The World Health Organization (WHO) Requirements for the whole-cell pertussis vaccine describe the potency test in a very general manner because it varies from one laboratory to another; one of the reasons for that variation could be the mouse strain used, therefore every laboratory shall evaluate the best conditions for its performance. To be considered valid, the effective dose 50% (ED50) value shall be between the largest and the smallest immunizing doses and the regression do not show significant deviations from linearity. The optimal dose range is experimentally determined in each laboratory. For the establishment of this assay in our laboratory the OF-1 mouse strain was used. Different immunizing doses were inoculated to get a surviving response which had to fulfil a linear regression analysis for be considered appropriate. Ten assays were performed following the same methodology. Six resulted valid. The logarithmic transformation of the doses used and their survival percent showed a good linear regression (R> 0.99) in the range of immunizing doses containing 2; 0.4 and 0.08 International Units (IU). Eight lots of Diphtheria-Tetanus- Pertussis (DTP) vaccine were also evaluated to prove that the potency test worked well. All the assays were valid according to WHO requirements. The methodology described in the present paper was considered appropriate to evaluate in our laboratory the potency of the whole-cell pertussis component in DTP vaccines.
|Translated title of the contribution
|Methodology for the establishment of the potency test of the whole-cell pertussis vaccine
|Number of pages
|Published - 1998