In silico design and validation of a Plasmodium falciparum multi-epitope diagnostic antigen (PfMEDA1) for the diagnosis of falciparum Malaria

Background: Despite efforts invested by both national and international organizations to curb the debilitating effects of malaria, incidences are still on the rise. Rapid diagnosis, prompt and effective treatments are key strategies aimed at reducing morbidity and mortality associated with this ancient scourge. Demerits of common antigens used in rapid diagnosis necessitate the search for alternative antigens with improved diagnostic characteristics. This study is therefore aimed at designing and validating a specific and sensitive multi-epitope antigen to detect P. falciparum malaria Methods The amino acid sequences of five proteins previously reported to be immunogenic in infected malaria cases were retrieved from the Uniprot database and Linear B cell epitopes predicted and joined using GSGSG linkers to produce a chimeric protein ( Pf MEDA1). The physicochemical properties of the protein as well as the secondary and tertiary structures were predicted. The gene sequence of the protein after reverse transcription and codon optimization was synthesized, cloned in a pET30a vector, expressed and purified from E coli. Antibody reactivity against Pf MEDA1 was checked using an indirect ELISA with human serum samples from infected and non-infected malaria cases. Results The in silico-designed protein was predicted to be soluble, stable in varying climatic conditions, and immunogenic. There was a significant difference (P > 0.0001) observed between the mean OD in infected and non-infected samples, with a diagnostic sensitivity of 89.69% and a Cohen kappa value of 0.61 implying substantial agreement with the PCR serving as the reference method. Conclusion Based on the antibody capture ELISA test, Pf MEDA 1 exhibited the potential to be used in the development of a diagnostic tool for the diagnosis of P. falciparum in malaria endemic settings.