Abstract

Traditional vaccines based on killed or attenuated microorganisms or inactivated toxins have disadvantages associated with the risks of pathogenicity reversion, contamination with infectious material, variations between vaccine batches, storage problems, among others. Peptide identification containing important epitopes within antigens could be an attractive possibility to avoid those risks. However, in general, peptides are poorly immunogenic. Adjuvants are a part of the solution to improve the immunogenicity of these peptide based vaccines. Recently, a peptide from the tick P0 acidic ribosomal protein chemically conjugated to the Bm86 protein has been assayed as vaccine candidate against ticks. This antigen formulated in oily preparations containing MontanideTM ISA50 (SEPPIC, France) generated a specific antibody response against the P0 peptide which showed an efficacy around 85% against R. sanguineus ticks when used for dog immunization. This efficacy was positively correlated with the anti-P0 antibody titers. In this paper, the immunogenicity of this chemical conjugate was assayed in dogs when Montanide™ GEL 01 (SEPPIC, France) was used as adjuvant instead of oily MontanideTM ISA 50. The antibody titers against the P0 peptide did not show statistically significant differences between the experimental groups and the evaluation of changes in the inoculation site showed significantly lesser adverse side effects in the group immunized with the antigen in Montanide™ GEL. These results validate the use of this gel as a safer adjuvant for dogs than oily Montanide, encouraging the use of this adjuvant for the technological development of the pP0-Bm86 conjugate as an anti-tick vaccine for dogs.

Key words: Peptide vaccine, ticks, adjuvant, Montanide, dogs, P0 peptide.