The preparation of malaria haemagglutination antigen.

Methods of preparing malaria antigen were compared. In one experiment a Ficoll density gradient was used to obtain a purified suspension of Plasmodium knowlesi schizonts from which antigen was prepared. Evaluation of methods such as freeze-thawing and the use of the French press following saponin lysis of schizonts demonstrated that a single freeze-thaw was the best method for obtaining the most antigen. A second experiment was done comparing the antigen prepared from schizont infected erythrocytes separated on a Ficoll density gradient with antigen prepared without separation of schizont infected erythrocytes on a Ficoll gradient. Saponin treatment of erythrocytes without the use of a Ficoll gradient followed by either freeze-thawing or the French press appeared to be the method of choice in preparing malaria IHA antigen.