Potentiation of the Immune response elicited by a commercial vaccine against Bovine Respiratory Disease (BRD) employing an immunomodulator in a murine model.

MANGONE F; CASTRO MS; DÍAZ AM; CANELLADA A.; ALMOZNI B; SOTELO A

Mar del Plata

Congreso; SAIC-SAI-SAFIS 2018; 2018

SAIC-SAI-SAFIS

BRD is a multi-factorial disease that causes high morbidity andmortality in cattle. BRD etiology is composed by viruses and bacteria:Mannheimia haemolytica (MH), Pasteurella multocida (PM),Histophilus somni (HS). Although BRD vaccines are worldwide utilized,there is a need of new therapeutic-adjuvant strategies in orderto minimize the disease impact. Propionibacterium acnes (Pa)is a Gram-positive anaerobic bacillus and it is used as a heat-killedsuspension for treatment of non-specific respiratory disease in horsesbecause it has beneficial immunomodulatory activity. This workaimed to evaluate the effect of Pa on the humoral and cellular immuneresponse elicited by a commercial BRD vaccine.BALB/c mice were subcutaneously (sc) injected with P. acnes (350μg or 500 μg/animal) on days -7, 10 and 21. The BRD immunizationwas performed on days 0, 15 and 27 by sc injection. Blood sampleswere obtained on days 0, 10, 27 and day 38 when animals weresacrificed. Control group received the commercial vaccine. Serumspecific antibody levels (IgG, IgG1, and IgG2a anti-PM, MH and HS)and cytokines in spleen supernatants, were determined by ELISA.At final day, BRD immunization induced specific IgG titers and theproduction of IFNg, in all immunized mice. Treatment with Pa increasedanti-PM IgG levels (p< 0,001) and IgG2a for MH, PM andHS (p< 0,05). In relation with anti-MH and HS IgG and IgG1, antibodylevels in Pa treated-mice were higher than the immunizedcontrol group, although without reaching a statistical significance.These results indicate that the administration of P. acnes was ableto enhance the response elicited by a BRD vaccine, so it could beused as an adjuvant strategy to potentiate weak immune responses.