2B). Importantly, when titrating the amount of antigen used in these antigen-presentation experiments, we observed https://www.selleckchem.com/JAK.html that low concentrations (30 μg/mL) of the neo-glycoconjugates were already sufficient
to result in potent T-cell proliferation compared to native OVA (i.e. 500 μg/mL; 14, 15), herewith illustrating the strong potential of the neo-glycoconjugates in the activation of T cells. Proliferation of CD4+ T cells activated by DCs pulsed with OVA-3-sulfo-LeA and OVA-tri-GlcNAc was slightly increased compared to T cells primed by native OVA-loaded DCs, despite the presence of mannose on native OVA (Fig. 3A). A much stronger effect of the neo-glycoconjugates was observed on CD8+ T-cell proliferation. OVA-3-sulfo-LeA and OVA-tri-GlcNAc were significantly enhanced cross-presented compared to native OVA, as shown by a tenfold increased Inhibitor Library price proliferation of OVA-specific CD8+ T cells (Fig. 3B). Similar results were obtained when BMDCs were used (Supporting Information Fig. 3). Controls in experiments also included DCs loaded with non-glycan-modified OVA and maltohexaose-modified OVA, which yielded responses that were not significantly different from
those generated with native OVA (proliferation measured at highest concentration of antigen was 6.75×104±749 and 8.55×104±1093 respectively, for CD8+ T cells and 2.14×104±632 and 3.33×104±1093 respectively, for CD4+ T cells (data not shown). Experiments performed with BMDCs derived from MR−/− revealed that the uptake and processing route of the neo-glycoconjugates was MR-dependent as the proliferation of OVA-specific CD4+ and CD8+ T cells was significantly decreased compared to their response using WT BMDCs (Fig. 3C and D). Although the cross-presentation was greatly reduced Alanine-glyoxylate transaminase using the MR−/− BMDCs, there was still some background presentation of OVA-3-sulfo-LeA and OVA-tri-GlcNAc. As our neo-glycoconjugate
preparations did not contain endotoxin above detection level, we conclude that the observed enhanced cross-presentation of OVA-3-sulfo-LeA and OVA-tri-GlcNAc is glycan-mediated and distinct from the previously reported TLR-dependent cross-presentation of native OVA 15. This was confirmed using MyD88-TRIFF−/− BMDCs; similar to using WT BMDCs, cross-presentation of the neo-glycoconjugates was enhanced in MyD88-TRIFF−/− BMDCs compared to native OVA, indicating that the cross-presentation induced by 3-sulfo-LeA and tri-GlcNAc is independent of TLR-signaling (Fig. 3E). Indeed, addition of LPS improved cross-presentation of native OVA. However, when LPS was mixed with the neo-glycoconjugates, mostly cross-presentation of the lowest antigen doses (e.g. 10 and 3 μg/mL) was affected (Fig. 3F). Together these data indicate that both OVA-neo-glycoconjugates target the MR and upon uptake are potently cross-presented to CD8+ T cells. The entered cross-presentation pathway is different from native OVA, as the observed cross-presentation occurs independent of TLR-signaling.