Multiple antigenic glycopeptide (MAG):Tn-poliovirus (PV) glycopeptide uptake and presentation is enhanced in macrophage galactose-type lectin (MGL) positive bone marrow–derived dendritic cells (BMDCs). (A) BMDCs or splenic conventional DCs (cDCs) from BALB/c mice were incubated with an anti-MGL monoclonal antibody (ERMP23 clone) or with an isotype IgG2a antibody, followed by a PE-conjugated anti–rat IgG2a antibody. MGL expression was analyzed by flow cytometry on CD11c⁺, CD45RA⁻, and CD11b⁺ gated cells for murine cDC (BMcDC); on CD11c⁺ for splenic cDC; and on CD11c⁺, CD45RA⁺, PDCA1⁺, and CD11b⁻ gated cells for plasmacytoid DC (BMpDC). (B) To assess the binding capacity of BMDCs to antigens, BMpDCs and murine conventional DCs (BMcDCs) were incubated at 4°C with Alexa⁴⁸⁸-labeled glycosylated MAG:Tn3-TT (bold line), unglycosylated MAP:TT (shaded gray), or medium (dashed line). (C) MAG:Tn3-PV and nonglycosylated MAP-PV Alexa⁶⁴⁷-labeled antigen were incubated with BMDCs. We monitored internalization by flow cytometry on BMpDC (closed symbols) or BMcDC (open symbols) gated cells. Data are expressed as the mean ± SD of triplicates. Representative results from 3 experiments are presented. (D) The Tn-glycopeptide and nonglycosylated peptide were incubated with purified BMcDC (open symbols) or BMpDC (closed symbols) and the PV-specific T-cell hybridoma 45G10 T-cell hybridoma. IL-2 responses were assessed using the IL-2–dependent CTLL cell line. Data are expressed as the mean ± SD of triplicates. Representative results from 3 experiments are shown.