ANTIBODIES TO SEQUENCES IN A NON-REPEAT REGION OF PLASMODIUM-FALCIPARUM ANTIGEN PF155 RESA INHIBIT EITHER CYTOADHERENCE OR PARASITE GROWTH IN-VITRO/

Antibodies to a non-repeat region of the Plasmodium falciparum antigen Pf155/RESA were investigated for their capacity to inhibit parasite c ytoadherence to melanoma cells and parasite growth in vitro. The activ ities of these antibodies were studied since the target region in Pf15 5/RESA includes a cytoadherence-related motif also found in loop 3 and 7 of human erythrocyte band 3 protein. Overlapping multiple antigen p eptides (MAPs) together spanning residues 199-220 of Pf155/RESA were u sed to raise antibodies in rabbits. Analysis of the fine specificity o f these antibodies revealed that antibodies raised against largely ove rlapping sequences displayed highly different specificity patterns. Si milarly, striking differences were seen when analysing the biological effect of antibodies to these MAPs. Antibodies to the cytoadherence-re lated motif of Pf155/RESA, as well as antibodies raised against a MAP based on a corresponding band 3 motif, inhibited cytoadherence but not parasite growth. In contrast, antibodies to sequences adjacent to the Pf155/RESA cytoadherence motif inhibited parasite growth in vitro but had no effect on cytoadherence.