites of Toxoplasma gondii and acquisition of immunity to peroral and congenital toxoplasma challenge
McLeod, R.; Frenkel, J.K.; Estes, R.G.; Mack, D.G.; Eisenhauer, P.B.; Gibori, G.
Journal of Immunology 140(5): 1632-1637
1988
ISSN/ISBN: 0022-1767 PMID: 3346545 Document Number: 325106
Mice were immunized sc or intraintestinally with 2 injections of a temperature-sensitive mutant of T. gondii (ts4). Nonpersistence of the vaccine strain was documented by subinoculation of tissues of a subgroup of mice 3 months or more after the 2nd immunization. Mice were immune to otherwise lethal parenteral challenges with tachyzoites of the M7741 strain or to peroral challenge with bradyzoites of the Me49 strain of T. gondii. Although 2 sc or intraintestinal immunizations did not completely protect against development of T. gondii in the brains of mice, fewer cysts developed in the sc immunized mice than in control mice (2+or-3 cysts/0.01 ml in immunized mice compared with 75+or-48 cysts/0.01 ml in controls). Reduction in cyst number after intraintestinal immunization was more variable, but also statistically significant. Female mice were first immunized, than mated, and then challenged perorally. Neonates of the sc immunized mice were not protected. Neonates of intraintestinally immunized mice were protected in part (36% of 115) against congenital infection compared with controls (7% of 107).