Pathogenic low affinity CD8 T cells in malaria

It is estimated that annually more than 500 million people are infected with malaria worldwide resulting in 0.5 million deaths. T cell responses against the Plasmodium parasites that cause malaria are critical in orchestrating immune effector mechanisms such as phagocytosis and antibody production to control parasitemia. However, T cells are also responsible for the pathogenesis of infection. The features that determine beneficial versus pathogenic T cells in malaria are incompletely understood. Here we propose that the affinity of CD8 T cells reacting to Plasmodium peptides shapes the repertoire of expanded cells and profoundly alters their function, in turn impacting pathogenesis. Although others have identified T cell epitopes that are immunodominant in Plasmodium infections, we know very little about the antigen reactivity profile of these pathogenic T cells as infection progresses. In general, it is believed that high affinity T cells predominate any polyclonal T cell response, yet this is not supported by our preliminary data which clearly shows that low affinity T cells make up >80% of the pathogenic anti-Plasmodium response. Based on our preliminary data, we hypothesize that this predominance of low affinity CD8 T cells is a unique feature of Plasmodium infection that leads to organ specific damage because CD8 T cells with low affinity T cell receptors induce different responses in cross-presenting brain microvascular endothelial cells (BMECs) compared with high affinity CD8 T cells. The rationale for the proposed work is that T cell responses are central to the organ-specific attack associated with malaria, and a more comprehensive understanding of the T cell response will provide key information for the rational use and design of novel anti-malaria interventions as well as future vaccines.

NIH project details

Vaccines (Immune Correlates)

Sep 2021 — Aug 2026

$1.31M

United States