Fig. 1.
Characterization of anti-FVIII antibodies in the plasma of a patient.
Binding of antibodies to metabolically labeled FVIII fragments corresponding to the FVIII heavy chain (HCh), the A2 domain (A2), the FVIII light chain (LCh), and the C2 domain (C2) was evaluated by immunoprecipitation. (A) Reactivity of anti-FVIII antibodies in the patient's plasma. (lane 1, +) Positive control. mAb CLB-CAg 9 for HCh and A2, mAb CLB-CAg 117 for LCh and C2. (lane 2, −) Control plasma. (lane 3, P) Antibodies in the patient's plasma. (B) Subclass typing of anti-FVIII antibodies. (left panel, A2) Anti-A2 domain antibodies. (right panel, LCh) FVIII light-chain–specific antibodies. (lane 1, +) Total IgG. (lanes 2-5)1-4 IgG1, IgG2, IgG3, IgG4. (lane 6, −) Control plasma. In the patient's plasma no anti-FVIII antibodies of the IgM class could be detected (data not shown). Molecular weight markers are indicated at the right of the figures.