Table 1.
Evaluation of antibody detection of ZEBOV Mayinga and Makona variants of sGP or GP, and Marburg GP.
Fig 1.
Evaluation of Ebola sGP Detection Kit: LOD of recombinant sGP, repeatability, cross-reactivity and stability.
(A) Recombinant ZEBOV Makona sGP was diluted in human plasma at the indicated concentration and subjected to Ebola sGP detection kit test. (B) Supernatant of infected Vero cells (3 x 106 FFU/ml) was diluted 10 and 250 times (1.03 x 108 and 2.11 x 106 RNA copies/ml respectively) in human plasma and subjected to sGP Detection Kit. Results are test line delta OD of single measurement (n = 10), mean and coefficient of variation (%) as indicated. (C) Supernatant of Vero cells infected with several different viruses responsible for hemorrhagic fevers were diluted 1/10 in human plasma and subjected to sGP Detection Kit. Results are test line delta OD of single measurement. (D) Kit long term stability was assayed at week 0, 4 and 17 on plasma spiked with 125 ng/ml or 31.3 ng/ml of recombinant ZEBOV Makona sGP protein as indicated. sGP Detection Kit was stored at 4°C (white bars), 20°C (grey bars) or 37°C (black bars). Results are test line delta OD of measurement of duplicate and mean indicated as an horizontal bar for each time points and storage conditions. Only one value is indicated at week 0, as tests were freshly manufactured.
Fig 2.
Evaluation of Ebola sGP Detection Kit LOD with supernatant from cell culture and infected monkey plasma.
(A) Supernatant of Vero cells containing ZEBOV viral particles at 3 x 106 FFU/ml was diluted as indicated in human plasma or blood and subjected to RT-qPCR and Ebola sGP Detection Kit. Results are test line delta OD of single measurement or mean of genome copies/ml from RT-qPCR duplicates performed on dilutions made in plasma. Sample positively detected by sGP Detection Kit are in bold characters. (B) Monkey infected intravenously with 102 FFU of EBOV Gabon 2002 was bled at day 7 post-infection. The plasma containing 2.15 x 1010 genome copies/ml was subsequently diluted in human plasma or blood. Genome copies and sGP Detection Kit test were then performed. Results are test line delta OD (positive Ebola sGP Detection Kit tests are in bold characters) and mean of genome copies/ml from RT-qPCR duplicates performed on dilutions made in plasma. (C) Delta OD and related Log 2 genome copies/ml of samples tested in Fig 2A and 2B diluted human plasma (black) or in human blood (white) were plotted, adjusted R2 values calculated with positive values, are 0.95 and 0.925 for monkey plasma and cell supernatant respectively. Linear regression analysis showed no effect of human matrices on Delta OD measurement (Student p values of 0.797 and 0.37 for monkey plasma and cell supernatant respectively). Culture supernatant diluted in human blood and plasma are shown as white circle and black square respectively. Infected monkey plasma diluted in human blood and plasma are shown as white and black triangle respectively.
Table 2.
Evaluation of Ebola sGP detection kit analytical sensitivity in infected monkey cohort.
Fig 3.
Clinical specificity and sensitivity evaluation.
Plasmas from Healthy European (n = 30) (A) and African (n = 67) (B) donors were subjected to Ebola sGP Detection Kit test. Results are express in delta OD for each donor (white bars), donors mean + S.D. (black bars) and plasma spiked with 125μg/ml of sGP (Ct+ grey bar). (C) Plasmas from EBOV-infected patients were subjected to RT-qPCR and sGP Detection Kit. Results are test line delta OD of single measurement or mean Ct values of qRT-PCR duplicates (performed within the ETC of Macenta). EBOV patients were stratified based on disease outcome (Death: white triangle, Cured: black round) and plotted together with EBOV negatives patients (Negative: black triangle).