Pertussis antigens--screening models on toxicity.

From the same batch of B. pertussis bacteria two types of DPT-vaccines were produced after harvest of the inactivated organisms by centrifugation or acid precipitation. The first vaccine contained whole pertussis bacteria and the second an extracted antigen complex. In a screening programme with reliable animal tests, such as a modified mouse-weight-gain assay, mouse leukocytosis test, histamine sensitization in mice, allergic encephalitis in rats, and the limulus test it could be demonstrated that the vaccine with whole inactivated bacteria was more toxic than that with extracted antigens. Cell material harvested by centrifugation showed a lower rate of toxicity than that containing acid-precipitated pertussis organisms.