Plasmodium falciparum merozoite surface protein 1 (MSP1) variants could not be linked with clinical malaria in some Ghanaian children

Abstract

To determine whether clinical malaria was associated with the acquisition of the novel Merozoite surface Protein 1 (MSP1) Plasmodium falciparum allelic types, a longitudinal immunoepidemiological study was conducted on school children of 3-15 years, living in a stable malaria endemic area with seasonal transmission in Ghana. DNA extracted from selected blood samples previously spotted on filter papers before, during and after asymptomatic and clinical malaria episodes was typed using the Polymerase Chain Reaction (PCR) technique based on the amplification
of the polymorphic region of the merozoite surface protein 1 (MSP1) of the Plasmodium falciparum gene. Electrophoresis revealed 35 different MSP1 allelic forms that could not be linked to a specific malaria transmission season. Clinical malaria could not be attributed to any specific allelic type, and the acquisition of new alleles was not necessarily associated with clinical malaria. Malaria episode was, however, synchronized with significant (P<0.05) increase in parasitaemia. About half (51.85%) of 27 selected children with malaria attacks had antibodies against the C-terminal of the 19 kDa fragment of PfMSP1 in their plasma. After a malaria attack, 23.07% showed negative to positive sero-conversion whereas 14.28% showed positive to negative sero-conversion.