PROCESSING OF THE PLASMODIUM-CHABAUDI CHABAUDI AS MEROZOITE SURFACE PROTEIN-1 IN-VIVO AND IN-VITRO

Processing of the Plasmodium merozoite surface protein 1 (MSP-1) has b een described for parasites maintained under in vitro conditions. We h ave now demonstrated, using CBA/Ca mice infected with Plasmodium chaba udi chabaudi AS, that MSP-1 processing also occurs in vivo. The major proteolytic cleavage sites and a processing scheme were deduced from N -terminal amino-acid sequences of the MSP-1 breakdown products. Compar ison of MSP-1 processing in P. falciparum and P.c. chabaudi indicates a degree of conservation and in two cases the position of protease cle avage appears identical. Significant amounts of MSP-1 polypeptides are found in plasma during schizogony. Various aspects of MSP-1 processin g including immunological and physiological reactions in the host duri ng the critical period of schizogony can now be examined in vivo.