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

The uptake of Cap-AuNPs by antigen-presenting cells (APCs) was detected by indirect immunofluorescence (IFA). Briefly, RAW264.7 macrophages and DC2.4 dendritic cells were seeded on 96-well cell culture plates at 2×10 4 cells/well (100 μL) and allowed to grow overnight at 37°C in 5% CO 2 . Cap or Cap-AuNPs were diluted 10-fold by DMEM and 100 μL of Cap protein (1.2 μg/mL) or Cap-AuNPs (11.2 μg/mL) containing the same amount of Cap protein was added to incubate with the cells. After incubation for 1 h, the medium was removed, and the cells were fixed in precooled methanol for 10 min at room temperature, followed by three washes with PBS. After blocking with skim milk (5% in PBST), the cells were incubated with mouse anti-PCV2 serum, followed by a fluorescein isothiocyanatelabeled anti-mouse antibody and counterstained with 4′,6diamidino-2-phenylindole before plates were examined by fluorescence microscopy.