Understanding the Immune Response to Equine Protozoal Myeloencephalitis

Presentation Description / Summary: This lecture will review the fundamental and current information on the role of the immune response to Sarcocystis neurona and Neospora hughesi in protection and disease. Studies demonstrating the critical roles for the cell mediated T-helper cell (CD4) and T-cytotoxic cell (CD8) and interferon-gamma (IFN-γ) immune response in protection against disease, (Equine Protozoal Myeloencephalitis, EPM) will be presented. Essential knowledge reporting the altered immune response, including decreased proliferative response to T-cell mitogens, decreased antigen specific proliferation, decreased proliferation to non-specific phorbol myristate acetate and ionomycin, as well as decreased IFN-γ expression in some horses EPM will also be presented. The talk will also review more recent studies assessing other markers, such as cell-surface sCD14 and their association with disease. Information from more recent studies, including the increased degenerative changes and the ability for S. neurona to persist despite treatment will also be presented. Critical murine studies demonstrating the role of IFN-gamma and CD8 in protection and disease will also be described. Finally, remaining gaps in knowledge will be described. From this lecture, the audience will gain an understanding of both the fundamental immune response for protection against S. neurona and N. hughesi, the pathology associated with disease, and the gaps which still remain.