Table 1.
Comparison of antibody detection in 32 horse serum samples by CFT, indirect ELISA (iELISA) based on semi-purified B. mallei, and iELISA and Western blot based on glycosylated CtxB-BCAL2737a
| Sample | Origin | CFTa | iELISAb- semi-purified B. mallei (S/P%) |
iELISAc CtxB-BCAL2737a |
Western blot CtxB-BCAL2737a |
|---|---|---|---|---|---|
| 18–117/302 | France | - | - (3%) | - | - |
| 18–1575/2905 | France | ± (1) | - (4%) | - | - |
| 13–3290/7936 | Ireland | - | - (3%) | - | - |
| 13–3290/7937 | Ireland | - | - (1%) | - | - |
| 13–3290/7938 | Ireland | - | - (0%) | - | - |
| 13–3290/7939 | Ireland | - | - (12%) | - | - |
| 13–3290/7940 | Ireland | - | - (1%) | - | - |
| 18–103/214 | Tunisia | - | - (7%) | - | - |
| 18–103/215 | Tunisia | - | - (3%) | - | - |
| 18–103/216 | Tunisia | - | - (4%) | - | - |
| 18–103/218 | Tunisia | - | - (7%) | - | - |
| 14–566_1831 | South America | + (421) | + (149%) | + | + |
| 14–566_1850 | South America | + (44,431) | + (128%) | + | + |
| 14–566_1861 | South America | + (42) | + (180%) | + | + |
| 14–566_1899 | South America | + (4) | + (134%) | + | + |
| 14–566_1917 | South America | + (432) | + (173%) | + | + |
| 16–2439_81 | South America | + (44,442) | + (63%) | + | + |
| 16–2439_85 | South America | + (4442) | + (146%) | + | + |
| 19–5577_3 | Middle East | + (444,443) | + (73%) | + | - |
| 19–5577_4 | Middle East | + (4442) | + (107%) | + | + |
| 19–5577_6 | Middle East | + (444,441) | + (119%) | + | + |
| 19–5577_37 | Middle East | + (4441) | + (96%) | + | + |
| 19–5577_38 | Middle East | + (333) | + (47%) | + | - |
| 19–5577_39 | Middle East | ± (1) | - (29%) | - | - |
| Horse_1 (Océane) | D08/02 immunization triald | - | - | - | - |
| Horse_2 (Poupée) | D08/02 immunization triald | - | - | - | - |
| Horse_3 (Princese) | D08/02 immunization triald | - | - | - | - |
| Horse_4 (Quirina) | D08/02 immunization triald | - | - | - | - |
| Horse_1 (Océane) | D19/04 immunization triald | + (32) | + (47%) | - | - |
| Horse_2 (Poupée) | D19/04 immunization triald | + (444) | + (60%) | - | + |
| Horse_3 (Princese) | D26/04 immunization triald | + (443) | + (119%) | - | + |
| MRI#1 | Lyophilized serum from a naturally infected horse | - | + (111%) | - | - |
aNumbers in parenthesis indicate the magnitude of the CFT reported from the combination of two parameters: the last dilution giving a positive result combined with the intensity of hemolysis inhibition indicated as 0 = 0%, 1 = 25%, 2 = 50%, 3 = 75%, and 4 = 100%. Typically, sera were tested at dilutions 1/5, 1/10, 1/20, 1/40 and 1/80 and in some strong positives at 1/160.
bNumbers in parenthesis result from the following formula: (OD_Sample-OD_Negative control)/(OD_Positive control-OD_Negative control) × 100. Values above 40% are considered positive.
cBased on the cutoff OD value indicated in Figure 4.
dThese sera are from an immunization trial with a heat-inactivated B. mallei suspension performed in three horses; D, day/month) of sampling. 08/02: day 0; 19/04 and 26/04, days 63 and 70 post-immunization.