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Naturally acquired antibody responses to the components of the Plasmodium falciparum merozoite surface protein 1 complex
Author(s) -
Wang Lina,
Crouch Lucy,
Richie Thomas L.,
Nhan Doan Hanh,
Coppel Ross L.
Publication year - 2003
Publication title -
parasite immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.795
H-Index - 75
eISSN - 1365-3024
pISSN - 0141-9838
DOI - 10.1111/j.1365-3024.2003.00647.x
Subject(s) - merozoite surface protein , antibody , biology , isotype , subclass , plasmodium falciparum , immune system , virology , immunology , immunoglobulin g , parasitemia , recombinant dna , malaria , malaria vaccine , monoclonal antibody , biochemistry , gene
SUMMARY Merozoite surface protein 6 (MSP6) and 7 (MSP7) of Plasmodium falciparum are peripheral membrane proteins whose cleaved products, MSP6 36 , MSP7 22 and MSP7 19 , are found on the merozoite surface as components of a non‐covalently bound complex which also contains four polypeptides derived from merozoite surface protein 1 (MSP1). We have expressed both the precursor regions and the processed mature products of MSP6 and MSP7 in Escherichia coli and showed that these recombinant proteins react with human immune sera. In a set of sera collected from individuals living in malaria‐endemic areas of Southern‐central Vietnam, antibodies to the mature polypeptides of MSP6 36 and MSP7 22 were detected in 50·6 and 85·6% of the serum samples, whereas antibodies to the precursor regions of MSP6 and MSP7 were detected in only 12·1 and 42·5% of the serum samples, respectively. The predominant subclass of anti‐MSP6 antibodies was IgG1, whereas the predominant subclass of anti‐MSP7 antibodies was IgG3. In the same set of serum samples, the antibody responses to MSP1 19 are predominantly IgGI, whereas antibodies to merozoite surface protein 4 (MSP4) are mainly IgG3. This data is consistent with the proposition that, during malaria infection, variable proteins induce responses that are predominantly of the IgG3 isotype, and conserved proteins induce responses that are predominantly IgG1. The antibodies to MSP6, MSP7 and MSP1 19 all decreased at the time of infection, but increased during the convalescent period. No correlation was observed between the antibodies at the commencement of the study and absence of parasitaemia during surveillance in this population.