Novel Control Strategy for Cattle Tick: Development of a recombinant vaccine Performance optimization and Efficacy

THELMA VERONICA POGGIO; EDUARDO ALBERTO SCODELLER; LA TORRE JOSE

Buenos Aires

Congreso; 23rd International Conference of the World Association for the Advancement of Veterinary Parasitology; 2011

World Association for the Advancement of Veterinary Parasitology

Novel Control Strategy for Cattle Tick: Development of a recombinant vaccine Performance optimization and Efficacy Poggio Thelma1, Scodeller Eduardo2, La Torre Jose1 1. Centro de Virología Animal ? CEVAN-ICT Milstein (CONICET) 2Centro regional de Investigaciones Cientificas y Tecnicas (CRICYT) Introduction In Argentina the cattle tick Boophilus microplus is considered the most important endemic ectoparasite and causes significant economic losses. We propose an approach to reduce the incidence of infestation and tick borne diseases by means of cattle immunization with recombinant concealed gut antigens of ticks. Because of sequence variations in the Bm86 locus, among other factors, could affect the effectiveness of Bm86-containing vaccines, in the present study larval isolates from endemic areas of our country were selected for sequencing and alignment of the Bm86 coding sequence. A gene coding for autochthonous tick gut protein was cloned and the recombinant BmTVP protein expressed in bacteria was evaluated as an antigen in a single optimized oil formulation, called Providean Garrattack, in target specie. Methods A nucleotide sequence of the cDNA containing a 933 base-pair open reading frame was cloned and a N terminal truncated fusion protein BmTVP consisting of 311 amino acids was expressed as inclusion bodies. Providean Garrattack contained 100ug/dose of recombinant BmTVP antigen combined with Montanide ISA 61 plus saponin as emulsifying agent. Two groups of five bovines were immunized intramuscularly on day 0 ? 28 ? 49. One group received Providean Garrattack and a Control Group received only adjuvant plus saponin. Three weeks after the last immunization, cattle were infested individually with 1000 larvae per day for 3 weeks. After 21 days, teleogines dropped from the cattle were daily collected, counted, weighted and assessed for oviposition and egg fertility. Efficacy of Providean Garrattack was proved by monitoring the seroresponse by ELISA, and the protection rate after challenge as described in Canales et al (2009). Results and Conclusions The recombinant truncated BmTVP protein showed a sequence identical to those of Boophilus microplus from Mexican origin (Canales et al 2009) and Brazilian Campo Grande strain (Andreotti et al 2008). Our sequence differed from Argentinean strain A (Garcia-Garcia et al, 1999) in a single position and shared 97% identity with Cuban Camcord strain (Gavac Vaccine). Providean Garrattack vaccine was secure, harmless and highly immunogenic. Specific-IgG against BmTVP elicited in bovine immunized were 100-1000-fold higher than those obtained in the control group (p