Fig 2: Prediction of immunogenicity of human MrgX2 antigen by bioinformatics method. A Prediction of the secondary structure of the human MrgX2 antigen (a) Prediction of the alpha helix of the sequence by the Gamier-Robson method. b Prediction of the alpha helix of the sequence by the Chou-Fasman method. c Prediction of the beta fold of the sequence by the Gamier-Robson method. d The Chou-Fasman method predicts the ß-fold of the sequence. e The Gamier-Robson method predicts the rotation angle of the sequence. f The Chou-Fasman method predicts the rotation angle of the sequence. g The Gamier-Robson method predicts the sequence curl. h Eisenberg method predicts alpha-helix hydrophilicity. i Eisenberg method predicts beta-sheet hydrophilicity. j Karplus-Schulz method predicts sequence flexibility. B Kyte-Doolittle method predicts sequence hydrophilicity. C Jameson-Wolf method predicts sequence antigen index. D Emini method predicts sequence surface accessibility. T1 in the red box showed the 286–330 amino acid sequence of human MrgX2 peptide

Fig 3: Clinical application of human MrgX2-ELISA. a Healthy subjects frequency distribution of human blood MrgX2 concentration in the population (n = 75). b ROC curve of human MrgX2 protein expression (n = 150), green line represents the diagnostic reference line; blue line represents the ROC curve of MrgX2. c Scatter plot of blood MrgX2 concentration in CU patients (n = 75) and healthy subjects (n = 75). d Histogram of blood MrgX2 concentration in CU patients (n = 75) and healthy subjects (n = 75). e Comparison of blood MrgX2 concentration in healthy male (n = 31) and healthy famale (n = 44). f Comparison of blood MrgX2 concentration in CU male (n = 31) and CU famale (n = 44). Student’s t test (nonparametric tests) was used to determine statistical significance. Data are expressed as mean ± SEM from at least three independent experiments. ****p < .0001 vs. control group

Fig 4: Establishment and methodological investigation of human MrgX2-ELISA. a Double antibody sandwich screening of matched antibodies. Student’s t test (nonparametric tests) was used to determine statistical significance. b Western blot to examine the specificity of E7630 rabbit polyclonal purified antibody. c Western blot to investigate the specificity of mouse monoclonal purified antibody. d Human MrgX2-Inspection of standard curve of ELISA. e Investigation of stability of human MrgX2-ELISA. f Investigation of specificity of human MrgX2-ELISA. One-way analysis of variance (Bonferroni’s multiple comparisons test) was used to determine statistical significance. Data are expressed as mean ± SEM from at least three independent experiments. **p < .01, ***p < .001, ****p < .0001 vs. negative control

Fig 5: Titer detection diagram of human MrgX2 rabbit polyclonal antibody. a Dot blot method to verify the potency of human MrgX2 rabbit polyclonal purified antibody recognition polypeptide. b Indirect ELISA method to verify the ability of human MrgX2 rabbit polyclonal purified antibody to recognize natural MrgX2 protein. Student’s t test (nonparametric tests) was used to determine statistical significance. Data are expressed as mean ± SEM from at least three independent experiments. **p < .01, vs negative control