6746 SERA peptide analogues immunogenicity and protective efficacy against malaria is associated with short alpha helix formation: malaria protection associated with peptides alpha helix shortening

Erythrocyte high activity binding peptides (HABPs) have been identified for the Plasmodium falciparum serine repeat antigen (SERA). HABP 6746, located in this protein's 50 kDa fragment had its critical binding residues replaced by amino acids having similar mass but different charge to change their immunologic properties. This peptide analogues were used to immunize Aotus monkeys that were challenged later on with a virulent P. falciparum strain to determine their protective efficacy. A shortening in alpha helix structure was found in the immunogenic and protective ones when their secondary structure was analyzed by NMR, to correlate their structure with their immunologic properties. These data, together with results from previous studies, suggest that this shortening in HABP helical configuration may lead to better fitting with immune system molecules, rendering them immunogenic and protective and therefore making them excellent candidates for consideration as components of a subunit based multicomponent synthetic vaccine against malaria.