Figure 3
Identification of linear epitopes and serological detection. A Indirect ELISAs were performed using synthetic peptides to verify the reactivity of the 3A9 and 4F7 mAbs. The inset shows that the 3A9 mAb can react with 25GLTTTWKEYSHDLQL39 and that the 4F7 mAb can react with 259GNTTVKVHASDERGP273. Neither epitope was cross-reactive with sera positive for BVDV or BDV. The results were obtained from at least three biological replicates (mean ± SD) and analysed using a t test with GraphPad Prism software; ***p < 0.001 and ****p < 0.0001. Characteristic analysis of the linear B-cell epitope of the VP2 protein. B The relative spatial position of the identified epitope is presented in a surface view from a partially predicted 3D structure of CSFV E2 (reference structure, PDB ID: 2YQ2). The 25GLTTTWKEYSHDLQL39 linear epitope recognized by the 3A9 mAb is shown in blue, and the 259GNTTVKVHASDERGP273 epitope recognized by the 4F7 mAb is shown in red. C Indirect immunofluorescence analysis of the immunoreactivity of the mAbs. PK-15 cells were used for indirect immunofluorescence assays with the 3A9 and 4F7 mAbs (green), and nuclei were stained with DAPI (blue). Fluorescence images were acquired with a confocal laser scanning microscope. Bright field, scale bar = 25 μm.