Interaction evaluation of a sunflower mannose-binding lectin with viral surface glycoproteins of influenza and SARS-CoV-2

TICCHI J; PIGNATARO MF; CIMMINO C; DEL RIO M; IDROVO T; SILVA A; REGENTE M; RADICIONI MB; FERNÁNDEZ NB ; D'ALESSIO C; UEZ O

Virtual

Congreso; LXVI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC); 2021

Sociedad Argentina de Investigación Clínica

Each year, influenza virus infections cause more than half a million deaths worldwide. The novel coronavirus (SARS-CoV-2) has caused over 4.6 million deaths as of September 2021. The influenza virus hemagglutinin (HA) and coronavirus spike (S) glycoproteins mediate virus entry. HA and S are heavily glycosylated, making them potential targets for carbohydrate binding agents such as lectins. We have previously isolated a mannose-binding sunflower lectin (Helja) that showed the ability to inhibit hemagglutination mediated by influenza, suggesting the binding of Helja to the HA glycoprotein. Here we evaluated the interaction of Helja both to influenza virus antigens and to the receptor binding domain of S (RBD). Using a ligand blot assay, the interaction of Helja with antigens of the H1N1 and H3N2 variants of the influenza A was demonstrated. Also, using an experimental strategy based on the interaction of Helja with mannose-agarose matrices, the ability of the Victoria variant antigens of influenza B to detach the lectin bound to the affinity matrix was observed. We used a similar experimental approach to detect the presence of a protein recognized by anti-Helja antibodies in the fractions eluted from affinity matrix by competence with RBD. These findings suggested the interaction of Helja with viral surface glycoproteins of influenza and SARS-CoV-2 that play a key role in the entry of both viruses into the host cells. Future research could contribute to designing of Helja-based new antiviral agents.