Concordance between two monoclonal antibody (mAb)-based enzyme-linked immunosorbent assays for the measurement of cysticercal antigen levels in sera of pigs experimentally infected with Taenia solium and Taenia hydatigena

Abstract

Background Antigen detection in Taenia solium cysticercosis confirms viable infection in the intermediate host (either pig or human). The reference B158 / B60 antigen-detection ELISA (Ag-ELISA) has high levels of sensitivity and specificity in human neurocysticercosis (94% and 99% according to the manufacturer), although its sensitivity is lower in cases with single brain cysts, whereas in porcine cysticercosis the assay performance is affected by its frequent cross-reaction with Taenia hydatigena. Our group has produced 21 anti-T. solium monoclonal antibodies (mAbs) reacting against antigens of the whole cyst, vesicular fluid, and secretory/excretory products, identifying TsW8 / TsW5 as the most promising pair of mAbs for an Ag-ELISA. Methods We report the use of our TsW8 / TsW5 Ag-ELISA for the measurement of parasite antigen levels in two panels of sera from pigs experimentally infected with T. solium (n = 26) and T. hydatigena (n = 12) from day 0 to day 90 post-infection (PI) and assessed the concordance of our assay with the reference B158 / B60 Ag-ELISA using Bland-Altman (BA) plots and Lin’s concordance coefficients (LCC). Results Our TsW8 / TsW5 Ag-ELISA measured antigen levels efficiently during the course of T. solium cysticercosis infections in pigs with a strong agreement with the reference B158 / B60 Ag-ELISA in almost all paired log-transformed optical density (OD) values. The limits of agreement (LoA) in the BA plot at days 0, 28, and 90 PI were 92.3%, 100% and 100%, respectively, and high concordance between assays was also found (LCC: 0.69, 0.92, and 0.96, respectively, all P < 0.001). In pigs infected with T. hydatigena, almost all paired log-transformed ODs were also within the LoA, whereas concordance between assays was low or moderate at days 0 and 28 PI, (LCC: 0.24 and 0.88), but higher at day 90 PI (LCC: 0.98, P < 0.001). Conclusions / significance: The TsW8 / TsW5 Ag-ELISA recognizes antigens in pigs with T. solium cysticercosis and is highly concordant with the B158 / B60 Ag-ELISA. However, its diagnostic use is hampered by cross-reactions with T. hydatigena, as in other mAb antigen detection assays.