Abstract
Unadsorbed, regular production pertussis vaccine was treated with polymyxin B sulphate at concentrations of 25,50 and 100 μg/ml. The toxic activity of treated and untreated vaccines was compared using both the limulus amoebocyte lysate test and the mouse-weight-gain test. Protective efficacy was also assessed by the mouse protection test. No discernible effect on either toxicity or efficacy of the pertussis vaccine was observed. When the vaccine was treated with 5000 μg/ml of polymyxin, endotoxic activity assessed by the limulus lysate test appeared to be abolished.