Abstract: The present invention provides polypeptides having an amino acid sequence derived from the 190 kD precursor to the major merozoite surface antigens of the K1 isolate of Plasmodium falciparum. These polypeptides are capable of eliciting an immune response against different isolates of Plasmodium falciparum. The invention further provides immunogenic compositions and vaccines containing such polypeptides, antibodies raised against the polypeptides. a DNA sequence coding for one of the polypeptides, a replicable microbial vector containing such a DNA sequence and a microorganism transformed with such a vector. The invention also provides processes for the production of the polypeptides, immunogenic compositions, microorganisms and antibodies of the invention and for the use of the polypeptides and immunogenic compositions for the immunization of mammals against malaria.