Expression and determination of immunization dose of recombinant tropomyosin protein of Hyalomma anatolicum for the development of anti-tick vaccine

Present investigation was carried out to standardize the immunization dose of one recombinant antigen in rat model before conducting large animal experimentation. Tropomyosin (TPM), a muscle associated and highly conserved protein found in all species of invertebrates, was cloned, expressed in prokaryotic system and the downstream process was standardized. SDS-PAGE analysis showed a distinct band of approximately 51 kDa. Western blot analysis using specific sera gave a strong reaction of approximately the same size as that of SDS-PAGE. For standardization of immunization dose, the rTPM at three different dosages viz., 150, 300, 450 mu g was used to immunize wister rats and the antibody response was titrated by ELISA. Applying ANOVA, highly significant difference in anti-rTPM titre was recorded between the animals injected with 300 mu g total dose (TD) and other dosages selected for the study. The significantly high antibody tire at 1:25600 dilution observed in animals immunized with 300 mu g TD was selected for further study on in vivo immunization of calves and experimental challenge by the tick stages.