Presence of high concentrations of circulating Toxoplasma antigens during acute Toxoplasma infection in athymic nude mice

Suzuki, Yasuhiro; Kobayashi, Akio

doi:10.1128/iai.55.4.1017-1018.1987

Cited by 9 publications

(1 citation statement)

References 12 publications

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“…The test lacks, therefore, reliability in the use for discrimination between recent and more distant infection. Moreover, it may be inconclusive in patients with underlying diseases causing suppressed antibody responses or in patients receiving immunosuppressive therapy (7). IgM class antibodies in patients with toxoplasmosis were shown to peak at 2 months, persisting for up to 6 months (8).…”

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Evaluation of a rapid ELISA technique for detection of circulating antigens of Toxoplasma gondii

Chen

Lou

et al. 2008

Microbiology and Immunology

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To evaluate a modified rapid ELISA method for detecting CAg during Toxoplasma gondii infection, we analyzed the specificity and sensitivity of the ELISA method by using experimental Toxoplasma infection in rabbits and also tested this method in human samples including 5428 serum, 548 cerebrospinal fluid and two breast milk samples. We prepared PcAb, and used it for rapid one-step sandwich ELISA testing in which an incubation time in the regular ELISA procedure was omitted. This method detected CAg at the concentration of 31.2 ng/mL, and no cross-reaction was found with antigens of protozoa (Cryptosporidium parvum, Plasmodium falciparum), trematode (Schistosoma japonicum, Paragonimus sp.) and nematode (Brugia malayi, Ancylostoma duodenale, Ascaris lumbricoides and Trichinella spiralis). CAg was detected in rabbit serum 3 days after infection, and optical density values reached a peak 9 ∼ 13 days after infection, then declined gradually. Among human serum samples, the positive rate of CAg was 2.11% in cerebral paralysis patients, whereas it was 0.22% or 0.71% in patients without neurological symptoms or in uncomplicated pregnant women. The difference among these three groups was statistically significant (P < 0.05). The positive rate of cerebrospinal fluid samples from cerebral paralysis patients was 10.58%. There is a statistically significant difference between the positive rates of meat-packing workers and blood donors (P < 0.01). In the retrospective analysis, CAg was detected in accordance with the onset of clinical symptoms, suggesting that CAg could reflect the clinical course in humans. Together with these results, CAg detected in the modified rapid sandwich ELISA could be a sensitive marker for acute and active infection of T. gondii.Toxoplasmosis is caused by Toxoplasma gondii, an obligate intracellular protozoan parasite. It is one of the most epidemic parasitic diseases in human beings and animals, and infects as many as 35-40% of the adult population worldwide and demonstrates varying clinical manifestations. People are infected by inadvertent ingestion of oocysts or sporozoites in cat feces, or tissue cysts in undercooked infected meat or contaminated foods (1), and less frequently infected by direct recipience of tissue or blood from other contaminated humans, and vertical transmission from acutely infected mothers (2). Ingestion leads to the formation of tachyzoites acutely, which cause parasitemia and further dissemination and, along with the development of host immunity, parasites change to become the form of bradyzoites, which lead to latent infection with the formation of tissue cysts in skeletal muscle, heart muscle, and CNS tissue. Immunocompetent adults and adolescents with primary infection are generally asymptomatic, 180

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