Abstract
Natural killer (NK) cells are pivotal in the early immune response to Plasmodium falciparum infection, yet their functional dynamics and regulation remain incompletely understood. In a longitudinal study of patients with malaria in a nonendemic setting, we observed a transient but potent activation of NK cell cytotoxicity during acute malaria, characterized by rapid granzyme B–mediated killing and elevated expression of genes associated with cytotoxicity (PRF1, GZMB, and GZMA). This heightened activity was supported by increased plasma levels of granzymes and proinflammatory cytokines, which enhanced NK cell function in vitro. However, plasma samples from clinical malaria also contained inhibitory mediators, including soluble cytokine receptors, which dampened NK cell responses. These findings reveal that the host microenvironment orchestrates a tightly regulated NK cell response that potentiates cytotoxicity during acute infection and rapidly downmodulates it after treatment. Understanding this balance between activation and suppression may inform strategies to harness NK cells for malaria control while minimizing immunopathology.
Authors
Pengjun Xi, Patrick A. Sandoz, Maximilian Julius Lautenbach, Eleni Bilev, Björn Önfelt, Anna Färnert, Quirin Hammer, Christopher Sundling
Figure 3
NK cells during acute malaria have increased expression of perforin and granzymes.
