Development and In Vivo Evaluation of a MGF110-1L Deletion Mutant in African Swine Fever Strain Georgia

Figure 1. (A) Location and orientation of all MGF110 family of genes. The MGF110 genes are depicted in Blue. Other multi-gene family (MGF) genes within this region of the ASFV-G genome are depicted in yellow (B) Expression levels of individual MGF 110 genes at the indicated timepoints, expression is measured in Log10 Signal Intensity.

Figure 2. Multiple sequence alignment of the indicated African swine fever virus (ASFV) isolates of viral protein MGF110-1L. Matching residues are represented as dots. The degree of conservation is below the alignment.

Figure 3. Schematic for the development of ASFV-G-ΔMGF110-1L. The transfer vector contains the p72 promoter and a mCherry cassette; the flanking left and right arms are indicated, and were designed to have flanking ends to both sides of the deletion/insertion cassette. The resulting ASFV-G-ΔMGF110-1L virus with the cassette inserted is shown on the bottom.

Figure 4. In vitro growth kinetics in primary swine macrophage cell cultures for ASFV-G-Δ MGF110-1L and parental ASFV-G, infected (MOI = 0.01) with ASFV-G-Δ MGF110-1L or parental ASFV-G viruses. Samples were taken from three independent experiments at the indicated time points and titrated. Data represent means and standard deviations. Sensitivity using this methodology for detecting virus is >log10 1.8 HAD50/mL. No significant differences in viral yields between viruses were observed at any time point tested determined using the Holm-Sidak method (α = 0.05), without assuming a consistent standard deviation. All calculations were conducted using the software Graphpad Prism version 8.

Figure 5. Evolution of mortality (A) and body temperature (B) in animals (5 animals/group) intramuscularly (IM) infected with 102 HAD50 of either ASFV-G-ΔMGF110-1L (filled symbols) or parental ASFV-G (open symbols). Significant differences (p-value = 0.0201) in the survival course between groups of pigs were found using the test de Long-rank (Mantel-cox test). No statistical differences were found in body temperatures between pigs in both groups, when evaluated by the Holm-Sidak method (α = 0.05). All calculations were conducted using the software Graphpad Prism version 8.

Figure 6. Viremia titers detected in pigs IM inoculated with 102 HAD50 of either ASFV-G-ΔMGF110-1L (filled symbols) or ASFV-G (empty symbols). Each symbol represents the average of animal titers in each of the groups. Sensitivity of virus detection: >log10 1.8 TCID50/mL. Significant differences in viremia values between both groups of pigs were found at day four post-infection using the Holm-Sidak method (α = 0.05) without assuming a consistent standard deviation. All calculations were conducted on the software Graphpad Prism version 8.