Desarrollo de las vacunas antivirales y antitumorales basadas en la utilización del dominio extra a de la fibronectina

Resumen

In the immunotherapy of cancer and other diseases, it is very important to be able to induce strong cellular immune responses. In the last years many vaccination strategies have been developed, but unfortunately, their efficacy to control the illness is being very poor. Therefore, it is necessary to develop new strategies to enhance de immune responses in order to better these results. In this project, we have developed a new strategy for vaccination consisting in the extra domain A from fibronectin linked to an antigen. The extra domain A is an endogenous protein which is produced by an alternative splicing of fibronectin under conditions of tissue damage or stress. It has been described that EDA is able to induce the expression of proinflammatory cytokines and to active de TLR4 signalling pathway. We have demonstrated that EDA protein was able to bind to TLR4 expressing HEK-293 cells and to activate TLR4 signaling pathway. EDA also stimulated the production by DC of proinflammatory cytokines, such as IL-12 or TNF-alpha, and induced their maturation in vitro and in vivo. A fusion protein between EDA and a cytotoxic T-cell epitope from ovalbumin (OVA), presented efficiently this epitope to specific T cells and induced the in vivo activation of a strong and specific CTL response. Moreover, a fusion protein containing EDA and the full ovalbumin, also improved OVA presentation by DC and induced CTL responses in vivo. These EDA recombinant proteins protected mice from a challenge with tumor cells expressing OVA. Once demonstrated the concept proof, we have applied this strategy of vaccination to induce cellular immune responses against tumoral and viral antigens of pathogens such as HCV, HIV and HPV. We found that EDA-NS3 (a protein from HCV) was able to induce maturation of DC and to enhance an anti-NS3 cellular immune response. EDA-NS3, in combination with the adjuvants poly I:C and anti-CD40 antibodies, was able to down-regulate HCV RNA expression in the liver in a murine model. Similarly, the fusion protein EDA-HPVE7 (containing the E7 protein from HPV-16), induced strong anti-E7 immune responses and in combination with poly I:C was able to eradicate large established TC-1 tumors. EDA platform was also efficient to improve the immunogenicity of the gp120 protein from HIV. In summary, these results suggest that linkage of EDA to an antigen, in combination with other adjuvant, may be considered as a candidate for the development of vaccines.