Name: Staalsø, Trine Home country: Denmark Research country: Sudan Project period: 1998-2001 Title Antibodies to variant surface antigens of Plasmodium falciparum and protection from malaria in an area of low and seasonal transmission Abstract For more than ten years research on malaria immunology and  epidemiology has been carried out in Daraweesh village in Eastern Sudan, where malaria transmission is low, seasonal and unstable. Some of the results of this work suggest that the inhabitants of this village are capable of controlling the parasites in their chronic asymptomatic infections while still being vulnerable to newly introduced parasites. Therefore it seems that during these long chronic asymptomatic infections the parasites are controlled by variant specific mechanisms. A recent study from Kilifi, Kenya has demonstrated that antibodies to parasite antigens on infected erythrocytes protects children from clinical falciparum malaria in a variant specific manner. The most well characterised parasite antigen on infected erythrocytes is the PfEMP1 antigen family which is both clonaly variant, with up to 50 different genes per parasite genome, and polymorphic. In the present longitudinal study we aim at describing the antibody responses to such variant parasite antigens in individuals who are not infected by new parasites. A cohord has been followed by monthly blood sampling throughout an entire dry season. The levels of antibodies to surface antigens on infected erythrocytes of different antigenic types in these samples is measured. By combining these results with PCR based parasite detection and genotyping data from the same set of samples valuable information on the dynamics between the parasite and the immune system of the host can be generated. Involved research institutions Centre for Medical Parasitology (CMP), University of Copenhagen Supervisor(s) Thor Theander and Lars Hviid (CMP) Correspondence