Hepatitis C Virus Resistance to Carbohydrate-Binding Agents

Izquierdo, Laure; Oliveira, Catarina; Fournier, Carole; Descamps, Véronique; Morel, Virginie; Dubuisson, Jean; Brochot, Etienne; Francois, Catherine; Castelain, Sandrine; Duverlie, Gilles; Helle, Francois

HCV entry into hepatocytes is a complex multistep process that involves viral envelope glycoproteins and several cell entry factors including CD81, SR-BI, CLDN1 and OCLN [3] . E1 and E2 are the two envelope glycoproteins that are present on the surface of viral particles as large covalent complexes stabilized by disulfide bridges [4] . Both glycoproteins are heavily Nglycosylated and, as a result, one third of the molecular mass of E1E2 heterodimers corresponds to N-glycans. Indeed, 4 and 11 N-glycosylation sites are conserved in E1 and E2 sequences from most genotypes and it has been shown that the majority of these sites harbor high-mannose-type glycans, even after egress of viral particles from the cells [4] . In addition, we contributed to demonstrate that the corresponding N-glycans play an important role for the function of these proteins: i) they enable the correct folding of the envelope proteins, ii) they modulate the efficiency of the entry step and iii) they mask conserved neutralizing epitopes on E2 envelope glycoprotein close to the binding site to the cellular receptor CD81 [5] [6] [7] [8] [9] . These features make HCV N-glycans promising target for new antiviral strategies, all the more as high-mannose glycans are rarely present on cellular proteins after their exit from the endoplasmic reticulum. A proof of concept has been provided in vitro and in vivo by using several lectins such as Cyanovirin-N, Griffithsin or Scytovirin as well as the non-peptidic carbohydrate binding agent (CBA) Pradimicin-A [10] [11] [12] [13] [14] [15] . However, a potential resistance of HCV to such a therapeutic strategy has never been investigated.