Antibodies corresponding to the 18 selected peptides were tested for direct and cell-mediated anti-parasite activity. Clinical experiments have shown that the Antibody-Dependent Cellmediated Inhibition (ADCI) of P. falciparum malaria represents one of the mechanisms controlling parasitemia and thereby clinical manifestations in humans [16] . Twelve peptide-specific antibodies proved able to induce a strong (more than 40%) and intermediate (lower than 40%) monocyte-dependent parasite killing (Table 1) , whereas, in the absence of monocytes, no direct effect of antibodies on parasite growth was observed. The effects were in the range observed with antibodies from African adults who have the highest natural protection known against malaria. Therefore peptidespecific, human affinity-purified antibodies were functionally effective as shown by their ability to react with parasite proteins and to inhibit parasite growth. Thus, in vitro functional assays show that peptide-specific antibodies elicited by natural exposure to the parasite can induce protective mechanisms effective against malaria.