Liposomal constructs for antitumoral vaccination by the nasal route

Mucosal surfaces are promising routes for vaccination. Among mucosa, airway mucosa provides the opportunity to develop non-invasive approaches for vaccine delivery. In the current study, nasal route was used to investigate the potency of highly versatile di-epitopic liposomal constructs of different size, structure and composition to exhibit antitumor efficiency after prophylactic vaccination in mice. Well-characterized small unilamellar (SUV), multilamellar (MLV), reverse-phase evaporation (REV) and ultraflexible small unilamellar vesicles (Uf-SUV), containing the ErbB2 T-cytotoxic epitope, the influenza-derived HA T-helper epitope and the lipopeptide adjuvant Pam₂CAG, were formulated. These vaccines were administered into the nasal cavity of BALB/c mice, followed by i.v. or s.c. implantation of ErbB2-surexpressing cancer cells. Nasal vaccination with the SUV vaccine resulted in an efficient antitumor activity against lung tumors and a non-significant protection against s.c. tumors. Size, structure and flexibility of liposomes did not impact vaccine immunity and antitumoral efficiency against lung tumors, in contrast to total dose of vaccine or dose of adjuvant. These results showed an undeniable interest of liposomes as lipid-based carriers for antitumor vaccine delivery by the nasal route, opening new perspectives for cancer treatment.