PED subunit vaccine based on COE domain replacement of flagellin domain D3 improved specific humoral and mucosal immunity in mice

A flagellin-adjuvanted inactivated porcine epidemic diarrhea virus (PEDV) vaccine provides enhanced immune protection against PEDV challenge in piglets

“…Currently, research in the field of PEDV vaccine development mainly focuses on screening new PEDV strains or optimizing the dose of PEDV antigens [2,6,20,21,24]. In this study, we attempted to identify a PEDV vaccine adjuvant that could efficiently induce N-protein-specific IgG immune responses, mucosal immune responses in pregnant sows, ensuring delivery of colostral IgA antibody to piglets in order to protect them from PEDV infection, as well as T cell responses.…”

“…Numerous studies have demonstrated that FliC contributes to the efficacy of various novel vaccines against Yersinia pestis [15], West Nile virus [23], Plasmodium falciparum [3], tetanus toxoid [18], and influenza virus [1,5]. Studies have demonstrated that a flagellin-adjuvanted PED subunit vaccine elicits enhanced systemic, local mucosal and T cell immune responses in mice and pigs [20,21]. However, there have been no studies of FliC as a mucosal adjuvant for inactivated PEDV vaccines in pregnant sows for which the immune responses in newborn piglets were evaluated after delivery.…”

“…In future studies, we will determine what ratio of virus, adjuvant and FliC is necessary for an optimal immune response in the sow and passive transfer of IgA antibodies to the piglets. In this study, we used PEDV and FliC separately rather than as a fusion protein of the target antigen and FliC [20,21]. This method was used to enable separate modification of PEDV while preserving the antigenicity of the virus.…”

“…Considering the route of PEDV infection, a mucosal adjuvant, flagellin, was used in the development of the inactivated PEDV vaccine (Vac201-FliC), prepared by mixing the inactivated PEDV vaccine antigens with Montanide™ ISA201 adjuvant and then adding flagellin (FliC) before use. Flagellin is a Toll-like receptor 5 (TLR5) ligand, suggesting its potential utility as an adjuvant [20]. Unlike many TLR agonists, flagellin tends to produce mixed Th1 and Th2 cell responses rather than a strongly polarized Th1 response [16].…”

Study of the immunogenicity of recombinant protein consisting of multiple epitopes of porcine epidemic diarrhea virus highly expressed in Sf9 cells

“…Previous work has shown that the S1 domain contains the main neutralizing epitopes, including the CO-26K-equivalent epitope (COE), and the S1D domain [14] . The COE epitope (499 ~ 638aa), which corresponds to the collagenase-digested fragment (namely CO-26K) of transmissible gastroenteritis virus (TGEV), has been considered an ideal antigenic candidate for development of subunit vaccine [15,16] . In addition, previous studies have shown that the epitope region designated S1D (636 ~ 789aa) in the S1 domain has the capacity to induce neutralization antibodies against PEDV.…”