Protection of Piglets with Maternally Derived Antibodies from Sows Inoculated with an Attenuated Live Marker Classical Swine Fever Vaccine (Flc-LOM-BErns)

Seeun Choe,Bang-Hun Hyun,Byung-Il Jung,Bong-Kyun Park,Ki-Sun Kim,Sok Song,Ra Mi Cha,Jihye Shin,Dong-Jun An

doi:10.3390/pathogens9080608

Abstract

Here, we investigated the protective efficacy provided by passive immunity induced by a classical swine fever (Flc-LOM-BErns) vaccine with the newly developed DIVA (Differentiating Infected from Vaccinated Animals) function. Ten pigs (aged 40–60 days) with maternally derived antibodies (MDAs) obtained from sows inoculated with the Flc-LOM-BErns vaccine were challenged with virulent classical swine fever virus (CSFV). Pigs with an MDA titer of 6 log2 induced by the Flc-LOM-BErns vaccine were fully protected against virulent CSFV challenge but not the pigs with an MDA titer under 5 log2. In addition, Flc-LOM-BErns vaccine-derived MDAs successfully differentiated vaccinated pigs by bovine viral diarrhea virus (BVDV) Erns/CSFV Erns antibody detection, functioning as a DIVA.

Highlights

Classical swine fever virus (CSFV) is a member of the genus Pestivirus [1,2,3].CSFV harbors a single-stranded positive RNA genome comprising approximately 12,300 nucleotides.CSFV is classified into three different genotypes, which in turn comprise three or four sub-genotypes [1,2,3].CSFV is a highly contagious, multi-systemic, hemorrhagic disease that is fatal to swine (Sus scrofa); it infects both breeding pigs and wild boars [1]
Ten pigs that obtained maternally derived antibodies (MDAs) from Flc-LOM-BErns -vaccinated sows were divided into subgroups by their MDA levels: V1 (6 log2 MDA), V2 (5 log2 MDA), V3 (4 log2 MDA), and V4 (3 ≤ log2 MDA)
The MDA levels of all pigs were obtained on the day of challenge and a threshold of 3 ≤ log2 was used to determine positive/negative based on serum neutralization titer

Summary

Introduction

Classical swine fever virus (CSFV) is a member of the genus Pestivirus (family, Flaviviridae) [1,2,3].CSFV harbors a single-stranded positive RNA genome comprising approximately 12,300 nucleotides.CSFV is classified into three different genotypes, which in turn comprise three or four sub-genotypes [1,2,3].CSFV is a highly contagious, multi-systemic, hemorrhagic disease that is fatal to swine (Sus scrofa); it infects both breeding pigs and wild boars [1]. Classical swine fever virus (CSFV) is a member of the genus Pestivirus (family, Flaviviridae) [1,2,3]. CSFV harbors a single-stranded positive RNA genome comprising approximately 12,300 nucleotides. CSFV is classified into three different genotypes, which in turn comprise three or four sub-genotypes [1,2,3]. CSFV is a highly contagious, multi-systemic, hemorrhagic disease that is fatal to swine (Sus scrofa); it infects both breeding pigs and wild boars [1]. The development of DIVA (Differentiating Infected from Vaccinated Animals) vaccines, which make it possible to distinguishing vaccinated animals from infected animals, has drawn great attention [2]. A CSF live marker vaccine (Flc-LOM-BErns )

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