Subcellular fractions for immunizing against pertussis.

Differential centrifugation was used to prepare fractions from broken cells of Bordetella pertussis strain 114. Whole cells and several fractions were then assayed for potency and for safety. Crude ribosomal fractions were uniformly protective. However, ribosomes purified by washing in high salt solution and recentrifugation were at least 40 fold less potent. Protective antigen was found in the wash fluid. Wash fluid was subjected to SDS-polyacrylamide gel electrophoresis. No specific protein or carbohydrate has yet been identified as a protective immunogen. It is clear that ribosomes are not protective, but copurify with protective antigen. SDS-polyacrylamide gel analysis of soluble material purified from ribosomes may be of value in experimental studies on pertussis vaccine. If the protective immunogen can be identified, this procedure may also be of value in vaccine standardization.