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Preliminary multiplex microarray IgG immunoassay for the diagnosis of toxoplasmosis and rubella
Baschirotto, Priscila T; Krieger, Marco A & Foti, Leonardo
Abstract
BACKGROUND During pregnancy, toxoplasmosis and rubella can cause serious damage to the mother and the foetus through
vertical transmission. Early diagnosis enables implementation of health measures aimed at preventing vertical transmission and
minimising damage caused by these diseases.
OBJECTIVE Here, we report the development of a multiplex assay for simultaneous detection of IgG antibodies produced during
toxoplasmosis and rubella infection.
METHODS This assay is based on xMap technology. Initially, by singleplex assays, we evaluated the following antigens: one Toxoplasma
gondii lysate; two antigenic extracts of T. gondii (TOX8131 and TOX8122); fragments of T. gondii antigens [SAG-1 (amino acids 45-
198), GRA-7 (24-100), GRA-1 (57-149), ROP-4, and MIC-3 (234-306)]; two chimeric antigens composed of fragments of SAG-1, GRA-
7, and P35 (CTOX and CTOXH); and fragments of Rubella virus antigens [E-1 (157-176, 213-239, 374-390), E-2 (31-105), and C (1-123)].
FINDINGS A multiplex assay to simultaneously diagnose toxoplasmosis and rubella was designed with the best-performing antigens in
singleplex and multiplex assays, which included CTOXH, T. gondii lysate, TOX8131, E-1, and E-2. The multiplex assay showed 100%
sensitivity and specificity for anti-T. gondii IgG detection and 95.6% sensitivity and 100% specificity for anti-R. virus IgG detection.
MAIN CONCLUSIONS We found that, despite the difficulties related to developing multiplex systems, different types of antigens
(extracts and recombinant proteins) can be used to develop high-performance diagnostic tests. The assay developed is suitable
to screen for prior T. gondii and R. virus infections, because it is a rapid, high-throughput, low-cost alternative to the current
standard diagnostic tools, which require multiple individual tests.
Keywords
toxoplasmosis; rubella; diagnosis; multiplex; liquid microarray
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