Biology ETDs

New Insights into T Lymphocyte-Mediated Immunity to Toxoplasma gondii

Claire M. Doherty, University of New Mexico - Main Campus


With nearly a third of the global population infected with the protozoan, Toxoplasma gondii, this parasite sits at a unique, immune-mediated interface of health and disease. In healthy individuals, Toxoplasma results in a chronic yet asymptomatic infection of the central nervous system. This quiescent infection is the result of parasite exploitation of host immune barriers, yet Toxoplasma can quickly become an opportunistic pathogen when immunity is disrupted by illness or immunosuppressive therapies. During the HIV-AIDS pandemic, it was observed that once latent Toxoplasma infections became the cause of severe, even fatal, disease in the absence of an intact T lymphocyte compartment. The research resulting from the need to address this aggressive opportunistic pathogen gave way to seminal findings in the field of immunology; insights into MyD88/TLR signaling, immunopathology, and Th1- mediated protection were all greatly enabled by studies in Toxoplasma. Even as HIV- management became a reality in recent decades, the study of Toxoplasma has remained a pressing concern due to the global distribution of this parasite. This has resulted in further study that continues to reveal further insight into fundamental mechanisms underlying infection and immunity.