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 withCpG in the presence of supernantant (SN) from LPS-stimulated (SN B16+LPS) B16 cells overcome the inhibition ofactivation observed when they are stimulated in the presence of non-stimulated B16-SN. Our goal was to further analyzethe effect of SN B16+LPS on the maturation of DC. We show that SN B16+LPS increases IL6, TNF-, and IL12p70produced 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 withLPS, showed higher percentage of CD11c+ cells, expressing increased levels of CD40 marker (p<0.05) than thoseobserved in mice bearing tumors induced with non-stimulated B16 cells . In contrast, animals of this group show areduced percentage Gr1+CD11b+ cells in the spleen and lymph nodes of animals. Therefore, stimulation of murinemelanoma cells with LPS promotes an improvement in the activation state of DCs in vitro and in vivo.