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

Cap-AuNPs were prepared by mixing AuNPs (1 mL) with recombinant Cap protein (100 μL, 1 mg/mL) and stirred for 1 h at 4°C. To obtain washed Cap-AuNP formulation, excess free Cap protein was removed by repeated centrifugation (12,000 rpm for 60 min at 4°C) and resuspension of the pellet in PBS for a total of three wash cycles. The stability of the conjugate was assessed by adding 10% sodium chloride. 30 The conjugates were confirmed by UV-Vis, DLS, and Fourier transform infrared spectroscopy (FTIR) (Thermo Fisher Scientific). The quantification of Cap-AuNPs was measured as follows: 1 mL Cap (20 μg/mL) was added into 1 mL AuNPs, stirred for 1 h at 4°C, and then AuNPs suspension was centrifuged down at 12,000 rpm for 60 min at 4°C. The supernatant was collected and the concentration of Cap was measured by Micro BCA Protein Assay Kit (Boster, Wuhan, People's Republic of China).