Table I.
Binding of FN, 70-kD FN Fragment, L8, and C6F10 mAbs to Unstretched and Stretched FN
| Specific binding | Nonspecific binding | Ratio stretched/ unstretched | p value | |||||
|---|---|---|---|---|---|---|---|---|
| cpm | cpm | t test | ||||||
| FN, unstretched | 498 (± 103) | 6,947 (± 499) | ||||||
| FN, stretched | 3,688 (± 735) | 6,948 (± 298) | 7.4 | 0.01 | ||||
| 70 kD, unstretched | 1,447 (± 283) | 4,469 (± 589) | ||||||
| 70 kD, stretched | 4,099 (± 588) | 5,464 (± 334) | 2.8 | 0.005 | ||||
| L8, unstretched | 2,052 (± 839) | 7,327 (± 92) | ||||||
| L8, stretched | 15,497 (± 897) | 10,905 (± 508) | 7.6 | 0.0004 | ||||
| C6F10, unstretched | 23,941 (± 2,255) | 3,239 (± 72) | ||||||
| C6F10, stretched | 27,382 (± 2,457) | 5,049 (± 241) | 1.1 | 0.36 |
Values for binding of 125I-labeled ligands and antibodies to unstretched and stretched FN are shown. Specific binding is the binding obtained after subtraction of the nonspecific binding. Nonspecific binding was the value obtained in the presence of 1 mg/ ml of unlabeled ligand (FN or 70-kD FN fragment) or 0.5 mg/ml of unlabeled antibody. For FN and 70-kD FN fragment, the means of six measurements are shown; for the antibodies, the means of triplicate measurements are shown. The standard errors of the means are indicated in parentheses. The ratio of counts bound to the stretched versus the unstretched FN (i.e., the fold increase in binding in response to stretching) is shown.