Epitopes prediction of PfEMP1-DBL2? recombinant protein from Indonesian Plasmodium falciparum Isolate for malaria vaccine development

Abstract

The development of an effective vaccine against malaria is essential. Domain Duffy-binding-like (DBL)2?
in Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) protein is one of the vaccine
candidate proteins because of its binding capacity to ICAM-1 receptor. However, the high polymorphism
needs epitope identification before formulating a peptide-based vaccine. This study aimed to identify the
conserved epitopes in PfEMP1-DBL2? by an immunoinformatic approach. The protein sequences were
analyzed to predict the hydrophobicity attributes, T-cell and B-cell epitopes. T-cell epitopes were identified
using the NetCTL and Propred server and analyzed for population coverage rate using the IEDB analysis
tool. Moreover, the Bepipred 2.0 and Kolaskar Tangaonkar method combined with the K-means clustering
were used to predict the B-cell epitopes. This study found that the hydrophobicity value of PfEMP1-DBL2?
recombinant protein is 32.62, indicating that this protein is soluble and potentially fit into HLA alleles active
site. Two conserved antigenic CTL epitopes with near 90% population coverage rate in the malaria target
population were identified. For Th cell epitopes, the NN-align algorithm showed no overlapping strong
binding epitope positions for three chosen Indonesian and African alleles. Three B-cell conserved epitopes
were identified at the position of 77-89, 236-254 and 360-377 amino acids with one cluster overlapping with
ICAM-1 determinant binding area. The predicted conserved epitopes within the protein in this study are
valuable in constructing a subunit peptide-based malaria vaccine candidate. A further experimental study is
needed to validate this approach as the next step in vaccine development.