[HIV1 Env N-glycans and their interactions with the immune system]

N-glycans determine both the conformational and functional characteristics of the HIV1 envelope glycoprotein (Env). In addition, the significant glycosylation modulates the recognition of Env by the different immune system effectors. N-glycans confer to Env the capacity to interact with the type C lectins. Thus, MBLs (mannose binding lectins) recognise the gp120 in a specific manner and exert an antiviral action. Conversely, the interaction between gp120 and DC-SIGN at the dendritic cells surface interferes with the induction of the adaptive immune response. N-glycans also modulate the presentation of the T helper epitopes and thus indirectly influence the induction and the maturation of both the Env cytotoxic cellular and humoral response. Moreover, the N-glycans form a shield which limits the accessibility of the proteic backbone to the antibodies. The constant evolving glycan shield enables neutralising response escape. However, in some cases, N-glycans can constitute clusters which represent a target for the antibodies. The understanding of the multiple roles of N-glycans could significantly contribute to the optimisation of an Env immunogen potentially usable in a vaccine preparation.