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Allele‐specific antibodies to Plasmodium falciparum merozoite surface protein‐2 and protection against clinical malaria
Author(s) -
OSIER F. H. A.,
MURUNGI L. M.,
FEGAN G.,
TUJU J.,
TETTEH K. K.,
BULL P. C.,
CONWAY D. J.,
MARSH K.
Publication year - 2010
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.1365-3024.2009.01178.x
Subject(s) - biology , malaria , plasmodium falciparum , immunology , antigen , antibody , allele , merozoite surface protein , genotype , epitope , virology , immunoglobulin g , malaria vaccine , genetics , gene
Summary IgG and IgG3 antibodies to merozoite surface protein‐2 (MSP‐2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies. We determined whether this protection was allele‐specific by testing whether children who developed clinical malaria lacked IgG/IgG3 antibodies specific to the dominant msp2 parasite genotypes detected during clinical episodes. We analysed pre‐existing IgG and IgG1/IgG3 antibodies to antigens representing the major dimorphic types of MSP‐2 by ELISA. We used quantitative real‐time PCR to determine the dominant msp2 alleles in parasites detected in clinical episodes. Over half (55%, 80/146) of infections contained both allelic types. Single or dominant IC1‐ and FC27‐like alleles were detected in 46% and 42% of infections respectively, and both types were equally dominant in 12%. High levels of IgG/IgG3 antibodies to the FC27‐like antigen were not significantly associated with a lower likelihood of clinical episodes caused by parasites bearing FC27‐like compared to IC1‐like alleles, and vice versa for IgG/IgG3 antibodies to the IC1‐like antigen. These findings were supported by competition ELISAs which demonstrated the presence of IgG antibodies to allele‐specific epitopes within both antigens. Thus, even for this well‐studied antigen, the importance of an allele‐specific component of naturally acquired protective immunity to malaria remains to be confirmed.