POTENTIATION OF HUMORAL IMMUNE RESPONSE ELICITED BY A COMMERCIAL VACCINE AGAINST BOVINE RESPIRATORY DISEASE IN A MURINE MODEL EMPLOYING AN IMMUNOMODULATORY BACTERIAL STRAIN.

ALMOZNI B; MANGHI MA; DÍAZ AM; SPARO, MÓNICA; CASTRO MS; MANGONE F; CANELLADA, A

Mar del Plata

Congreso; LXI REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA (SAIC), LXIV REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI); 2016

Previously, we demonstrated that the intragastric (ig) inoculationof an immunomodulatory strain (Enterococcus faecalisCECT7121 (Ef)), enhances the cellular immune response in miceafter DTP immunization. Actually, we are studying the immuneresponse induced by a commercial vaccine against the RespiratoryBovine Disease (RBD). RBD affects cattle causing big economiclosses. The etiologic agent is complex and includes bacteria andviruses, highlighting Pasteurella multocida (PM) and Mannheimiahaemolytica (MH) as the main bacterial agents. The RBD vaccinesused in Argentine do not always provide an adequate control forthe disease, reason why it is necessary to improve their potency.This work aimed to evaluate the adjuvanteffect of Ef on the humoralimmune response elicited by a commercial RBD vaccine. Efsuspensions (0,2 ml; 3.108 CFU/ml) were administered daily by theig route to BALB/c mice on days -3 to -1; 12 to 14 of the immunizationschedule. The RBD immunization (0,25 ml) was performedon days 0, 15 and 27 by sc injection. Mice were grouped in: *Ef/Vac (inoculated with Ef ig and immunized with the vaccine sc);*Ef/PBS (Ef ig and PBS sc); *PBS/Vac (PBS ig and vaccine sc);*PBS/PBS (PBS ig and PBS sc). Blood samples were obtained ondays 0, 10, 27 and day 37 when animals were sacrificed. Specificantibody levels (IgG, IgG1, and IgG2a anti-PM and anti-MH) insera, and IL-2, IL-12 e IFN-g in spleen supernatants were determinedby ELISA. RBD immunization induced specific IgG titers inboth immunized groups at day 37. Treatment with Ef increasedlevels of IgG (p