Ponente
Descripción
Cancer vaccines capable of promoting antitumor cytotoxic CD8+ T lymphocytes responses are promising therapies to fight tumors. Tumor cell lysates, as vaccine antigens source, have shown advantages in patients by inducing potent antitumor responses. The aim of the present work was to explore if inclusion of the E.G7-OVA tumor lysate (Lysate) into liposomes encapsulating or not an immunomodulatory protein (immP), previously studied1,2,3, could promote an antigen-specific antitumor response. The encapsulation efficiency of liposomes for the lysate, was relatively high and independent of the presence of immP, as well as the lysate retention into liposomes. Antitumor assays showed that the group treated with the liposomes co-encapsulating Lysate and immP (Lp/Lysate/immP) exhibited a slightly retarded growth of tumor and a superior survival rate with regard to the negative control group treated with PBS. However, the tendency was not remarkable and significant differences between the mice groups immunized with Lp/Lysate (with and without immP) were not observed. Therefore, optimization in the tumor lysates preparation was carried out. In this sense, different methods for obtaining cell lysates were performed. The procedure based on freeze and thaw followed of sonication of tumor cells produced high yielding of proteins, nanoparticles with less sizes and high homogeneity. Consequently, tumor lysate obtained by such method could be used in the preparation of Lp/Lysate with superior effectiveness. These results, although not yet conclusive, suggest the potentialities of the Lp/Lysate containing or not immP as vaccine platform for stimulating antigen-specific immune responses.
