Cattle Specific Immune Mechanisms used against the Protozoan Theileria annulata

Theileria annulata, the causative agent of tropical
theileriosis, is an intracellular protozoan parasite transmitted by
ticks of the genus Hyalomma. This tick-borne disease (TBD) exerts
a high impact on livestock production in many developing tropical
and subtropical countries. With an intricate life cycle and wide
distribution around the world, many advances were made to
restrict the impact and to control this TBD through the use of
acaricides, chemotherapy and attenuated vaccines. However, an
overreliance on these chemicals has meant new approaches for
developing more effective vaccines are needed. Decades of studies
support the idea that the humoral immune response elicited against the sporozoite stage of the tick life cycle may protect the host from infection. Further protective responses provided by cytotoxic T-cells, macrophages, and Natural Killer cells have also been identified as critically important during T. annulata infection. Here our focus will be the bovine immune response
upon T. annulata infection, particularly the differential humoral and cellular immune responses. Our aim is to highlight the importance of the mechanisms potentially involved in protective immunity as well as significant findings, which may be incorporated into novel strategies for tropical theileriosis control.