Table 3.
Injection of live but not killed parasites results in loss of electrical and mechanical activity in transplanted hearts
| Group | D.P.I. | Treatment | ECG | Heart failure |
|---|---|---|---|---|
| 1 | Not infected | PBS | ND | 0/4 |
| 2 | Not infected | Live T. cruzi | ND | 8/8 |
| 3 | 315–338 | PBS | ND | 0/4* |
| 4 | 315–338 | Live T. cruzi | ND | 6/6 |
| 5 | 131 | Live T. cruzi | 0/4 positive | 4/4 |
| 6 | 530 | Live T. cruzi | 0/8 positive | 8/8 |
| 7 | 265 | Live T. cruzi | 0/3 positive | 3/3 |
| 8 | 265 | Dead T. cruzi | 2/3 positive | 1/3 |
Transplanted hearts were allowed to establish in mice for 14–21 days and were then injected with 10 μl of PBS or 1 million live trypomastigotes of T. cruzi or the same number of heat-killed (100°C, 5 min) trypomastigotes in 10 μl of PBS. Hearts were observed for ECG activity prior to injection and at 14–21 days postinjection (DPI). Heart failure was determined by visual examination of beating on days 6 and 12 postinjection. ND, not determined. *The heart in one mouse in group 3 stopped beating immediately after injection of PBS but showed no signs of inflammation.