Vaccine Efficacy of Bm86 Ortholog of H. a. anatolicum, rHaa86 Expressed in Prokaryotic Expression System

Abstract

The use of tick vaccine in controlling ticks and tick borne diseases has been proved effective in integrated tick management format. For the control of H. a. anatolicum, Bm86 ortholog of H. a. anatolicum was cloned and expressed as fusion protein in E. coli as E. coli-pETHaa86. The molecular weight of the rHaa86 was 97 kDa with a 19 kDa fusion tag of thioredoxin protein. The expressed protein was characterized immunologically and vaccine efficacy was evaluated. After 120 hours of challenge, only 26% tick could successfully fed on immunized animals. Besides significant reduction in feeding percentages, a significant reduction of 49.6 mg; P < .01 in the weight of fed females in comparison to the females fed on control animals was recorded. Following oviposition, a significant reduction of 68.1 mg; P < .05 in the egg masses of ticks fed on immunized animals in comparison to the ticks fed on control animals was noted. The reduction of number of females, mean weight of eggs, adult females and efficacy of immunogen were 73.8%, 31.3%, 15.8%, and 82.3%, respectively. The results indicated the possibility of development of rHaa86 based vaccine as a component of integrated control of tick species.

Figure 1

Release of insert after restriction digestion with EcoRI and XhoI. The 1.755 bp Haa86 gene was released by the restriction enzyme digestion reaction.

Figure 2

The SDS-PAGE profile of rHaa86. Legends: UN-uninduced, IN induced, M-molecular weight marker, Haa86-97 kDa expressed protein.

Figure 3

Immunoblot showing reaction of rHaa86 with (a) mouse antipenta histidine antibody; lane 1, strong reaction with rHaa86 and lane M, molecular weight marker and (b) with anti-Bm86 antibody; lane 1, no reaction with normal sera and lane 2, reaction with anti-H. a. anatolicum larval antibody.

Figure 4

Antibody response in calves immunized with rHaa86 (Gr. 1) and control animals (Gr. 2).