Consumption of complement components following exposure of human sera to isolated human heart mitochondria was studied under a variety of experimental conditions. The mitochondria dependent consumption of the first 4 components occurred in the absence ofdetectable antibody to heart mitochondria. Incubation of mitochondria (4 mg protein) with 0.5 ml fresh human serum for 30 min at 37°C led to significant reductions of C1 (61%), C4 (90%), C2 (20%) and C3 (31%) but not of C6 through C9. The consumption was calcium dependent and was inhibited by either 0.01 M EDTA or EGTA, indicating that C3 consumption did not occur by the alternate pathway. Specific absorption of C1q from human serum inhibited the mitochondria dependent consumption of C4 but not of C3. Direct evidence for binding of C1 to mitochondria was obtained by C1 fixation and transfer. Mitochondria C1 complexes incubated with C1 depleted serum or with isolated C4 led to C4 consumption. These data indicate that human C1 can combine directly with human heart mitochondria and result in consumption of C4 and C2, and suggest an explanation for the precipitous drops in C1 through C4 seen in patients following acute myocardial infarction.
|Original language||English (US)|
|Number of pages||1|
|State||Published - Jan 1 1975|
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