Division of Veterinary Medicine, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicines), Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany.
Division of Veterinary Medicine, Paul-Ehrlich-Institut (Federal Institute for Vaccines and Biomedicines), Paul-Ehrlich-Strasse 51-59, 63225 Langen, Germany.
Vaccine. 2019 Mar 22;37(13):1721-1724. doi: 10.1016/j.vaccine.2019.02.054. Epub 2019 Feb 28.
Tetanus vaccines for human and veterinary use are based on toxoids resulting from a formaldehyde-mediated inactivation of tetanus neurotoxin (TeNT). Due to the high toxicity of TeNT, safety tests are mandatory for each batch of these toxoids. One of the tests addresses the irreversibility of inactivation: The toxoid is stored at 37 °C for 6 weeks and then subjected to in vivo toxicity testing. However, we found that TeNT solutions rapidly lose their activity at 37 °C. Accordingly, any active TeNT molecules arising in the toxoid due to reversion events may no longer be detectable after the 37 °C storage period. Furthermore, there is no evidence that a "reversion to toxicity" has ever been observed for tetanus toxoids during vaccine production. Thus, we conclude that the irreversibility test that is prescribed for human and veterinary vaccines has no relevance for vaccine safety.
人用和兽用破伤风疫苗基于通过甲醛介导的破伤风神经毒素（TeNT）失活而产生的类毒素。由于 TeNT 的高毒性，必须对这些类毒素的每一批进行安全性测试。其中一项测试涉及失活的不可逆性：将类毒素在 37°C 下储存 6 周，然后进行体内毒性测试。然而，我们发现 TeNT 溶液在 37°C 下迅速失去活性。因此，由于回复事件而在类毒素中产生的任何活性 TeNT 分子在 37°C 储存期后可能不再可检测到。此外，没有证据表明在疫苗生产过程中破伤风类毒素曾经观察到“毒性回复”。因此，我们得出结论，规定用于人和兽医疫苗的不可逆性测试与疫苗安全性无关。
