Effective preparation and immunogenicity analysis of antigenic proteins for prevention of porcine enteropathogenic coronaviruses PEDV/TGEV/PDCoV.

Porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and porcine deltacoronavirus (PDCoV) cause highly contagious gastrointestinal damage to piglets with high coinfection in clinical. However, there is no available trivalent vaccine against the three viruses. Here, a trivalent subunit vaccine by combining PEDV-SCOE, TGEV-SAD, and PDCoV-RBD proteins with ISA 201 adjuvant was effectively prepared, and the immunogenicity was evaluated. The detection results showed that the vaccine induced specific humoral IgG, neutralizing antibodies, and increased levels of Th1 and Th2 cytokines. Splenocytes proliferation and specific cytotoxic T lymphocytes (CTL) were activated. Furthermore, the three antigenic proteins up-regulated CD4+ and CD8+ T lymphocytes, activated the germinal center (GC) through the Tfh-GC axis, and promoted the differentiation of GC B cells in to plasma cells and memory B cells. Overall, the three antigenic proteins will provide helpful information for further exploration of trivalent vaccines against PEDV, TGEV, and PDCoV.