Davis S W, Dubey J P
Parasite Biology and Epidemiology Laboratory, Agricultural Research Service, United States Department of Agriculture, Beltsville, Maryland 20705-2350, USA.
J Parasitol. 1995 Dec;81(6):882-6.
Immunity to Toxoplasma gondii, as measured by oocyst shedding, was studied in cats. In 3 trials, 12 3-mo-old T. gondii-free cats were fed tissue cysts of the ME-49 strain of T. gondii. All cats shed T. gondii oocysts for approximately 1 wk starting 3-5 days after ingesting tissue cysts. One cat became ill because of toxoplasmic pneumonia and was killed 17 days after inoculation. The remaining cats remained clinically normal. Approximately 3 mo after primary infection, these 11 cats (immune) and 11 age-matched or littermate uninfected cats (nonimmune) were challenged orally with tissue cysts of the ME-49 strain. In trials 1 and 3, 1 immune and 1 nonimmune cat were killed at 36 hr, 60 hr, 5 days, and 12 days after challenge and the development of T. gondii in intestines was studied histologically; in trial 2, cats were killed at 36 hr, 60 hr, and 5 days only. None of the "immune" cats shed oocysts after challenge. Asexual T. gondii types were found at 36 and 60 hr and at 5 days, indicating partial development of T. gondii in the intestine of immune cats. There were no significant differences in lymphocyte CD4+/CD8+ from spleen, popliteal, and mesenteric lymph nodes of immune cats compared to nonimmune cats.
通过卵囊排泄来衡量猫对刚地弓形虫的免疫力进行了研究。在3次试验中，给12只3月龄未感染刚地弓形虫的猫喂食刚地弓形虫ME-49株的组织包囊。所有猫在摄入组织包囊后3 - 5天开始，约1周内排出刚地弓形虫卵囊。1只猫因弓形虫肺炎生病，接种后17天死亡。其余猫临床状态正常。初次感染约3个月后，这11只猫（免疫组）和11只年龄匹配或同窝未感染的猫（非免疫组）经口用ME-49株的组织包囊进行攻毒。在试验1和3中，攻毒后36小时、60小时、5天和12天处死1只免疫组和1只非免疫组猫，组织学研究肠道内刚地弓形虫的发育情况；在试验2中，仅在36小时、60小时和5天处死猫。攻毒后，“免疫”组猫均未排出卵囊。在36小时、60小时和5天时发现无性型刚地弓形虫，表明免疫组猫肠道内刚地弓形虫有部分发育。与非免疫组猫相比，免疫组猫脾脏、腘窝和肠系膜淋巴结的淋巴细胞CD4+/CD8+无显著差异。
