Design and characterization of liposomes as vaccine adjuvants

A. GIORELLO; I. MARCIPAR; A. NCASTRO; L. CALVINHO; A. M. GENNARO; C. VEAUTE

Buenos Aires

Congreso; Primer Congreso Franco-Argentino de Inmunología y LVIII Reunión Anual de la Sociedad Argentina de Inmunología; 2010

Sociedad Argentia de Inmunologia

98. Design and characterization of liposomes as vaccine adjuvants Giorello, Antonella1; Marcipar, Iván1; Nicastro, Alcides2; Calvinho, Luis3; Gennaro, Ana2,4; Veaute, Carolina1 1Laboratorio de Tecnología Inmunológica, Fac. de Bioquímica y Ciencias Biológicas, UNL, Santa Fe, Argentina; 2Departamento de Física, Fac. de Bioquímica y Ciencias Biológicas, UNL, Santa Fe, Argentina; 3Estación Experimental Animal, INTA, Rafaela, Argentina; 4INTEC, CONICET-UNL, Santa Fe, Argentina. antonellagiorello@gmail.com The great progress in subunit vaccines development requires the design and exhaustive study of new adjuvant formulations. Although liposomes have been widely used as drugs vehicle and immune adjuvants, scarce work exists on the characterization and standardization of these formulations. The aim of this work was to design a liposome formulation containing bovine serum albumin (BSA) as a model immunogen and to set up a protocol of characterization of the formulation. Lyophilization process was also assessed in order to obtain a stable formulation. Liposomes were prepared with dipalmitoylphosphatidylcholine, cholesterol and stearylamine, in a 7:2:2 w/w ratio and antigen was added at 0.23 mg/ml in a solution with sucrose as cryoprotectant. The amount of BSA incorporated into lyophilized and non-lyophilized liposomes was analyzed by the bicinchoninic acid assay and competitive ELISA. The ability of the formulations to induce an immune response was assessed by immunization of mice with two doses of 1 or 10 µg of antigen in lyophilized or non-lyophilized liposomes. Liposomes incorporated 33.9% of the offered BSA, 10.2% being on the particle surface. After the lyophilization and resuspension of liposomes, 18.3% of the BSA initially used remained in the particles, being 4.8% of this protein in the particle surface. Nevertheless, both lyophilized and non-lyophilized liposomes induced a humoral immune response significantly different from control without adjuvant and not different among them (p<0.05, Kruskall Wallis test). No significant differences were observed in antibody levels when 1 or 10 µg of antigen were inoculated. Our results confirm the efficacy of liposomes as vaccine adjuvants and introduce a protocol to standardize a manufacturing process. They also demonstrated that lyophilization is a suitable alternative for the conservation of vaccines containing liposomes.