Purpose: Using aptamers previously selected for binding specificity to Snow Mountain virus (SMV, a GII.2 strain), the purpose of this study was to characterize aptamer binding specificity to a variety of human NoV strains using virus-like particles (VLPs).
Methods: Five aptamer candidates (13, 19, 21, 22, and 24) were chosen for characterization based on previous studies demonstrating their high binding affinity to SMV and their low free energy (dG) values. Screening was done using an aptamer-linked enzyme assay, which was developed as a modification of a previously reported enzyme immunoassay. The aptamers were screened for binding to Norwalk (GI.1), Houston (GII.4) and Snow Mountain (GII.2) VLPs.
Results: Three aptamer candidates (19, 22 and 24) showed high binding affinity to SMV and Houston VLPs, and reduced yet still significant binding affinity to Norwalk VLPs (P ≤ 0.05). The binding affinity of these aptamers for SMV and Houston VLPs was as high as that observed for commercial antibodies. Interestingly, two aptamers (13 and 21) showed high binding affinity to all three VLPs tested. This affinity was equal to that observed for commercial antibodies specific to the GII strains (SMV and Houston), and better than that for Norwalk antibody.
Significance: Several aptamer candidates may be promising broadly reactive reagents for use in human NoV capture and detection assays. Studies now focus on further characterization of these aptamers using a broader group of viruses and VLPs, and scale-up for their use in virus capture and detection in foods, environmental, and clinical samples.