The invention relates to a merozoite surface protein 1 ("MSP-1 ") preparation of Plasmodium falciparum , said MSP-1 preparation comprising a) a purified fragment p83/30 of the gp190/MSP-1 from Plasmodium without heterologous sequences, and b) a purified fragment p38/42 of the gp190/MSP-1 from Plasmodium without heterologous sequences.