We investigated the inhibition of infection activities of lectins using SARS-CoV-2 pseudoviruses and ACE2-expressing HEK-293T cells at the outset of this project. Three lectins were compared, namely CV-N, MVN and GRFT. CV-N is a bivalent, mannose-binding lectin that is capable of dimerizing to a 4 binding-site form. Griffithsin is a trivalent, mannose-binding lectin, known to be an obligate domain-swapped dimer, in this case to a 6 binding-site form. In contrast, Microvirin is a monovalent mannose-binding lectin, with no propensity for dimerizing, remaining at 1 binding site per molecule. For direct infection inhibition, CV-N and GRFT both exhibited dose-dependent inhibition (Figure ) of SARS-CoV-2 pseudovirus infection, CV-N with an IC 50 of 45.96±26.17 nM and GRFT with an IC 50 of 631.6±378.6 nM. Notably, GRFT as tested in our experiment exhibited comparable potency as found in other pseudovirus assays observed in literature (IC 50 = 293-886 nM (4, 16)), but poorer potencies than in live virus assays (IC 50 = 33-63 nM ). In contrast, the monovalent MVN did not inhibit infection at concentrations up to 2000 nM, suggesting that multivalent binding of the S protein is necessary for inhibition.