Effect of factors secreted by murine melanoma B16 cells activated via Toll Like Receptor 4 on the maturation state of dendritic cells

VIRGINIA ANDREANI; MARÍA INÉS CRESPO; GABRIEL MORÓN; VIRGINIA RIVERO; MARIANA MACCIONI

Viña del Mar, Chile

Congreso; IX Congreso de la Asociación Latinoamericana de Inmunología; 2009

Asoc. Latinoamericana de Inmunología

Stimulation of melanoma B16 cells in vitro via TLR4 inhibits subsequent tumor growth in vivo in TLR4 deficient
(TLR4lps-del) mice, indicating that TLR4 on tumor but not on host cells is involved. TLR4lps-del DCs stimulated with
CpG in the presence of supernantant (SN) from LPS-stimulated (SN B16+LPS) B16 cells overcome the inhibition of
activation observed when they are stimulated in the presence of non-stimulated B16-SN. Our goal was to further analyze
the effect of SN B16+LPS on the maturation of DC. We show that SN B16+LPS increases IL6, TNF-, and IL12p70
produced by TLR4lps-del DCs, stimulated or not with CpG, compared to the levels produced in the presence of B16-SN.
CD11c+ cells from spleen and lymph nodes of TLR4lps-del mice bearing tumors induced with B16 cells stimulated with
LPS, showed higher percentage of CD11c+ cells, expressing increased levels of CD40 marker (p<0.05) than those
observed in mice bearing tumors induced with non-stimulated B16 cells . In contrast, animals of this group show a
reduced percentage Gr1+CD11b+ cells in the spleen and lymph nodes of animals. Therefore, stimulation of murine
melanoma cells with LPS promotes an improvement in the activation state of DCs in vitro and in vivo.