Monophosphoryl lipid A as adjuvant for recombinant influenza nucleoprotein vaccine in mice

CARGNELUTTI, DIEGO ESTEBAN; SANCHEZ, MARÍA VICTORIA; MACKEM OBERTI, JUAN PABLO; ALVAREZ, PAULA; BOADO, LORENA; MATTION, NORA; SCODELLER, EDUARDO ALBERTO

Buenos Aires

Congreso; 1° Congreso Franco Argentino de Inmunología; 2010

Influenza is one of the most important respiratory pathogens worldwide. Vaccination is the best way to control influenza. Lipopolysaccharides (LPS) trigger innate immune response through activation of Toll-like receptor 4 (TLR4). Such responses may be exploited for the development of adjuvants and in particular monophosphoryl lipid A (MPLA) obtained by controlled hydrolysis of LPS of Salmonella minnesota. The use of influenza A virus recombinant nucleoprotein (rNP) as a vaccine antigen, stems from the fact that NP show less antigenic variation than the influenza virus surface glycoproteins, haemagglutinin and neuraminidase. The object of this work is to describe the production and immunogenicity of rNP from influenza A virus formulated with MPLA as a vaccine. Method: Homologous prime and boost subcutaneous vaccination of BALB/c mice with 10ug of the rNP (control group) and 10ug of rNP formulated with 25ug of MPLA (experimental group) were administered 3 weeks apart. On day 60 post prime, serum samples were collected to evaluate the specific titre of total IgG, IgG1 and IgG2a isotypes. At the same time, culture supernatants of spleen cells were collected, after antigen stimulation to test the presence of IFNby ELISA. Result: Subcutaneous injection of rNP with MPLA into BALB/c mice elicited both humoral and cellular immune responses. Animals injected with rNP/MPLA developed NPspecific antibodies, with total IgG titers of 11,200 and increase the ratio IgG2a/IgG1 from 0.045 to 0.96. In addition, the rNP/MPLA vaccine induced a significant different on the productionwithin control group and experimental group. Conclusion:This study demonstrates that the formulation of rNPr with MPLA induces a strong specific Th1 type immune response, humoral as well as cellular. This is a first step to demonstrate that MPLA can be use as an adjuvant in the formulation of a recombinant NP influenza vaccine