Fig 1.
(A) Schematic of plasmids used for rescue of rCHICV. Two plasmids containing the full-length MACV Chicava S and L segments including the 5’ and 3’ untranslated regions (UTR) and intergenic regions (IGR) downstream of a murine Pol-I promoter (mPol-I.p) were transfected alongside two expression plasmids encoding the MACV Carvallo NP and L genes downstream of a chicken β-actin promoter (chicken β-actin.p). The silent A525G single-nucleotide substitution was added in the L segment as a marker for recombinant virus. (B) Multiplication kinetics of rescued MACV Chicava compared to the wild-type isolate in Vero cells at a MOI of 0.01. The mean of three replicates is shown, with error bars displaying standard deviation.
Fig 2.
Wild-type and recombinant MACV produce similar disease in 6–8 week-old Hartley guinea pigs.
(A) Survival rate of guinea pigs (n = 5 per group) challenged with 104 pfu of the indicated MACV strains. (B) Mean body weight change compared to baseline weight. (C) Mean body temperature. The dotted line indicates the clinical definition of fever (39.5°C) for a 6–8-week-old guinea pig. Pink asterisk (*) indicates a broken transponder that prevented the collection of further body temperature readings in one surviving animal (#49).
Fig 3.
Wild-type and recombinant MACV cause inflammation in the liver and brain.
Representative H&E-stained images of (A) liver and (B) brain tissues collected at the time of euthanasia. Images are representative of animals that succumbed to challenge. Black arrows indicate areas of (A) focal hepatic inflammation or (B) perivascular cuffs.
Fig 4.
Guinea pigs infected with recombinant MACV Chicava produce a heterologous neutralizing antibody response.
(A) Individual serum PRNT50 titers against wtMACV Carvallo or (B) rMACV Carvallo GPCΔN83/N166/F438I. Box plots extend from the 25th to 75th percentiles, with the center line indicating the median. Whiskers represent the minimum and maximum values. The dotted line indicates the lower limit of detection (LOD), i.e., 1:30 PRNT50 titer. Samples with no neutralizing activity detected were plotted at 1:15 PRNT50 titer (50% LOD).