Time series of Balb/c spleen infected with Plasmodium yoelii non-lethal vs lethal strains. Mus musculus

Knowledge on the dynamic features of the processes driven by malaria parasites in the spleen, our biggest lymphoid organ, is lacking. We have implemented intravital microscopy and magnetic resonance imaging of the mouse spleen in experimental infections with the Plasmodium yoelii non-lethal (17X) and lethal (17XL) strains. Notably, there was higher parasite accumulation, reduced motility, lost of directionality and different T2 relaxation times only in spleens of mice infected with the 17X strain. Moreover, these differences were associated with the formation of a strain-specific induced spleen tissue barrier, with macrophage-clearance escape, and with cytoadherence of infected reticulocytes to this barrier. This is a novel spleen-immune evasion mechanism in which parasite-induced spleen remodeling and adherence to this organ allow establishment of chronic infections. Overall design: We performed time-series global transcriptional analyses from spleens of mice infected with the P. yoelii 17X and 17XL strains at days 3, 4, 5, 10% and 50% of parasitemia post-infection, together with non-infected spleens as a reference day 0, using commercially available arrays representing the complete mouse genome (Agilent Whole Mouse Genome G4122A).