A process for the preparation of anti-theileriosis vaccine comprising the steps of isolating lymphoid cells infected with schizonts of Theileria annulata present in an infected animal, culturing the infected cells in a growth medium, subjecting said cultured cells to the step of in-vitro propagation by-serial passaging, developing cloned curltures from a single cell by limiting dilution technique and further passaging these, karyotyping the cells in the medium to ascertain the diploid character, and obtaining viable cells with maximum infectivity rates, determining macroschizont nuclear number, subjecting a number of viable cells with diploid character to the step of cryoprotectant in liquid nitrogen in the presence of a cryoprotectant in the said growth medium to obtain a suspension of viable cells, testing these cultures at different passages and in varying dose levels in groups of calves for ascertaining their pathogencity / antigenicity, determining passage level and dose for the safety and efficacy of candidate vaccine, its safe use in new born calves and pregnant cows, time taken to induce immunity, serological responses and erect on haematological parameters, and testing its efficacy under wide field conditions in the susceptible stock.
