B16 murine melanoma cells stimulated in vitro with a TLR4-
ligand during 48h prior to their inoculation into TLR4 deficient
mice (TLR4lps-del), induce tumors significantly smaller than
controls. The apoptosis-proliferation balance of LPS-stimulated
B16 cells is not modified and inhibition of tumor growth was not
observed in nude mice; thus we hypothesized that TLR4 triggering
on B16 cells themselves could induce the expression of proinflammatory
mediators, that even if they are transitory, could
dramatically alter the function of dendritic cells (DCs) present at
the site of inoculation and switch the type of immune response
elicited against the tumor. TLR4lps-del DCs matured with CpG
in the presence of supernantant (SN) from LPS-stimulated (SN
B16+LPS) B16 cells were capable of overcoming the inhibition
of activation observed when they were matured in the presence
of non-stimulated B16-SN. To further analyze the DCs and
T cell function in vivo, infiltrating mononuclear cells (TILs) from
tumors induced with B16 cells stimulated (B16 + LPS) or not (B16
Basal) with LPS in TLR4lps-del mice obtained at day 20 and 32
post injection (p.i), were cultured in vitro with PMA-Ionomycin
and their cytokine expression was evaluated by intracellular flow cytometry. Interestingly, we observed an increase in CD11c+ IL-12+ cells (2.64%・}0.45 vs 0.43・}0.02%), higher levels of IFNg+ cells (11.18・}2.81% vs 3.46・}0.54%) and reduced levels
of IL10+ cells (2.11・}0.45% vs 4.35・}0.42%, p<0.05) in TILs from B16+LPS tumors, in comparison with those induced by B16 cells at day 20 p.i. Similar results were observed when we analyzed TILs isolated at day 32 p.i (IFNg+ cells: 5.24・}3.19% vs 1.66・}1.34%,
p<0.05; IL-10+ cells: 0.19%・}0.06 vs 0.31・}0.05%). Therefore, stimulation of murine melanoma cells with LPS in vitro before inoculating them into TLR4lps-del, promotes an improvement of the immune response, activating DCs and enhancing IFNg+ TILs in
vivo, at early and later times p.i of tumor cells.
and their cytokine expression was evaluated by intracellular
flow cytometry. Interestingly, we observed an increase in
CD11c+ IL-12+ cells (2.64%・}0.45 vs 0.43・}0.02%), higher levels
of IFNg+ cells (11.18・}2.81% vs 3.46・}0.54%) and reduced levels
of IL10+ cells (2.11・}0.45% vs 4.35・}0.42%, p<0.05) in TILs from B16+LPS tumors, in comparison with those induced by B16 cells at day 20 p.i. Similar results were observed when we analyzed TILs isolated at day 32 p.i (IFNg+ cells: 5.24・}3.19% vs 1.66・}1.34%,
p<0.05; IL-10+ cells: 0.19%・}0.06 vs 0.31・}0.05%). Therefore, stimulation of murine melanoma cells with LPS in vitro before inoculating them into TLR4lps-del, promotes an improvement of the immune response, activating DCs and enhancing IFNg+ TILs in
vivo, at early and later times p.i of tumor cells.
of IL10+ cells (2.11・}0.45% vs 4.35・}0.42%, p<0.05) in TILs from
B16+LPS tumors, in comparison with those induced by B16 cells
at day 20 p.i. Similar results were observed when we analyzed
TILs isolated at day 32 p.i (IFNg+ cells: 5.24・}3.19% vs 1.66・}1.34%,
p<0.05; IL-10+ cells: 0.19%・}0.06 vs 0.31・}0.05%). Therefore, stimulation of murine melanoma cells with LPS in vitro before inoculating them into TLR4lps-del, promotes an improvement of the immune response, activating DCs and enhancing IFNg+ TILs in
vivo, at early and later times p.i of tumor cells.
p<0.05; IL-10+ cells: 0.19%・}0.06 vs 0.31・}0.05%). Therefore, stimulation
of murine melanoma cells with LPS in vitro before inoculating
them into TLR4lps-del, promotes an improvement of the
immune response, activating DCs and enhancing IFNg+ TILs in
vivo, at early and later times p.i of tumor cells.
vivo, at early and later times p.i of tumor cells.
