Recombinant lectins as pioneering anti-viral agents against COVID-19

The primary target for vaccine design and anti-viral therapeutics for the deadly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing coronavirus disease 2019 (COVID-19) is the coronavirus surface spike (S) glycoprotein. Like other enveloped viruses, S glycoproteins are masked by a dense sugar “coat” of host-derived glycans that mediate immune evasion by molecular mimicry through shielding the immunogenic surface proteins from host immune responses. Paradoxically, this same protective glycan shield can make these sugar-coated viruses vulnerable to immune attack by soluble lectins of the innate immune system that are still able to recognise these glycans as pathogen-associated molecular patterns (PAMPs) leading to complement activation. In reality, recombinant lectins that target virus-associated glycans have the potential to be used as anti-viral agents; and therefore, binding of recombinant lectins to viruses could represent a paradigm shift for viral infection therapy. Likewise, SARS-CoV-2- associated glycans can offer novel targets for recombinant lectins as innovative anti-SARSCoV-2 agents. Unfortunately, pharmacological hurdles currently constrain the entry of recombinant lectins into clinical trials but more vigorous research into potentially useful modifications of these agents can truly develop a new landscape of anti-viral lectin-based therapeutics.