We are interested in understanding the mechanisms of T cell-mediated immunity against intracellular pathogens of ruminants and how dysregulation of such responses can result in enhanced pathology. Our work is focused particularly on the intracellular protozoan parasites Theileria parva and T. annulata, but also includes studies of bovine herpesvirus-1,Staphylococcus aureus and Ehrlichia ruminantium.
We have previously demonstrated that CD8 T cell responses play an important role in immunity to T. parva and that the parasite strain specificity of these responses correlates with protection against challenge with heterologous parasite strains. Much of our current work is focused on dissecting the antigenic specificity and function of CD8 T cell responses toT. parva and T annulata and investigating how immunodominance of the response contributes to strain specificity of immunity. We are also using Theileria-transformed cell lines as antigen-presenting cells to investigate T cell responses to bovine herpesvirus-1 and Ehrlichia ruminantium.
In the course of our studies we have developed methods to analyse the T cell receptor (TCR) variable gene repertoire of bovine T cells, as a means of determining the clonal composition of responding T cell populations. These tools are also being employed (in collaborative work with Ross Fitzgerald) to determine the TCR Vβ gene specificity of superantigens produced by bovine strains of Staphylococcus aureus.