抄録
There have been opinions that mouse is less suitable for the assay of tetanus toxoid. The author has tried to reinvestigate the mouse-assay-method by selecting the mouse strain and improving the experimental conditions. Among various mouse strains used, gpc proved to be most suitable for assay. The immunizability of dd strain varied greatly depending on the season of the year. The immunizability of dd was almost similar as that of gpc in summer, while the former was significantly inferior to the latter in winter. The extent of the variation in dd strain was larger than the standard error of ID50in each experiment, while that of gpc remained in the scope of experimental error calculated from each experiment during the whole experimental period of 46 months. Such variations in immunizability sometime inf iuenced greatly the relative potency of two tetanus toxoid, -i. e. the value measured by two mouse strains showed a significant difference in winter time.
The reason of such variation could not be ascribed to the low room temperature in winter. Some of the possible reasons were discussed.
In conclusion, dd was inadequate in the potency test of tetanus toxoid and it was possible to get the reliable and reproducible results of assay by using gpc strain.
