Dubey J P, Andrews C D, Thulliez P, Lind P, Kwok O C
Parasite Biology and Epidemiology Laboratory, US Department of Agriculture, Beltsville, MD 20705-2350, USA.
Vet Parasitol. 1997 Jan;68(1-2):41-50. doi: 10.1016/s0304-4017(96)01053-9.
Antibody titers to Toxoplasma gondii were determined in 16 pigs orally inoculated with 1000 or 10,000 oocysts of one of the four strains (GT-1, ME-49, TS-2, TC-2) of T. gondii. Pigs were euthanized on postinoculation days 103-875 and their tissues were bioassayed for T. gondii. Antibody titers were measured in the modified agglutination test (MAT) using formalin-preserved (test A) or acetone-preserved (test B) tachyzoites, latex agglutination test (LAT), indirect hemagglutination test (IHA), enzyme-linked immunobsorbant assay (ELISA), and the Sabin-Feldman dye test (DT). Toxoplasma gondii was isolated from all but two (one with GT-1 strain and one with TC-2 strain) of the inoculated pigs. Results of the serologic tests varied by test used, by strain of T. gondii and from pig to pig within groups. One pig inoculated with the TC-2 strain was considered not to be infected because it remained seronegative in all tests and T. gondii was not isolated from its tissues by bioassay. The IHA and LAT did not produce consistently positive results with infected pigs and two pigs remained seronegative (< 1:64) in both tests. At the time of necropsy, IHA titers had declined to < 1:64 in five pigs and LAT titers had declined to < 1:64 in four pigs. The MAT (test A) and ELISA detected antibodies in all infected pigs but ELISA did not detect antibody at the time of necropsy in one pig. Antibody titers peaked earliest in the DT. Antibody titers in the MAT (test B) peaked at 2560 in all seropositive pigs by 6 weeks postinoculation (PI) but declined to < 1:160 by 15 weeks PI; this test may be useful in determining recency of T. gondii infection in pigs. Overall, the MAT (test A) gave most consistent results.
对16头口服接种1000或10000个四种弓形虫菌株（GT - 1、ME - 49、TS - 2、TC - 2）之一卵囊的猪，测定了抗弓形虫抗体滴度。在接种后第103 - 875天对猪实施安乐死，并对其组织进行弓形虫生物测定。使用福尔马林保存的速殖子（试验A）或丙酮保存的速殖子（试验B）通过改良凝集试验（MAT）、乳胶凝集试验（LAT）、间接血凝试验（IHA）、酶联免疫吸附测定（ELISA）和Sabin - Feldman染色试验（DT）测量抗体滴度。除了两头接种猪（一头接种GT - 1菌株，一头接种TC - 2菌株）外，从所有接种猪中分离出了弓形虫。血清学检测结果因所用检测方法、弓形虫菌株以及组内猪只个体不同而有所差异。一头接种TC - 2菌株的猪被认为未感染，因为它在所有检测中均保持血清阴性，且通过生物测定未从其组织中分离出弓形虫。IHA和LAT对感染猪未产生一致的阳性结果，两头猪在这两种检测中均保持血清阴性（<1:64）。在尸检时，5头猪的IHA滴度降至<1:64，4头猪的LAT滴度降至<1:64。MAT（试验A）和ELISA在所有感染猪中均检测到抗体，但ELISA在一头猪尸检时未检测到抗体。DT中抗体滴度最早达到峰值。MAT（试验B）中所有血清阳性猪的抗体滴度在接种后6周时达到2560，但在接种后15周时降至<1:160；该试验可能有助于确定猪近期弓形虫感染情况。总体而言，MAT（试验A）给出的结果最一致。
