Elevant genetic features) E.coli MLK3 E.coli MLK53 (htrB-) E.coli MLK 1067 (msbB-) E.coli MLK986 (msbB-, htrB-) Y. pestis KIMProportions of lipid A species (molecular mass) .90 hexaacyl (1823.3 Da); traces of penta and tetraacyl. rough-LPS; pentaacyl lipid A deficient in C12 oxyacyl of 3-OH-C14 acyl at GlcN C29 (1615.1 Da) rough-LPS; .90 pentaacyl (1587.0 Da); tetraacyl traces rough-LPS; 29 pentaacyl (1643.0 Da); 54 tetraacyl (1404.8 Da); and 17 triacyl (1178.6 Da) rough-LPS, 9 hexaacyl (1797.2 Da); 10 pentaacyl; 40 tetraacyl (1404.8 Da); 7 arabinosamine- tetraacyl (1535.9 Da); 30 triacyl (1178.6 1531364 Da)a All are rough-type LPSs. doi:10.1371/journal.pone.0055117.tTetraacyl LPS Potentiate Intracellular 23115181 SignallingTetraacyl LPS Potentiate Intracellular SignallingFigure 2. Tetra-acyl LPS induce the activation of TLR4-dependent molecular pathways involved in mouse DC maturation. BMDC were activated with medium (grey), E. coli hexa-acyl LPS (dark blue), E. coli tetra-acyl LPS (purple) or Y. pestis tetra-acyl LPS (light blue) for 15 min, 30 min, 1 h and 2 h. NF-kB translocation was analyzed by confocal microscopy(A). Cells were fixed and stained for CD11c (in blue), MHC-II (in green) and NF-kB subunit p65/RelA (in red). The percentage of BMDC with translocated NF-kB into the nucleus was quantified (B). BMDC were AH252723 stimulated for 30 min, 1 h, 4 h and 6 h with medium or different LPS. Cell lysates were subjected to SDS-PAGE and, after transfer to nitrocellulose, the membrane was probed with the antibodies against phospho-S6 (Ser235/236), S6 and an anti-actin antibody (C). Data represent means 6 standard errors of at least 4 independent experiments, **p,0.01. doi:10.1371/journal.pone.0055117.gBMDC incubated with LPS alone or OVA alone could not induce any T cell response (data not shown). However, BMDC incubated with OVA and activated by different LPS efficiently induced antigen-specific CD8+ and CD4+ T cell responses (Figure 6A). DC activated by tetra-acyl LPS induced a higher OTI and OTII T cell proliferation than cells treated by hexa-acyl LPS (Figure 6A). DC stimulated by tetra-acyl and hexa-acyl LPS were able to trigger T cell activation characterized by a CD25 up-regulation and a CD62L down-regulation. However hexa-acyl LPS-treated BMDC led to a higher down-regulation of CD62L by OT II T cells than those treated with tetra-acyl LPS (Figure 6A). Altogether, these data show that BMDC induced by LPS with acylation defects are able to efficiently promote antigen presentation and induce CD8+ and CD4+ T cell responses. We then investigated the functional properties of human DC stimulated with LPS variants (Figure 6B). Human blood myeloid DC (mDC) activated by the different LPS were able to induce the ?proliferation of allogeneic naive CD4+ and CD8+ T cells, although to a lower level for E. coli tetra-acyl LPS compared to other LPS (Figure 6B). Tetra-acyl LPS from Y. pestis, which contains small amounts of hexa-acyl LPS had a stronger capacity to trigger T cellresponses than LPS purified from E. coli (msbB-, htrB-) double mutant (devoid of hexa-acyl LPS) (Figure 6B, Table 1). These results show that tetra-acyl LPS-treated DC are able to promote CD4+ and CD8+ T cell responses both in mouse and human Fexaramine biological activity models. We then characterized the effector T cells induced by LPStreated mDC (Figure 7). Cells were stimulated with PMA/ Ionomycin and stained for intracellular IFN-c (TH1 response), IL13 (TH2 response) and IL-17 (TH17 response). mDC stimulated ?eit.Elevant genetic features) E.coli MLK3 E.coli MLK53 (htrB-) E.coli MLK 1067 (msbB-) E.coli MLK986 (msbB-, htrB-) Y. pestis KIMProportions of lipid A species (molecular mass) .90 hexaacyl (1823.3 Da); traces of penta and tetraacyl. rough-LPS; pentaacyl lipid A deficient in C12 oxyacyl of 3-OH-C14 acyl at GlcN C29 (1615.1 Da) rough-LPS; .90 pentaacyl (1587.0 Da); tetraacyl traces rough-LPS; 29 pentaacyl (1643.0 Da); 54 tetraacyl (1404.8 Da); and 17 triacyl (1178.6 Da) rough-LPS, 9 hexaacyl (1797.2 Da); 10 pentaacyl; 40 tetraacyl (1404.8 Da); 7 arabinosamine- tetraacyl (1535.9 Da); 30 triacyl (1178.6 1531364 Da)a All are rough-type LPSs. doi:10.1371/journal.pone.0055117.tTetraacyl LPS Potentiate Intracellular 23115181 SignallingTetraacyl LPS Potentiate Intracellular SignallingFigure 2. Tetra-acyl LPS induce the activation of TLR4-dependent molecular pathways involved in mouse DC maturation. BMDC were activated with medium (grey), E. coli hexa-acyl LPS (dark blue), E. coli tetra-acyl LPS (purple) or Y. pestis tetra-acyl LPS (light blue) for 15 min, 30 min, 1 h and 2 h. NF-kB translocation was analyzed by confocal microscopy(A). Cells were fixed and stained for CD11c (in blue), MHC-II (in green) and NF-kB subunit p65/RelA (in red). The percentage of BMDC with translocated NF-kB into the nucleus was quantified (B). BMDC were stimulated for 30 min, 1 h, 4 h and 6 h with medium or different LPS. Cell lysates were subjected to SDS-PAGE and, after transfer to nitrocellulose, the membrane was probed with the antibodies against phospho-S6 (Ser235/236), S6 and an anti-actin antibody (C). Data represent means 6 standard errors of at least 4 independent experiments, **p,0.01. doi:10.1371/journal.pone.0055117.gBMDC incubated with LPS alone or OVA alone could not induce any T cell response (data not shown). However, BMDC incubated with OVA and activated by different LPS efficiently induced antigen-specific CD8+ and CD4+ T cell responses (Figure 6A). DC activated by tetra-acyl LPS induced a higher OTI and OTII T cell proliferation than cells treated by hexa-acyl LPS (Figure 6A). DC stimulated by tetra-acyl and hexa-acyl LPS were able to trigger T cell activation characterized by a CD25 up-regulation and a CD62L down-regulation. However hexa-acyl LPS-treated BMDC led to a higher down-regulation of CD62L by OT II T cells than those treated with tetra-acyl LPS (Figure 6A). Altogether, these data show that BMDC induced by LPS with acylation defects are able to efficiently promote antigen presentation and induce CD8+ and CD4+ T cell responses. We then investigated the functional properties of human DC stimulated with LPS variants (Figure 6B). Human blood myeloid DC (mDC) activated by the different LPS were able to induce the ?proliferation of allogeneic naive CD4+ and CD8+ T cells, although to a lower level for E. coli tetra-acyl LPS compared to other LPS (Figure 6B). Tetra-acyl LPS from Y. pestis, which contains small amounts of hexa-acyl LPS had a stronger capacity to trigger T cellresponses than LPS purified from E. coli (msbB-, htrB-) double mutant (devoid of hexa-acyl LPS) (Figure 6B, Table 1). These results show that tetra-acyl LPS-treated DC are able to promote CD4+ and CD8+ T cell responses both in mouse and human models. We then characterized the effector T cells induced by LPStreated mDC (Figure 7). Cells were stimulated with PMA/ Ionomycin and stained for intracellular IFN-c (TH1 response), IL13 (TH2 response) and IL-17 (TH17 response). mDC stimulated ?eit.
