A recombinant multi-antigen vaccine formulation containing Babesia bovis merozoite surface antigens MSA-2a， MSA-2b and MSA-2c elicits invasion-inhibitory antibodies and IFN-γ producing cells.

Babesia bovis is a tick-transmitted protozoan hemoparasite and the causative agent of bovine babesiosis， a potential risk to more than 500 million cattle worldwide. The vaccines currently available are based on attenuated parasites， which are difficult to produce， and are only recommended for use in bovines under one year of age. When used in older animals， these vaccines may cause life-threatening clinical symptoms and eventually death. The development of a multi-subunit recombinant vaccine against B. bovis would be attractive from an economic standpoint and， most importantly， could be recommended for animals of any age. In the present study， recombinant ectodomains of MSA-2a， MSA-2b and MSA-2c antigens were expressed in Pichia pastoris yeast as secreted soluble peptides.