Immunoprecipitation of biosynthetically-labelled products in the identification of antigens of murine red cells infected with the protozoan parasite, Plasmodium berghei.

In this methodological paper an immunoprecipitation technique has been optimised for the identification of antigens of Plasmodium berghei-infected blood which react with antibody specificities in a host-protective antiserum. Extracted 3H-leucine biosynthetically-labelled products of infected blood were sequentially reacted and precipitated with sera from mice which had been exposed to P. berghei but which were either non-protected or protected against lethal infection, protection having been shown to be transferable to naive recipients with the appropriate serum. As analysed by polyacrylamide gel electrophoresis under reducing conditions, a small number of molecular species was detected in immunoprecipitates using host-protective sera which were apparently not quantitatively precipitated out of the complex mixture of labelled products of infected blood using sera from non-protected mice.