Detection of Circulating Antigens in the Diagnosis of Acute toxoplasmosis

Acebes, Maria V.; Díez, Begoña; Garcı́a-Rodrı́guez, J.A.; Viens, P.; Cisterna, R

doi:10.4269/ajtmh.1994.51.506

Cited by 13 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this study, circulating antigens of T. gondii began to be detected on day 2 PI, and the antigen titers increased on day 4 and peaked on day 12 PI. The appearance of positive circulating antigens after T. gondii infection in rabbits were similar with the previous reports [5,9,10]. Interestingly, the detection time of circulating antigens in rabbits coincided with the parasitemia period.…”

supporting

confidence: 91%

“…An alternative serologic test is detection of parasite components and metabolites, circulating antigens which are present in blood during the acute phase of infection. The circulating antigens have been found in both experimental and human toxoplasmosis [5][6][7][8][9][10]. In this study, circulating antigens of T. gondii began to be detected on day 2 PI, and the antigen titers increased on day 4 and peaked on day 12 PI.…”

mentioning

confidence: 57%

See 1 more Smart Citation

Antigenemia and Specific IgM and IgG Antibody Responses in Rabbits Infected with Toxoplasma gondii

et al. 2009

View full text Add to dashboard Cite

Toxoplasmosis is usually diagnosed using serological tests with increases in specific IgG and IgM antibodies. However, these tests are not reliable in immunocompromised patients, nor is it possible to differentiate clearly between the acute and latent forms of toxoplasmosis [1,2]. Because a relatively high percentage of individuals have antibodies without a recognized parasite infection, the early detection of Toxoplasma gondii antigen in the serum or other body fluids of patients would help to diagnose correctly and prevent late complications. For detecting Toxoplasma antigen, several laboratory procedures are available. Direct detection procedures, such as microscopic examination, immune histology, or cell culture are reliable, but they are either insensitive or time-consuming [1,2]. PCR is highly sensitive and specific, although heme, heparin, and other poorly characterized substances have been reported to decrease the efficiency of PCR [3]. ELISA is considered to be a highly sensitive, practical method for detecting the parasite antigen [2]. Many reports have discussed titrating serum antibodies in hosts after Toxoplasma infection, however, little information is available on the correlations among parasitemia, circulating antigens, and antibody titers in T. gondii-infected hosts.To assess the sequential changes in parasite antigen and antibody responses in blood, 5 New Zealand white rabbits weighing 2-3 kg were infected with 1,000 tachyzoites of the RH strain of T. gondii subcutaneously. Then, blood samples were drawn from an ear vein of each rabbit every other day for 20 days. To check parasitemia in the rabbits, 0.5 ml of heparinized blood from each rabbit was injected intraperitoneally into 4 mice, and their survival was monitored for 20 days after infection.The ELISA for detecting circulating antigens was performed in microtitration trays [4,5]. To obtain mouse anti-Toxoplasma antisera, mice were infected with 20 brain cysts of avirulent Me49 strain of T. gondii orally. The mice were then sacrificed at 6 months after infection, and the sera were precipitated with saturated ammonium sulfate solution, resuspended in 0.01 M phosphate buffered saline. Mouse anti-Toxoplasma antisera were diluted with 0.1 M carbonate-bicarbonate buffer (pH 9.6, 10 mg/ml). Then, 100 ml were pipetted into 96-well microtiter plates (Nunc, Roskilde, Denmark) and incubated at 4℃ overnight. The plates were washed with PBS containing 0.05% Tween 20 (PBS/Tween 20), to which 0.1 ml of rabbit serum diluted 1 : 50 with PBS/ Tween 20 containing 0.1% bovine serum albumin was added. Toxoplasma lysate antigen (TLA) was prepared as a control. The plates were incubated at room temperature (RT) for 2 hr, and then 0.1 ml sample serum from the infected rabbit was added. After washing, 150 ml of horseradish peroxidase (HRP)-conju- Antigenemia and Specific IgM and IgG Antibody Responses in Rabbits Infected with Toxoplasma gondiiKorean J Parasitol. Vol. 47, No. 4: 409-412, December 2009 DOI: 10.3347/kjp.2009 Abstract: In this experiment, the correla...

show abstract

supporting

confidence: 91%

mentioning

confidence: 57%

Antigenemia and Specific IgM and IgG Antibody Responses in Rabbits Infected with Toxoplasma gondii

et al. 2009

View full text Add to dashboard Cite

show abstract

“…However, some problems can be observed in laboratory practice, such as false negative results after treatment with anti-toxoplasma drugs, low and focal distribution of parasites in the tissues or the presence of non-viable parasites in autolyzed tissue. Excreted and secreted antigen (ESA) of T. gondii has been used in detection of specific antibodies for the diagnosis of acute toxoplasmosis 1,2,3,4,6,7,15,27 . As previously mentioned, circulating antigens in infected humans are constituted by T. gondii ESA, and are one of the first targets of the host immune response 26 .…”

Section: Discussionmentioning

confidence: 99%

“…These facts imply that the reactivity among antigens may vary greatly, contributing to inaccurate provision of diagnostic efficiency by assay systems. Several reports 1,2,4,6,7,10,16,23,27,29 have emphasized the value of the detection of specific antibodies raised to excreted-secreted antigens (ESA) of T. gondii for the diagnosis of acute toxoplasmosis. The T. gondii ESA constitutes 90% of the circulating antigens in infected humans, thus is one of the first targets of the host immune response 6. Recombinant antigens and synthetic peptides have been prepared from ESA antigens, however, the exact composition and association of recombinant antigens and peptides to be used in immunoassays to detect toxoplasma antibodies is still an open question.…”

Section: Introductionmentioning

confidence: 99%

High diagnostic efficiency of IgM-ELISA with the use of multiple antigen peptides (MAP1) from T. gondii ESA (SAG-1, GRA-1 and GRA-7), in acute toxoplasmosis

Araújo

Ferreira

2010

Rev. Inst. Med. trop. S. Paulo

View full text Add to dashboard Cite

SUMMARYThe main serological marker for the diagnosis of recent toxoplasmosis is the specific IgM antibody, along with IgG antibodies of low avidity. However, in some patients these antibodies may persist long after the acute/recent phase, contributing to misdiagnosis in suspected cases of toxoplasmosis. In the present study, the diagnostic efficiency of ELISA was evaluated, with the use of peptides derived from T. gondii ESA antigens, named SAG-1, GRA-1 and GRA-7. In the assay referred to, we studied each of these peptides individually, as well as in four different combinations, as Multiple Antigen Peptides (MAP), aiming to establish a reliable profile for the acute/recent toxoplasmosis with only one patient serum sample. The diagnostic performance of the assay using MAP1, with the combination of SAG-1, GRA-1 and GRA-7 peptides, demonstrated better discrimination of the acute/recent phase from non acute/ recent phase of toxoplasmosis. Our results show that IgM antibodies to MAP1 may be useful as a serological marker, enhancing the diagnostic efficiency of the assay for acute/recent phase of toxoplasmosis.

show abstract

“…Immunoenzymatic assays, ELISA (Enzyme-linked Immunosorbent Assay), have been used in the diagnostics of toxoplasmosis 6,12,30 . Quantification of antigenemia has been studied by ELISA and immunoblot method 1,2,4,16 .…”

Section: Introductionmentioning

confidence: 99%

Detection of Toxoplasma gondii soluble antigen, SAG-1(p30), antibody and immune complex in the cerebrospinal fluid of HIV positive or negative individuals

Chaves-Borges

Souza

Silva

et al. 1999

Rev. Inst. Med. trop. S. Paulo

View full text Add to dashboard Cite

Active infection by T. gondii was evaluated by immunoassay for soluble SAG-1 (p30), the major surface antigen from T. gondii, specific antibodies and immune complexes in human cerebrospinal fluid (CSF) samples. A total of 263 samples of CSF were collected from hospitalized patients presenting neurological disorders and analyzed for antibodies to HIV. Patients were divided into two groups: HIV positive (n = 96) or HIV negative (n =167). The results of the assays showed that 45% of all samples were positive for soluble SAG-1. Toxoplasma Ag/Ab immune complexes were detected in 19% of the CSF samples and 62% were positive for T. gondii- specific IgG. A combination of these assays in the presence of clinical findings consistent with active Toxoplasma infection may predict the presence of toxoplasmic encephalitis. Moreover, detection of soluble SAG-1 in the CSF of these individuals appears consistent with active infection.

show abstract

Detection of Circulating Antigens in the Diagnosis of Acute toxoplasmosis

Cited by 13 publications

References 0 publications

Antigenemia and Specific IgM and IgG Antibody Responses in Rabbits Infected with Toxoplasma gondii

Antigenemia and Specific IgM and IgG Antibody Responses in Rabbits Infected with Toxoplasma gondii

High diagnostic efficiency of IgM-ELISA with the use of multiple antigen peptides (MAP1) from T. gondii ESA (SAG-1, GRA-1 and GRA-7), in acute toxoplasmosis

Detection of Toxoplasma gondii soluble antigen, SAG-1(p30), antibody and immune complex in the cerebrospinal fluid of HIV positive or negative individuals

Contact Info

Product

Resources

About