The broad-spectrum conjugate vaccine against ticks, Bm86-Ac-Cys 1 pP0, was synthesized by the maleimide thiol chemistry using a procedure similar to the one described previously . Very briefly, in a first step, the Bm86 carrier protein was modified by adding an excess of BMPS crosslinker reagent to introduce several Npropionyl maleimide groups in lysine residues and at N-terminal end. In a second step, the activated carrier protein reacted with the Cys 1 pP0 peptide acetylated at the Nterminal end (Ac-Cys 1 pP0). The conjugate was purified by size exclusion chromatography to discard excess of reagents and dimeric Ac-Cys 1 pP0 generated as a byproduct of the synthesis.