Production and immunogenicity of chimeric virus-like particles containing the spike glycoprotein of infectious bronchitis virus

Lv, Lishan; Li, Xiaoming; Liu, Genmei; Li, Ran; Liu, Qiliang; Shen, Huifang; Wang, Wei; Xue, Chunyi; Cao, Yongchang

Serum S1-specific antibodies were analyzed by Enzyme-Linked Immunosorbent Assay (ELISA). Briefly, S1 proteins were purified from 293T cells expressing S1 proteins. Each well of a 96-well plate was then coated with 100 μL of S1-proteins at 3 μg/mL. After washing and blocking, each well was incubated with serum samples from immunized mice or from immunized SPF chickens at a 400-fold dilution for 2 h. Following washing, horseradish peroxidase (HRP)-labeled rabbit anti-mouse secondary antibodies (Proteintech Group) diluted 5000-fold were added and incubated for 1 h for murine sera. For chicken sera, HRP-labeled donkey anti-chicken secondary antibodies (Proteintech Group) diluted 5000-fold were added and incubated for 1 h. Signals were visualized with ELISA substrate reagents and measured at 450 nm using a spectrophotometer (ELx800UV; BioTek, USA).