Oronasal vaccination with classical swine fever virus (CSFV) replicon particles with either partial or complete deletion of the E2 gene induces partial protection against lethal challenge with highly virulent CSFV.
A cDNA clone of the classical swine fever virus (CSFV) strain Alfort/187 [Ruggli N, Tratschin JD, Mittelholzer C, Hofmann MA. Nucleotide sequence of classical swine fever virus strain Alfort/187 and transcription of infectious RNA from stably cloned full-length cDNA. J Virol 1996;70(6):3478-87] was used to construct two E2 deletion mutants lacking either the complete E2 gene or, alternatively, a stretch of 204 nucleotides encoding 68 amino acids located in the C-terminal region of the E2 glycoprotein. The respective in vitro synthesized mutant RNAs replicated in SK-6 cells but no infectious virus was generated. Both replicons could be packaged into virus particles in SK-6 cells constitutively expressing E2 of CSFV. For the resulting CSF virus replicon particles (CSF-VRP) A187-E2del373 and A187-E2del68 titers of 10(6) and 10(7) TCID(50)/ml, respectively, were obtained. Oronasal vaccination with 10(7) TCID(50) of either of the two CSF-VRP protected pigs against a challenge with a lethal dose of CSFV strain Eystrup. In contrast, after intradermal vaccination VRP A187-E2del68 but not VRP A187-E2del373 lacking the complete E2 gene induced a protective immune response. We conclude that E2-complemented CSF-VRP have the potential to be used as live-attenuated non-transmissible oral vaccines for pigs. In addition, our data suggest that E2 of CSFV is dispensable for the induction of mucosal but not of parenteral immunity.
Maurer
Roland
R
Institute of Virology and Immunoprophylaxis, Mittelhäusern, Switzerland. roland.maurer@ivi.admin.ch
Stettler
Peter
P
Ruggli
Nicolas
N
Hofmann
Martin A
MA
Tratschin
Jon-Duri
JD
D000281:Administration, Intranasal; D000284:Administration, Oral; D000818:Animals; D002478:Cells, Cultured; D006691:Classical Swine Fever / Q000276:immunology* / Q000517:prevention & control*; D006692:Classical Swine Fever Virus / Q000276:immunology*; D017353:Gene Deletion; D007271:Injections, Intradermal; D012367:RNA, Viral / Q000032:analysis / Q000096:biosynthesis; D013552:Swine; D014614:Vaccines, Synthetic / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000276:immunology*
D012367:RNA, Viral; D014614:Vaccines, Synthetic; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C087086:glycoprotein E2, classical swine fever virus