A review of cattle tick vaccine technologies

Summary

At the time of its commercial release in 1994, the TickGARD vaccine against Boophilus microplus was the first, and it remains the only, commercially available anti-parasite vaccine using a recombinant antigen. It was therefore highly novel, with a unique mode of action and recommendations for use that were very different from those of conventional acaricides. The last decade and a half have seen an escalation of problems with chemical resistance.
Since the original release of the vaccine, resistance has been reported in Australia or South America to three additional classes of chemical acaricide: the macrocyclic lactones, fipronil and the insect growth regulators. There is increasingly a realisation that any successful, sustainable program of parasite control is likely to require an integrated approach and a desire for green alternatives. All these factors make an improved anti-tick vaccine a desirable product. Vaccine development is a complex, multi-stage process. Investment by the MLA could accelerate progress along the development pathway at a number of points.
Currently, the greatest lack is in the availability of recombinant antigens of proven efficacy. A number of strategies can be used to identify these, as described in this report. Currently there is only one significant antigen discovery project in Australia and it is in early stage discovery with a restricted focus. Secondly, in the expectation that a vaccine superior to the previous TickGARD will require more than one antigen, the efficacy of antigen combinations using currently known or future antigens could be explored. MLA could consider projects in either or both of these areas now. It is also in the identification of novel antigens or antigen combinations that the clearest intellectual property lies. Research issues downstream of antigen discovery are described and opportunities identified.