Phosphorylcholine determinants in six pneumococcal capsular polysaccharides detected by monoclonal antibody

The presence of phosphorylcholine in pneumococcal capsular polysaccharides was examined by using monoclonal antiphosphorylcholine antibody. Of the 83 known capsular types of Streptococcus pneumoniae, 6 types, viz., 24A, 27, 28F, 28A, 32F, and 32A, gave a positive capsular reaction (quellung) which could be inhibited by phosphorylcholine. The capsular polysaccharides of these six types, therefore, contain phosphorylcholine.