Bioprocess design and economics of recombinant BM86/BM95 antigen production for anti-tick vaccines

Cattle ticks, Rhipicephalus (Boophilus) spp., infestations are a major veterinary problem that impacts cattle production worldwide. Recently, vaccination has emerged as an alternative to control tick infestations that has shown the advantage of being cost-effective, avoids environmental contamination and prevents selection of drug-resistant ticks resulting from repeated acaricides applications. However, the success of vaccination is highly dependent on the availability of effective vaccines at affordable prices. Recombinant DNA technology has provided the mean for producing antigens in large quantities making possible the development and commercialization of anti-tick vaccines. In the early 1990s, a technology was developed to produce a commercial anti-tick vaccine based on the recombinant BM86 (rBM86) antigen isolated from R. (Boophilus) microplus and intracellularly expressed in Pichia pastoris. However, the technological process for its production was expensive. Herein we conducted an economical analysis of this technology in comparison with other reported processes. The results allowed the identification of critical steps in the technology and addressed research for bioprocess optimization. As a result, two alternative bioprocesses were developed to produce anti-tick vaccines based on the rBM86 protein secreted in P. pastoris and by displaying antigenic peptides on the Escherichia coli membrane (BM95-MSP1a antigen). Vaccine production costs were reduced from US$0.92/dose for the intracellular rBM86 to US$0.72/dose and US$0.56/dose for the secreted rBM86 and BM95-MSP1a, respectively.