Construction and efficacy of a new live chimeric C-strain vaccine with DIVA characteristics against classical swine fever.

Abstract

To develop the new classical swine fever (CSF) vaccine candidate with differentiating infected vaccinated animals (DIVA) characteristics, a chimeric CSF virus (CSFV) was constructed based on an infectious cDNA clone of the CSF vaccine C-strain. The 5'- and 3'-untranslated regions (UTRs) and partial E2 region (residues 690-860) of the C-strain were substituted with the corresponding regions of bovine viral diarrhoea virus (BVDV) to construct the chimeric cDNA clone pC/bUTRs-tE2. The chimeric virus rC/bUTRs-tE2 was generated by several passages of pC/bUTRs-tE2-transfected PK15 cells. Stable growth and genetic properties of rC/bUTRs-tE2 were obtained after 30 serial passages. Compared to parental rC/bUTRs-tE2 (1st passage), two residue mutations (M834K and M979K) located in E2 in rC/bUTRs-tE2 P30 were observed. Compared to the C-strain, rC/bUTRs-tE2 exhibited unchanged cell tropism and decreased plaque-forming ability. Substituting the C-strain UTRs with the BVDV UTRs resulted in significantly increased viral replication in PK15 cells. Compared to CSFV Erns-positive and BVDV tE2-negative antibody responses induced by the CSF vaccine C-strain, immunization of rabbits and piglets with rC/bUTRs-tE2 resulted in serological profiles of CSFV Erns- and BVDV tE2-positive antibodies, which are used to serologically discriminate pigs that are clinically infected and vaccinated. Vaccination of piglets with rC/bUTRs-tE2 conferred complete protection against lethal CSFV challenge. Our results suggest that rC/bUTRs-tE2 is a promising new CSF marker vaccine candidate.

• Authors: Weicheng Yi, Hao Wang, Huan Qin, Qin Wang, Rui Guo, Guoyuan Wen, Zishu Pan
• Journal: Vaccine (Vaccine) Vol. 41 Issue 12 Pg. 2003-2012 (03 17 2023) ISSN: 1873-2518 [Electronic] Netherlands
• PMID: 36803898 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2023 Elsevier Ltd. All rights reserved.

Chemical References

• DNA, Complementary
• Viral Vaccines
• Antibodies, Viral
• Viral Envelope Proteins

Topics

• Animals
• Swine
• Rabbits
• Classical Swine Fever (prevention & control)
• DNA, Complementary
• Viral Vaccines (genetics)
• Classical Swine Fever Virus (genetics)
• Vaccination
• Diarrhea Viruses, Bovine Viral
• Antibodies, Viral
• Viral Envelope Proteins (genetics)