Nanoparticle orientationally displayed antigen epitopes improve neutralizing antibody level in a model of porcine circovirus type 2

Ding, Peiyang; Zhang, Teng; Li, Yafei; Teng, Man; Sun, Yaning; Liu, Xiao; Chai, Shujun; Zhou, Enmin; Jin, Qianyue; Zhang, Gaiping

High levels of anti-Cap (169-180) antibodies is the result of host recognition of Cap protein monomer or fragments produced during virus replication and is associated with PCV2-SD, diverting the humoral response away from protective epitopes. The Cap (169-180) epitope located on the surface of Cap protein, however, due to its location and orientation, is not accessible on the surface of the PCV2. Cap protein is attached to AuNPs via an Au-S bond, thus masking some epitopes. Considering that AuNPs promoted the presentation of Cap protein and enhanced the antibody to all epitopes, the ratio of IgG against Cap (169-180)/IgG against PCV2 was more meaningful than IgG against Cap (169-180) level. After adding AuNPs, the ratio of IgG against Cap (169-180)/IgG against PCV2 was significantly reduced, indicating the Cap (169-180) epitope was buried ( Figure 6C ).