Safety and Immunogenicity of Chimeric Pestivirus KD26_E2LOM in Piglets and Calves

Figures

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  Figure 1. Schematic representation showing construction of the KD26_E2LOM infectious clone based on the BVDV1 KD26 genome. (A) Strategy for construction of a full-length BVDV1 KD26 cDNA clone (pACKD plasmid). Eight cDNA fragments encompassing the complete KD26 genome were amplified and assembled into the pACYC177 low-copy plasmid vector using restriction enzymes and DNA ligase. The T7 promoter and a SrfI site were added to the 5′-UTR and 3′-UTR of KD26 genome, respectively (underlined). (B) Strategy used to construct an infectious cDNA clone of KD26_E2LOM containing the LOM-E2-encoding region (pACKD26_E2LOM). The LOM-E2 cDNA fragment was modified by insertion of restriction enzyme sites (BsmI and Bsu36I) at either end to allow replacement of the KD26 genome. (C) Generation of pACKD26_E2LOM cDNA construct.

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  Figure 2. KD26_E2LOM virus was rescued after transfection of pACKD26_E2LOM. Indirect immunofluorescence analysis (IFA) using a CSFV E2-specific mAb was conducted at 24 h (A), 36 h (B), and 48 h (C) post-inoculation of KD26_E2LOM into PK-15 cells. IFA was also conducted using a CSFV E2-specific mAb (D), a BVDV Erns-specific mAb, and (E) a BVDV E2-specific mAb (F) after inoculation of KD26_E2LOM into PK-15 cells.

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  Figure 3. Proliferation of the KD26_E2LOM strain, the KD26 strain, and the CSFV LOM strain in cells. Titration of the KD26_E2LOM virus in PK-15 cells (A). Proliferation of the KD26_E2LOM strain, the KD26 strain, and the CSFV LOM strain in PK-15 (B) and MDBK (C) cells.

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  Figure 4. Antibody titers in growing pigs and pregnant sows inoculated with KD26_E2LOM. Serum-neutralizing anti-CSF-antibodies (A), the ELISA S/P ratio for CSFV E2-antibodies (B), and the ELISA for BVDV E2-antibodies (C) in growing pigs, and the ELISA S/P ratio for anti-CSFV E2 antibodies in pregnant sows (D). The KD26_E2LOM, sentinel, and control (mock) groups are marked by red circles, blue squares, and black triangles, respectively. Data are presented as mean ± standard deviation (SD).