DISRUPTION OF ERYTHROCYTE ROSETTES AND AGGLUTINATION OF ERYTHROCYTES INFECTED WITH PLASMODIUM-FALCIPARUM BY THE SERA OF PAPUA-NEW-GUINEANS

People living in areas endemic for Plasmodium falciparum develop humor al responses which may contribute to protection against clinical disea se but the specificity of such protective antibody responses remains t o be defined. Antibodies disrupting erythrocyte rosettes have been ass ociated with protection against cerebral malaria, and antibodies agglu tinating infected erythrocytes with reduced episodes of clinical disea se. We have studied the capacity of serum from Papua New Guinean adult s and children with a spectrum of malaria exposure, including children and adults at the time of clinical disease, to disrupt erythrocyte ro settes and cause agglutination of infected erythrocytes. Using a singl e parasite isolate, almost all sera from adults from highly endemic ar eas agglutinated infected erythrocytes, and the majority disrupted ros ettes, in some cases at greater titres than hitherto described. There was a correlation between rosette disruption and agglutination in high ly exposed adults. Rosette disrupting antibodies were equally frequent in children with cerebral and uncomplicated malaria. Antibodies causi ng rosette disruption were frequent only in adults with a long history of malarial exposure. Rosette disrupting antibodies do not appear to protect Papua New Guinean children or adults against cerebral malaria.