Mouse diaphragm assay for detection of antibodies against botulinum toxin type B

Mov Disord. 2005 Dec;20(12):1617-9. doi: 10.1002/mds.20625.

Abstract

With the advent of a commercial preparation of botulinum toxin type B (BT-B) for treatment of cervical dystonia detection of antibodies against BT-B (BT-B-AB) becomes necessary. For this purpose, we carried out a mouse diaphragm assay (MDA) by continuous measurement of the twitch force of a mouse hemidiaphragm preparation elicited by electric stimulation of its phrenic nerve. After exposing the preparation to BT-B 3 ng/ml the time to half-maximal twitch force reduction (paralysis time [PT]) was 69 +/- 4 min (n = 25). Addition of sera from patients with antibodies against BT-A produced a PT of 68 +/- 5 min (n = 24), whereas addition of sera from controls with antibodies against tetanus toxoid produced a PT of 67 +/- 6 min (n = 30). When defined amounts of BT-B-AB were added to the MDA, PT was prolonged. This prolongation was correlated closely to the amount of BT-B-AB added, thus producing a calibration curve. The threshold for BT-B-AB detection was 0.4 mU/ml. When sera from 7 patients (4 women, 3 men; age 50.6 +/- 14.2 years) with cervical dystonia (Toronto Western Spasmodic Torticollis Rating Scale score, 18.9 +/- 2.9) and complete secondary failure of BT-B therapy (NeuroBloc; Elan Pharmaceuticals, Shannon, Ireland; 12,229 +/- 2,601 MU/injection series, 1.86 +/- 0.69 injection series before complete secondary therapy failure; 100.4 +/- 15.8 days between injection series with normal therapeutic effect) were tested, BT-B-AB titers of more than 10 mU/ml were found in all of them. The MDA can be used to measure neutralizing BT-B-AB titers quantitatively and with adequate sensitivity and specificity. Further studies are necessary to understand the role of intermediate BT-B-AB titers in partial BT-B therapy failure.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Anti-Dyskinesia Agents / immunology*
  • Anti-Dyskinesia Agents / therapeutic use
  • Antibodies / analysis*
  • Biological Assay / methods
  • Botulinum Toxins / immunology*
  • Botulinum Toxins / therapeutic use
  • Botulinum Toxins, Type A
  • Diaphragm / drug effects
  • Diaphragm / immunology*
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Female
  • Humans
  • Male
  • Mice
  • Middle Aged
  • Time Factors
  • Torticollis / blood
  • Torticollis / drug therapy
  • Torticollis / immunology*
  • Treatment Failure

Substances

  • Anti-Dyskinesia Agents
  • Antibodies
  • rimabotulinumtoxinB
  • Botulinum Toxins
  • Botulinum Toxins, Type A