EVALUATION OF GENE IMMUNIZATION AGAINST GP51 GLYCOPROTEIN OF BOVINE LEUKEMIA VIRUS IN MICE. ADJUVANT EFFECT OF IL-12 GENE ADMINISTRATION.

MARTORELLI L; RACCA AL; VEAUTE C; MALAN BOREL I; SOUTULLO A; BAILAT A

Lima

Congreso; X Congreso de la Asociación Latinoamericana de Inmunología; 2012

Asociación Latinoamericana de Inmunología

Infection by Bovine Leukemia Virus affects the 84% of dairy herds in Argentina. Until present, a protective vaccine has not been designed, thus the control of the disease depends on the application of sanitary programs. The aim was to evaluate the immune response raised by gene immunization with gp51 coding region in mice, as well as the adjuvant effect of mIL-12 gene administration. To this purpose, a 700 bp fragment of gp51 coding region was cloned into pET32a(+), for recombinant expression in E. coli, and cloned into pcDNA3.1, for gene immunization. Mice were injected intramuscularly 4 times, at 3-week intervals. Blood samples were taken before injections. Animals were divided in 3 groups, and immunized as follows: gp51 (n=7): gp51-pcDNA; gp51 + IL-12 (n=7): gp51-pcDNA + commercial plasmid with murine IL-12 coding region and control (n=6): backbone. Humoral response was evaluated by indirect ELISA, using recombinant gp51 as antigen. Cellular response was estimated by delayed-type hypersensitivity in footpads. Results show that anti gp51 antibodies raised at the end of the immunization protocol, in groups gp51” and gp51 + IL-12, by 14-fold and 12-fold over control group levels, respectively (p 0.001). DTH revealed significant differences among groups 24 hr after challenge (p 0.05), being the group gp51 + IL-12 the one with the highest levels of inflammation. Gene immunization of mice against gp51 was able to induce a specific immune response, both humoral and cellular. Results suggest that IL-12 would be an effective adjuvant to potentiate the cellular immune response to this viral protein. Overall, these findings support further studies in order to design a protective vaccine for VBL.