A replacement approach to rodent model for the toxicity evaluation of gram-positive autogenous vaccine

The Abnormal Toxicity Test (ATT) is an in vivo assay traditionally used in the autogenous vaccine release. That test, commonly applied to verify vaccine quality, is subject to ethical and practical limitations and should be removed as reference methods. This approach is necessary to update the regulatory framework and to apply the 3Rs principle in the pharmaceutical field. In this study, two in vitro cell viability assays were used to evaluate the potential toxicity of autogenous vaccines. Cells were treated with base-2 dilutions of autogenous vaccines, and viability was detected by MTT and ATP assays. Differences and similarities between these tests were analysed. The ATP test showed good cell viability at 1:32 or 1:64 vaccine dilutions. The MTT assay gave discordant results and vaccines were not cytotoxic from the first dilutions. For this reason, a preference has been highlighted for the ATP method, a more sensitive test, capable of providing more accurate results.