Ponentes
Descripción
CIGB550-E7 is a chimeric protein based on the fusion of the E7 protein from the human papillomavirus type 16 (HPV-16) and a cell-penetrating peptide with immunostimulatory properties. CIGB550-E7 fusion protein per se favors the generation of an antigen (Ag)-specific cytotoxic cellular immune response and consequently an antitumoral effect on tumors that express the E7 Ag. Although the results have been outstanding, they only benefit a small number of patients, which has motivated the search for new therapeutic strategies. Liposomes co-encapsulating tumor Ags and immunomodulatory compounds are promising alternatives, due to they meet the requirements of an ideal adjuvant. Previously, our group demonstrated that Sticholysin II (StII), a pore-forming protein from the sea anemone Stichodactyla helianthus, co-encapsulated with the model antigen ovalbumin (OVA) into liposomes, is able to induce a robust INFγ T CD8+ cell response with memory capacity and antitumor activity. In this work, we have produced the liposomal platform carrying StII together with the Ag CIGB550-E7 in nanometric and micrometric sizes by adding or not saccharose, respectively and previous to the lyophilization step. Liposomes with different sizes displayed similar and high encapsulation efficiency. The results obtained show that the liposomal formulation co-encapsulating StII and CIGB550-E7 is capable of inducing an Ag-specific effector TCD8+ lymphocyte response and antitumor activity in C57BL/6 mice challenged with the TC-1 tumor model, in a therapeutic scenery. Furthermore, immunizing with the vaccine platform is possible to observe a comparable delay in tumor growth even with lower doses of Ag, highlighting the potential of the liposomes/StII/CIGB550-E7 formulation. Interestingly, the reduction of particle size promoted the antitumoral activity observed.
