Background: HIV-1 entry into host cells is mediated by interactions between the virus envelope glycoprotein\n(gp120/gp41) and host-cell receptors. N-glycans represent approximately 50% of the molecular mass of gp120 and\nserve as potential antigenic determinants and/or as a shield against immune recognition. We previously reported\nthat N-glycosylation of recombinant gp120 varied, depending on the producer cells, and the glycosylation variability\naffected gp120 recognition by serum antibodies from persons infected with HIV-1 subtype B. However, the impact\nof gp120 differential glycosylation on recognition by broadly neutralizing monoclonal antibodies or by polyclonal\nantibodies of individuals infected with other HIV-1 subtypes is unknown.\nMethods: Recombinant multimerizing gp120 antigens were expressed in different cells, HEK 293T, T-cell,\nrhabdomyosarcoma, hepatocellular carcinoma, and Chinese hamster ovary cell lines. Binding of broadly neutralizing\nmonoclonal antibodies and polyclonal antibodies from sera of subtype A/C HIV-1-infected subjects with individual\ngp120 glycoforms was assessed by ELISA. In addition, immunodetection was performed using Western and dot blot\nassays. Recombinant gp120 glycoforms were tested for inhibition of infection of reporter cells by SF162 and YU.2\nEnv-pseudotyped R5 viruses.\nResults: We demonstrated, using ELISA, that gp120 glycans sterically adjacent to the V3 loop only moderately\ncontribute to differential recognition of a short apex motif GPGRA and GPGR by monoclonal antibodies F425 B4e8 and\n447-52D, respectively. The binding of antibodies recognizing longer peptide motifs overlapping with GPGR epitope\n(268 D4, 257 D4, 19b) was significantly altered. Recognition of gp120 glycoforms by monoclonal antibodies specific for\nother than V3-loop epitopes was significantly affected by cell types used for gp120 expression. These epitopes included\nCD4-binding site (VRC03, VRC01, b12), discontinuous epitope involving V1/V2 loop with the associated glycans (PG9,\nPG16), and an epitope including V3-base-, N332 oligomannose-, and surrounding glycans-containing epitope (PGT 121).\nMoreover, the different gp120 glycoforms variably inhibited HIV-1 infection of reporter cells.\nConclusion: Our data support the hypothesis that the glycosylation machinery of different cells shapes gp120\nglycosylation and, consequently, impacts envelope recognition by specific antibodies as well as the interaction of HIV-1\ngp120 with cellular receptors. These findings underscore the importance of selection of appropriately glycosylated\nHIV-1 envelope as a vaccine antigen.
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