Towards development of aptamers that specifically bind to lactate dehydrogenase of Plasmodium falciparum through epitopic targeting

• Published in: Malaria Journal
• Main Authors: Kelly-Anne Frith, Ronen Fogel, J. P. Dean Goldring, Robert G. E. Krause, Makobetsa Khati, Heinrich Hoppe, Mary E. Cromhout, Meesbah Jiwaji, Janice L. Limson
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2018
• Subjects: Aptamer; Oligonucleotide; Lactate dehydrogenase; Malaria; Biorecognition; Detection; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-018-2336-z; https://doaj.org/article/e5d1265b473b4c0c9b04527ca66a2577

Abstract Background Early detection is crucial for the effective treatment of malaria, particularly in those cases infected with Plasmodium falciparum. There is a need for diagnostic devices with the capacity to distinguish P. falciparum from other strains of malaria. Here, aptamers generated against targeted species-specific epitopes of P. falciparum lactate dehydrogenase (rPfLDH) are described. Results Two classes of aptamers bearing high binding affinity and specificity for recombinant P. falciparum lactate dehydrogenase (rPfLDH) and P. falciparum-specific lactate dehydrogenase epitopic oligopeptide (LDHp) were separately generated. Structurally-relevant moieties with particular consensus sequences (GGTAG and GGCG) were found in aptamers reported here and previously published, confirming their importance in recognition of the target, while novel moieties particular to this work (ATTAT and poly-A stretches) were identified. Aptamers with diagnostically-supportive functions were synthesized, prime examples of which are the aptamers designated as LDHp 1, LDHp 11 and rLDH 4 and rLDH 15 in work presented herein. Of the sampled aptamers raised against the recombinant protein, rLDH 4 showed the highest binding to the target rPfLDH in the ELONA assay, with both rLDH 4 and rLDH 15 indicating an ability to discriminate between rPfLDH and rPvLDH. LDHp 11 was generated against a peptide selected as a unique P. falciparum LDH peptide. The aptamer, LDHp 11, like antibodies against the same peptide, only detected rPfLDH and discriminated between rPfLDH and rPvLDH. This was supported by affinity binding experiments where only aptamers generated against a unique species-specific epitope showed an ability to preferentially bind to rPfLDH relative to rPvLDH rather than those generated against the whole recombinant protein. In addition, rLDH 4 and LDHp 11 demonstrated in situ binding to P. falciparum cells during confocal microscopy. Conclusions The utilization and application of LDHp 11, an aptamer generated against a unique ...