Recombinant Antigens To DetectToxoplasma gondii-Specific Immunoglobulin G and Immunoglobulin M in Human Sera by Enzyme Immunoassay

Abstract

We have evaluated the diagnostic utility of eleven Toxoplasma gondii recombinant antigens (P22 [SAG2], P24 [GRA1], P25, P28 [GRA2], P29 [GRA7], P30 [SAG1], P35, P41 [GRA4], P54 [ROP2], P66 [ROP1], and P68) in immunoglobulin G (IgG) and IgM recombinant enzyme-linked immunosorbent assays (Rec-ELISAs). Following an initial evaluation, six recombinant antigens (P29, P30, P35, P54, P66, and P68) were tested in the IgG and IgM Rec-ELISAs with four groups of samples which span the toxoplasmosis disease spectrum (negative, chronic infection, acute infection, and recent seroconversion). Our results suggest that the combination of P29, P30, and P35 in an IgG Rec-ELISA and the combination of P29, P35, and P66 in an IgM Rec-ELISA can replace the tachyzoite antigen in IgG and IgM serologic tests, respectively. The relative sensitivity, specificity, and agreement for the IgG P29-P30-P35 Rec-ELISA were 98.4, 95.7, and 97.2%, respectively. The resolved sensitivity, specificity, and agreement for the IgM P29-P35-P66 Rec-ELISA were 93.1, 95.0, and 94.5%, respectively. Relative to the tachyzoite-based immunocapture IgM assay, the IgM P29-P35-P66 Rec-ELISA detects fewer samples that contain IgG antibodies with elevated avidity from individuals with an acute toxoplasmosis.

Toxoplasma gondii infection in pregnancy: opportunities and pitfalls of serological diagnosis

“…Therefore, the selection of sera used for evaluation influences the accuracy of the test markedly [46]. Several groups of investigators are working to find specific antigens and ⁄ or to produce recombinant antigens to improve the performance of IgM assays [47][48][49][50][51][52][53].…”

Detection of Immunoglobulin M Antibodies to P35 Antigen of Toxoplasma gondii for Serodiagnosis of Recently Acquired Infection in Pregnant Women

“…To provide proper clinical care for pregnant women, it is important to have a rapid and accurate method for diagnosis to distinguish recently acquired infections from those acquired in the distant past. Although recombinant T. gondii antigens have been evaluated for their ability to detect IgM antibodies (1,4,5,8), it remains unclear which antigen of the parasite is effective for detection of acute stage-specfic IgM antibodies. The present study demonstrated that IgM antibodies to the P35 antigen of T. gondii could be detected by ELISA in 90.0% (18 of 20) of serum samples from pregnant women with an acute TSP but not in those (0 of 33) with a chronic TSP.…”

“…Potasman et al (12) previously reported that a 35-kDa antigen of T. gondii is recognized in immunoblots by IgM antibodies in sera from patients with acute infection. Recently, Aubert et al (1) reported the efficiencies of six recombinant T. gondii antigens, including P35, for detection of IgM antibodies in human serum samples. In their studies, the sensitivity of an ELISA for the detection of P35 IgM antibodies in sera from individuals with acute infection was 46.1% (41 of 89 samples); this sensitivity is far lower than that of our P35-IgM-ELISA (90.0%).…”

Recent trends in the diagnosis of toxoplasmosis

“…SAG2 (P22) is major surface protein known as attachment ligand (Grimwood and Smith, 1996) that also has good antigenicity and immunogenicity (Aubert et al, 2000;Zhou et al, 2012). To evaluate the potential use of rSAG2 for diagnosis of feline toxoplasmosis by ELISA, it is shown that out of 192 samples screened, 21.9% were positive and there was significant co-relation between the titers of ELISA and LAT that led to the conclusion that ELISA with rSAG2 can be a useful method for detection of T. gondii in cats, as there was no cross reactivity with Neospora caninum (Huang et al, 2002).…”

“…When GRA7 was combined with Tg34AR (rhoptry protein 2, C-terminal fragment), the sensitivity rose to 96%. Aubert et al (2000) evaluated the diagnostic utility of 11 T. gondii recombinant antigens which include P22…”