A procedure for the harvesting of mammalian plasmodia.

Immunochemical research into the antigenic structure of a given disease agent presupposes the availability of undegraded antigen. Some types of immunochemical studies of plasmodia can be carried out with the intracellular parasites in situ in the host cell (for example, studies using the fluorescent antibody technique). In other techniques (such as double diffusion in gel, disc electrophoresis) the presence of host cell contaminants is undesirable, and these require to be reduced to a minimum.A method is described for harvesting mammalian (rodent, simian, and human) plasmodia. Plasmodia in the product are significantly concentrated as compared with the original samples. This point is particularly important in harvesting human plasmodia, in which parasitaemias tend to be very low. Significant reduction of red- and white-cell contaminants is achieved. Antigens in the cell-free plasmodial products obtained are apparently in their native state, and give replicable results in studies of double diffusion in gel, immunoelectrophoresis and disc electrophoresis, passive haemagglutination and vaccination.