Abstract
BackgroundOutbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry. Vaccination is the major method to prevent and control the disease. As live attenuated vaccines fail to elicit differentiable immunity between infected and vaccinated animals, subunit vaccine was considered as an alternative candidate to prevent and eradicate CSFV. Subunit vaccines present advantages in DIVA immunogenicity and safety. The technology was limited due to the low yield and the high cost with multiple and large doses. The native E2 signal peptide has not been well defined before. Here, the aim of this study is to develop a cost-effective and efficacious E2 vaccine candidate against CSFV with signal peptide and E2 sequence selection.ResultsA novel CSFV E2 sequence (E2ZJ) was identified from an epidemic strain of Zhejiang for outstanding secretion in baculovirus and enhanced immunogenicity. E2 secretion induced with the selected signal peptide, SPZJ (SP23), increase at least 50% as compared to any other signal peptides tested. Besides, unique antigenic features were identified in E2ZJ. As indicated with immunized sera in IFA against CSFV infection, E2ZJ elicited CSFV antibodies at the earlier stage than other E2 types tested in mice. Moreover, higher level of neutralizing and CSFV antibodies against CSFV with E2ZJ was detected than other E2s with the same dosage at 28 dpi. Further, E2ZJ successfully elicited neutralizing immunity in piglets. A single dose of 5 μg of E2ZJ was sufficient to induce protective antibodies against CSFV in piglets and provided 100% protection against lethal virus challenge.ConclusionsOur studies provide evidence that E2ZJ guided by a novel E2 signal peptide (SPZJ) was efficiently secreted and presented significantly improved immunogenicity than conventional E2 vaccines. Moreover, a single dose of 5 μg E2ZJ is efficacious against CSFV in piglets.
Highlights
Outbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry
Identification of a novel signal peptide SP23 of ZJ01 (SPZJ) for robust E2 production To identify the efficient native signal peptide for E2 secretion, E2 protein was fused to a series of truncated candidates (SP13, SP18, SP21, SP23, SP25, SP28 or SP33) individually (Fig. 1a)
SP23 of ZJ01 (SPZJ) was able to induce the expression of other E2s (E2C and E2HZ) as well as its native E2ZJ, indicating SPZJ is a common signal peptide for variable E2 production (Fig. 2b-a)
Summary
Outbreaks of Classical swine fever virus (CSFV) cause significant economic losses in the swine industry. Commercially available vaccines mainly consist of live attenuated CSFV of cell line origin or rabbit tissue origin, derived from the commonly used C-strain These live attenuated vaccines have outstanding efficacy and safety but lack a serological concept of differentiating infected from vaccinated animals (DIVA) hampering CSF eradication and cause concern in animal welfare when live rabbits are exploited in vaccine production [16, 17]. In these years, efforts have been made on E2 based subunit vaccines for alternative option against CSFV. The enhancement of soluble E2 expression with effective immunogenicity is the corner stone for this CSFV vaccine to be one of the most efficacious and practical strategies against CSFV in future
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
