EFFECT OF FACTORS SECRETED BY MURINE MELANOMA B16 CELLS ACTIVATED VIA TLR4 ON THE MATURATION STATE OF DENDRITIC CELLS

VIRGINIA ANDREANI; CRESPO MI; GABRIEL MORÓN; RIVERO V; MACCIONI M

Congreso; 9th Latin American Congress of Immunology; 2009

ALAI

Stimulation of melanoma B16 cells in vitro via TLR4 inhibits subseuent tumor growth in vivo in TLR4 deficient (TLR4lps-del) mice, indicating that TLR4 on tumor but not on host cells is involved. TLR4lps-del DC 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 futher analyze the effect of SN B16+LPS on the maturation of DC. We show that SN B16+LPS increases IL6, TNF-a 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 (p<0.05)than those observed in mice bearing tumors induced with non-stimulated B16 cells. In contrast, animales 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 actiation state of DCs in vitro and in vivo.