[Preparation of a standardized antigenic extract from several strains of African trypansomes]

The preparation of a soluble antigen from african trypanosomes is described below. It is important to observe the following steps: --minimal dose of the phytohemagglutinin must be placed in rapid contact with the trypanosomes; --the standard speed of the different centrifugations must be strictly observed; --a thorough washing of the trypanosomes must be carried out to eliminate the hetero-antigens, but caution should be excercised, as over washing is harmful to the Trypanosomes.