Type a botulinum toxin-induced antibody production: a murine model of antibody response.

Background: The use of modified botulinum toxin type A (BCB2024 BTA; Allergan, Irvine, CA) has burgeoned worldwide since 1998. However, the drug's potential to create an immunogenic response has remained unclear. Objective: The authors report on a prospective murine model study to evaluate the potential immunogenic effect of BTA and to determine the effect of dose size and frequency of administration on antibody formation. Methods: Forty female CD-1 mice were divided into four equal groups that received injections of BCB2024 BTA as follows: group A, 0.12 U every two months; group B, 0.12 U once a month; group C, 0.24 U every two months; and group D, 0.24 U once a month. Blood was collected before the first injection and then every month for four months. Immune response was determined by measuring the level of serum immunoglobulin G using enzyme-linked immunosorbent assay. Data were analyzed with a mixed-model, repeated measures analysis of variance. Results: Nascent antibotox antibody (ABA) production in response to BCB2024 BTA administration was observed in all four subgroups. Levels of ABA were significantly higher in the higher-frequency dosage groups than in the lower-frequency groups. ABA levels were slightly lower in the low-dosage groups than in the higher-dosage groups, but the differences were not statistically significant. Conclusions: Our study showed frequency-dependent production of ABA in response to BCB2024 BTA administration in a murine model. The clinical significance of such antibody production remains to be determined. Presently however, no standardized scale of conversion exists to relate murine doses of BTA to those used in human treatment regimens.