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. 2019 Nov 18;87(12):e00536-19. doi: 10.1128/IAI.00536-19

FIG 3.

FIG 3

Leptospirosis-positive sera of various hosts recognize recombinant ErpY-like protein. ELISA was performed with two antigens (rErpY-like and rLoa22) independently to determine the reactivity of human, bovine, and canine sera testing MAT positive or negative for leptospirosis. Serum sample reactivity against the two antigens was recorded in triplicate. The mean absorbance values obtained from each serum sample are demarcated as empty circles or as empty triangles for leptospirosis MAT-positive or -negative samples, respectively. Solid black horizontal lines represent the means for each group. The cutoff value (dashed black horizontal lines) of the assay was derived from the mean absorbance values obtained from leptospirosis MAT-negative samples (control group) plus two SD for the antigen used. (A) ELISA to detect rErpY-like antigen (400 ng) using MAT-positive (n = 50) and -negative (n = 20) serum samples of human (1:100) for leptospirosis. Infected human sera recognized the rErpY-like protein with 100% sensitivity and specificity. OD450, optical density at 450 nm. (B) ELISA to detect rLoa22 (400 ng) antigen using MAT-positive and -negative human serum samples for leptospirosis. Infected human sera recognized the rLoa22 antigen with 100% sensitivity and specificity. (C) Immunoblot of antigens (rErpY-like and rLoa22) using the pooled human serum. (Left) Pooled human serum testing MAT positive for leptospirosis recognized both antigens. (Right) In contrast, there was no recognition of both antigens using a pooled human serum testing negative for leptospirosis. (D) ELISA to detect rErpY-like antigen using bovine serum samples testing MAT positive (n = 50) or negative (n = 20) for leptospirosis. (E) ELISA to detect rLoa22 antigen using bovine serum samples testing MAT positive or negative for leptospirosis. (F) Immunoblot using pooled bovine serum testing MAT positive or negative for leptospirosis. (G) ELISA to detect rErpY-like antigen using canine serum samples testing MAT positive (n = 18) or negative (n = 18) for leptospirosis. (H) ELISA to detect rLoa22 antigen using canine serum samples testing MAT positive or negative for leptospirosis. (I) Immunoblot using pooled canine serum testing MAT positive or negative for leptospirosis.