Regulation of immunopathogenesis during Plasmodium and Toxoplasma infections: more parallels than distinctions?

• Experimental models of toxoplasmosis and malaria reveal parallel pathways of immunoregulation.
• Immunopathology is limited by inhibitory receptors, cytokines, and distinct cell subsets.
• Rodent models of toxoplasmosis and malaria continue to reveal new insight into immunoregulatory networks.

Toxoplasma and Plasmodium parasites exact a significant toll on public health. Host immunity required for efficient control of infection by these Apicomplexans involves the induction of potent T cell responses, which sometimes results in immunopathological damage. Thus, protective immune responses must be balanced by regulatory networks that limit immunopathology. We review several key cellular and molecular immunoregulatory networks operational during Toxoplasma and Plasmodium infections. Accumulating data show that despite differences in how the immune response controls these parasites, many host immunoregulatory pathways and cellular networks are common to both. Thus, understanding the cellular and molecular circuits that prevent or regulate immunopathological responses against one parasite is likely to inform our understanding of the host response to the other parasite.