Antigenicity of recombinant proteins derived from Plasmodium falciparum merozoite surface protein 1.
We have expressed seven recombinant antigens representing two N-terminal regions of the polymorphic merozoite surface protein 1 (MSP-1) of Plasmodium falciparum. The antigens include the MAD20 and Palo Alto forms of the relatively conserved Block 1 region, and variants of the Block 2 region from isolates 3D7, Palo Alto FUP, MAD20, Wellcome and RO33, that are representative of a range or amino acid sequence diversity in this most polymorphic section of MSP-1. All recombinant antigens have been able to immunise mice to produce polyclonal antibodies which specifically recognise parasite MSP-1 in indirect immunofluorescence assays and in Western blots. The recombinant antigens also react appropriately in ELISA with murine monoclonal antibodies specific for variant epitopes in Block 2 of MSP-1. These results show that the antigenic structure of the recombinant proteins is similar to that of the native MSP-1 product from parasites. Importantly, human sera from malaria-exposed individuals contain IgG antibodies that recognise very specifically one or another of the Block 2 types, showing that different Block 2 types are immunogenic, antigenically distinct and distinguishable when presented during natural infections. In contrast, the conserved Block 1 is rarely recognised by human antibodies.
Cavanagh
D R
DR
Institute of Cell, Animal and Population Biology, University of Edinburgh, UK. david.cavanagh@ed.ac.uk
McBride
J S
JS
D000483:Alleles; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000378:metabolism; D000953:Antigens, Protozoan / Q000276:immunology* / Q000378:metabolism; D001029:Aotus trivirgatus; D006801:Humans; D007106:Immune Sera / Q000235:genetics / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D020066:Merozoite Surface Protein 1; D051379:Mice; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics* / Q000254:growth & development / Q000276:immunology*; D011485:Protein Binding; D011498:Protein Precursors / Q000235:genetics* / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics* / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D012453:Saimiri
D000911:Antibodies, Monoclonal; D000953:Antigens, Protozoan; D007106:Immune Sera; D007074:Immunoglobulin G; D020066:Merozoite Surface Protein 1; D011498:Protein Precursors; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins