The truncated form of flagellin (tFlic) provides the 2dCap subunit vaccine with better immunogenicity and protective effects in mice

Abstract

Porcine circovirus type 2 (PCV2) is the main causative agent of porcine circovirus-associated diseases, and it causes substantial economic losses in the swine industry each year. It is crucial to develop an effective vaccine against the circulating strain PCV2d, which is prone to substantial degrees of mutation. In this study, a truncated form of flagellin (tFlic: 85-111 aa) was inserted into the C-terminal sequence of 2dCap, and Western blotting results showed that recombinant Cap-tFlic VLPs were successfully expressed. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) data indicated that purified recombinant Cap-tFlic fusion proteins existed in the form of polymers and that tFlic could not affect the formation and internalization of VLPs. Integrated Cap-tFlic VLPs induced the expression of antigen presentation-related factors (MHC-II and CD86) by bone marrow-derived dendritic cells (BM-DCs), and the expression of TLR5-related factors (TNF-α) was dramatically elevated. Mice intramuscularly immunized with Cap-tFlic VLPs exhibited significantly higher levels of Cap-specific antibodies and neutralizing antibodies than mice immunized with wild-type Cap VLPs. The data obtained in the current study indicate that Cap-tFlic may be a candidate for a subunit vaccine against PCV2 in the future.

A modular and self-adjuvanted multivalent vaccine platform based on porcine circovirus virus-like nanoparticles

“…According to detection tests of CSFV and PCV2 antibodies established in our previous studies [ 37 , 39 , 47 , 48 ], indirect enzyme-linked immunosorbent assay (ELISA) was used to determine serum PCV2- and CSFV-specific antibody. Briefly, recombinant Cap or E2 protein was diluted to 2 µg/mL using carbonate coating solution (pH 9.5), added to ELISA plates at 100 µL/well and incubated overnight at 4 °C.…”

Porcine Circovirus Type 2 Vaccines: Commercial Application and Research Advances

“…Flagellins of Salmonella typhimurium (FliC and FljB) exert immunomodulatory effects by activating TLR 5-positive DCs [95,96]. The fusion expression of flagellin and PCV2 Cap in the baculovirus system or the use of flagellins of FliC as adjuvants in PCV2 vaccines can enhance B and T cell-mediated immune responses in mice and pigs [89][90][91][92]. Compared with inactivated vaccines, attenuated vaccines better mediate cellular immunity and produce faster immune effects.…”