Investigation of Theileria annulata as modulator of activation associated host cell gene expression

Infection of bovine leukocytes by the intracellular protozoan parasites Theileria annulata and Theileria parva represents a unique model of reversible host cell transformation; characterised by uncontrolled proliferation and protection against apoptosis. Host cell transformation is known to involve parasite dependent manipulation of a number of signalling pathways that result in constitutive activation of pro-inflammatory transcription factors. Activation of these factors has been shown to confer protection against apoptosis or influence the metastatic potential of the infected cell, respectively. However, transcription factors have the potential to be detrimental as well as beneficial to the infected cell and the infected animal. This study investigated the potential of the parasite to manipulate the outcome of cellular activation by comparing the outcome of stimulating Theileria-infected and uninfected bovine cells with LPS. The results clearly indicate that prolonged stimulation of uninfected cells generated a phenotype associated with loss of proliferation, cell death and activation of NF-B. In contrast, infected TBL20 cells were refractory to stimulation, despite displaying high levels of constitutively activated NF-B