A NANOSTRUCTURED VACCINE AGAINST BOVINE RESPIRATORY DISEASE IMPROVES HUMORAL IMMUNE RESPONSE IN A MURINE MODEL

DIAZ, AILEN ; ALMOZNI, BRENDA; MARIA FERNANDA SANCHEZ VALLECILLO; MARIN, CONSTANZA; PALMA, SANTIAGO D.; MALETTO, BELKYS A.; CASTRO, MARISA

Congreso; LXIV Reunión Anual de la Sociedad Argentina de Inmunología; 2018

Bovine Respiratory Disease (BRD) is a multi-factorial disease that causes high morbidity and mortality in cattle. Pasteurella multocida (Pm) and Mannheimia haemolytica (Mh) are, among others, pneumonia-causing bacterial agents. Although BRD vaccines are worldwide employed, they do not always provide an adequate control of the pneumonic form of the disease. Consequently, it is recommendable the improvement of antigens and adjuvants to enhance their immunogenicity. Coa-ASC16 or Coagel is a liquid crystal nanostructure formed by self-assembly of 6-O-ascorbyl palmitate that has been shown to improves antigen-specific immune response when is used as vaccine platform. This work aimed to evaluate the action of Coagel as platform in an experimental BRD vaccine, studying the humoral and cellular immune response specific for Pm and Mh. To this end, BALB/c mice (n:5/group) were immunized with heat-killed Pm-Coagel, heat-killed Mh-Coagel or a commercial BRD vaccine. Immunizations were performed on days 0, 15 and 27 by subcutaneous injection. Control group received PBS and Coagel. Blood samples were obtained on days 0, 10, 27 and 38 when animals were sacrificed. Specific Pm and Mh antibody levels (IgG, IgG1, and IgG2a) were measured in sera, and cytokines (IL-2, IL-12) in spleen supernatants (ELISA). All immunized mice generated specific antibodies. Coagel immunized mice presented higher IgG levels for both bacteria compared with commercial vaccine immunized mice (p<0.05). Mh-specific IgG1and IgG2a levels were also higher when Coagel was used (p<0.001 and p=0.069, respectively). For Pm, no differences between groups were found. Cytokine levels were higher in mice immunized with the nanostructured vaccine although statistical significance was not reached. Our results indicate that Coagel would be a good vaccine platform for use in bovines and thus enhance the weak immune response elicited by vaccination for ERB.