ACELLULAR VACCINES BASED ON OUTER MEMBRANE VESICLES FROM B. SUIS STRAINS

FLORENCIA MUÑOZ GONZALEZ; BIALER MAGALÍ; ESTEIN SILVIA; BALDI P; FERRERO MARIANA CRISTINA

San Luis

Congreso; LXXI Reunion Anual de la Sociedad Argentina de Inmunología; 2023

Sociedad Argentina de Inmunología

(11) ACELLULAR VACCINES BASED ON OUTER MEMBRANE VESICLESFROM B. SUIS STRAINSFlorencia Muñoz González 1,2, Magalí Bialer 3 , Lucía Zavattieri1,2, Silvia M. Estein4, PabloBaldi 1,2 , Mariana Ferrero 1,21 Instituto de Estudios de la Inmunidad Humoral (IDEHU), CONICET-Universidad de BuenosAires, Buenos Aires, Argentina. 2Facultad de Farmacia y Bioquímica, Cátedra de Inmunología,Universidad de Buenos Aires, Buenos Aires, Argentina. 3Fundación Instituto Leloir, IIBBACONICET, Buenos Aires, Argentina. 4Laboratorio de Inmunología, Departamento de SanidadAnimal y Medicina Preventiva (SAMP), Centro de Investigación Veterinaria Tandil (CIVETANCONICET-CICPBA), Facultad de Ciencias Veterinarias (FCV), Universidad Nacional del Centro de la Provincia de Buenos Aires (UNCPBA), Tandil, Buenos Aires, Argentina.Outer Membrane Vesicles (OMV) from various Gram-negative bacteria have been studied as potential acellular vaccines. We have previously demonstrated that vaccination with B. suis wt and ∆mapB OMV induced systemic and mucosal specific humoral immune response, and protected against systemic and respiratory acquired brucellosis. In this work we continued characterizing the immune response after OMVwt and OMV∆mapB vaccination and evaluated the protective capacity of this vaccines against intragastric Brucella infection. Female BALB/c mice were immunized intramuscularly (i.m.) with OMVwt (20 μg), OMVΔmapB (20 μg) or saline at 0 and 30 days. One week after last immunization serum samples were obtained and spleens were harvested, processed and the cells obtained were cultured in the presence of both OMV, ConA mitogen orRPMI. After 24h cells were stained with anti-CD3, anti-CD4 and anti-CD8 antibodies for flow cytometry analysis. In vitro production of IFN-, IL-2, IL-17 and IL-5 was determined after 72h of stimulation. Other batch of vaccinated mice were injected intradermally in opposite footpads with the correspondent OMV or saline to evaluate DTH (48 and 72h). Two weeks after last immunization mice were challenged with B. suis through the intragastric route. CFU counts were determined in spleens and mediastinal lymph nodes 20 days after challenge. Antibodies capacity to neutralize Brucella infection and to induce opsonophagocytosis were determined in Caco-2 and RAW cells cultures, respectively. Serum specific antibodies from OMVwt and OMVΔmapB mice promoted Brucella phagocytosis by RAW cells (p