Design and characterisation of high-affinity aptamers for detecting HIV integrase.

BACKGROUND: Currently, 39.9 million people are infected with the human immunodeficiency virus (HIV), and 1.3 million new infections occur annually, with over 170 circulating variants. Early HIV detection is essential for timely antiretroviral therapy and preventing transmission, but no existing serological or molecular diagnostic tests can detect the virus within the first 10 days of infection. Aptamers, single-stranded oligonucleotides, can recognise specific proteins with high affinity and specificity, presenting advantages compared to antibodies. Molecular assays utilising aptamers selected against highly conserved peptides in HIV proteins have the potential to enable earlier virus detection.

RESULTS: We selected and characterised three aptamers targeting an exposed and highly conserved peptide across HIV variants in the HIV integrase (IN), after analysing 13,606 HIV-1 and 6,436 HIV-2 IN sequences by an in-house bioinformatics program (EpiMolBio), covering nearly 150 HIV variants (including types, groups, subtypes, sub-subtypes, and circulating recombinants). The selected aptamers were further characterised through bioinformatics analysis to assess their affinity, sensitivity, and optimal combinations for recombinant HIV IN detection using Enzyme-Linked Oligonucleotide Assays (ELONA). The most effective aptamer combination found (C5: Apt2-HCINp1/Apt2-HCINp1) demonstrated the ability to detect HIV in infected samples with at least 3.65 log HIV cp/mL, not recognising negative controls or other viruses.

SIGNIFICANCE: Our anti-HIV IN aptamers show promise for use when integrating them in ultrasensitive nanotechnologies, enabling early detection of HIV across all variants. The future new aptamer-based ultrasensitive biosensor could allow HIV diagnosis from the first day of infection, regardless of the patient's age, infection stage, or location.