Protection of piglets with maternally derived antibodies from sows inoculated with an attenuated live marker classical swine fever vaccine (Flc-LOM-BE^rns)

Abstract

Here, we investigated the protective efficacy provided by passive immunity induced by a classical swine fever (Flc-LOM-BE^rns) 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-BE^rns vaccine were challenged with virulent classical swine fever virus (CSFV). Pigs with an MDA titer of 6 log2 induced by the Flc-LOM-BE^rns vaccine were fully protected against virulent CSFV challenge but not the pigs with an MDA titer under 5 log2. In addition, Flc-LOM-BE^rns vaccine-derived MDAs successfully differentiated vaccinated pigs by bovine viral diarrhea virus (BVDV) E^rns/CSFV E^rns antibody detection, functioning as a DIVA.