An antibody binds only to the antigen that stimulated its production because
- A. all antibody molecules are identical
- B. antigens destroy competing antibodies
- C. the blood filters out mismatched antibodies
- D. the shape of its binding site matches a specific epitope of that antigen
Explanation
Antibody arms carry binding sites shaped for one epitope, like a lock for one key, which is why each clone makes only one specificity. Uniform antibodies would make targeted immunity impossible.