ASSESSMENT OF THE ROLE OF THE HUMORAL RESPONSE TO PLASMODIUM-FALCIPARUM MSP2 COMPARED TO RESA AND SPF66 IN PROTECTING PAPUA-NEW-GUINEAN CHILDREN FROM CLINICAL MALARIA

The prevalence and concentration of naturally acquired humoral respons e (IgG) to merozoite surface protein 2 (MSP2), RESA, SPf66 and crude s chizont extract were measured in a population living in a malaria high ly endemic area of Papua New Guinea. A prospective longitudinal study in 0.5-15 year old children was conducted for one year in order to exa mine the relationship between the humoral response to these antigens a nd subsequent susceptibility to clinical malaria using a series of cli nical definitions. The prevalence and concentration of antibodies to a ll antigens increased with age. Such correlation with age was most mar ked for MSP2 recombinant proteins. When age and previous exposure were controlled for, only antibody levels to MSP2 recombinant proteins (3D 7 and d3D7) and to RESA predicted a reduction in incidence rate of epi sodes of clinical malaria. Our results support the inclusion of the re combinant proteins of the 3D7 allelic family of merozoite surface anti gen 2 and RESA into a subunit vaccine against malaria.