Aptamer-Based Diagnosis for Specific Malaria

Area of Science:

• Parasitology
• Molecular Diagnostics
• Biotechnology

Background:

• Malaria remains a significant global health burden, particularly Plasmodium vivax malaria in India.
• Current diagnostic methods for P. vivax malaria often suffer from high costs, complexity, or low accuracy.
• There is a critical need for a specific and reliable diagnostic assay for P. vivax malaria.

Purpose of the Study:

• To develop novel DNA aptamers with high specificity for Plasmodium vivax tryptophan-rich antigen (PvTRAg).
• To evaluate the diagnostic potential of these aptamers using an aptamer-linked immobilized sorbent assay (ALISA).
• To establish a foundation for a new aptamer-based diagnostic test for P. vivax malaria.

Main Methods:

• Systematic Evolution of Ligands by Exponential Enrichment (SELEX) was used to identify specific aptamers against PvTRAg.
• Two high-affinity aptamers, Apt_14 and Apt_16, with dissociation constants (KD) of 1.9 nM and 1.2 nM respectively, were selected.
• The aptamers were employed in an ALISA format for the detection of P. vivax malaria infections in clinical validation.

Main Results:

• Apt_14 and Apt_16 demonstrated high affinity for PvTRAg, with a limit of detection at 2.5 nM.
• Clinical validation showed high specificity (100%) and good sensitivity (96% for Apt_14, 84% for Apt_16).
• The aptamers exhibited minimal cross-reactivity with other antigens, confirming their selectivity for PvTRAg.

Conclusions:

• DNA aptamers are effective tools for the accurate diagnosis of Plasmodium vivax malaria.
• The developed aptamers and ALISA method show promise for a novel, specific diagnostic assay.
• This research paves the way for improved malaria diagnostics, particularly for P. vivax infections.