Table 2.
Innate stimulatory properties of different development stages of live schistosome larvae and larval released products
| Larval stage/product | Fold increasea in IL-6 production over untreated control by tMφ cultured with larvae (number of parasites per well) |
||
|---|---|---|---|
| 50 | 100 | 200 | |
| Cercariaeb | 1.48 ± 0.67 | 3.39 ± 2.81 | 14.1 ± 8.25 |
| Transformed cercariaeb | 3.71 ± 0.22 | 12.1 ± 3.42 | 14.4 ± 4.99 |
| 0-3 h supernatantc | 0.65 ± 0.49 | 3.58 ± 1.25 | 8.41 ± 2.53 |
| 3-h schistosomulac | 0.65 ± 0.49 | 2.64 ± 2.32 | 10.1 ± 2.56 |
Values are means ± SD of fold increase in IL-6 production by tMφ (2 × 105 per well) cultured for 24 h compared with untreated cells. All cells were cultured in the presence of PMB (3 μg ml-1).
Cercariae obtained from a single shed were left intact or mechanically transformed by vortexing immediately prior to addition to tMφ cultures.
Cercariae were mechanically transformed and cultured in vitro for 3 h. The resulting transformed larval heads and tails were subsequently isolated from the culture supernatant and added to the tMφ cultures. The un-concentrated culture supernatant (0-3 h supernatant) was added to the tMφ cultures in quantities equivalent to that released by the different stated numbers of larvae.